The nontuberculous mycobacterial pulmonary disease (NTM-PD) caused by Mycobacterium species has increased in prevalence all over the world. The distributions of NTM-PD are possibly determined by the westerly wind traveling at high altitudes over East Asia. However, the long-range transport of Mycobacterium species has not been demonstrated by analyzing the bacterial communities in aerosols such as desert mineral particles and anthropogenic pollutants transported by the westerly wind. Here, airborne bacterial compositions were investigated including Mycobacterium species in high-elevation aerosols, which were captured in the snow cover at 2,450 m altitude on Mt. Tateyama. This was further compared to the ground-level or high-altitude aerosols collected at six sampling sites distributed from Asian-dust source region (Tsogt-Ovoo) to downwind areas in East Asia (Asian continental cities; Erenhot, Beijing, Yongin, Japanese cities; Yonago, Suzu, Noto Peninsula). The cell concentrations and taxonomic diversities of airborne bacteria decreased from the Asian continent to the Japan area. Terrestrial bacterial populations belonging to Firmicutes and Actinobacteria showed higher relative abundance at high-elevation and Japanese cities. Additionally, Mycobacterium species captured in the snow cover on Mt. Tateyama increased in relative abundance in correspondence to the increase of black carbon concentrations. The relative abundance of Mycobacterium sequences was higher in the aerosol samples of Asian continental cities and Japanese cities than in the desert area. Presumably, anthropogenic pollution over East Asia carries potential Mycobacterium species, which induce NTM-PD, thereby impacting upon the public health.

© 2020 Elsevier B.V. Salinity affects the biochemical and physiological activities of marine biota, including phytoplankton. The salinity tolerance and biotransformation capacity of phytoplankton depends on the species type and characteristics. In this study, we investigated the arsenic (As) biotransformation potential of three marine phytoplankton species, namely Prymnesium parvum, Oltmannsiellopsis viridis, and Eutreptiella gymnestica under a broad salinity gradient. Phytoplanktons were cultured in an f/2-based medium. Growth and As biotransformation potential were observed in As-poor and As-rich conditions in combination with phosphate (PO43−)-poor and PO43−-rich conditions, and different salinities (0–50‰). For all species, the highest cell concentrations were observed on day 14 of culture. Among the three species, O. viridis showed maximum growth, photosynthetic efficiency, As biotransformation, and total As accumulation ability under a broad range of salinities (≥5‰ to ≤45‰). However, As biotransformation and other physiological activities decreased for all the phytoplankton species at ≤5‰ and ≥45‰. Phytoplankton growth and As biotransformation potential was significantly influenced by salinity and by the availability of As and PO43− in the culture medium. A conceptual model of salinity effects on As uptake and biotransformation in the three marine phytoplankton species is proposed based on the findings of this study.

© 2019 Elsevier Ltd Chelators have proven to be effective extractants in soil washing and represent a suitable remediation technology for potentially toxic elements (PTEs) from contaminated sites. In this paper, the extraction of lead (Pb), copper (Cu), and zinc (Zn) from contaminated real and reference soils using both biodegradable (EDDS and HIDS) and persistent (EDTA and DTPA) chelators was investigated. Different metal–chelator complex formation constants, pH, extraction temperature, and mechanochemical energy were tested. The PTEs were extracted at a relatively higher rate under acidic to neutral conditions (pH 5 and 7), with the greatest extraction being observed at pH 5. The metal extraction efficiencies of the chelators for the real sample at pH 5 were as follows: Pb – EDTA > DTPA > EDDS > HIDS; Cu – DTPA > EDTA > EDDS > HIDS; and Zn – DTPA > EDTA > HIDS > EDDS. The data suggested that EDDS was more effective than HIDS for Cu and Zn extraction in neutral to slightly alkaline solutions, as well as at raised temperature. Furthermore, EDTA washing using mechanochemical agitation was found to enhance the removal efficiency of Cu and Zn. Sequential chemical extraction showed that the apparent metal mobilities were reduced by soil washing. EDTA and DTPA appeared to offer greater potential than the biodegradable chelators in extracting metals from the relatively mobile carbonate- and Fe–Mn oxide-bound fractions. The residual fraction of Pb displayed considerable stability (≥70%), and was not entirely amenable under washing treatments, and hence could be considered non-bioavailable and non-toxic.

© 2019, The Author(s). The biotransformation and detoxification mechanisms of arsenic (As) species have been active research topics because of their significance to environmental and human health. Biotransformation of As in phytoplankton has been extensively studied. However, how different growth phases of phytoplankton impact As biotransformation in them remains uncertain. This study investigated the biotransformation of As species in freshwater phytoplankton at different growth phases to ascertain at which growth phase different types of biotransformation occur. At the logarithmic growth phase, arsenate (AsV) (>90%) and arsenite (AsIII) (>80%) predominated in culture media when phytoplankton were exposed to 20 nmol L−1 and 1.0 µmol L−1 of AsV, respectively, and methylarsenic (methylAs) species were not detected in them at all. Intracellular As was mainly present in inorganic forms (iAs) at the logarithmic phase, while substantial amounts of organoarsenic (orgAs) species were detected at the stationary phase. At the stationary phase, AsV comprised the majority of the total As in culture media, followed by AsIII and methylAs, although the methylation of AsV occurred slowly at the stationary phase. Biotransformation of AsV into AsIII and As methylation inside phytoplankton cells occurred mainly at the logarithmic phase, while the biotransformation of As into complex orgAs compounds occurred at the stationary phase. Phytoplankton rapidly released iAs and methylAs species out of their cells at the logarithmic phase, while orgAs mostly remained inside their cells.

© 2019, Springer Nature B.V. The toxicity and bioaccumulation and biotransformation potential of inorganic arsenic (IAs) species As(V) and As(III) were investigated using Sargassum patens under laboratory culture for 7 days. Algal chlorophyll fluorescence decreased with increasing As(V) and As(III) concentrations, being significantly affected by As(III) treatments. Higher As(III) concentration negatively affected growth rate, and P and Fe limitation greatly enhanced IAs toxicity. The extracellular, intracellular, and total bioaccumulation of As(III) and As(V) varied significantly depending on initial concentrations and addition of P and Fe. P and Fe availability suppressed intracellular As accumulation in As(V) medium but not in As(III) medium. In P-rich (10 μmol L−1) medium, intracellular As was reduced by 4.7% and 9.9% when As(V) in the medium was constant (4.0 μmol L−1), under Fe-limited (0 μmol L−1) and Fe-rich (10 μmol L−1) conditions, respectively. However, the Fe-rich condition positively affected extracellular As accumulation from both As source. Extracellular As increased by 43.5% and 38.8% in P-limited + Fe-rich cultures with 4.0 μmol L−1 of As(V) and As(III), respectively. Algae exhibited greater absorption and adsorption to As(V) than to As(III). The reduced metabolites of As(III) (3.5 to 4.9% of the total As) and oxidized metabolites of As(V) (2.0 to 3.7% of the total As) were recorded as biotransformed species from coexisting media containing As(V) and As(III) at a constant 4.0 μmol L−1, respectively. Both P and Fe had significant influences on the variation in behaviors of IAs. This information is vital in terms of As research in marine ecosystems.

© 2019 Elsevier Ltd Algae accumulate and metabolize arsenic (As) and facilitate cycling and speciation of As in seawater. The laboratory-controlled macroalgal cultures were exposed to different molar ratios of As(V) and phosphate (P) in seawater for evaluating the uptake and metabolism of As, as a function of As(V) detoxification through biotransformation. Chlorophyll fluorescence of algal species was not significantly affected by the culture conditions (p > 0.05). Addition of 10 μM P positively reduce As stress, but different As(V)/P ratios significantly affect the growth rate (p < 0.05). Algae readily accumulated As(V) after the inoculation, transformed intracellularly, and released gradually into the medium along the incubation period, depending on As(V)/P molar ratios. Reduction and methylation were the leading processes of As(V) metabolism by Pyropia yezoensis, whereas Sargassum patens showed only the reduction. Sargassum horneri reduced As(V) under low level (0.1 μM), but both reduction and methylation were observed under a high level (1 μM). At the end of incubation, 0.17, 0.15, 0.1 μM of reduced metabolite (As[III]) were recorded from 1 μM of As(V)/P containing cultures of Sargassum horneri, Sargassum patens, and Pyropia yezoensis, respectively. On the other hand, 0.024 and 0.28 μM of methylated metabolite (DMAA[V]) were detected under the same culture conditions from Sargassum horneri and Pyropia yezoensis, respectively. The results also indicated that P in medium inhibits the intracellular uptake of As(V) and subsequent extrusion of biotransformed metabolites into the medium. These findings can help to understand the metabolic diversity of macroalgae species on As biogeochemistry in the marine environment.

© 2019, The Author(s). Temperature and salinity effects on marine diatom species growth has been studied extensively; however, their effect on arsenic (As) biotransformation has been imprecise. This study reports the growth, and As biotransformation and speciation patterns at various temperatures and salinities of six marine diatom species: Asteroplanus karianus, Thalassionema nitzschioides, Nitzschia longissima, Skeletonema sp., Ditylum brightwellii, and Chaetoceros didymus. The growth rate and As biotransformation potentials of these species during three weeks of culture in f/2 based medium were significantly affected by wide temperature (0–35 °C) and salinity (0.3–50‰) ranges. Growth and As biotransformation were higher at optimum temperatures of 10–25 °C, and salinity of 10–35‰, whereas growth and arsenic biotransformation were lower at <5 °C and 5‰ and >25 °C and 35‰, respectively. The results showed that As(V) to As(III) biotransformation differed significantly (p < 0.05) between day 10 and 17. At optimum temperature and salinity levels, the cell size and As biotransformation were higher for all the species. A conceptual model on temperature and salinity effects on growth and As uptake and biotransformation mechanisms by these species has been proposed based on the findings of this study.

© 2019 Elsevier Ltd Airborne microorganisms transported by dust events from Asian Deserts influence climate changes, ecosystem dynamics and human health in the westerly-wind blowing areas of East Asia. However, the vertical transport of airborne microorganisms was not understood in detail. We collected aerosols at high altitudes (800 m and 500 m) and ground levels (5 m and 10 m) at Asian dust-source area, such as the Taklimakan and Gobi Deserts, for analyzing compositions and abundances of the airborne microorganisms that are distributed vertically over desert area. Assessment of the dust particles using an optical particle counter and microscopic observation counts demonstrated that the mineral and microbial particles remained suspended at altitudes of over 300 m and decreased to half to one-tenth of concentrations compared to those at the ground level. High-throughput sequencing of 16S rRNA genes (bacterial taxonomic marker) revealed that the airborne bacterial communities were mixed vertically at the altitudes of some hundreds of meters over both the sites and were predominantly composed of the phyla Actinobacteria, Firmicutes, Bacteroidetes, and Proteobacteria. In contrast, using sequencing analysis of internally transcribed spacer regions (fungal taxonomic markers), the fungal community structures over both the sites were different at high altitudes and ground levels. Sequences belonging to the phylum Ascomycota increased at high altitudes and comprised those of a commonly detected mold that includes the genera Cladosporium and Alternaria and is thought to be resistant to atmospheric stressors. Our results indicate that airborne bacterial communities are easily mixed vertically over dust-source desert, while stressor-tolerant fungi of airborne Ascomycota remain at high altitudes of desert atmosphere.

© 2019 Elsevier Ltd Freshwater and marine organisms are capable of metabolizing arsenic (As) efficiently and regulating the As biogeochemical cycles. In this study, Undaria pinnatifida was exposed to As(V) (0, 0.1, and 1 μM) and phosphate (P; 1 and 10 μM) in seawater under laboratory-controlled conditions for up to seven days to analyze As biotransformation. The growth rates and chlorophyll fluorescence of the alga were unaffected by As stress, and statistically insignificant differences were observed among the cultures (p > 0.05). As(V) was readily accumulated by this macroalga through phosphate transporters, transformed intracellularly, and excreted into the medium, depending on the As(V) to P molar ratios. The concentration of As(V) and biotransformed species As(III) and DMAA(V) varied significantly in the algal cultures on the basis of the exposure period (p < 0.05). The concentration of As(III) was initially higher but decreased with the incubation period, whereas the concentration of DMAA(V) increased gradually. At the end of the incubation, 0.04 and 0.32 μM DMAA(V) were recorded in the media containing 0.1 and 1 μM As(V) with a constant 1.0 μM P, respectively. The results also indicated that the cellular uptake of As(V) and subsequent release of DMAA(V) were inhibited by P in the medium. The biotransformation was consistent with the As(V) detoxification mechanism based on reduction and methylation, which was enhanced by the lower As(V) to P molar ratios. These findings can be helpful in understanding the contribution of macroalgae to As biogeochemistry in marine environments and the potential risks of As dietary intake.

©2019. The Authors. Aeolian dust is emerging as a significant vehicle for long-range transport of microorganisms. Nonetheless, many factors relating to this highly influential dispersal mechanisms remain unresolved, including the variation in dispersal bacterial communities during stochastic desert dust events, and the effect of aeolian transit over continental and oceanic surfaces to these communities. Here we report a temporal study that encompassed multiple dust events to elucidate 16S rRNA gene-defined changes in airborne bacterial communities at a continental-peninsula site (Yongin, central South Korea) and a downwind offshore island site (Yonago, Honshu Island, Japan) both lying along the trajectory for dust event transport. Aerosol collected on nondust days at both sites generally reflected local origin from freshwater, marine, plant, and animal sources. At both sites, the relative abundance of spore-forming bacteria (Bacillaceae) and organic-aggregating bacteria (Cytophagaceae) was positively correlated with the mineral particle. Actinobacteria increased in relative abundance at the continental-peninsula site during dust events, while marine bacterial signatures (mainly Alphaproteobacteria) were more prevalent in island site after dust events dissipated upon Japanese Sea. Overall, dust events increased the richness of airborne bacteria communities originating from inland desert and other area during early spring and are associated with more variations in airborne bacteria in the island site than the continental-peninsula site. Airborne desert dust is likely a significant transport vehicle for bacteria. The transit of air masses over continental and marine surfaces is selective for some taxa which can be transported to distant sinks with potential impacts toward ecosystems and public health.

© 2018 Elsevier B.V. The determination of aminopolycarboxylate chelators in environmental samples has remained an analytical challenge due to the structural similarities of these species and their minute concentrations in such matrices. Herein, we report a fast and sensitive technique for the determination of multiple chelator complexes in an aqueous matrix using ultra-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Eight chelators, including non-biodegradable (EDTA, EDTAOH, GEDTA, DPTAOH and DTPA) and biodegradable (EDDS, GLDA, and MGDA) variants were examined after complexation with CuII. The detection of these species using reverse-phase chromatography was compared with that achieved with hydrophilic interaction chromatography based on the corresponding peak resolution and retention time. The effect of varying the composition and pH of the mobile phase on the corresponding peak profiles and intensities for the chelator complexes was also evaluated. The CuII-derivatives of the chelators were individually detected under the optimized operating conditions. Relative to high-performance liquid chromatography equipped with a photodiode array detector, the developed UPLC-Q-TOF-MS technique provides rapid determination of chelator complexes in aqueous matrices with high sensitivity and superior peak resolution. The limit of detection ranged from 1.7–36 nmol L–1, and the limit of quantification ranged from 5.7–120 nmol L–1 for the eight chelator complexes in solution. The coefficients of determination (R2) were 0.962–0.999 for the chelators with an average relative uncertainty of 2.2%. The method was validated using a simulated mixed matrix and river water by standard addition (recovery: 83−100%).

We observed the atmospheric resuspension of radiocaesium, derived from the Fukushima Dai-ichi Nuclear Power Plant accident, at Namie, a heavily contaminated area of Fukushima, since 2012. During the survey periods from 2012 to 2015, the activity concentrations of radiocaesium in air ranged from approximately 10(-5) to 10(-2) Bq per m(3) and were higher in the warm season than in the cold season. Electron microscopy showed that the particles collected on filters in summer were predominantly of biological origin (bioaerosols), with which the observed radiocaesium activity concentration varied. We conducted an additional aerosol analysis based on fluorescent optical microscopic observation and high-throughput DNA sequencing technique to identify bioaerosols at Namie in 2015 summer. The concentrations of bioaerosols fluctuated the order of 10(6) particles per m(3), and the phyla Basidiomycota and Ascomycota (true Fungi) accounted for approximately two-thirds of the bioaerosols. Moreover, the fungal spore concentration in air was positively correlated with the radiocaesium concentration at Namie in summer 2016. The bioaerosol emissions from Japanese mixed forests in the temperate zone predominately included fungal cells, which are known to accumulate radiocaesium, and should be considered an important scientific issue that must be addressed.

© 2018 Elsevier B.V. A technique for the concurrent on-site quantitative analysis of gold (Au), palladium (Pd), or platinum (Pt) in the aqueous acidic matrix has been proposed. The Au, Pd, or Pt in the matrix was selectively concentrated in macrocycle-equipped solid-phase extraction (SPE) system, followed by analysis of the concentrates in a portable liquid electrode plasma-optical emission spectrometer (LEP-OES). The SPE-retention or recovery behavior towards Au, Pd, or Pt has been optimized for solution pH, sample-loading flow-rates, eluent-type or eluent-volume, and matrix components. The SPE-assisted pre-treatment minimized interfering impacts due to the competing ions in solution and limitations in LEP-OES sensitivity at low Au, Pd, or Pt content in the matrix. The preconcentration factor was 250 for Au, Pd, or Pt. The LEP-OES operating variables such as applied voltage, on-time, off-time, and pulse count for applied voltage have been optimized to obtain distinct peaks in spectra for Au (λmax, 274.826 nm), Pd (λmax, 267.958 nm), and Pt (λmax, 270.240 nm). The limit of detection (3σ) for Au, Pd, Pt determination using the technique were found, respectively, as 0.8, 3.1, 57.3 ng mL−1. The proposed method was applied to the analysis of Au, Pd, or Pt contents in the European Commission Joint Research Center certified reference material of wastewaters (ERM-CA713; recovery by the standard addition method, >96%), and real aqueous waste from the plating process (recovery, >95%). A relative standard deviation of ≤ 5% indicated a good precision in Au, Pd, or Pt analysis using the technique. The LEP-OES data-sets were also comparable with those obtained from the inductively coupled plasma optical emission spectrometric measurements for the same matrix.

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. End-of-life (EOL) ships contribute significantly to the flow of recycled industrial Fe and non-Fe metal materials in resource-poor developing countries. The ship scrapping (breaking) and recycling industry (SBRI) recycles 90–95% of the total weight of EOL ships and is currently concentrated in Bangladesh, India, Pakistan, Turkey, and China, due to the high demand for recyclable and reusable materials there, an abundance of low-cost labor, and lenient environmental regulations. However, the SBRI has long been criticized for non-compliance with standards relating to occupational health, labor safety, and to the management of hazardous materials. Among the different EOL recycling options, Bangladesh, India, and Pakistan use open beaching, a technique that exposes all spheres of the environment to the release of hazardous materials from EOL ships. This article summarizes the current state of knowledge on the environmental exposure of hazardous materials from SBRI, to judge the risks associated with the dismantling of EOL ships on open beaches. Our work includes an overview of the industry and its recent growth, compares available ship-breaking methods, provides an inventory of hazardous releases from EOL ships, and reviews their movement into different spheres of the environment. The economic dynamics behind openbeaching, and apportionment of responsibility for hazards related to it, are discussed, in order to generate policy and legal recommendations to mitigate the environmental harm stemming from this industry.

© 2018 Elsevier Ltd Rare-earths (REs) are key components for the transition to a greener energy profile and low carbon society. The elements turn out to be of limited availability in the market, due to the supply-demand issues, exponential price rises, or geopolitics, which has led to a focus on the exploration of secondary sources for RE reclamation. End-of-life (EoL) nickel-metal hydride batteries, permanent magnets, and fluorescent lamps (FL) have been the primary sources for recyclable REs, while the recovery of REs in EoL FL (Ce, Eu, La, Tb, or Y) includes comparatively fewer processing steps than the other potential sources. In the current work, we proposed a simple, energy-efficient protocol for EoL FL processing, using chelators in combination with ball milling. The parameters for optimum chelator-assisted recovery (chelator concentration, solid-to-liquid ratio, solution pH), and milling variables (ball size, ball weight, milling speed, milling duration), were evaluated at room temperature (RT, 25 ± 2 °C). The dissolution of REs with ethylenediaminetetraacetic acid (EDTA), ethylenediaminedisuccinic acid, methylglycinediacetic Acid, or 3-hydroxy-2,2′-iminodisuccinic acid, was compared at RT, while EDTA was used as the reference chelator throughout. Increasing the system temperature from 25 to 135 °C achieved at least double Eu and Y recovery, relative to that at RT, whereas the recovery rate improvement for Ce, La or Tb was insignificant. Mechano-chemical treatment at RT, via wet milling of EoL FL, with chelators, yielded a five order of magnitude increase in Ce, La and Tb recovery, however, plus a two-order increase for Eu or Y, compared with non-abetted operating conditions. It was also found that higher impact energy achieved improved recovery over a reduced milling duration with this technique having the added advantage of minimal acid consumption and reduced effluent production.

© 2018, Springer Science+Business Media B.V., part of Springer Nature. Iron (Fe) is an important nutrient for phytoplankton. The low solubility of Fe in oxic waters can be a growth-limiting factor for phytoplankton. Synthetic aminopolycarboxylates (APCs) such as ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) are widely used as Fe complexing agents for microalgae culture. However, the presence of these non-ready biodegradable APCS in aquatic systems may have serious environmental consequences. In the present study, the effects of biodegradable chelating ligands (hydroxyiminodisuccinic acid (HIDS), methylglycinediacetic acid (MGDA), and iminodisuccinate (IDS)) on Fe uptake in and growth of three coastal microalgae (Heterosigma akashiwo, Prymnesium parvum, and Skeletonema marinoi-dohrnii complex) were investigated, and the results were compared with those of non-ready biodegradable APCs (EDTA, ethylenediamine tetra-methylene phosphonic acid (EDTMP), and DTPA). The biodegradable chelating ligands did not have significant growth inhibition effect on the phytoplankton. Although the growth of the algae (except S. marinoi-dohrnii complex) was not affected substantially by 1.5 and 7.5 μM of DTPA, growth inhibition occurred by 7.5 μM of EDTMP and 150 μM of EDTA, DTPA, and EDTMP. The effect of chelating ligands on microalgal growth was likely to be associated with the intracellular Fe uptake influenced by the chelating ligands. On average, intracellular Fe concentrations for biodegradable chelating ligands were substantially higher than those for non-ready biodegradable APCs. Except H. akashiwo, the ratio of intra/extracellular Fe concentrations was highest for MGDA followed by IDS and HIDS. The results indicate that biodegradable chelating ligands are more efficient than non-ready biodegradable APCs in intracellular Fe uptake and algal growth.

The westerly wind travelling at high altitudes over eastern Asia transports aerosols from the Asian deserts and urban areas to downwind areas such as Japan. These long-range-transported aerosols include not only mineral particles but also microbial particles (bioaerosols), that impact the ice-cloud formation processes as ice nuclei. However, the detailed relations of airborne bacterial dynamics to ice nucleation in high-elevation aerosols have not been investigated. Here, we used the aerosol particles captured in the snow cover at altitudes of 2450 m on Mt Tateyama to investigate sequential changes in the ice-nucleation activities and bacterial communities in aerosols and elucidate the relationships between the two processes. After stratification of the snow layers formed on the walls of a snow pit on Mt Tateyama, snow samples, including aerosol particles, were collected from 70 layers at the lower (winter accumulation) and upper (spring accumulation) parts of the snow wall. The aerosols recorded in the lower parts mainly came from Siberia (Russia), northern Asia and the Sea of Japan, whereas those in the upper parts showed an increase in Asian dust particles originating from the desert regions and industrial coasts of Asia. The snow samples exhibited high levels of ice nucleation corresponding to the increase in Asian dust particles. Amplicon sequencing analysis using 16S rRNA genes revealed that the bacterial communities in the snow samples predominately included plant associated and marine bacteria (phyla Proteobacteria) during winter, whereas during spring, when dust events arrived frequently, the majority were terrestrial bacteria of phyla Actinobacteria and Firmicutes. The relative abundances of Firmicutes (Bacilli) showed a significant positive relationship with the ice nucleation in snow samples. Presumably, Asian dust events change the airborne bacterial communities over Mt Tateyama and carry terrestrial bacterial populations, which possibly induce ice-nucleation activities, thereby indirectly impacting climate change.

© 2018 Elsevier B.V. End-of-life electrical and electronic equipment is the potential secondary resource for economically-viable precious metals (PMs), e.g., gold (Au), palladium (Pd), or platinum (Pt). The hydrometallurgical processes produce acidic leachates during the recovery of PMs from waste sources, while the selective recovery of Au, Pd, or Pt from such a matrix is challenging either due to the chemical similarities of elements or complexities in the sources and matrices. A total of nine solid-phase extraction (SPE) systems, all claimed to designed for separation of PMs from complex matrices, was evaluated at varying solution pH (≤2 to 10) based on the selectivity towards Au, Pd, or Pt. The observation was used to develop a technique for selective Au, Pd, or Pt separation from acidic waste solutions using a macrocycle-equipped SPE. The feed solution flow-rates, eluent-type or compositions has been optimized to achieve maximum separation efficiency of the target analytes. The relative affinity of the macrocycles in solid-phase towards the ions (Pd > Au > Pt) is the core phenomenon of the proposed technique, and the host-guest type interaction is expected to be more stable than the resin-based separation processes. Furthermore, application of the macrocycle-equipped SPE system is advantageous regarding economics as it minimizes the impact of coexisting ions in the matrix and provides unaltered separation performance for several loading-elution cycles.

Previous studies have shown that bioaerosols are injected into the atmosphere during dust events. These bioaerosols may affect leeward ecosystems, human health, and agricultural productivity and may even induce climate change. However, bioaerosol dynamics have rarely been investigated along the transport pathway of Asian dust, especially in China where dust events affect huge areas and massive numbers of people. Given this situation, the Dust- Bioaerosol (DuBi) Campaign was carried out over northern China, and the effects of dust events on the amount and diversity of bioaerosols were investigated. The results indicate that the number of bacteria showed remarkable increases during the dust events, and the diversity of the bacterial communities also increased significantly, as determined by means of microscopic observations with 4,6- diamidino-2-phenylindole (DAPI) staining and MiSeq sequencing analysis. These results indicate that dust clouds can carry many bacteria of various types into downwind regions and may have potentially important impacts on ecological environments and climate change. The abundances of DAPI-stained bacteria in the dust samples were 1 to 2 orders of magnitude greater than those in the non-dust samples and reached 105-106 particlesm 3. Moreover, the concentration ratios of DAPI-stained bacteria to yellow fluorescent particles increased from 5.1%-6.3% (non-dust samples) to 9.8%-6.3%(dust samples). A beta diversity analysis of the bacterial communities demonstrated the distinct clustering of separate prokaryotic communities in the dust and non-dust samples. Actinobacteria, Bacteroidetes, and Proteobacteria remained the dominant phyla in all samples. As for Erenhot, the relative abundances of Acidobacteria and Chloroflexi had a remarkable rise in dust events. In contrast, the relative abundances of Acidobacteria and Chloroflexi in non-dust samples of R-DzToUb were greater than those in dust samples. Alphaproteobacteria made the major contribution to the increasing relative abundance of the phylum Proteobacteria in all dust samples. The relative abundance of Firmicutes did not exceed 5% in all the air samples, even though it is the predominant phylum in the surface sand samples from the Gobi Desert. These results illustrate that the bacterial community contained in dust aerosol samples has a different pattern compared with non-dust aerosol samples, and the relative abundances of airborne bacteria are different from those in the surface sand or soil and differ by location and transmitting vector

Aerosol particles, including airborne microorganisms, are transported through the free troposphere from the Asian continental area to the downwind area in East Asia and can influence climate changes, ecosystem dynamics, and human health. However, the variations present in airborne bacterial communities in the free troposphere over downwind areas are poorly understood, and there are few studies that provide an in-depth examination of the effects of long-range transport of aerosols (natural and anthropogenic particles) on bacterial variations. In this study, the vertical distributions of airborne bacterial communities at high altitudes were investigated and the bacterial variations were compared between dust events and non-dust events. Aerosols were collected at three altitudes from ground level to the free troposphere (upper level: 3000 or 2500 m middle level: 1200 or 500 m and low level: 10 m) during Asian dust events and non-dust events over the Noto Peninsula, Japan, where westerly winds carry aerosols from the Asian continental areas. During Asian dust events, air masses at high altitudes were transported from the Asian continental area by westerly winds, and laser imaging detection and ranging (lidar) data indicated high concentrations of nonspherical particles, suggesting that dust-sand particles were transported from the central desert regions of Asia. The air samples collected during the dust events contained 10-100 times higher concentrations of microscopic fluorescent particles and optical particle counter (OPC) measured particles than in non-dust events. The air masses of non-dust events contained lower amounts of dust-sand particles. Additionally, some air samples showed relatively high levels of black carbon, which were likely transported from the Asian continental coasts. Moreover, during the dust events, microbial particles at altitudes of > 1200m increased to the concentrations ranging from 1:2×106 to 6:6×106 particlesm-3. In contrast, when dust events disappeared, the microbial particles at> 1200mdecreased slightly to microbial-particle concentrations ranging from 6:4×104 to 8:9×105 particlesm-3. High-throughput sequencing technology targeting 16S rRNA genes (16S rDNA) revealed that the bacterial communities collected at high altitudes (from 500 to 3000 m) during dust events exhibited higher diversities and were predominantly composed of natural-sand/terrestrial bacteria, such as Bacillus members. During non-dust periods, airborne bacteria at high altitudes were mainly composed of anthropogenic/terrestrial bacteria (Actinobacteria), marine bacteria (Cyanobacteria and Alphaproteobacteria), and plantassociated bacteria (Gammaproteobacteria), which shifted in composition in correspondence with the origins of the air masses and the meteorological conditions. The airborne bacterial structures at high altitudes suggested remarkable changes in response to air mass sources, which contributed to the increases in community richness and to the domination of a few bacterial taxa.

Aerosol particles, including airborne microorganisms, are transported through the free troposphere from the Asian continental area to the downwind area in East Asia and can influence climate changes, ecosystem dynamics, and human health. However, the variations present in airborne bacterial communities in the free troposphere over downwind areas are poorly understood, and there are few studies that provide an in-depth examination of the effects of long-range transport of aerosols (natural and anthropogenic particles) on bacterial variations. In this study, the vertical distributions of airborne bacterial communities at high altitudes were investigated and the bacterial variations were compared between dust events and non-dust events. Aerosols were collected at three altitudes from ground level to the free troposphere (upper level: 3000 or 2500 m;middle level: 1200 or 500 m; and low level: 10 m) during Asian dust events and non-dust events over the Noto Peninsula, Japan, where westerly winds carry aerosols from the Asian continental areas. During Asian dust events, air masses at high altitudes were transported from the Asian continental area by westerly winds, and laser imaging detection and ranging (lidar) data indicated high concentrations of nonspherical particles, suggesting that dust-sand particles were transported from the central desert regions of Asia. The air samples collected during the dust events contained 10-100 times higher concentrations of microscopic fluorescent particles and optical particle counter (OPC) measured particles than in non-dust events. The air masses of non-dust events contained lower amounts of dust-sand particles. Additionally, some air samples showed relatively high levels of black carbon, which were likely transported from the Asian continental coasts. Moreover, during the dust events, microbial particles at altitudes of > 1200m increased to the concentrations ranging from 1 : 2 x 106 to 6 : 6 x 10(6) particlesm 3. In contrast, when dust events disappeared, the microbial particles at > 1200mdecreased slightly to microbial-particle concentrations ranging from 6 : 4 x 10(4) to 8 : 9 x10(5) particles m(-3). High-throughput sequencing technology targeting 16S rRNA genes (16S rDNA) revealed that the bacterial communities collected at high altitudes (from 500 to 3000 m) during dust events exhibited higher diversities and were predominantly composed of natural-sand/terrestrial bacteria, such as Bacillus members. During non-dust periods, airborne bacteria at high altitudes were mainly composed of anthropogenic/ terrestrial bacteria (Actinobacteria), marine bacteria (Cyanobacteria and Alphaproteobacteria), and plantassociated bacteria (Gammaproteobacteria), which shifted in composition in correspondence with the origins of the air masses and the meteorological conditions. The airborne bacterial structures at high altitudes suggested remarkable changes in response to air mass sources, which contributed to the increases in community richness and to the domination of a few bacterial taxa.

A relatively rapid and precise method is presented for the determination of lead in aqueous matrix. The method consists of analyte quantitation using the liquid electrode plasma-optical emission spectrometry (LEP-OES) coupled with selective separation/preconcentration by solid-phase extraction (SPE). The impact of operating variables on the retention of lead in SPEs such as pH, flow rate of the sample solution; type, volume, flow rate of the eluent; and matrix effects were investigated. Selective SPE-separation/preconcentration minimized the interfering effect due to manganese in solution and limitations in lead-detection in low-concentration samples by LEP-OES. The LEP-OES operating parameters such as the electrical conductivity of sample solution; applied voltage; on-time, off-time, pulse count for applied voltage; number of measurements; and matrix effects have also been optimized to obtain a distinct peak for the lead at lambda(max) = 405.8 nm. The limit of detection (3 sigma) and the limit of quantification (10 sigma) for lead determination using the technique were found as 1.9 and 6.5 ng mL(-1), respectively. The precision, as relative standard deviation, was lower than 5% at 0.1 mu g mL(-1) Pb, and the preconcentration factor was found to be 187. The proposed method was applied to the analysis of lead contents in the natural aqueous matrix (recovery rate: > 95%). The method accuracy was verified using certified reference material of wastewaters: SPS-WW1 and ERM-CA713. The results from LEP-OES were in good agreement with inductively coupled plasma optical emission spectrometry measurements of the same samples. The application of the method is rapid (<= 5 min, without preconcentration) with a reliable detection limit at trace levels.

Global patterns in diversity were estimated for cyanobacteria-dominated hypolithic communities that colonize ventral surfaces of quartz stones and are common in desert environments. A total of 64 hypolithic communities were recovered from deserts on every continent plus a tropical moisture sufficient location. Community diversity was estimated using a combined t-RFLP fingerprinting and high throughput sequencing approach. The t-RFLP analysis revealed desert communities were different from the single non-desert location. A striking pattern also emerged where Antarctic desert communities were clearly distinct from all other deserts. Some overlap in community similarity occurred for hot, cold and tundra deserts. A further observation was that the producer-consumer ratio displayed a significant negative correlation with growing season, such that shorter growing seasons supported communities with greater abundance of producers, and this pattern was independent of macroclimate. High-throughput sequencing of 16S rRNA and nifH genes from four representative samples validated the t-RFLP study and revealed patterns of taxonomic and putative diazotrophic diversity for desert communities from the Taklimakan Desert, Tibetan Plateau, Canadian Arctic and Antarctic. All communities were dominated by cyanobacteria and among these 21 taxa were potentially endemic to any given desert location. Some others occurred in all but the most extreme hot and polar deserts suggesting they were relatively less well adapted to environmental stress. The t-RFLP and sequencing data revealed the two most abundant cyanobacterial taxa were Phormidium in Antarctic and Tibetan deserts and Chroococcidiopsis in hot and cold deserts. The Arctic tundra displayed a more heterogenous cyanobacterial assemblage and this was attributed to the maritime-influenced sampling location. The most abundant heterotrophic taxa were ubiquitous among samples and belonged to the Acidobacteria, Actinobacteria, Bacteroidetes, and Proteobacteria. Sequencing using nitrogenase gene-specific primers revealed all putative diazotrophs were Proteobacteria of the orders Burkholderiales, Rhizobiales, and Rhodospirillales. We envisage cyanobacterial carbon input to the system is accompanied by nitrogen fixation largely from non-cyanobacterial taxa. Overall the results indicate desert hypoliths worldwide are dominated by cyanobacteria and that growing season is a useful predictor of their abundance. Differences in cyanobacterial taxa encountered may reflect their adaptation to different moisture availability regimes in polar and non-polar deserts.

Asian dust events transport the airborne bacteria in Chinese desert regions as well as mineral particles and influence downwind area varying biological ecosystems and climate changes. However, the airborne bacterial dynamics were rarely investigated in the Gobi desert area, where dust events are highly frequent. In this study, air samplings were sequentially performed at a 2-m high above the ground at the sampling site located in desert area (Tsogt-Ovoo of Gobi desert; Mongolia 44.2304A degrees N, 105.1700A degrees E). During the dust event days, the bacterial cells and mineral particles increased to more than tenfold of concentrations. MiSeq sequencing targeting 16S ribosomal DNA revealed that the airborne bacteria in desert area mainly belonged to the classes Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Bacilli, Alpha-proteobacteria, Beta-proteobacteria, and Gamma-proteobacteria. The bacterial community structures were different between dust events and non-dust events. The air samples collected at the dust events indicated high abundance rates of Alpha-proteobacteria, which were reported to dominate on the leaf surfaces of plants or in the saline lake environments. After the dust events, the members of Firmicutes (Bacilli) and Bacteroidetes, which are known to form endospore and attach with coarse particles, respectively, increased their relative abundances in the air samples. Presumably, the bacterial compositions and diversities in atmosphere significantly vary during dust events, which carry some particles from grassland (phyllo-sphere), dry lake, and sand surfaces, as well as some bacterial populations such as Firmicutes and Bacteroidetes maintain in the atmosphere for longer time.

The major fractions of dissolved iron in seawater exist as a complex with organic ligands. A high bioavailability of iron bound to humic acid (HA) compared to the other model ligands, such as desferrioxamine B or ferrichrome, has been reported, which implies the importance of HA to control the geochemical behavior and the transfer of Fe to marine phytoplankton, particularly in estuarine and coastal waters. In the current work, the effect of different HA fractions (> 100, 100-30, 30-10, 10-5, and 5-3 kDa), which were extracted from lignite, on the comparative solubility of iron in seawater and the corresponding influence on iron uptake and growth rate of the phytoplankton Prymnesium parvum (Haptophyta) was studied using laboratory cultures. The lower-molecular-weight (MW) HA fractions, such as 30-10, 10-5, and 5-3 kDa, remained soluble in the simulated seawater medium for a longer time span compared to the higher MW fractions. The lower MW fractions facilitated higher iron solubility and assisted in achieving a better phytoplankton growth rate. However, a reciprocal impact on phytoplankton growth rates was observed when the HA concentration increased to a higher range (0.18 to 18 mg-C L-1). The highest intracellular Fe uptake in phytoplankton occurred with 30-10 kDa HA in seawater, and the extracellular dissolved Fe concentrations were higher for smaller-sized HA fractions. In summary, our study showed that the controlled addition of lower MW fractions of HA (up to 30-10 kDa) in estuarine waters could ensure the accelerated uptake of Fe in phytoplankton as well as a better growth rate.

Atmospheric aerosols contain particulates that are deposited to oceanic surface waters. These can represent a major source of nutrients, trace metals, and organic compounds for the marine environment. The Japan Sea and the western Pacific Ocean are particularly affected by aerosols due to the transport of desert dust and industrially derived particulate matter with aerodynamic diameter less than 2.5 mu m (PM2.5) from continental Asia. We hypothesized that supplementing seawater with aerosol particulates would lead to measurable changes in surface water nutrient composition as well as shifts in the marine microbial community. Shipboard experiments in the Pacific Ocean involved the recovery of oligotrophic oceanic surface water and subsequent supplementation with aerosol particulates obtained from the nearby coastal mountains, to simulate marine particulate input in this region. Initial increases in nitrates due to the addition of aerosol particulates were followed by a decrease correlated with the increase in phytoplankton biomass, which was composed largely of Bacillariophyta (diatoms), including Pseudo-nitzschia and Chaetoceros species. This shift was accompanied by changes in the bacterial community, with apparent increases in the relative abundance of heterotrophic Rhodobacteraceae and Colwelliaceae in aerosol particulate treated seawater. Our findings provide empirical evidence revealing the impact of aerosol particulates on oceanic surface water microbiology by alleviating nitrogen limitation in the organisms.

The heat tolerance of biological ice nucleation activity (INA) depends on their types. Different temperature treatments may cause varying degrees of inactivation on biological ice nuclei (IN) in precipitation samples. In this study, we measured IN concentration and bacterial INA in snow samples using a drop freezing assay, and compared the results for unheated snow and snow treated at 40 degrees C and 90 degrees C. At a measured temperature of -7 degrees C, the concentration of IN in untreated snow was 100-570 L-1, whereas the concentration in snow treated at 40 degrees C and 90 degrees C was 31-270 L-1 and 2.5-14 L-1, respectively. In the present study, heat sensitive IN inactivated by heating at 40 degrees C were predominant, and ranged 23-78% of IN at -7 degrees C compared with untreated samples. Ice nucleation active Pseudomonas strains were also isolated from the snow samples, and heating at 40 degrees C and 90 degrees C inactivated these microorganisms. Consequently, different temperature treatments induced varying degrees of inactivation on IN in snow samples. Differences in the concentration of IN across a range of treatment temperatures might reflect the abundance of different heat sensitive biological IN components. (C) 2016 Elsevier Ltd. All rights reserved.

Airborne microorganisms (bioaerosol) from the China desert region, which are released into the atmosphere, disperse by the Asian dust event and affect ecosystems, human life, and atmospheric processes in downwind areas. However, the dynamics of airborne bacteria over the China desert regions have rarely been investigated. In this study, we analyzed bacterial communities in aerosols of the Asian dust source region (Taklimakan Desert) and compared them with the bacterial communities in sand dunes, for evaluating the mixtures from sand area to atmosphere. Air samples were collected at 10 m above the ground level from Dunhuang City during a dust event. The cell densities of airborne bacteria during a dust event were ten times more than that in non-dust periods. The 16S rDNA clone libraries from four air samples mainly belonged to two phyla, Firmicutes and Proteobacteria. During a dust event, the proportion of Proteobacteria clones decreased, whereas that of Firmicutes clones increased. Sand samples were collected from the sand dunes in four sampling sites of the Taklimakan Desert. The bacterial communities in sand samples comprised of the members of Firmicutes and Actinobacteria. The clones of Firmicutes in both air and sand samples included Bacillus species, constituting more than 10 % of total clones. Airborne bacterial communities would be carried by the dust events from sand dunes. Propionibacterium species from the class Actinobacteria that were dominant in sand samples were not detected in the air samples, suggesting that atmospheric stressors eliminate some bacterial species. Presumably, airborne bacterial communities in the Asian dust source region are composed of local environmental bacteria, and their dynamics depend on the occurrence of a dust event.

Waste foundry sand (WFS), which is a hazardous byproduct from the foundry industry, is often contaminated with potentially toxic elements (PTEs), such as Cu, Pb and Zn, and widely re-utilized as a construction_ material. Therefore, the depollution of WFS has been suggested due to its environment friendly reprocessing to avoid potential long-term hazardous impacts. In the current study, a unique chemically induced technique has been proposed for the removal of PTEs from WFS. EDTA, NaOH and NH3 were used as extractants in combination or in succession. The optimum removal of PTEs was accomplished using a solid (WFS) to solution (50 mmol L-1 EDTA) ratio of 10 under strongly basic pH conditions, which was achieved with NaOH addition. The washing efficiency was further enhanced with the addition of NH3 to the solution. The complete process cycle duration was adjusted to 9 h with a washing sequence that was repeated three times for 3 h each. The ultimate efficiencies (%) for the removal of PTEs were as follows: Cu, 98; Pb, 81; Sn, 83; and Zn, 50. The leaching of residual PTEs (%) from the decontaminated WFS was also in compliance with the regulatory levels that are defined by the monitoring authorities. (C) 2016 Elsevier By. All rights reserved.

The relationship between atmospheric bioaerosols and ecosystems is currently of global importance. Antarctica has an extreme climate, meaning that ecosystem behavior in this region is relatively simple. Direct sampling of atmospheric bioaerosols was performed at an Adelie penguin (Pygoscelis adeliae) colony at Hukuro Cove, Langhovde, Antarctica on 22 January 2013. The aim of the sampling was to reveal the effect of the penguins on the Antarctic ecosystem within the atmospheric bioaerosols. Samples were bio-analyzed using a next-generation sequencing method. Biomass concentrations of Bacilli-class bacteria were 19.4 times higher when sampled leeward of the penguin colony compared with windward sampling. The source of these bacteria was the feces of the penguins. Predicted atmospheric trajectories indicate that the bacteria disperse towards the Southern Ocean. The largest biomass concentration in the windward bacteria was of the Gammaproteobacteria class, which decreased markedly with distance through the penguin colony, being deposited on soil, surface water, and ocean. It is concluded that bioaerosols and ecosystems near the penguin colony strongly influence each other. (C) 2015 Elsevier B.V. and NIPR. All rights reserved.

Kosa (Asian duststorm) is a well-known phenomenon where particles are transported from Mongolia and northwestern China via Eastern Asia to the American continent. Kosa bioaerosols (airborne microorganisms within Kosa) were frequently found during Kosa event, and there is concern that they may affect human health. For biological observation and evaluation of Kosa events, we made sampling of aerosols in Kosa events on May 2 (KOSA1) and May 13 (KOSA2), 2011, at Kanazawa, Japan. From the data of lidar from Toyama, SPRINTARS simulation model and the backward trajectories of air masses, both events were originated in desert area of Mongolia. KOSA episode 1 was stronger than KOSA episode 2 above the surface boundary layer, and KOSA episode 2 contained the particles from the local source such as soil, sea salt, and various particles formed in the polluted atmosphere. The DNA to total suspended particle matter (SPM) ratios in KOSA1 and KOSA2 were 0.012 and 0.00978, respectively. Bacterial species compositions were identified qualitatively. Many Gammaproteobacteria were cloned and identified from both KOSA. Quantitative toxicity observations to assess the risk of food poisoning were performed by real-time PCR of food poisoning bacteria, Bacillus and Staphylococcus spp. The ratios of the concentrations of Bacillus and Staphylococcus spp. relative to SPM in KOSA1 and KOSA2 were 33.1 and 43.1 copies mu g-SPM-1, respectively. The results of toxicity evaluations by the mathematical simulations suggested that compared with KOSA1, KOSA2 had a 1.35 times higher risk of causing food poisoning.

Biological ice nuclei (IN) such as certain species of bacteria and fungi are believed to have impacts on ice nucleation in mixed-phase clouds at temperatures warmer than -15 degrees C. Recent studies have indicated that rain is closely related to increases of biological IN in the near-surface atmosphere. However, variations of IN concentrations during rain and snowfall have not been compared. In the present study, field measurements of atmospheric IN were carried out under fine, cloudy, rain and snow at a local forested site in Japan. IN concentrations at -7 degrees C in spring were dramatically increased by rain, and concentrations associated with rain (0.86-2.2 m(-3)) were greater than 2.6 times higher than the mean concentration during fine weather (0.33 m(-3)). In winter, concentrations associated with rain (1.6 to >5.7 m(-3)) were also higher than those under cloudy sky (1.1 m(-3)), but increases were not observed during snowfall (0.21-0.4 m(-3)). Detectable IN concentrations associated with rain considerably decreased after heat treatment at 90 degrees C, indicating that IN increased during rain were likely biological substances such as heat-sensitive ice nucleation active proteins. Consequently, different types of precipitation may have varying effects on IN concentration associated with biological substances. (C) 2015 Elsevier Ltd. All rights reserved.

アジア大陸から飛来した黄砂やPM_2.5といったエアロゾルは，日本海や太平洋へ沈着すると，栄養塩，微量金属及び有機物を海洋へ供給し，海洋の植物プランクトンなどの一次生産者の増殖を促進させる．そのため，エアロゾルの海洋沈着は，炭酸固定や炭素循環に少なからず影響を与えると言われている．しかし，エアロゾルが海洋沈着を介して微生物の動態に及ぼす影響は，フィールド観測やモデル解析に基づいて分析されている報告が多数を占め，エアロゾルを海水に直接添加し微生物動態を詳細に検討した報告例は少ない．そこで本研究では，2013年4月に，富山県に位置する立山の積雪層から黄砂粒子を含む積雪試料を採取し，この積雪試料を海水に添加し，エアロゾルが海洋微生物の増殖及び群集構造へ与える影響を船上での培養実験により評価した．船上培養実験は，2013年5月に，静岡県御前崎より70 km離れた遠州灘沖の貧栄養海域で実施した．積雪試料を添加した実験区では，添加直後に硝酸態窒素濃度が増加し，3 日間の培養の後，硝酸態窒素の減少に伴い，マイクロプランクトンの画分のクロロフィルα濃度の増加が観察された．細菌群集では，積雪試料を添加した実験区において，有機物分解細菌（Rhodobacterace，OM60など）に近縁な細菌グループの増殖が促進された．本研究において実施した貧栄養海域では，黄砂粒子を含む積雪試料は，硝酸態窒素を海洋へ供給し，微細藻類の増殖を促進させ，細菌群集構造を変動させることが分かった．

Bjerkandera adusta (B. adusta) causes fungus-associated chronic cough. However, the inflammatory response is not yet fully understood. Recently, B. adusta was identified in Asian sand dust (ASD) aerosol. This study investigated the enhancing effects of ASD on B. adusta-induced lung inflammation. B. adusta was inactivated by formalin. ASD was heated to remove toxic organic substances. ICR mice were intratracheally instilled with saline, B. adusta 0.2 mu g, or B. adusta 0.8 mu g with or without heated ASD 0.1 mg (H-ASD), four times at 2-week intervals. Two in vitro experiments were conducted to investigate any enhancing effects using bone marrow-derived macrophages (BMDM) from Toll-like receptor (TLR) knockout mice and ICR mice. Co-exposure to H-ASD and B. adusta, especially at high doses, caused eosinophil infiltration, proliferation of goblet cells in the airway, and fibrous thickening of the subepithelial layer, and remarkable increases in expression of Th2 cytokines and eosinophil-related cytokine and chemokine expression in bronchoalveolar lavage fluid. In the in vitro study using BMDM from wild-type, TLR2-/-, and TLR4-/- mice, the TLR-signaling pathway for cytokine production caused by B. adusta was predominantly TLR2 rather than TLR4. H-ASD increased the expression of NF-B and cytokine production by B. adusta in BMDM from ICR mice. The results suggest that co-exposure to H-ASD and B. adusta caused aggravated lung eosinophilia via remarkable increases of pro-inflammatory mediators. The aggravation of inflammation may be related, at least in part, to the activation of the TLR2-NF-B signaling pathway in antigen presenting cells by H-ASD. (c) 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 93-105, 2016.

Non-ferrous smelting dust, especially lead-smelting dust (LSD), contains percent levels of indium and thus constitutes a novel indium resource. The main difficulty in recovering indium from LSD is the coexisting presence of lead and zinc. In this study, a unique indium separation process was designed, combining techniques that involve washing with a chelant, leaching with acid and precipitation as hydroxide. The majority of the Pb in the LSD was selectively separated during chelant-assisted washing with ethylenediaminedisuccinate (EDDS), while the residual Pb was diminished through an acid leaching treatment with a mixed solution of sulfuric acid and hydrochloric acid. The chelant washing step also ensures a decrease in the raw LSD weight at a ratio of approximately 82% due to the removal of lead and counterions such as sulfate, and the washing step also minimizes the consumption of corrosive acids in the subsequent step. Selective indium separation from LSD is further complicated by the similarity of the behavior of zinc during the acid leaching step. Therefore, hydroxide precipitation at pH 5 has been introduced as the final step, ensuring the maintenance of zinc as a soluble species in the supernatant and the selective separation of indium (similar to 88%) as a hydroxide precipitate. (C) 2015 Elsevier B.V. All rights reserved.

Bacterial populations transported from ground environments to the atmosphere get dispersed throughout downwind areas and can influence ecosystem dynamics, human health, and climate change. However, the vertical bacterial distribution in the free troposphere was rarely investigated in detail. We collected aerosols at altitudes of 3000 m, 1000 m, and 10 m over the Noto Peninsula, Japan, where the westerly winds carry aerosols from continental and marine areas. During the sampling period on March 10, 2012, the air mass at 3000 m was transported from the Chinese desert region by the westerly winds, and a boundary layer was formed below 2000 m. Pyrosequencing targeting 16S rRNA genes (16S rDNA) revealed that the bacterial community at 3000 m was predominantly composed of terrestrial bacteria, such as Bacillus and Actinobacterium species. In contrast, those at 1000 m and 10 m included marine bacteria belonging to the classes Cyanobacteria and Alphaproteobacteria. The entire 16S rDNA sequences in the clone libraries were identical to those of the terrestrial and marine bacterial species, which originated from the Chinese desert region and the Sea of Japan, respectively. The origins of air masses and meteorological conditions contribute to vertical variations in the bacterial communities in downwind atmosphere. (C) 2015 Elsevier Ltd. All rights reserved.

Kosa (Asian dust) is a well-known weather phenomenon in which aerosols are carried by the westerly winds from inland China to East Asia. Recently, the frequency of this phenomenon and the extent of damage caused have been increasing. The airborne bacteria within Kosa are called Kosa bioaerosols. Kosa bioaerosols have affected ecosystems, human health and agricultural productivity in downwind areas. In order to develop a new and useful bacterial source and to identify the source region of Kosa bioaerosols, sampling, isolation, identification, measurement of ultraviolet (UV) radiation tolerance and experimental simulation of UV radiation conditions were performed during Kosa bioaerosol transportation. We sampled these bioaerosols using a Cessna 404 airplane and a bioaerosol sampler at an altitude of approximately 2900 m over the Noto Peninsula on March 27, 2010. The bioaerosol particles were isolated and identified as Bacillus sp. BASZHR 1001. The results of the UV irradiation experiment showed that the UV radiation tolerance of Kosa bioaerosol bacteria was very high compared with that of a soil bacterium. Moreover, the UV radiation tolerance of Kosa bioaerosol spores was higher than that of soil bacterial spores. This suggested that Kosa bioaerosols are transported across the atmosphere as living spores. Similarly, by the experimental simulation of IN radiation conditions, the limited source region of this Kosa bioaerosol was found to be southern Russia and there was a possibility of transport from the Kosa source area. (C) 2014, The Society for Biotechnology, Japan. All rights reserved.

The accumulation behaviors and solid phase partitioning patterns of stable cesium, which have been recognized as an indicator of the long-term movement of radioactive cesium (Cs-137 or Cs-134) in ecosystems, were studied in typical and natural soils of Japanese origin, namely, red clay, leaf-mold and andosol soils. The retention and migration of soil-phase cesium have been explained relative to various factors, such as soil organic matter contents, competitive cation concentrations and the adsorption ratio of Cs to the solid phase. Cesium was adsorbed nearly quantitatively in the leaf-mold type soil, and the rate of Cs absorption increased as the particle size decreased in the red clay and andosol soils. The distributions of Cs within the soil solid phases were defined using the selective sequential extraction scheme and were used to explain its relative incorporation in the soil fractions. Solid phase fractionation indicated that nearly half of the total cesium concentrations in the soils were in the 'residual' fraction (representing the metal that was incorporated within the crystalline lattice of the soil and was difficult to extract). These findings are expected to provide information regarding suitable conditions for remediation, immobilization or the recovery of cesium from contaminated soils with excess cesium concentrations. (C) 2014 Elsevier B.V. All rights reserved.

Background: Recently, a cluster of patients with an intractable allergic fungal cough who were characterized by sensitization to Bjerkandera adusta was reported. In the present study, the role of Toll-like receptors and myeloid differentiation factor 88 (MyD88) in B. adusta-induced lung inflammation was investigated. Methods: Wild-type (WT), TLR2(-/-), TLR4(-/-), and MyD88(-/-) BALB/c mice were intratracheally challenged with B. adusta 4 times at 2-week intervals. Lung pathology, bronchoalveolar lavage fluid (BALF) cytological profiles, and inflammatory mediators in BALF were investigated. Bone marrow-derived macrophages (BMDM) from TLR2(-/-), TLR4(-/-), TLR2/4(-/-), TLR7/9(-/-), MyD88(-/-), and WT C57BL/6J mice were stimulated with B. adusta for 12 h, and inflammatory mediators in the culture medium were measured. Results: B. adusta caused lung inflammation along with Th2 cytokine [interleukin (IL)-5 and IL-13] and eosinophil-related chemokine [eotaxin and monocyte chemotactic protein (MCP-3)] production, an increase in eosinophils in BALF, and eosinophil infiltration in the airways in WT and TLR4(-/-) mice. However, Th2 and eosinophil-related responses in TLR2(-/-) and MyD88(-/-) mice were low or undetectable. The induction of neutrophils and IL-6, IL-12, IL-17A, and MCP-1 in the BALF of MyD88(-/-) mice was attenuated compared to that in WT mice. The induction of IL-6, TNF-alpha, MCP1, and macrophage inflammatory protein-1 alpha was reduced or undetectable in B. adusta-stimulated BMDM from TLR7/9(-/-) and MyD88(-/-) mice compared to WT mice. Conclusions: These results suggest that TLR2 and the adapter protein MyD88 may play an important role in the induction of eosinophils by B. adusta. However, TLR7/9-MyD88 might be important in the induction of neutrophils and the relevant inflammatory mediators, especially IL-17A. (C) 2015 S. Karger AG, Basel

© 2015, The Institute of Experimental Botany. Iron is an essential limiting factor for primary production in many marine systems. The present study investigated differential regulation of protein expression in marine phytoplankton Prymnesium parvum under low Fe concentration. The phytoplankton was grown in f/2 culture medium in artificial seawater with low (0.0025 μM) and high (0.05 μM) Fe concentrations. Two-dimensional differential gel electrophoresis and matrix-assisted laser desorption-ionization-time of flight-mass spectrometer analysis were performed for protein identification and characterization. The growth of the alga declined substantially under the low Fe compared to the high Fe concentration. Under low Fe conditions, P. parvum upregulated 10 proteins including chloroplastic ATP synthase subunit b, D2 protein of PSII, D1 protein of PSII reaction centre, and light harvesting complex II protein, most of which are associated with photosynthetic activities in PSII. The results suggest that the marine alga P. parvum altered the biosynthesis of several photosynthetic proteins in order to cope with low Fe conditions.

© 2014, Springer-Verlag Berlin Heidelberg. A new fluorescent-based high-performance liquid chromatography (HPLC) assay using 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-C1) was employed to determine iron (Fe) bioavailability to red tide phytoplankton in seawater. After growing four red tide species (Prymnesium parvum, Heterosigma akashiwo, Eutreptiella gymnastica, and Oltmannsiellopsis viridis) in f/2 artificial seawater under different Fe conditions, soluble extracts of the phytoplankton were derivatized using different fluorescent reagents (NBD-C1, 4-fluoro-7-nitrobenzo-2-oxa-1,3-diazole; NBD-F, fluorescamine, and ortho-phthalaldehyde; OPA) followed by HPLC assay. Among the four fluorescent reagents, NBD-C1 was most effective for derivatizing the phytoplankton extracts which would consist of proteins and peptides. HPLC chromatograms of the NBD-derivatized extracts showed gradual changes (decrease/increase) of six peaks for different Fe conditions. Four of the peaks decreased, while two peaks increased with the increase of Fe concentrations in the culture medium. Considering the consistency and sensitivity of chromatogram peaks E and A to different Fe, phosphate and nitrate conditions for all phytoplankton studied, the ratio of these two peaks (IE/A) has been proposed as the indicator of Fe bioavailability to red tide phytoplankton.

The incineration fly ash (IFA), molten fly ash (MFA), thermal power plant fly ash (TPP-FA), and nonferrous metal processing plant ash (MMA) have been screened in terms of the following rare-termed metal contents: B, Ce, Co, Dy, Eu, Ga, Gd, Hf, In, Li, Lu, Mn, Nb, Nd, Ni, Pr, Rb, Sb, Se, Sm, Sr, Ta, Tb, Te, Ti, Tm, V, W, Y, and Yb. The pseudo-potential for recycling of the waste ashes, as compared to the cumulative concentration in the crust (mg kg(-1)), was determined as follows: MMA>IFA>MFA>TPP-FA. The comparison with the crude ore contents indicates that the MMA is the best resource for reprocessing. The recovery of the target metals using aminopolycarboxylate chelants (APCs) has been attempted at varying experimental conditions and ultrasound-induced environment. A better APC-induced extraction yield can be achieved at 0.10 mol L-1 concentration of chelant, or if the system temperature was maintained between 60 to 80 degrees C. Nevertheless, the mechanochemical reaction induced by the ultrasound irradiation has been, so far, the better option for rare metal dissolution with chelants as it can be conducted at a minimum chelant concentration (0.01 mol L-1) and at room temperature (25 +/- 0.5 degrees C).

Asian dust (Rosa) events transport airborne microorganisms that significantly impact biological ecosystems, human health, and ice-cloud formation in downwind areas. However, the composition and population dynamics of airborne bacteria have rarely been investigated in downwind areas during Kosa events. In this study, air samplings were sequentially performed at the top of a 10-m high building within the Rosa event arrival area (Kanazawa City, Japan) from May 1 to May 7, 2011, during a Rosa event. The particle concentrations of bacterial cells and mineral particles were ten-fold higher during the Rosa event than on non-Rosa event days. A 16S ribosomal DNA clone library prepared from the air samples primarily contained sequences from three phyla: Cyanobacteria, Firmicutes, and Alphaproteobacteria. The clones from Cyanobacteria were mainly from a marine type of Synechococcus species that was dominant during the first phase of the Rosa event and was continuously detected throughout the Rosa event. The clones from Alphaproteobacteria were mainly detected at the initial and final periods of the Rosa event, and phylogenetic analysis showed that their sequences clustered with those from a marine bacterial clade (the SAR clade) and Sphingomonas spp. During the middle of the Rosa event, the Firmicutes species Bacillus subtilis and Bacillus pumilus were predominant; these species are known to be predominant in the atmosphere above the Chinese desert, which is the source of the dust during Rosa events. The clones obtained after the Rosa event had finished were mainly from Bacillus megaterium, which is thought to originate from local terrestrial areas. Our results suggest that airborne bacterial communities at the ground level in areas affected by Rosa events change their species compositions during a Rosa event toward those containing terrestrial and pelagic bacteria transported from the Sea of Japan and the continental area of China by the Rosa event. (C) 2014 Elsevier B.V. All rights reserved.

This study investigated the distribution of magnesium (Mg), phosphorus (P), sulfur (S) and strontium (Sr) using micro Xray fluorescence (mu-XRF), and the speciation of S using X-ray absorption near edge spectroscopy (XANES) along the annual growth rings in the skeleton of Japanese red coral Paracorallium japonicum. The Mg, P and S distribution in mu-XRF mapping images correspond to the dark and light bands along the annual growth rings in microscopic images of the coral skeleton. The mu-XRF mapping data showed a positive correlation (r = 0.6) between P and S distribution in the coral skeleton. A contrasting distribution pattern of S and Mg along the axial skeleton of P. japonicum indicates a weak negative correlation (r = -0.2) between these two elements. The distribution pattern of S, P and Mg in the axial skeleton of P. japonicum reveals linkage between the trace element distribution and the formation of dark/light bands along the annual growth rings. Sulfur and P were distributed in the organic matrix rich dark bands, while Mg was distributed in the light bands of the annual growth rings. XANES analysis showed that inorganic sulfate is the major species of S in the skeleton of P. japonicum with a ratio of 1: 20 for organic and inorganic sulfate. (C) 2013 Elsevier Ltd. All rights reserved.

Background: Bjerkandera adusta (B. adusta) is one of the most important etiological fungi associated with chronic cough. However, precise details of the inflammatory response to exposure are not well understood yet. B. adusta was recently identified in Asian sand dust (ASD) aerosol. Therefore, in the present study the exacerbating effects of ASD on B. adusta-induced lung inflammation and B. adusta + ASD on ovalbumin (OVA)-induced murine lung eosinophilia were investigated using experimental mice. Methods: In order to prepare testing samples, B. adusta obtained from ASD aerosol was inactivated by formalin and ASD collected from the atmosphere was heated to remove toxic organic substances (H-ASD). CD-1 mice were instilled intratracheally with 12 different samples prepared with various combinations of B. adusta, H-ASD, and OVA in a normal saline solution. The lung pathology, cytological profiles in bronchoalveolar lavage fluid (BALF), and the levels of inflammatory cytokines/chemokines in BALF were investigated. Results: H-ASD aggravated the lung eosinophilia induced by B. adusta alone, which also aggravated the lung eosinophilia induced by OVA. The mixture of OVA, H-ASD, and B. adusta caused serious fibrous thickening of the subepithelial layer, eosinophil infiltration, and proliferation of goblet cells in the airways along with remarkable increases of IL-13, eotaxin, IL-5, and MCP-3 in BALF. Conclusions: The results of the present study demonstrated that B. adusta isolated from ASD aerosol induces allergic lung diseases. H-ASD enhanced allergic reactions caused by OVA or B. adusta. A mixture of B. adusta, H-ASD, and OVA caused the most remarkable exacerbation to the allergic airway inflammation via remarkable increases of pro-inflammatory mediators.

近年、黄砂と共に風送される微生物群（黄砂バイオエアロゾル）が及ぼす人健康への影響が懸念されている。しかし、黄砂による微生物の長距離輸送を直接実証した研究は殆どない。そこで、黄砂時の大気粒子から細菌株を分離培養し、細菌株の飛来源をＭＬＳＴ(遺伝子多型解析)を用いて推定した。黄砂発生地（敦煌）及び飛来地（珠洲，金沢，立山）において採取したエアロゾル試料を，高塩分の液体培地に接種し、全177の環境ストレス耐性細菌株を分離培養した。全株の16S rDNA塩基配列を決定し、系統分類学的に解析すると、64株がバチルス属に属し、バチルス サブチリスと近縁となった。更に、本種と近縁な細菌株を株レベルで比較する為、５種のハウスキーピング遺伝子配列を解析した。結果、バチルス サブチリス群の中で、敦煌大気と立山及び金沢の黄砂粒子から得た株が、一つのクラスターを形成し、本菌株の黄砂による越境輸送が示唆された。

海洋に沈着した黄砂は、海水の化学組成を変動させ、海洋微生物群を消長に影響を及ぼす。しかし，その影響を直接的に実証した培養実験例は乏しい。そこで、本研究では、黄砂を海洋試水に添加する船上培養実験を実施した。黄砂は、富山県立山連峰の室堂平（2450m）において、春季に積雪断面調査を実施し、積雪のよごれ層から、黄砂鉱物粒子を含む積雪試料を採取した。また、比較のため、純白層の積雪試料も採取した。よごれ層の積雪試料は、粗大粒子密度が高く、高濃度の硝酸窒素が含まれていた。 紀伊半島沖合の70km地点で採取した海水に、よごれ層の試料を添加した海水では、硝酸窒素及び珪酸濃度が著しく減少するとともに、20μm以上の画分でChl.a濃度が著しく増えたため、大型珪藻類が生長促進されたと推察できる。また、細菌細胞密度の増大もみられ、超並列シーケンサーを用いて、細菌群集構造の動態解析も試みた。

Iron (Fe) is one of the vital limiting factors for phytoplankton in vast regions of the contemporary oceans, notably the high nutrient low chlorophyll regions. Therefore, it is apparent to be acquainted with the Fe uptake strategy of marine phytoplankton under Fe-limited condition. In the present study, marine phytoplankton Prymnesium parvum was grown under Fe-deplete (0.0025 μM) and Fe-rich (0.05 μM) conditions, and proteomic responses of the organism to Fe conditions were compared. In sodium dodecyl sulfate (SDS) gel electrophoresis, 7 proteins (16, 18, 32, 34, 75, 82, and 116. kDa) were highly expressed under Fe-deplete condition, while one protein (23. kDa) was highly expressed under Fe-rich condition. These proteins were subjected to 2-dimensional gel electrophoresis (2-D DIGE) to differentiate individual proteins, and were identified by matrix-assisted laser desorption-ionization-time of flight-mass spectrometer (MALDI-TOF-MS) analysis. The results showed that under Fe-deplete condition P. parvum increases the biosynthesis of ATP binding cassette (ABC) transporters, flagellar associated protein (FAP), and Phosphoribosylaminoimidazole-succinocarboxamide synthase. These proteins are assumed to be involved in a number of cellular biochemical processes that facilitate Fe acquisition in phytoplankton. Under Fe-deplete condition, P. parvum increases the synthesis of ribulose biphosphate carboxylase (RuBisCo), malate dehydrogenase, and two Fe-independent oxidative stress response proteins, manganese superoxide dismutase (MnSOD) and Serine threonine kinase (STK). Thus, marine phytoplankton may change their Fe acquisition strategy by altering the biosynthesis of several proteins in order to cope with Fe-limitation. © 2013 Elsevier Ltd.

The waste byproducts from the indium-consuming fabrication processes are considered as the viable resource for indium due to the unique preference to the element in designing optoelectronic devices. The present work introduces a new technique for the selective recovery of indium from the etching waste, which produced during the patterning of indium tin oxide (ITO) layer on the flat-panel displays. The process includes the application of a solid phase extraction (SPE) assembly, known as molecular recognition technology (MRT) gel, consisting of a metal-selective ligand immobilized to silica gel or polymer substrates. The samples were the real solution of etching waste from the liquid-crystal display fabrication process, and the simulated waste solution prepared using the commercially available etching solution composition containing ethanedioic acid. The retention and the corresponding indium recovery rate (%) were the key characteristics for the appraisal of MRT-SPE types: AnaLig TE 02 (TE 02), AnaLig TE 03, AnaLig TE 07, AnaLig TE 13 and AnaLig PM 02. The other conclusive factors were the influence of ion intensity in solution and the interfering effects from tin, the co-content element in the ITO-formulation. The TE 02 MRT-SPE came across all the requisite aspects for the selective recovery of indium from the etching effluent. The indium retention or recovery with TE 02 MRT-SPE from the real etching waste solution was in the range of 97 to 99% with the relative standard deviation of <4.4%. The separation of the ITO co-element tin from the waste mixture was successively selective, and thereby minimizes the possibility of interference. A three-step elution with 03 mol L-1HNO3, 6 mol L-1 HCl and 1 mol L-1 HCl/10 mmol L-1 EDTA was required to accomplish the sequential selectivity in the process. The indium retention capacity of the TE 02 MRT-SPE was 0.147 mmol g(-1). (C) 2013 Elsevier B.V. All rights reserved.

Bioaerosol particles including bacteria, fungi, and virus are originated from marine and terrestrial environments. The airborne microorganisms are transported for long distance through the free troposphere and are thought to influence the downwind ecosystems and human life. However, microbial communities in the free troposphere have not been understood in detail because the direct sampling of microbial cells at high altitude requires sophisticated sampling techniques. In this study, for the investigation of microbial species compositions in the free troposphere, air sampling using an aircraft was performed over the Noto Peninsula in Japan, where the tropospheric winds carry aerosol particles from continental areas. Two air samples were collected at 3,000 m on March 27, 2010, when air mass was carried from the Gobi Desert to Japan area. Microorganisms from one air sample grew in culture media containing up to 15 % NaCl, suggesting that halotolerant bacteria maintain their viabilities in the free troposphere. DGGE analysis revealed that the amended cultures were dominated by Bacillus subtilis, and the isolates obtained from the amended cultures were identical to B. subtilis. Furthermore, the 16S rDNA clone library (culture-independent survey) of the other air sample grew was composed of three phylotypes belonging to Firmicutes, Bacteroidetes, and Proteobacteria with the sequences of Firmicutes phylotype corresponding to that of the cultured B. subtilis sequence. Microscopic observation using FISH method indicated that B. subtilis particles occupied 80 % of total eubacterial particles on the mineral particles. The halotolerant bacteria identical to B. subtilis would dominate at high altitudes over Noto Peninsula where the prevailing westerly wind was blowing.

This is the first study to demonstrate that Microcystis aeruginosa, a typical algal bloom-forming cyanobacterium, can be effectively inactivated by ultrasound (US) irradiation in the presence of titanium dioxide (TiO2) particles as a sonocatalyst. When a culture broth of M. aeruginosa was ultrasonically irradiated for 15 min in the presence of 0.5 g/mL of TiO2 particles 2 mm in diameter, the cell survival ratio was 0.13, which was significantly lower than that in the case of US irradiation alone (0.87). Moreover, regrowth of M. aeruginosa in the culture was also inhibited for 10 days following ultrasonic disinfection in the presence of TiO2 particles for 15 min. (c) 2013, The Society for Biotechnology, Japan. All rights reserved.

Long-range transport of airborne microorganisms through the free troposphere significantly impacts biological ecosystems, human life, and atmospheric processes in downwind areas. However, microbial communities in the free troposphere have rarely been investigated because the direct collection of microbial cells at high altitudes requires sophisticated sampling techniques. In this study, tropospheric air sampling was performed using a balloon and an aircraft at 800 m and 3000 m, respectively, over the Noto Peninsula in Japan (37.5 degrees N, 137.4 degrees E) where free tropospheric winds carry aerosols from continental areas. The air samples were collected during four different sampling periods when air masses came from desert regions of Asian continent (west samples) and from Siberia of Russia North Asia (north samples). The west samples contained higher levels of aerosols, and bacteria from the west samples grew in culture media containing up to 15% NaCl. In contrast, bacteria from the north samples could not be cultured in the same media. All isolates obtained from the NaCl-amended cultures were similar to Bacillus subtilis and classified as Firmicutes. A 16S rDNA clone library prepared from the west samples was mainly composed of one phylotype of Firmicutes that corresponded to the cultured B. subtilis sequence. A clone library prepared from the north samples consisted primarily of two phyla, i.e., Actinobacteria and Proteobacteria, which are known to dominantly inhabit low-temperature environments of North Asia. Our results suggest that airborne bacterial communities at high altitudes include several species that vary by the direction and interaction of free tropospheric winds. (C) 2013 Elsevier Ltd. All rights reserved.

Being predominant inorganic arsenicals, methylarsenicals also occur in anaerobic paddy soils. Therefore, this study investigated the influence of Fe2+ concentrations and arsenic speciation [arsenate (As(V)) and dimethylarsinate (DMA)] in paddy soils on arsenic uptake in rice plant. Rice seedlings were grown in soil irrigated with a Murashige and Skoog (MS) growth solution containing As(V) or DMA with or without 1.8 mM Fe2+ in excess to the background concentration of total iron (0.03 mM) in the soil. Arsenic concentration in rice roots increased initially and then decreased gradually when the seedlings were grown with excess Fe2+ and As(V). In contrast, arsenic concentration in the roots increased steadily (P<0.01) when the seedlings were grown without excess Fe2+ and As(V). When the form of the arsenic was DMA, total arsenic (tAs) concentration in rice roots increased gradually (P<0.01) and was not affected by the addition of excess Fe2+ in the soil. When rice seedlings were grown with As(V), tAs concentration in rice roots and shoots increased steadily (P<0.01) for gradual increase of Fe2+ concentrations in soil. However, tAs concentration in roots and shoots was independent of Fe2+ concentrations in soil when the form of arsenic was DMA. The tAs concentrations in rice shoots also increased significantly (P<0.01) with increasing exposure time for both As(V) and DMA. Thus, Fe2+ concentrations in soil affect arsenic uptake in rice plant depending on the speciation of arsenic.

Sand filters devised with iron-rich adsorbents are extensively promoted and deployed in the arsenic-prone south and south-east Asian countries (e.g., Bangladesh). The approach offers superior performance in removing arsenic while the spent sludge from the sand filters is an issue of concern due to the possibility of toxic releases after being discarded. In this work, a new technique is proposed for the treatment of spent iron-oxide coated sand (IOCS) from filters used in arsenic removal. Chelant-washing of the arsenic-loaded IOCS is combined with the solid phase extraction treatment to accomplish the objective. The unique point of the proposed process is the cost-effective scheme, which includes the option of recycling of the washing solvent beside the decontamination of the spent arsenic-rich sludge. (C) 2013 Elsevier Ltd. All rights reserved.

Indium is a rare metal that is mostly consumed as indium tin oxide (ITO) in the fabrication process of liquid crystal display (LCD) panels. The spent LCD panels, termed as LCD-waste hereafter, is an increasing contributor of electronic waste burden worldwide and can be an impending secondary source of indium. The present work reports a new technique for the reclamation of indium from the unground LCD-waste using aminopolycarboxylate chelants (APCs) as the solvent in a hyperbaric environment and at a high-temperature. Microwave irradiation was used to create the desired system conditions, and a substantial abstraction of indium (>= 80%) from the LCD-waste with the APCs (EDTA or NTA) was attained in the acidic pH region (up to pH 5) at the temperature of >= 120 degrees C and the pressure of similar to 50 bar. The unique point of the reported process is the almost quantitative recovery of indium from the LCD-waste that ensured via the combination of the reaction facilitatory effect of microwave exposure and the metal extraction capability of APCs. A method for the selective isolation of indium from the extractant solution and recycle of the chelant in solution is also described. (C) 2013 Elsevier B.V. All rights reserved.

Selective separation of cadmium(II) on a macrocycle immobilized solid phase extraction (SPE) system namely AnaLig Cd-01, and commonly known as molecular recognition technology (MRT) gel, have been examined. The MRT-SPE able to retain the cadmium from the metal-affluent aqueous matrix at the pH range of 2 to 8, and the captured species can be recovered via elution with 1 and 6 M HNO3. Besides the effects of solution pH and eluent concentration, the impacts of sample loading flow rates and coexisting matrix ions were also investigated and optimized. The Cd(II) retention capacity of the MRT-SPE was 0.26 mmol g-1, and it can be reused for more than 100 loading and elution cycles. The Cd(II) recovery attained from the metal-spiked natural waters was satisfactory (95.3-98.1%). However, the Cd(II) retention ability of the MRT-SPE was significantly decreased when excess of chelant remain in the aqueous waste matrix.

The petrographic method has been a popular technique for estimating the ages and growth rates of corals based on growth ring density in their axial skeleton. The organic matrix staining (OMS) method, a modified method of petrographic method, has also been used for measuring age and growth rate of the Mediterranean red coral (Corallium rubrum) by staining the organic matrix (OM) in the calcite skeleton. Since the OMS method is based on the concentration of OM in the coral skeleton, this method may not be suitable for coral species with low OM content. In the presnt study, growth characteristics and growth rates of three Japanese precious corals (JPCs; Paracorallium japonicum, Corallium elatius and Corallium konojoi) were determined based on the principles of the petrographic method using a high resolution VHX-1000 digital microscope, termed as VIX-1000 hereafter, without staining the OM in the axial skeleton. Compared to the OM-stained cross-sections (slabs), growth rings in un-stained slabs of the Japanese red coral (P. japonicum) were more clearly visible with the VHX-1000. This may be due to low concentration of OM in the coral skeleton. Growth rate of JPCs differ significantly depending on coral species, habitat, and environmental conditions. Diametric and linear growth rates of the Japanese red coral (P. japonicum) were slower (0.20 +/- 0.08-027 +/- 0.01 and 2.22 +/- 0.82-6.66 +/- 5.52 mm yr(-1), respectively) than the Japanese pink (C elatius; 0.30 +/- 0.04 and 2.76 +/- 2.09 mm yr(-1), respectively) and white (C konojoi; 0.44 +/- 0.04 and 7.60 +/- 0.75 mm yr(-1), respectively) corals. In addition, the diametric growth rate of the Japanese red coral (P. japonicum) is slower (0.24 +/- 0.05-0.44 +/- 0.04 mm yr(-1)) than the Mediterranean red coral (C rubrum; 0.20-0.62 +/- 0.19 mm yr(-1)). (C) 2013 Elsevier B.V. All rights reserved.

Development of aminopolycarboxylate chelants (APCs) having enhanced biodegradability is gaining increasing focus to replace the EDTA and its homologs with those used widely for the ex situ treatment of contaminated soils and are potential eco-threats. The paper reports the chelant-assisted extraction of the toxic metals (Cd, Cu, Pb, and Zn) from the metal-spiked European reference soils (Eurosoil 1 and Eurosoil 4) using biodegradable APCs, namely EDDS, GLDA, and HIDS. The effects of chelant-to-metal molar ratio, solution pH, and metal/chelant stability constants were evaluated, and compared with that of EDTA. The selectivity aptitude of the biodegradable chelants towards the toxic metals was assumed from the speciation calculations, and a proportionate correlation was observed at neutral pH. Pre- and post-extractive solid phase distributions of the target metals were defined using the sequential extraction procedure and dissolution of metals from the theoretically immobilized fraction was witnessed. The effect of competing species (Al, Ca, Fe, Mg, and Mn) concentrations was proven to be minimized with an excess of chelant in solution. The highlight of the outcomes is the superior decontamination ability of GLDA, a biodegradable APC, at minimum chelant concentration in solution and applicability at a wide range of pH environments.

A simple flow-based method was developed for the selective separation of arsenic species (+3 and +5) using a macrocycle-immobilized solid phase extraction (SPE) system, commonly known as molecular recognition technology (MRT) gel. Arsenic species in solution or in the eluent were subsequently quantified with graphite furnace atomic absorption spectrometry. The separation behaviors of As(III) and As(V) on MRT-SPE were investigated. It was found that As(V) can be selectively collected on the SPE system within the range of pH 4 to 9, while As(III) was passed through the MRT-SPE. The retention capacity of the MRT-SPE material for As(V) was found to be 0.25 ± 0.04 mmol g -1. The detection limit of the method for As(V) was 0.06 μg L -1, and the relative standard deviation was 2.9 % (n = 10, C = 1 μmol L-1). Interference from the matrix ions was studied. In order to validate the developed method, certified reference materials of effluent wastewater and groundwater samples were analyzed, and the determined values were in good agreement with the certified values. The proposed method was successfully applied to the speciation analysis of tri- and pentavalent arsenic in natural water samples showing satisfactory recoveries (≥ 98.7 %). © 2013 Springer Science+Business Media Dordrecht.

Microbial communities transported by Asian desert dust (KOSA) events have attracted much attention as bioaerosols, because the transported microorganisms are thought to influence biological ecosystems, and human life as well as atmospheric processes in downwind areas. However, the microbial dynamics in Japan during a KOSA dust event are unclear. In this study, sequential air sampling was performed on the top of a building (10 m altitude) within the KOSA arrival area (Kanazawa City, Japan: 36.6°N, 136.7°E) from May 1 to May 7, 2013, when a dust event occurred. A 16S rDNA clone library prepared from air samples mainly belonged to three phyla, such as Firmicutes, Cyanobacteria, and Alpha-proteobacteria. Some clones of Firmicutes appeared specifically during the midst of a dust event, and consisted primarily of Bacillus subtilis and B. pumilus, which are known to dominantly inhabit atmospheric area in the KOSA source area (Chinese desert). The clones belonging to Cyanobacteria and Alphaproteobacteria were mainly detected at the initial and last periods of dust events they are relatives to marine bacterial species. Our results suggest that airborne bacterial communities on the surface of ground during a dust event are composed of terrestrial and pelagic bacterial populations, and that the dust event influences the dynamics of airborne bacterial communities on the ground surface of a downwind area. © 2013 The Japan Society for Analytical Chemistry.

The metal indium termed as 'rare' in recent days due to its increasing demand in the formulations of electronic and energy-related gadgets and scarce supply resources. Hence, the attempts to recover indium from the secondary resources, such as recycling of the indium abundant waste materials, received increasing research focus. The major indium consumption happens in the form of indium tin oxide (ITO) that used for the fabrication of liquid-crystal displays (LCD). The end-of-life LCD screens, termed as ITO-glass hereafter, are an emerging contributor to the global e-waste load and can be an impending secondary source of indium. The present work introduces a new technique for the treatment of waste ITO-glass using aminopolycarboxylate chelants (APCs) in combination with a mechanochemical treatment process. APCs are capable of forming stable complexes with the indium deposited on the ITO-glass, whereas the rate of recovery was not substantial. The mechanochemical treatment induces the destruction of crystalline structure with which the ITO fragments are attached and facilitate the increased indium dissolution with the chelants. The increase was more prominent followed by a decrease in the cumulative processing time from 24 to 6 h when the vitrified ITO-glass was simultaneously crushed and washed with the chelants. The extraction of indium was better at the acidic pH condition, and it was further intensified when the operating temperature was raised to >= 120 degrees C. (C) 2012 Elsevier B.V. All rights reserved.

Epifluorescent microscopy, coupled with fluorescence staining techniques, is useful for observations and quantitative estimation of airborne microbial communities (bioaerosols). Irradiation of short-wavelength excitation light onto a specimen results in luminescence of longer-wavelength fluorescence from materials in the specimen. Various fluorescent chemicals are used as stains bound to specific biomaterials. DAPI staining enables detection of all microbial cells in aerosol samples. Live/Dead staining method can estimate concentrations of both living and dead cells among microbial assemblages. Fluorescence in situ hybridization (FISH method) can be used as nucleotide probes for specific microbial species among bioaerosols. Epifluorescent microscopic observations provide information essential for elucidation of ecological characteristics of bioaerosols in atmospheric environments.

The protonation and complex formation equilibria of two biodegradable aminopolycarboxylate chelants {dl-2-(2-carboxymethyl)nitrilotriacetic acid (GLDA) and 3-hydroxy-2,2'-iminodisuccinic acid (HIDS)} with Ni2+, Cu2+, Zn2+, Cd2+ and Pb2+ ions were investigated using the potentiometric method at a constant ionic strength of I = 0.10 mol center dot dm(-3) (KCl) in aqueous solutions at 25 +/- A 0.1 A degrees C. The stability constants of the proton-chelant and metal-chelant species for each metal ion were determined, and the concentration distributions of various complex species in solution were evaluated for each ion. The stability constants (log(10) K (ML)) of the complexes containing Ni2+, Cu2+, Zn2+, Cd2+ and Pb2+ ions followed the identical order of log(10) K (CuL) > log(10) K (NiL) > log(10) K (PbL) > log(10) K (ZnL) > log(10) K (CdL) for either GLDA (13.03 > 12.74 > 11.60 > 11.52 > 10.31) or HIDS (12.63 > 11.30 > 10.21 > 9.76 > 7.58). In each case, the constants obtained for metal-GLDA complexes were larger than the corresponding constants for metal-HIDS complexes. The conditional stability constants (log(10) ) of the metal-chelant complexes containing GLDA and HIDS were calculated in terms of pH, and compared with the stability constants for EDTA and other biodegradable chelants.

The complex formation equilibria of Cr3+ and Fe3+ ions in aqueous solution with two biodegradable amino-polycarboxylate chelants (DL-2-(2-carboxymethyl)nitrilotriacetic acid (GLDA) and 3-hydroxy-2,2'-iminodisuccinic acid (HIDS)) were investigated. The potentiometric data obtained at the constant ionic strengths (I) of (0.1 and 1.0) mol.dm(-3) KCl and at (25 +/- 0.1) degrees C was processed with the aid of the computer program HYPERQUAD 2008. The formation constants of the proton-chelant and metal-chelant (log K-ML) species (M = Fe3+ or Cr3+; L = GLDA or HIDS) were determined, and the concentration distributions of complex species in solution were evaluated for both metal ions. In various pH conditions, the interaction between the chelants (L = GLDA or HIDS) and the metal ions (M = Fe3+ or Cr3+) leads to the formation of different complexes formulated as MH2L+, MHL, ML-, M(OH)L2-, and M(OH)(2)L3-. The log K-ML values at I = 0.1 mol.dm(-3) KCl (T = (25 +/- 0.1) degrees C) were 15.27 (log KFe-GLDA), 14.96 (log KFe-HIDS), 13.77 (log KCr-GLDA), 12.67 (log KCr-HIDS), and at I = 1.0 mol.dm(-3) KCl (T = (25 +/- 0.1) degrees C) were 14.79 (log KFe-GLDA), 14,34 (log KFe-HIDS)) 12.90 (log KCr-GLDA), 12.09 (log KCr-HIDS). The e conditional stability constants (log K'(ML)) of the ML complexes were calculated in terms of pH in the range of 2 to 12 and compared with the same for EDTA and other biodegradable chelants (NTA and EDDS).

Present study investigated the significance of the concentration of chelating ligand on Fe3+-solubility in growth medium and its influence on Fe bioavailability and uptake in rice plant. Rice seedlings were grown in modified Murashige and Skoog (MS) hydroponic growth medium with moderate (250 mu M) and high (500 mu M) concentrations of ethylenediaminetetraacetate (EDTA) and hydroxyiminodisuccinate (HIDS) under sterile and non-sterile conditions. Concentrations of soluble Fe in the growth medium increased with increasing ligand concentrations, and the growth of rice seedlings was higher at moderate ligand concentration than at control (without chelant) and high ligand concentration. This explains the relationship between Fe solubility and bioavailability in the growth medium, and its effect on Fe uptake in rice plant. Fe exists in the growth medium predominantly as particulate (insoluble) forms at low ligand concentration, and as soluble [Fe(OH)(2+), Fe(OH)(2)(+), Fe-L complex] and apparently soluble (colloidal) forms at moderate ligand concentration. At high ligand concentration, most of the Fe3+ in the growth medium forms soluble Fe L complex, however, the bioavailability of Fe from Fe L complex decreased due to lopsided complex formation equilibrium reaction (CFER) between Fe and the ligands. Also, Fe is solubilized forming stable and soluble Fe-L complex, which is then detached as less stable, but soluble and bioavailable substance(s) after (time-dependent) biodegradation. Therefore- i) ligand concentration and stability constant of Fe-L complex (KFe-L) influence Fe bioavailability and uptake in rice plant, and ii) the biodegradable ligands (e.g., HIDS) would be more effective Fe fertilizer than the environmentally persistent and less biodegradable ligands (e.g., EDTA). (C) 2012 Elsevier Masson SAS. All rights reserved.

Ex situ soil washing with synthetic extractants such as, aminopolycarboxylate chelants (APCs) is a viable treatment alternative for metal-contaminated site remediation. EDTA and its homologs are widely used among the APCs in the ex situ soil washing processes. These APCs are merely biodegradable and highly persistent in the aquatic environments leading to the post-use toxic effects. Therefore, an increasing interest is focused on the development and use of the eco-friendly APCs having better biodegradability and less environmental toxicity. The paper deals with the results from the lab-scale washing treatments of a real sample of metal-contaminated soil for the removal of the ecotoxic metal ions (Cd, Cu, Ni, Pb, and Zn) using five biodegradable APCs, namely [S,S]-ethylenediaminedisuccinic acid, imminodisuccinic acid, methylglycinediacetic acid. DL-2-(2-carboxymethyl) nitrilotriacetic acid (GLDA), and 3-hydroxy-2,2'-iminodisuccinic acid. The performance of those biodegradable APCs was evaluated for their interaction with the soil mineral constituents in terms of the solution pH and metal-chelant stability constants, and compared with that of EDTA. Speciation calculations were performed to identify the optimal conditions for the washing process in terms of the metal-chelant interactions as well as to understand the selectivity in the separation ability of the biodegradable chelants towards the metal ions. A linear relationship between the metal extraction capacity of the individual chelants towards each of the metal ions from the soil matrix and metal-chelant conditional stability constants for a solution pH greater than 6 was observed. Additional considerations were derived from the behavior of the major potentially interfering cations (Al, Ca, Fe, Mg, and Mn), and it was hypothesized that use of an excess of chelant may minimize the possible competition effects during the single-step washing treatments. Sequential extraction procedure was used to determine the metal distribution in the soil before and after the extractive decontamination using biodegradable APCs, and the capability of the APCs in removing the metal ions even from the theoretically immobilized fraction of the contaminated soil was observed. GLDA appeared to possess the greatest potential to decontaminate the soil through ex situ washing treatment compared to the other biodegradable chelants used in the study. (C) 2012 Elsevier Ltd. All rights reserved.

For the bioremediation of pollutants in seawater, the degradation of phenol using novel marine bacteria isolated from the intestinal contents of marine creatures was investigated. Twenty samples of marine creatures were collected, and bacteria in their intestinal contents were incubated in an artificial seawater agar medium containing phenol. Two colonies (EBR01 and EBR02) were observed from Dendrodoris fumata, and one colony (EBR04) was observed from Suggrundus meerdervoortii. Analysis of the bacterial properties, gene sequencing, similarities, and phylogenetic characteristics showed that strains EBR01 and EBR02 were Acinetobacter species and strain EBR04 was Cobetia marina. Acinetobacter spp. EBR01, EBR02, and C. marina EBR04 degraded almost 100 mg l(-1) phenol in seawater. The maximum phenol degradation rate using Acinetobacter sp. EBR01 was the highest value, and it was 2.7-fold higher than that using activated sludge. (C) 2011 Elsevier Ltd. All rights reserved.

Precious corals have been commercially exploited for many centuries around the world. The skeletons of these corals consist of calcium carbonate, and have been used as amulets or gemstones since ancient times. Different Corallium species of Coralidae family (e.g.. Corallium rubrum, Corallium elatus, Corallium konojoi, and Paracorellium japonicum) were collected from different locations of the Mediterranean Sea (off Italy) and Pacific Ocean (off Japan and off Midway Island), and trace elements in their skeletons were analyzed. Results show that trace element concentrations in the skeletons of Corallium spp. were attributable to their habitat and origin. In particular, Mg/Ca and Ba/Ca ratios in the skeletons of Corallium spp. from the Mediterranean Sea and Japanese and the Midway Islands' waters were found to be habitat-specific. This study also reveals that trace elements in the skeletons can be used as ecological indicator of the coral's origin, and are expected to play an important part in the cultural study and sustainable management of precious corals. Findings of this study will also be of great relevance to the coral industry to authenticate and identify the habitat and origin of the corals. (C) 2012 Elsevier B.V. All rights reserved.

The original version of the article was published in Cent. Eur. J. Chem. 9(6) (2011), pp 1019-1026. Unfortunately, the original version of this article contains mistakes in the body of Fig. 1. Here we display the corrected version of the Fig. 1.

A simple flow-based method was developed for the simultaneous separation of certain transition metal ions (Co, Ni, Cu, Zn, Cd) from aqueous systems, which ions show ecotoxic effects when present at elevated concentrations. A silica-gel-bonded macrocycle system, commonly known as molecular recognition technology (MRT) gel, was used for solid phase extraction (SPE) of the target analytes. The collection behavior of the MRT-SPE system was studied based on pH. Fortified deionized water samples containing 250 mu g L(-1) of each of the elements were treated at the flow rate of 1 mL min(-1). The collected analytes were then eluted by 3 M HNO(3) and analyzed using inductively coupled plasma spectrometry. Detection limits of the proposed technique were in the range of 0.004-0.040 mu g L(-1) for the studied metal ions. The validity of this separation technique was checked with spiked 'real' water samples, which produced satisfactory recoveries of 96-102%. The non-destructive nature and highly selective ion-extraction capability of the SPE material are the most important aspects of the proposed method and they are the main focus of this paper.

Microbial particles transported by Asian desert dust (KOSA) possibly impact ecosystems and human health in downwind environments and are commonly called "bioaerosols." The microbial communities associated with KOSA mineral particles (KOSA bioaerosol), which were collected from the snow cover on Mt. Tateyama, were investigated by means of a culture-amendment technique combined with denaturing gradient gel electrophoresis (DGGE) analysis using 16S rRNA genes. After the stratigraphy of the snow layer formed on the walls of a snow pit on Mt. Tateyama, samples were collected from 2 layers, which included KOSA particles and one which did not. The snow samples with KOSA particles indicated microbial growth in the 10 0 and 10(-1) dilution media and in the medium with NaCl below 10%, while the snow sample without KOSA particles showed no microbial growth in the culture media. The PCR-DGGE analysis revealed that the bacterial compositions in the snow samples including KOSA mineral particles were mainly composed of the members of the phyla Actinobacteria, Firmicutus, and Proteobacteria. In particular, the 2 phylotypes appeared in the microbial cultures were similar to the members of the B. subtilis group, which has been detected in bioaerosol samples collected from the atmosphere over KOSA arrival (Suzu City) and source (Dunhuang City) regions. Presumably, halo-tolerant and oligotrophic bacterial communities are associated with the KOSA particles that descend to the snow cover on Mt. Tateyama.

Asian dust which possibly carries microbial particles (KOSA bioaerosol) may impact ecosystems and human health in downwind environments. To confirm the atmospheric transport of microorganisms with KOSA, the KOSA bioaerosol preserved in seasonal snow cover on Mt. Tateyama in Toyama prefecture, Japan, was investigated by means of a culture-amendment technique targeting the halotolerant and oligotrophic bacteria which are known to be tolerant to atmospheric environmental stressors. The snow samples collected from the layers with and without KOSA particles in a 6.60 m deep-snow pit. The samples with KOSA particles indicated microbial growth in the culture media without dilution and with 10^-1 dilution and with NaCl up to 10%, while the sample without KOSA particles showed no microbial growth. The phylogenetic analysis using 16S rRNA genes revealed that the members of the genus Bacillus were one of the major groups in the microbial structures. In particular, some species were identified as members of the B. subtilis group, which have been detected from the KOSA mineral particles collected from the atmosphere over KOSA arrival region (Suzu City). Presumably, the halotolerant and oligotrophic bacteria detected in this study were associated with the KOSA particles that descended to the snow cover on Mt. Tateyama.

Aminopolycarboxylate chelants (APCs) are extremely useful for a variety of industrial applications, including the treatment of toxic metal-contaminated solid waste materials. Because non-toxic matrix elements compete with toxic metals for the binding sites of APCs, an excess of chelant is commonly added to ensure the adequate sequestration of toxic metal contaminants during waste treatment operations. The major environmental impacts of APCs are related to their ability to solubilize toxic heavy metals. If APCs are not sufficiently eliminated from the effluent, the aqueous transport of metals can occur through the introduction of APCs into the natural environment, increasing the magnitude of associated toxicity. Although several techniques that focus primarily on the degradation of APCs at the pre-release step have been proposed, methods that recycle not only the processed water, but also provide the option to recover and reuse the metals, might be economically feasible, considering the high costs involved due to the chelants used in metal ion sequestration. In this paper, we propose a separation process for the recovery of metals from effluents that contain an excess of APCs. Additionally, the option of recycling the processed water using a solid phase extraction (SPE) system with an ion-selective immobilized macrocyclic material, commonly known as a molecular recognition technology (MRT) gel, is presented. Simulated effluents containing As(V), Cd(II), Cr(III), Pb(II) or Se(IV) in the presence of APCs at molar ratios of 1:50 in H(2)O were studied with a flow rate of 0.2 mL min(-1). The 'captured' ions in the SPE system were quantitatively eluted with HNO(3). The effects of solution pH, metal-chelant stability constants and matrix elements were assessed. Better separation performance for the metals was achieved with the MRT-SPE compared to other SPE materials. Our proposed technique offers the advantage of a non-destructive separation of both metal ions and chelants compared to conventional treatment options for such effluents. (C) 2011 Elsevier Ltd. All rights reserved.

Arsenate (As(V)) transport into plant cells has been well studied. A study on rice (Oryza sativa L) showed that arsenite is transported across the plasma membrane via glycerol transporting channels. Previous studies reported that the dimethylarsinic acid (DMAA) and monomethylarsonic acid (MMAA) uptake in duckweed (Spirodela polyrhiza L) differed from that of As(V), and was unaffected by phosphate (H(2)PO(4)). This article reports the transport mechanisms of DMAA and MMAA in rice roots. Linear regression analysis showed that the DMAA and MMAA uptake in rice roots increased significantly (p <= 0.0002 and <= 0.0001 for DMAA and MMAA, respectively) with the increase of exposure time. Concentration-dependent influx of DMAA and MMAA showed that the uptake data were well described by Michaelis-Menten kinetics. The MMAA influx was higher than that of DMAA. The DMAA and MMAA uptake in rice roots were decreased significantly (p <= 0.0001 and <= 0.0077 for DMAA and MMAA, respectively) with the increase of glycerol concentration indicating that DMAA and MMAA were transported into rice roots using the same mechanisms of glycerol. Glycerol is transported into plant cells by aquaporins, and DMAA and MMAA are transported in a dose-dependent manner of glycerol which reveals that DMAA and MMAA are transported into rice roots through glycerol transporting channels. The DMAA and MMAA concentration in the solution did not affect the inhibition of their uptake rate by glycerol. (C) 2010 Elsevier B.V. All rights reserved.

Aquatic arsenic cycles mainly depend on microbial activities that change the arsenic chemical forms and influence human health and organism activities. The microbial aggregates degrading organic matter are significantly related to the turnover between inorganic arsenic and organoarsenic compounds. We investigated the effects of microbial aggregates on organoarsenic mineralization in Lake Kahokugata using lake water samples spiked with dimethylarsinic acid (DMA). The lake water samples converted 1 mu mol L(-1) of DMA to inorganic arsenic for 28 d only under anaerobic and dark conditions in the presence of microbial activities. During the DMA mineralization process, organic aggregates > 5.0 mu m with bacterial colonization increased the densities. When the organic aggregates > 5.0 mu m were eliminated from the lake water samples using filters, the degradation activities were reduced. DMA in the lake water would be mineralized by the microbial aggregates under anaerobic and dark conditions. Moreover, DMA amendment enhanced the degradation activities in the lake water samples, which mineralized 50 mu mol L(-1) of DMA. The DMA-amended aggregates > 5.0 mu m completely degraded 1 mu mol L(-1) of DMA with a shorter incubation time of 7 d. The supplement of KNO(3) and NaHCO(3) to lake water samples also shortened the DMA-degradation period. Presumably, the bacterial aggregates involved in the chemical heterotrophic process would contribute to the DMA-biodegradation process in Lake Kahokugata, which is induced by the DMA amendment. (c) 2011 Elsevier Ltd. All rights reserved.

A new technique for the separation and pre-concentration of dissolved Fe(III) from the ligand-rich aqueous system is proposed. A solid phase extraction (SPE) system with an immobilized macrocyclic material, commonly known as molecular recognition technology (MRT) gel and available commercially, was used. Synthetic Fe(III) solution in aqueous matrices spiked with a 100-fold concentration of EDTA was used. Dissolved iron that was 'captured' by the MRT gel was eluted using hydrochloric acid and subsequently determined by graphite furnace atomic absorption spectrometry. The effect of different variables, such as pH, reagent concentration, flow rate and interfering ions, on the recovery of analyte was investigated. Quantitative maximum separation (similar to 100%) of the dissolved Fe(III) from synthetic aqueous solutions at a natural pH range was observed at a flow rate of 0.2 mL min(-1). The extraction efficiency of the MRT gel is largely unaltered by the coexisting ions commonly found in natural water. When compared with different SPE materials, the separation performance of MRT gel is also much higher. (C) 2010 Elsevier Ltd. All rights reserved.

A combination of solid phase extraction (SPE) columns was used for selective separation of water-soluble arsenic species: arsenite, arsenate, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). The SPE columns, namely AnaLig TE-01 (TE-01), AnaLig AN-01 Si (AN-01) and AnaLig As-01 PA (As-01), contain immobilized macrocyclic material as the sorbent and commonly known as molecular recognition technology (MRT) gel. The retention, extraction and recovery behavior of the MRT gel SPE columns were studied at pH 4-10. Fortified deionized water spiked with 100 mu M of arsenic species were treated at the flow rate of 0.2 mL min(-1). HNO(3) (1.0 and 6.0 M) was used as eluent to recover the retained arsenic species from TE-01 and AN-01 SPE columns. Arsenic species retained in the As-01 column were eluted with HNO(3) (0.1 M) followed by NaOH (2.0 M). Likely interference from the various coexisting ions (Na(+), K(+), Ca(2+), Mg(2+), Cl(-), NO(3)(-), CH(3)COO(-), PO(4)(3-), SO(4)(2-), ClO(4)(-)) (10 mm) were negligible. Quantitative separation of As(III), As(V), MMA and DMA was achieved based on the differences in extraction and recovery behavior of the MRT gel SPE columns with pH for different arsenic species. Complexation between arsenic species and MRT gel is the core phenomenon of the proposed technique as the complexation of MRT gels is expected to be stronger than the resin-based separation processes. MRT gel SPE columns are advantageous as compared with other reported SPE columns in terms of its performance with As(III). Effortless regeneration and unaltered separation performance of the sorbent materials for more than 100 loading and elution cycles are other sturdy characteristics to consider the MRT gel SPE columns for sensitive and selective arsenic species separation. (C) 2010 Elsevier Ltd. All rights reserved.

Atmospheric aerosol deposition caused by Asian dust (KOSA) events provide nutrients, trace metals, and organic compounds over the Pacific Ocean that enhance ocean productivity and carbon sequestration and, thus, influence the atmospheric carbon dioxide concentrations and climate. Using dust particles obtained from the snow layers on Mt. Tateyama and the surface sand of Loess Plateau in incubation experiments with natural seawater samples on a shipboard, we demonstrate that dust-particle additions enhanced the bacterial growth on the first day of incubation. Gram-positive bacterial group and alpha-proteobacteria were specifically detected form seawater samples including the mineral particles. Although the remarkable dynamics of trace elements and nutrients depend on dust-particle additions, it is possible that organic compounds present in the mineral particles or transported microbial cells could also contribute to an increase in the quantities of bacteria. The chlorophyll concentrations at fractions of every size indicated a similar pattern of change between the seawater samples with and without the dust-particle additions. In contrast, the chlorophyll measurement using submersible fluorometer revealed that the dynamics of phytoplankton composition were influenced by the dust-particles treatments. We conclude that the phytoplankton that uses the bacterial products would increase their biomass. We show that KOSA deposition can potentially alter the structures of bacterial communities and indirectly influence the patterns of marine primary production in the Pacific Ocean.

This work focuses on the analysis of bioaerosols in the atmosphere at higher altitudes over Noto Peninsula, Japan. We carried out direct sampling via aircraft, separated cultures, and identified present isolates. Atmospheric bioaerosols at higher altitudes were collected using a Cessna 404 aircraft for an hour at an altitude of 3,500 m over the Noto Peninsula. The aircraft-based direct sampling system was devised to improve upon the system of balloon-based sampling. In order to examine pre-existing microorganism contamination on the surface of the aircraft body, bioaerosol sampling was carried out just before takeoff using the same method as atmospheric sampling. Identification was carried out by a homology search for 16S or 18S rDNA isolate sequences in DNA databases (GenBank). Isolate sampling just before takeoff revealed Stretpomyces sp., Micrococcus sp., and Cladosporium sp. One additional strain, Bacillus sp., was isolated from the sample after bioaerosol collection at high altitude. As the microorganism contamination on the aircraft body before takeoff differed from that while in the air, the presence of additional, higher atmosphere-based microorganisms was confirmed. It was found that Bacillus sp. was floating at an altitude of 3,500 m over Noto Peninsula.

The microbial communities transported by Asian desert dust (KOSA) events have attracted much attention as bioaerosols because the transported microorganisms are thought to influence the downwind ecosystems in Korea and Japan. However, the atmospheric microbial community has not been investigated at high altitude in the KOSA arrival area. In this study, to estimate the viability and diversity of atmospheric halotolerant bacteria, which are expected to resist to various environmental stresses as well as high salinities, bioaerosol samples were collected at 10 and 600 m above the ground within the KOSA arrival area, Suzu City, Japan, during KOSA events. During the sampling period, the particle numbers at 600 m were higher than those at 10 m, suggesting that large particles of aerosol fall from the high altitude of 600 m to the ground surface. The microorganisms in bioaerosol samples grew in media containing up to 15% NaCl concentrations demonstrating the viability of the halotolerant bacteria in bioaerosol samples. The PCR-DGGE analysis using 16S rDNA revealed that the bacterial species in NaCl-amended cultures were similar to the bacteria detected from the genomic DNA directly extracted from the bioaerosol samples. The 16S rDNA sequences of bacterial communities in bioaerosol samples were classified into 4 phylotypes belonging to the Bacillus cereus or Bacillus subtilis group. The bioaerosol samples collected at 600 m included 2 phylotypes belonging to B. subtilis. and one phylotype among all 4 phylotypes was identical between the samples at 10 and 600 m. In the atmosphere at 600 m, the halotolerant bacterial community was expected to remain viable, and the species composition was expected to include a few species of the genus Bacillus. During this investigation period, these atmospheric bacteria may have been vertically transported to the ground surface, where the long-range KOSA particle transport from China is frequently observed. (C) 2010 Elsevier B.V. All rights reserved.

Precious coral is one of the natural resources of which Japan is a major supplier. Since the concentrations of trace elements in the skeletons are less than 1 ppm, it is difficult to determine the behavior of trace elements other than Ca, Mg and Sr using conventional instruments for mapping analysis at a laboratory scale. In this study, the distributions of trace elements in the skeletons of precious corals were analysed with XRF mapping employing synchrotron radiation at a large circular accelerator in SPring-8. Using 37.6 keV X-rays with a beam size of 50 mu m (horizontally) x 50 mu m (vertically), Ba, I, Mo, Sn, Mn, Zn, Cd and Br, as well as the major element of Ca and Sr, were detected in the skeletons. Two-dimensional maps of the trace element distribution showed that those of Ba, I and Mo concentrations form fine granular structure in the skeletons of precious corals, while Ca and Sr are almost homogeneously distributed. As compared with the element composition in the skeletons of Corallium rubrum from the Mediterranean Sea, Corallium japonicum from Japanese waters, and deep sea corals from Ogasawara and Midway Islands, relatively high contents of Cd and Ba were detected in the deep corals, which suggested that Cd and Ba are incorporated in proportion to the concentrations in the surrounding seawater. These elements are expected to be good marker elements for identifying species and harvest areas.

The microbial particles transported by Asian desert dust (KOSA) possibly impact ecosystems and human health in the downwind environments, and are commonly termed "bioaerosols" including viruses, bacteria, fungi, and pollen. The snow cover at Mount Tateyama records the information of aerosol particles during the winter and early spring, and includes microorganisms with sand particles carried from the China. The microorganisms in snow samples including sand particles grew in media containing up to 10 % NaCl, while the control-snow sample showed no microbial growth, suggesting that bacteria tolerant to high salinities remain viable with sand particles. Denaturing gradient gel electrophoresis using 16S rDNA sequences revealed that the microbial compositions in the snow samples varied among the snow layers and that dominant bacterial species belonged to the members of the genus Bacillus and Propionibacterium. Minor species were composed of the members of Cytophaga-Flexibacter group and beta-proteobacterial subdivision, which are minor species in the atmosphere. Presumably, the viable halotolerant bacteria were frequently transported to Mt. Tateyama by the long-range KOSA particle transport from China and the bacterial species compositions may change depending on the dates of KOSA dust events.

In this study, the influence of eutrophication on arsenic speciation in lake waters was investigated. Surface water samples (n = 1-10) were collected from 18 lakes in Japan during July 2007 and February 2008. The lakes were classified into mesotrophic (7 lakes) and eutrophic (11 lakes) based on the total phosphate (T-P) and chlorophyll-a (Chl-a) concentrations in water column. Inorganic, methylated and ultraviolet-labile fractions of arsenic species were determined by combining hydride generation atomic absorption spectrometry with ultraviolet irradiation. Organoarsenicals (mainly methylated and ultraviolet-labile fractions) comprised 30-60% of the total arsenic in most lakes during summer. On the other hand, inorganic arsenic species (As(III + V)) dominates (about 60-85%) during winter. The occurrence of ultraviolet-labile fractions of arsenic was higher in eutrophic lakes than those in mesotrophic lakes in both seasons. The concentration of dimethyl arsenic (DMAA) was high in eutrophic lakes during winter; and in mesotrophic lakes during summer. The results suggest that the conversion of As(III + V) to more complicated organoarsenicals occurred frequently in eutrophic lakes compared to that in mesotrophic lakes, which is thought to be the influence of biological activity in the water column. The distribution of arsenic species were well correlated with phosphate concentrations than those of Chl-a. This might be due to the competitive uptake of As(V) and phosphate by phytoplankton. The organoarsenicals (OrgAs)/As(V) ratio was higher at low phosphate concentration indicating that conversion of As(V) to OrgAs species was more active in phosphate-exhausted lakes with high phytoplankton density. (C) 2009 Elsevier B.V. All rights reserved.

The microbial communities transported by Asian desert dust (KOSA) events have attracted much attention as bioaerosols, because the transported microorganisms are thought to influence the downwind ecosystems in Japan. In particular, halotolerant bacteria which are known to be tolerant to atmospheric environmental stresses were investigated for clarifying the long-range transport of microorganisms by KOSA. Bioaerosol samples were collected at high altitudes within the KOSA source area (Dunhuang City, China) and the KOSA arrival area (Suzu City, Japan). The microorganisms in bioaerosol samples grew in media containing up to 15 % NaCl, suggesting that bacteria tolerant to high salinities would remain viable in the atmosphere. The PCR-DGGE (Denaturing gradient gel electrophoresis) analysis using 16S rRNA genes sequences revealed that the halobacterial communities in bioaerosol samples belonged to the members of the genera Bacillus and Staphylococcus and that some bacterial species belonging to Bacillus subtilis group were similar among the samples of both cities. Moreover, some sequences of B. subtilis group were found to be identical for the species collected at high altitudes and on the ground surfaces. This suggests that active mixing of the boundary layer transports viable halotolerant bacteria up to the free atmosphere at the KOSA source area, while down to the ground surface at the KOSA arrival areas.

In order to study KOSA (Yellow dust) bioaerosols over a deposit region, we carried out direct samplings, separated culture, and identifications of KOSA bioaerosols over Noto peninsula, Suzu City in Ishikawa prefecture. KOSA bioaerosols were collected at a height of 400 m using a tethered balloon and bioaerosol sampler on May 7, 2008. After they were cultivated using a Nutrient agar, blood agar, potato dextrose agar, and Sabourand dextrose agar, 8 strains of isolates were obtained. The results of a homology search by 16S rDNA and 18S rDNA sequences of isolates in DNA databases (GenBank, DDBJ, and EMBL) revealed that the KOSA bioaerosols over KOSA deposit region contain Nocardiopsis sp., Bacillus sp., Streptomyces sp., and Bjercandera sp.

In aquatic environments, the bacterial decomposition of organoarsenic compounds, such as dimethylarsinic acid ((CH₃)₂AsO(OH); DMAA), was important for evaluation of the dynamics of each arsenic species. The process of the arsenic cycle has been investigated by many researchers. In study, the PCR-DGGE analytical method was established for investigating the microbial community in Lake Kahokugata. When the volume range from 50 to 1.5 mL of water samples were tested for the DNA extraction, the PCR products of 16S rDNA fragments were efficiently obtained from the 1.5 mL of water samples. When water samples were digested using enzyme with (shaken-sample) or without shaking (static-sample), the more amounts of 16S rDNA fragments were amplified from the shaken-samples. Moreover, the phenol extraction with CTAB treatment more efficiently induced the PCR amplification than that without CTAB treatment. On the acrylamide gels of DGGE analysis, the PCR products of shaken-sample with or without CTAB treatment and static-sample with or without CTAB treatment indicated similar band patterns, suggesting that the DNA extraction treatments used in this study did not influence the detectable bacterial compositions. After DMAA was added at final concentrations of 1 μmol/l to the sample water, the DMAA was remarkably degraded at the 14th day. On the DGGE gel image, a few of bands were specifically detected in the DMAA addition sample at the 14th day. Presumably, the DMAA addition induce the growth of specific bacteria relating to the aquatic DMAA-degradation.

Although the excellent metal-binding capacities of aminopolycarboxylate chelants (APCs) facilitate their extensive use, pre- and post-toxicity of APCs and their high persistence in aquatic environments evoke concerns. Several treatment techniques with a principal focus on the degradation of APCs at the pre-release step have been proposed. Here, we report a technique for the separation of metal ions from waste solution containing excess APCs using a solid phase extraction system with an ion-selective immobilized macrocyclic material, commonly known as a molecular recognition technology (MRT) gel. Synthetic metal solutions with 100-fold chelant content housed in H(2)O matrices were used as samples. The MRT gel showed a higher recovery rate compared with other SPE materials at 20 degrees C using a flow rate of 0.2 mL min(-1). The effects of solution pH, metal-chelant stability constants and ionic radii were assessed for 32 metals. Compared to the conventional treatment options for such waste solutions, our proposed technique has the advantage of non-destructive separation of both metal ions and chelants. (C) 2010 Elsevier Ltd. All rights reserved.

Bioaerosols are biological aerosols which contain microorganisms such as fungi, spores, bacteria, virus, and pollens. Bioaerosols should be considered an important factor which affects air quality, atmosphere of natural environment, and human health. At present, there are few reports for infectious risk management of bioaerosols (number concentration of microorganisms, organism species etc.), the role of bioaerosols in the ecosystem and the effect of bioaerosols on climate. In fact, it's difficult to investigate the total microorganisms in bioaerosols by culture-based method, because 99 % of bacteria in almost every environment on earth is unable to be detected and analyzed under laboratory conditions. As a method to overcome this bottleneck, a metagenomic analysis method for unculturable microorganisms in bioaerosols was described in this report.

The influence of biodegradable chelating ligands on arsenic and iron uptake by hydroponically grown rice seedlings (Oryza sativa L.) was investigated. Even though the growth solution contained sufficient Fe, the growth of rice seedlings gradually decreased up to 76% with the increase of pH of the solution from 7 to 11. Iron forms insoluble ferric hydroxide complexes at neutral or alkaline pH in oxic condition. Chelating ligands produce soluble 'Fe-ligand complex' which assist Fe uptake in plants. The biodegradable chelating ligand hydroxyiminodisuccinic acid (HIDS) was more efficient then those of ethylenediaminetetraacetic acid (EDTA), ethylenediaminedisuccinic acid (EDDS), and iminodisuccinic acid (IDS) in the increase of Fe uptake and growth of rice seedling. A total of 79 +/- 20, 87 +/- 6, 116 +/- 15, and 63 +/- 18 mg dry biomass of rice seedlings were produced with the addition of 0.5 mM of EDDS, EDTA, HIDS, and IDS in the nutrient solution, respectively. The Fe concentrations in rice tissues were 117 +/- 15, 82 +/- 8. 167 +/- 25, and 118 +/- 22 mu mol g(-1) dry weights when 0.25 mM of EDDS, EDTA, HIDS, and IDS were added to the nutrient solution, respectively. Most of the Fe accumulated in rice tissues was stored in roots after the addition of chelating ligands in the solution. The results indicate that the HIDS would be a potential alternative to environmentally persistent EDTA for the increase of Fe uptake and plant growth. The HIDS also increased As uptake in rice root though its translocation from root to shoot was not augmented. This study reports HIDS for the first time as a promising chelating ligand for the enhancement of Fe bioavailability and As phytoextraction. (C) 2009 Elsevier Ltd. All rights reserved.

The microbial activities in aquatic environments significantly influence arsenic cycles such as the turnover between inorganic arsenic and organoarsenic compounds. In Lake Kahokugata, inorganic arsenic was detected at concentrations ranging from 2.8 to 23 nM in all seasons, while the concentrations of dimethylarsinic acid (DMA) produced by microorganisms such as phytoplankton changed seasonally and showed a peak in winter. The changes in the concentrations of methylarsenic species did not correlate with the changes in phytoplankton abundance (chlorophyll a contents), suggesting that DMA-degradation is related to this inconsistency. DMA (1 mu M) added into the lake water was converted to inorganic arsenic at 20 degrees C only under anaerobic and dark conditions, while DMA degradation was diminished under aerobic or light conditions. Moreover, DMA added to the lake water samples collected through four seasons was degraded at the same rates under anaerobic and dark conditions at 20 degrees C. However, at 30 degrees C, 1 mu M of DMA in the summer lake water samples was rapidly degraded in 7 and 21 d. In contrast, DMA degradation was diminished in the winter lake water samples at 4 degrees C of incubation. Presumably, DMA-biodegradation activities are mainly controlled by changes in the water temperature in Lake Kahokugata, where the arsenic concentrations change seasonally. (C) 2009 Elsevier Ltd. All rights reserved.

The microbial communities transported by Asian desert dust (KOSA) events have attracted much attention as bioaerosols because the transported microorganisms are thought to influence the downwind ecosystems in Korea and Japan. Bioaerosol samples were collected at 10 and 600 m above the ground within the KOSA arrival area, Suzu City, Japan, during KOSA coming season. The microorganisms in bioaerosol samples grew in media containing up to 15 % NaCl, suggesting that bacteria tolerant to high salinities remain viable in the atmosphere. Denaturing gradient gel electrophoresis using 16S rDNA sequences revealed that the viable halobacterial communities in the bioaerosol samples were composed of members of the genus Bacillus. Moreover, the relative bacteria of B. subtilis was found to dominate in the atmosphere at 600 m and detected from a culture amended with 10% NaCl of aerosol sample at 10 m. Presumably, active mixing processes of the boundary layer transport viable halotolerant bacteria from the atmosphere to the ground surface in Suzu City, where the long-range KOSA particle transport from China is frequently observed.

The microbial activities in aquatic environments significantly influence arsenic cycles such as turnover between inorganic arsenic and organoarsenic compounds. In Lake Kahokugata, the inorganic arsenic was detected through all season, while the dimethylarsinic acid (DMAA) produced by microorganisms such as phytoplankton detected only at winter. Consequently, the changes in the methylarsenic species concentration did not correlate with the changes in phytoplankton abundance (chlorophyll a contents). The lake water spiked with 1 μmol/l of DMAA indicated the DMAA-diminish and the increase of inorganic arsenic under dark and anaerobic condition. Contrary, the lake water under aerobic or light condition did not show the DMAA-diminish. The lake water that bacterial activities were eliminated by filtration, NaN₃ addition and autoclave-sterilization also did not show the DMAA-diminish, indicating that anaerobic bacteria would degrade DMAA in the lake water. Moreover, the incubation at 30 °C, the water samples collected in summer rapidly degraded 1 μmol/l of DMAA within 7days. In the lake water collected in winter incubated at 4 °C, DMAA-degradation did not observed. Presumably, the DMAA-biodegradation activities in the natural lake water of Kahokugata seasonally change depending on water temperatures and several degrees of DMAA-degradation activities influence the seasonal changes of concentrations of arsenic compounds.

Long-range transport of atmospheric microbiota with Asian dust (Kosa) particles is of great concern in Northeast Asia in view of the health effect of Kosa particles on human being, disturbance of ecosystems caused through invasion of new microbe, contribution of microorganisms to biogeochemical cycle on global/regional scales, and others. Information on atmospheric microbes over the desert areas has been desired for a long time. Detection of atmospheric microbiota on the desert regions, on the base of balloon-borne measurements, has been made at Dunhuang, China (40 degrees 00' N, 94 degrees 30' E; east end of Taklamakan desert) in the summer of 2007. The measurements showed that microbiota mixed internally with Kosa particles were frequently floating from the ground to about 2-km heights (above sea level), and possible long-range transport of atmospheric microbiota with dust particles taking local circulations is strongly suggested, causing active mixing of atmospheric dust over the Taklamakan desert from the ground to the free troposphere where westerly jet dominates (Iwasaka et al. in J Geophys Res 108:8652, 2003a, J Geophys Res 108:8644, b). The concentration of the mixed particles of Kosa and microbiota having a size larger than about 1 mu m in diameter is estimated to be about 1 particle/cm(3) at those heights on the basis of measurements of particle concentration with an optical particle counter and analysis of particles having fluorescence light due to dye of DAPI (4'6-diamidino-2 phenylindole) with an epifluorescence microscope. The mixing situation of microbiota and Kosa particles is the important factor controlling atmospheric lifetime of floating microbiota, since the mixing state certainly can protect microbiota from stressful environments [dryness, solar ultraviolet (UV) radiation, low temperature] in the atmosphere, and therefore, it is useful to discuss the data of the first description of microbiota in the atmosphere on the Taklamakan desert.

Effects of eutrophication on arsenic speciation were studied in eutrophic Lake Kiba and mesotrophic Lake Biwa, Japan. By combining hydride generation atomic absorption spectrometry with ultraviolet irradiation, inorganic, methyl and ultraviolet-labile fractions of arsenic were determined. In both Lakes, inorganic species (As(V + III)) dominated over other forms of arsenic all the year round. Most of methylarsenic fraction was dimethylarsinic acid (DMAA), and the concentration of monomethylarsonic acid (MMAA) was below the detection limit. Measurements of size-fractioned arsenic concentrations in water column indicate that most of the DMAA was distributed in truly dissolved fraction (< 10 kDa), while ultraviolet-labile fractions were distributed in particulate (> 0.45 mu m) and colloidal (10 kDa-0.45 mu m) fractions. Arsenic speciation in eutrophic Lake Kiba fluctuated greatly with season. The ultraviolet-labile fractions were observed with the increase of DMAA from May to October, and they disappeared with the decrease of DMAA in January. In mesotrophic Lake Biwa, the ultraviolet-labile fractions of arsenic were not influenced as much as those in eutrophic Lake Kiba. On the other hand DMAA concentration was higher in Lake Biwa compared to that in Lake Kiba. The results suggest that the biosynthesis of complex organoarsenicals was enhanced by eutrophication, and the arsenic speciation would be influenced by the balance of biological processes in natural waters. (C) 2008 Elsevier B.V. All rights reserved.

The Asian dust phenomena, Kosa, have possibility to carry the microbial particles (Kosa bioaerosol) influencing the microbial habitats and the human health in Japan. In this study the bioacrosol were collected at 600 m and 2 in above ground in Kanazawa city at the Kosa coming season, April in 2007. In the culture media based on seawater and lake water, the bioaerosol at 600 m indicated the microbial growth only in the seawater medium, but no growth in the lake water medium. The bioaerosol at 2 m grew in the both media. The halophilic bacteria would maintain viable activities in the atmosphere. Furthermore, the microorganisms in the bioaerosol at 2 m indicated the better growth in this order of 0%, 3%, and 10% of NaCl concentration, and no growth was detected in the 20% NaCl medium. According to the PCR-DGGE (denaturing gradient gel electrophoresis) analysis, same bacterial species were detected in the every NaCl concentration of culture medium, and other bacterial species could grow only in the culture media with 3% or 10% NaCl concentrations. Therefore, the halophilic or halotolerant bacteria would survive in the aerosol at 2 m above ground, and may be related to the microbial transport across the ground-atmosphere.

In this study, we assessed the influence of eutrophication on arsenic speciation in lake waters. By combining hydride generation atomic absorption spectrometry with ultraviolet irradiation, inorganic, methyl and ultraviolet-labile fractions of arsenic were determined. Organoarsenicals, which are methyl and ultraviolet-labile arsenic, composed 30-60% of the total arsenic in most lakes in the summer of 2007. On the other hand, the percentage of ultraviolet-labile fractions was higher in eutrophic lakes. For the seasonal changes, the percentage of DMAA was higher in the winter of 2008. The observed results suggest that the conversion of inorganoarsenicals to the more complicated organoarsenicals was higher in the eutrophic lake.

The degradation processes of organoarsenic compounds in aquatic environments would depend on the bioactivities of microorganisms and significantly influence the cycles of the arsenic Species. The concentrations of arsenic species were determined in Lake Kahokugata. During the all season, the inorganic arsenic was detected. while the dimethylarsinic acid (DMAA) appeared in only winter seasons, and MMAA was not detected. Moreover, when DMAA was added to the water samples of Lake Kahokugata collected at every month from June in 2005 to November in 2006, the DMAA in the sample water of all seasons decreased and was converted to inorganic arsenic until the 28th day Of incubation. According to the Most Probable Number (MPN) procedure, the DMAA-degrading bacteria were detected at cell densities ranged from 120 cells/mL to 2 100 cells/mL during the all season. These facts Suggested that the lake water Of all season in Lake Kahokugata possessed the microbial activities for DMAA decomposition. To determine the composition of DMAA-degrading bacteria, the total 352 isolates obtained as dominated bacterial species were analyzed by the restriction-fragment-length polymorphism (RFLP) analysis of 16S rDNA genes. As a result, total 352 isolates were classified into 10 types of which the rates of total isolate numbers indicated seasonal changes. The diverse compositions of DMAA-degrading bacteria would seasonally change and control the organoarsenic degradation contributing 10 the seasonal arsenic cycles in Kahokugata.

The degradation processes of organoarsenic compounds in aquatic environments would depend on the bioactivities of microorganisms and significantly influence the cycles of the arsenic Species. The concentrations of arsenic species were determined in Lake Kahokugata. During the all season, the inorganic arsenic was detected. while the dimethylarsinic acid (DMAA) appeared in only winter seasons, and MMAA was not detected. Moreover, when DMAA was added to the water samples of Lake Kahokugata collected at every month from June in 2005 to November in 2006, the DMAA in the sample water of all seasons decreased and was converted to inorganic arsenic until the 28th day Of incubation. According to the Most Probable Number (MPN) procedure, the DMAA-degrading bacteria were detected at cell densities ranged from 120 cells/mL to 2 100 cells/mL during the all season. These facts Suggested that the lake water Of all season in Lake Kahokugata possessed the microbial activities for DMAA decomposition. To determine the composition of DMAA-degrading bacteria, the total 352 isolates obtained as dominated bacterial species were analyzed by the restriction-fragment-length polymorphism (RFLP) analysis of 16S rDNA genes. As a result, total 352 isolates were classified into 10 types of which the rates of total isolate numbers indicated seasonal changes. The diverse compositions of DMAA-degrading bacteria would seasonally change and control the organoarsenic degradation contributing 10 the seasonal arsenic cycles in Kahokugata.

In the present Study, the effect of phosphate ion anti iron hydroxides (Fe-plaques) on the selective uptake of arsenic species by water fern (Salvinia natans L.) was investigated. The plants were grown for 5 days it) aqueous Murashige and Skoog (MS) culture media modified in arsenic and phosphate concentrations. Arsenic accumulations in S. natans L. increased with the increase of arsenate and DMAA concentrations in the culture solutions. Compared to the control treatment, S. natans L. accumulated significantly higher amount of arsenic from phosphate-deficient solutions, when the source was arsenate. However, arsenic uptake was not affected significantly by phosphate, when the source was dimethylarsinic acid (DMAA). From solutions containing 100 p M of phosphate and 4.0 mu M of either arsenate or DMAA, the S. natans L. accumulated 0.14 +/- 0.02 and 0.02 +/- 0.00 mu mol (g dry weight)(-1) of arsenic, respectively. In contrast, plants accumulated 0.24 +/- 0.06 and 0.03 +/- 0.00 mu mol (g dry weight)(-1) of arsenic from solutions containing 4.0 mu M of either arsenate and DMAA in phosphate deficient conditions, respectively. Thus, it is reasonable to state that increasing phosphate concentration in culture solutions decreased the arsenic uptake into the water fern significantly, when the source was arsenate. Moreover, arsenic and phosphate content in plant tissue correlated significantly (r=-0.66; p<0.05). when initial source was arsenate while there were no correlation between arsenic and phosphate, where initial source was DMAA (r=-0.077; p>0.05). Similarly, significant correlation was observed between arsenic anti iron content in plant tissues (r=0.66; p<0.05). when initial source was arsenate while the correlation was not significant (r=0.23; p<0.05), when initial source was DMAA. The results indicate the adsorption of arsenate on Fe-plagues of aquatic plant surfaces. Furthermore, the study demonstrates that the DMAA uptake mechanisms into the water fern are deferent from those of arsenate. (C) 2008 Elsevier B.V. All rights reserved.

The uptake of arsenate (As(V)) and dimethylarsinic acid (DMAA) by aquatic macrophyte Spirodela polyrhiza L was investigated to determine the influence of arsenic interaction with PO(4)(3-) and Fe ions. Plants were grown hydroponically on standard Murashige and Skoog (MS) culture solutions. Arsenic concentrations in Fe-oxide (Fe-plaque) on plant surfaces were determined by citrate-bicarbonate-ethylenediaminetetraacetic acid (CBE) technique. S. polyrhiza L. accumulated 51-fold arsenic from arsenate solution compared to that from DMAA solution with initial concentrations of 4.0 and 0.02 mu M of arsenic and phosphate, respectively. The arsenate uptake was negatively (p < 0.001) correlated with phosphate uptake and positively (p < 0.05) correlated with iron uptake. About 56% of the total arsenic was accumulated into the plant tissues while 44% was adsorbed on Fe-plaque (CBE-extract), when the plants were grown on arsenate solution. The DMAA uptake into the plant was neither affected by the phosphate concentrations nor correlated (p > 0.05) with iron accumulation. The results suggest that adsorption of arsenate on Fe-plaque of the surface of S. polyrhiza L contributes to the arsenic uptake significantly. Thus, arsenate uptake in S. polyrhiza L. occurred through the phosphate uptake pathway and by physico-chemical adsorption on Fe-plaques of plant surfaces as well. The S. polyrhiza L uses different mechanisms for DMAA uptake. (C) 2008 Elsevier B.V. All rights reserved.

The dust event injects microorganisms into the atmosphere and could facilitate the dispersal of biological particles affecting leeward ecosystem and human health. In this study, the dustborne microorganisms in the atmosphere over the Taklimakan Desert, Asian dust source, were identified by culture-independent method. Dusts were collected using a balloon at about 800 m above the ground in an Asian dust source region, Dunhuang. After DNA were directly extracted from the dusts collected filters, 16S and 18S rRNA genes of microorganisms were amplified, cloned, and sequenced. The rDNA sequence data indicated that dust particles include fungi closely related to Rickenella fibula, Ceriporiopsis gilvescens, and bacteria belonging to the genus Brevibacillus, Staphylococcus, Rhodococcus, Delftia, Pseudomonas, and Agrobacterium tumefaciens. These results suggest that dust particles in the atmosphere over Dunhuang could carry these many fungi and bacteria and might play a significant role in leeward ecosystem.

The microbial communities transported by Asian desert dust (KOSA) events have attracted much attention as bioaerosols because the transported microorganisms are thought to influence the downwind ecosystems in Korea and Japan. We have analyzed bioaerosol samples collected at 10 and 800 m above the ground within the KOSA source area, Dunhuang City, China. The samples were studied by epifluorescent microscopy, revealing the presence of bacterial cells attached to mineral particles. The microorganisms in the bioaerosol samples were able to grow in media containing up to 20% NaCl, suggesting that bacteria tolerant to high salinities remain viable in the atmosphere. Phylogenetic analysis using 16S rDNA sequences revealed that halobacterial communities in the bioaerosol samples collected at both 10 and 800 m above the ground comprised a few bacterial species related to Bacillus pumilus and Staphylococcus spp. The active mixing processes of the boundary layer presumably transports viable halotolerant bacteria into the free atmosphere, where the long-range atmospheric transport of desert dust is frequently observed.

Ferric (oxyhydro-)oxides (FeOx) precipitate in the rhizosphere at neutral or alkaline pH and are adsorbed on the plant root surfaces. Consequently, the higher binding affinity of arsenate to FeOx and the low iron phytoavailability of the precipitated FeOx make the phytoremediation of arsenic difficult. In the present study, the influence of chelating ligands on arsenic and iron uptake by hydroponically grown rice seedlings (Oryza sativa L.) was investigated. When chelating ligands were not treated to the growth medium, about 63 and 71% of the total arsenic and iron were distributed in the root extract (outer root surfaces) of rice, respectively. On the other hand, ethylenediaminetetraacetic acid (EDTA), ethylenediaminedisuccinic acid (EDDS) and hydroxyiminodisuccinic acid (HIDS) desorbed a significant amount of arsenic from FeOx of the outer root surfaces. Therefore, the uptake of arsenic and iron into the roots and their subsequent translocation to the shoots of the rice seedlings increased significantly. The order of increasing arsenic uptake by chelating ligands was HIDS > EDTA > EDDS. Methylglycinediacetic acid (MGDA) and iminodisuccinic acid (IDS) might not be effective in arsenic solubilization from FeOx. The results suggest that EDDS and HIDS would be a good and environmentally safe choice to accelerate arsenic phytoavailability in the phytoremediation process because of their biodegradability and would be a competent alternative to the widely used non-biodegradable and environmentally persistent EDTA.

The adsorption of Au(III), Pt(IV) and Pd(II) onto glycine modified crosslinked chitosan resin (GMCCR) has been investigated. The parameters studied include the effects of pH, contact time, ionic strength and the initial metal ion concentrations by batch method. The optimal pH for the adsorption of Au(III), Pt(IV) and Pd(II) was found to range from 1.0 to 4.0 and the maximum uptake was obtained at pH 2.0 for Au(III), Pt(IV) and Pd(II). The results obtained from equilibrium adsorption studies are fitted in various adsorption models such as Langmuir and Freundlich and the model parameters have been evaluated. The maximum adsorption capacity of GMCCR for Au(III), Pt(IV) and Pd(II) was found to be 169.98, 122.47 and 120.39 mg/g, respectively. The kinetic data was tested using pseudo-first-order and pseudo-second-order kinetic models and an intraparticle diffusion model. The correlation results suggested that the pseudo-second-order model was the best choice among all the kinetic models to describe the adsorption behavior of Au(III), Pt(IV) and Pd(II) onto GMCCR. Various concentrations of HCl, thiourea and thiourea-HCl solutions were used to desorb the adsorbed precious metal ions from GMCCR. It was found that 0.7 M thiourea-2 M HCl solution provided effectiveness of the desorption of Au(III), Pt(IV) and Pd(II) from GMCCR. The modification of glycine on crosslinked chitosan resin (CCR) was studied by Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM). (c) 2007 Elsevier Ltd. All rights reserved.

The influence of ethylenediaminetetraacetic acid (EDTA) and chemical species on arsenic accumulation in aquatic floating macrophyte Spirodela polyrhiza L. (duckweed) was investigated. The uptake of inorganic arsenic species (arsenate; As(V) and arsenite; As(111)) into the plant tissue and their adsorption on iron plaque of plant surfaces were significantly (p < 0.05) higher than those of organic species (monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA)). The addition of EDTA to the culture media increased the uptake of As(V) and As(III) into the plant tissue though the MMAA and DMAA uptake were not affected. About 4-6% of the inorganic arsenic species were desorbed or mobilized from iron plaque by EDTA. Desorption of organic arsenic species was not affected by EDTA addition because the co-precipitation occurs only with inorganic species. Phosphate uptake was not affected by EDTA though its concentration in citrate-bicarbonate-EDTA (CBE)-extract was much higher than that of plant tissue. Iron uptake into the plant increased significantly (p > 0.05) by EDTA addition to the culture media while its concentration in CBE-extract decreased significantly (p < 0.05). The As (inorganic)/ Fe ratios in plant were higher than those of CBE-extract which indicate the increased uptake of these arsenic species into the plant relative to the iron. The lower As(organic)/Fe ratios in plant and on CBE-extract suggest the reduction of accumulation of these arsenic species relative to the iron. (c) 2007 Elsevier Inc. All rights reserved.

The Asian dust phenomena, Kosa, have possibility to carry the microbial particles (Kosa bioaerosol) influencing the microbial habitats and the human health in Japan. In this study, the bioaerosol were collected at 600 m and 2 m above ground in Kanazawa city at the Kosa coming season, April in 2007. In the culture medium produced using seawater and lake water, the bioaerosol at 600 m indicated the microbial growth only in the seawater medium, but no growth in the lake water medium. The bacteria in bioaerosol at 2 m grew in both of the seawater and lake water media. The halophilic bacteria would maintain viable activities in the atmosphere. When the bioaerosol at 2 m was inoculated to the culture media including NaCl at some ranges of concentrations, the microbial growth was higher in this order of 0%, 3%, and 10% of NaCl concentrations, and no growth was detected in the 20% NaCl medium. According to the DGGE (denaturing gradient gel electrophoresis) analysis, same bacterial species would be included in the every NaCl concentration of culture medium, and other bacterial species could grow only in the culture medium with 3% or 10% NaCl concentrations. Therefore, the halophilic or halotolerant bacteria would survive in the aerosol at 2 m above ground, and may be related to the long-distant transfer of microbial population. The approach targeting the halobacteria will provide valuable information about the microbial transport across the ground-atmospheric area.

Some unavoidable drawbacks of traditional technologies have made phytoremediation a promising alternative for removal of arsenic from contaminated soil and water. In the present study, the potential of an aquatic macrophyte Spirodela polyrhiza L. for phytofiltration of arsenic, and the mechanism of the arsenic uptake were investigated. The S. polyrhiza L. were grown in three test concentrations of arsenate and dimethylarsinic acid (DMAA) (i.e. 1.0, 2.0 and 4.0 mu M) with 0 (control), 100 or 500 mu M of phosphate. One control treatment was also set for each test concentrations of arsenic. The PO43- concentration in control treatment was 0.02 mu M. When S. polyrhiza L. was cultivated hydroponically for 6 d in culture solution containing 0.02 mu M phosphate and 4.0 mu M arsenate or DMAA, the arsenic uptake was 0.353 +/- 0.003 mu mol g(-1) and 7.65 +/- 0.27 nmol g(-1), respectively. Arsenic uptake into S. polyrhiza L. was negatively (p < 0.05) correlated with phosphate uptake when arsenate was applied to the culture solutions owing to similar in the sorption mechanism between AsO43- and PO43-, and positively (p < 0.05) correlated with iron uptake due to adsorption of AsO43- onto iron oxides. Thus, the S. polyrhiza L. accumulates arsenic by physico-chemical adsorption and via the phosphate uptake pathway when arsenate was added to the solutions. These results indicate that S. polyrhiza L. would be a good arsenic phytofiltrator. In contrast, DMAA accumulation into S. polyrhiza L. was neither affected by the phosphate concentration in the culture nor correlated (p > 0.05) with iron accumulation in plant tissues, which indicates that S. polyrhiza L. uses different mechanisms for DMAA uptake. (C) 2007 Elsevier Ltd. All rights reserved.

Adsorption of arsenite [As(III)], arsenate [As(V)] and dimethylarsinate (DMA) from aqueous solutions onto polymeric Al/Fe modified montmorillonite was studied. Batch adsorption studies were carried out on the adsorption of As(III), As(V) and DMA as a function of contact time, pH, adsorbent dose and initial metal concentration. Fourier transform infrared spectrometry (FT-IR) and scanning electron microscopy (SEM) were used to analyze the functional groups and surface morphology of the montmorillonite or polymeric Al/Fe modified montmorillonite, respectively. SEM images show that modification with polymeric Al/Fe species reduces the clay particle size and aggregation. The results indicate that the maximum adsorption of polymeric Al/Fe modified montmorillonite was obtained in the pH range 3.0-6.0 for As(V), 7.0-9.0 for As(III) and 3.0-7.0 for DMA. The adsorption data was analyzed by both Freundlich and Langmuir isotherm models and the data was well fit by the Freundlich isotherm model. Kinetic data correlated well with the pseudo-second-order kinetic model, suggesting that the adsorption process might be chemical sorption. Thermodynamic studies showed that the adsorption process was endothermic and spontaneous in nature. The presence of phosphate and iron reduced the adsorption efficiency of arsenic, whereas other common coexisting ions had no significant effect on arsenic adsorption. The desorption studies were carried out using dilute NaCl solution. (c) 2007 Elsevier B.V. All rights reserved.

Crosslinked chitosan resin chemically modified with L-lysine has been used to investigate the adsorption of Pt(IV), Pd(II) and Au(III) from aqueous solutions. Batch adsorption studies were carried out with various parameters, such as initial metal ion concentration, contact time, pH and temperature. The maximum adsorption capacity was found at pH 1.0 for Pt(IV), at pH 2.0 for Au(III) and Pd(II). Langmuir and Freundlich isotherm models were applied to analyze the experimental data. The best interpretation for the experimental data was given by the Langmuir isotherm and the maximum adsorption capacity was found to be 129.26 mg/g for Pt(IV), 109.47 mg/g for Pd(II) and 70.34 mg/g for Au(III). The kinetic data was tested using pseudo-first-order and pseudo-second-order kinetic models. Kinetic data correlated well with the pseudo-second-order kinetic model, indicating that the chemical sorption was the rate-limiting step. Thermodynamic parameters like Gibbs free energy (Delta G degrees), enthalpy (Delta H degrees) and entropy (Delta S degrees) were evaluated by applying the Van't Hoff equation. The thermodynamic study indicated that the adsorption process is spontaneous and exothermic in nature. The desorption studies were carried out using various reagents. The maximum percent desorption of precious metal ions were obtained when the reagent 0.7 M thiourea-2 M HCl was used. (C) 2006 Elsevier B.V. All rights reserved.

A method for solid phase extraction of trace metals such as Cd(2+), Cr(6+), Cu(2+), Fe(3+), Mn(2+), Ni(2+), Pb(2+) and Zn(2+) using nanometer coated with chromotropic acid prior to determination by inductively coupled plasma atomic emission spectrometry (ICP-AES) has been developed. Various influencing parameters on the separation and preconcentration of trace metals, pH, flow rate, sample volume, amount of adsorbent, concentration of eluent and sorption kinetics have been studied. The detection limits for Cd(2+), Cr(6+), Cu(2+), Fe(3+), Mn(2+), Ni(2+), Pb(2+) and Zn(2+) were found to be 0.14, 0.62, 0.22, 0.54, 0.27, 0.28, 0.53 and 0.38 ng ml-(1), respectively. The adsorption capacity of the solid phase adsorption material is 10.3, 11.3, 14.5, 16.4, 15.1, 11.7, 15.4 and 16.8 mg g(-1) for Cd(2+), Cr(6+), Cu(2+), Fe(3+), Mn(2+), Ni(2+), Pb(2+) and Zn(2+), respectively. The preconcentration factor was obtained in the range of 50-100 for all studied metal ions. Coexisting ions over a high concentration range have not shown any significant effects on the determination of aforesaid metal ions. The accuracy of the proposed method was tested by standard reference materials (NIST 1643e: water, NIST 1573a: tomato leaves and NIST 1568a rice flour) and natural waters and the results obtained were in good agreement with the certified values. (C) 2007 Elsevier B.V. All rights reserved.

Some plants that accumulate the arsenic compounds have attracted attention as hyperaccumulators, and contribute to metal-extraction technique for the clean-up of contaminated environments. This study investigated the effects of arsenic species and bacterial activities on the arsenic uptakes of the hyperaccumulator fern Pteris vittata. The microbial activities in the lake water mineralized DMAA to inorganic arsenic, and some bacterial isolates degraded DMAA. When P. vittata was cultivated in the hydroponic culture medium, the plant accumulated inorganic arsenic to about 1700 As-mg/kg, while it hardly accumulated dimethylarsinic acid (DMAA) showing lower accumulation of below 50 As-mg/kg. The DMAA-mineralizing bacteria and the lake water sample, which were added into P. vittata culture medium, increased until 20 fold the plant arsenic accumulations. Furthermore, the bacterial addition also induced the arsenic accumulation of P. vittata, which were cultivated in the sterilized normal soils spiked with DMAA or the arsenic contaminated soils. Presumably, the bacterial mineralization supported the plant accumulate DMAA via inorganic arsenic.

Radiochemical analysis using iron tracer, ⁵⁵Fe, with liquid scintillation counting is a simple, sensitive and reliable method for determination of low-level iron, and is useful for iron speciation in laboratory culture experiments of marine phytoplankton. In this paper, we studied interferences from the components of the culture media, established the analytical conditions, and measured iron distribution including dissolved, particle, intra- and extracellular iron in marine phytoplankton cultures. The results from iron uptake experiments showed that bioavailability of iron to phytoplankton was related to the iron speciation in the presence of the chelating ligands.

A method for solid phase extraction of trace metals such as Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn using nanometer sized alumina coated with chromotropic acid prior to determination by inductively coupled plasma atomic emission spectrometry (ICP-AES) has been developed. Various parameters influencing on the separation and preconcentration of trace metals, such as pH, flow rate, sample voulme and concentration of eluent were studied. The maximun adsorption capacity of the solid phase adsorption material was 10.3, 11.3, 14.5, 16.4, 15.1, 11.7, 15.4 and 16.8 mg/g for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn, respectively. The detection limits for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were found to be 0.14, 0.62, 0.22, 0.54, 0.27, 0.28, 0.53 and 0.38 ng/ml, respectively. The preconcentration factor was obtained in the range of 50–100 for all studied metal ions. Coexisting ions over high concentration range did not show any significant effect on the determination of aforesaid metal ions. The accuracy of the proposed method was tested by standard reference materials (NIST 1643e: water, NIST 1573a: tomato leaves and NIST 1568a: rice flour), and the results agreed well with the certified values.

Chemical warfare agents, composed of harmful organoarsenic compounds have contaminated the soils of Ohkunoshima Island with high levels of arsenic. As a basic research establishing useful bioremediation techniques, environmental factors such as arsenic concentrations and bacterial biomass in the soils were investigated. Among the five stations of Ohkunoshima Island, the soils of four stations were contaminated by high levels of arsenic compounds at concentrations of 125, 12.7, 3.29 and 0.504 g/kg soil, while the other station with low arsenic concentrations of 0.007 g/kg soil was considered an uncontaminated area. The distribution of arsenic compounds originating from the chemical weapon agent differs among the various areas of Ohkunoshima Island. The cell densities of arsenate-resistant bacteria also varied among the five stations, ranging from 10(6) to 10(8) cells/g soil. In an attempt to isolate bacteria that strongly mineralize the organoarsenic compounds, the mineralization activities for monomethylarsonic acid [MMAA(V)] of 48 isolates of arsenate-resistant bacteria were determined. Only nine isolates reduced 140 mu g/l of MMAA(V), giving decreasing percentages ranging from 5 to 100% within 14 days. Among the nine isolates, two remarkably converted 140 mu g/l of MMAA to more than 71 mu g/l of inorganic arsenic. Presumably only specific members of the environmental bacterial population have strong mineralization activities for MMAA. Phylogenetic analysis using 16S rDNA sequences showed that the two isolates belonged to the Pseudomonas putida strains, which are known to have strong mineralization activity for various organic compounds. In the soil contaminated by arsenic at a high level, few bacteria in the arsenate-resistant bacterial group would significantly mineralize orgartoarsenic compounds. Copyright (c) 2006 John Wiley & Sons, Ltd.

Antibiotic residues in marine sediments of fish farms negatively influence microbial ecologic systems. The microbial degradation of antibiotic residues was experimentally examined in the marine sediments of Uranouchi Bay, to which one of five antibiotics was added. After incubation reducing physical factors, ampicillin, doxycycline, oxytetracycline, and thiamphenicol were significantly degraded, while josamycin maintained most of the initial amounts. The isolates resistant to ampicillin, josamycin, oxytetracycline, or thiamphenicol degraded each antibiotic in wide ranges of degrees, whereas the isolates degrading doxycycline were not obtained. Microbial degradation may contribute to the disappearance of ampicillin, doxycycline, oxytetracycline, and thiamphenicol in the fish farm. In contrast, the disappearance of josamycin would depend on physical factors, but the bacteria degrading josamycin at least exist in the marine sediments. Phylogenetic analysis using 16S rDNA sequences demonstrated that the antibiotic-resistant isolates formed several clusters in the Gram-positive bacterial group, the Flavobacterium-Cytophaga-Bacteroides group, and the proteobacteria subdivisions. The antibiotic-resistant bacterial population would be composed of various species including ubiquitous coastal bacterial groups. Several species of antibiotic resistant bacteria show antibiotic degradation activities, and appear to contribute to the disappearance of antibiotics in Uranouchi Bay.

Degradation processes of organoarsenic compounds significantly influence arsenic cycles in aquatic environments and would depend on the bacterial activities. The bacterial population involving dimethylarsinic acid (DMAA) degradation was investigated in Lake Kibagata from April to December in 2003. During the experimental period, the methylated arsenic was not detected, although the inorganic arsenic concentration ranged from 3.4 nM to 9.2 nM. Moreover, in the sample water of Lake Kibagata to which DMAA added, DMAA decreased while inorganic arsenic increased for 25 days. These facts suggested that the bacteria remineralized methylate arsenic species to inorganic arsenic. In fact, monitoring the use of Most Probable Number (MPN) procedure demonstrated that the DMAA-degrading bacteria exist at cell densities ranged from 41 cells/ml to 510 cells/ml. To determine the composition of DMAA-degrading bacteria, the total 110 isolates obtained as dominated bacterial species were analyzed by the restriction-fragment-length polymorphism (RFLP) analysis of 16S rDNA. As a result, total 110 isolates were classified into 12 types, of which 4 types dominated during the spring and/or fall seasons, and the rest 8 types dominated during summer season. DMAA degrading activities of the 110 isolates ranged at various degrees. Especially, the some isolates of fall season tend to show high degradation activities. The phylogenetic analysis using 16S rDNA revealed that the representative isolates formed several clusters in the gram-positive bacterial group and the proteobacteria subdivision. The diverse compositions of DMAA-degrading bacteria would seasonally change to control the rates of organoarsenic degradation in Kibagata.

ハプト藻Prymnesium parvumは, 世界各地の沿岸海域で赤潮を引き起こし, 毒性の高い細胞外毒を産出することで, 多量の魚類を斃死させる. 本研究では, 鉄と強く結合する種々のキレート剤によるP. parvumの増殖阻害を生理実験によって検証した. その結果, P. parvumの増殖は, BipyridineおよびDesfferrioxamine Bによって顕著に阻害されたため, キレート剤は, 微細藻の摂取可能な鉄を奪い, 微細藻を鉄欠乏状態に追い込むと考えられる. よって, 本キレート剤は, P. parvumの増殖を制御するための有効な薬剤として期待できる. さらに, P. parvumの鉄欠乏に対する応答機構を分子レベルで明らかにするため, 鉄欠乏培養をディファレンシャル・ディスプレイ法に供し, 鉄欠乏下で誘導発現される遺伝子群を解析した. その結果, 鉄欠乏によって転写レベルで誘導されると見なせる全12の遺伝子タイプが得られた. さらにノーザンブロット法によって鉄欠乏下での誘導発現を確認したところ, 9タイプが鉄欠乏下で転写誘導されることが明らかとなった. その9タイプの内, 5タイプが既知遺伝子配列と高い相同性を示し, 4タイプが未知配列であった. 既知配列のなかでも, 特に, 真核生物翻訳終結因子, エノラーゼ, 熱ショック蛋白をコードする遺伝子のクローンが多く得られた. 従って, P. parvumは, これらの遺伝子を誘導転写し, 鉄欠乏による環境ストレスに適応していると考えられる. また, 未知配列の遺伝子タイプも, 鉄欠乏への応答機構に関わっている可能性が得られた.

Phytoremediation is an innovative technology that utilizes the natural properties of plants to remediate hazardous waste sites. For more cost-effective phytoremediation, it is important to utilize a hyperaccumulating plant after phytoremediation, i.e. the recovery of valuable metals and the production of useful materials. In this work, the determination of metals in plant component polymers in a fern, Athyrium yokoscense, as a hyper-accumulating plant was established using steam explosion, Wayman's extraction method, and ICP emission spectrometry. After A. yokoscense plants were treated by steam explosion, the steam-exploded A. yokoscense were separated into four plant component polymers, i.e. water-soluble material fraction, holocellulose fraction, methanol-soluble lignin fraction, and residual lignin fraction. The concentrations of Cu, Pb, Fe, and Zn in these plant component polymers and the dry weights of plant component polymers were measured. These analytical process determining metals in the plants will contribute to not only the evaluation and the efforts of phytoremediation using a hyperaccumulating plant, but also to the development of more effective phytoremediation. 2005 © The Japan Society for Analytical Chemistry.

Heterocapsa circularisquama, a noxious marine dinoflagellate, has frequently caused red tides and killed cultured bivalves in western Japanese embayments. Observations by electron and epifluorescence microscopy revealed that many bacterial particles were detected inside the H. circularisquama cells. To elucidate the identity and origin of the intracellular bacteria associated with H, circularisquama, bacterial 16S ribosomal RNA genes (16S rDNA) were directly amplified by polymerase chain reaction from 5 clonal cultures of the algal strains that had been isolated from different localities. After cloning, randomly selected clones including the bacterial 16S rDNA fragments were sequenced. The results showed that intracellular bacterial populations consisted of only 2 ribotypes of bacteria, even though the algal strains were established from different localities. One ribotype (bac-G), which was dominant in the intracellular bacterial population, belonged to the gamma-proteobacteria group, and the other (bac-F) clustered with the Flexibacter-Cytophaga-Bacteroides group, Both of these are novel species of endosymbiotic bacteria because of their unique 16S rDNA sequences. Furthermore, the populations of extracellularly associated bacteria were also composed of bac-G and bac-F, indicating that they originated from the intracellular bacteria. Fluorescence in situ hybridization targeting 16S rRNA indicated that bac-G appeared to localize on the algal nuclear surface, while bac-F was distributed in the cytoplasmic space of algal cells. These results strongly suggest that only a few species of specific bacteria reside and share their habitat in the H. circularisquama cells as endosymbionts.

Phytoremediation, a new plant-based technology for the removal of toxic contaminants from soil and water, is a potentially attractive approach. Though a number of plants have been identified as hyperaccumulators for the phytoextraction of a variety of metals and some has been used in field applications, no study on recovery and recycle of heavy metals from contaminated soil has been investigated. Recently, Athyrium yokoscense has been discovered as an efficacious heavy metallic hyperaccumulating fern plant. In this work, the purification of contaminated soil with heavy metals using A. yokoscense and the development of system for recovering valuable metals by steam explosion and Wayman's extraction were investigated. After the harvest of A. yokoscense adsorbed heavy metals from contaminated soil, it was treated by steam explosion and separated into extractive components, i.e. holocellulose, water-soluble material, Klason lignin, and methanol-soluble lignin, using Wayman's extraction method. The distribution of metals in the components was clarified using ICP emission spectrometry.

The sample preparation and analytical methodology are described for detecting biologically produced iron(III)-binding ligands in laboratory cultures of coastal marine phytoplankton. The iron (III)-binding ligands from the culture media were purified by passage through a column packing with a hydrophobic absorbent. The concentrations and stability constants of the ligands were determined by adsorptive cathodic stripping voltammetry with competitive ligand equilibration. The analytical results of the cultivated cultures suggest that eukaryotic phytoplankton would produce iron(III)-binding ligands in analogy with other microorganisms.

A new monitoring system for bacterial communities involving dimethylarsinic acid (DMAA) decomposition was provided by combining the MPN (Most Probable Number) method and RFLP (restriction-fragment-length polymorphism analysis). The abundance of DMAA decomposing bacteria was estimated by the MPN method using a bacterial culture medium, which included DMAA as the sole carbon source, indicating bacterial cell densities of 1700 cells/ml in Lake Kahokugata and 330 cells/ml in Lake Kibagata. After isolating the dominant bacteria using agar plates, the isolates were classified into some genotype groups by RFLP analysis using 16S rDNA sequences. Classification of the RFLP analysis indicated that 14 isolates of Lake Kahokugata were classified into 6 types, which included 2 dominant types related to genus Pseudomonas, while 8 isolates of Lake Kibagata displayed 6 types including one or two isolates. Moreover, the RFLP types were unique for each lake, suggesting that DMAA decomposing bacteria were specific for the aquatic environment related to the arsenic cycle. The activities of DMAA decomposition mostly matched with the RFLP type category of the isolates. Accordingly, combining the MPN method with the RFLP analysis will play an important role in elucidating the distributions and dynamics of the DMAA-decomposing bacterial community.

The sample, preparation and analytical methodology are described for determining minor and trace elements (Al, As, Ba, Cd, Co, Cr, Fe, Mg, Mn, Mo, Ni, Sb, Sr, U, V, W, Y and Zn) in biogenic carbonate minerals of coccolithophores. Coccolith particles isolated from cultivated coccolithophores were purified by centrifugation and resuspension with 0.5 mM sodium hydrogencarbonate solutions (1 M = 1 mol L-1). The concentrations of the elements in the final solutions were determined by high-resolution inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry. The analytical results of coccolith particles suggest that the molar ratios of the minor and trace elements in coccoliths vary with the compositions of the medium in which the coccolithophores are grown.

Relationships between the growths of five different clonal strains of Heterocapsa circularisquama and intracellular bacteria were investigated using culture experiments. Although each H. circularisquama strain culture was established from one cell by repeated and careful washings with micropipettes, intracellular and extracellular bacteria in each strain culture were still observed under a epifluorescence microscope using the DAPI (4 ' ,6-diamidino-2-phenylindole) staining technique. The extracellular bacteria are derived, presumably, from the inside of algal cells after the death and collapse of algal cells in culture. Using an electron microscope, bacteria were constantly observed in the cytoplasm and food vacuoles of H. circularisquama cells. The growth of five algal strains containing bacteria was compared with that of a bacteria-free strain using culture experiments under combined conditions of five different light intensities and five different strengths of culture medium. Bacteria showed no significant effect on the growth or survival of the algal cells. During the algal exponential growth phase, the intracellular bacterial cell numbers per algal cell decreased, whereas the total bacterial cell density in each algal culture increased. Final cell yield (total number) of the intracellular and extracellular bacteria varied considerably according to the algal strains. These results suggest that the intracellular bacteria of H. circularisquama grow or survive depending on the host alga, and that the alga can grow independently.

The red tide dinoflagellate Heterocapsa circularisquama Horiguchi has intracellular bacteria. The isolation and cultivation of these bacteria were attempted for three-clonal strains of H. circularisquama (HY9423, HA92-1, and HU9433) using various culture media containing cell components of the host alga prepared by homogenization and heat killing, in addition to different organic materials (peptone and extracts). Only one intracellular bacterium of the bacterial population UBb in H. circularisquama strain HU9433 was successfully cultivated on many kinds of culture media. The intracellular bacterial populations of Yb and Ab in the algal clones HY9423 and HA92-1, respectively, could not grow in the culture media used. The presence of live algal cells is thought to be essential for the growth and survival of the bacterial populations Yb and Ab. These results indicate that the degree of dependence of the intracellular bacteria on the host algal cells differs greatly among the algae-bacteria sets of strains. © 2001, Japanese Society of Microbial Ecology & The Japanese Society of Soil Microbiology. All rights reserved.

黄砂や煙霧とともに微生物群(バイオエアロゾル)が，アジア大陸から日本へ越境輸送され，日本各地へと拡散沈着するため，その環境・健康影響に学術的関心が集まる。申請者らは，東アジア(日中韓蒙)において，黄砂を捕集する高高度調査(気球, ヘリコプター, 山岳積雪を使用)を実施し，日本へと越境輸送された微生物の種組成とその健康影響が，日本海沿岸と太平洋沿岸で大別できる可能性を突き止めた。しかし，観測地点は日本海側に偏り，太平洋側への国内移送や沈着程度を講じる観測が不十分であった。本申請では，日本本土(日本海ー太平洋)の観測地を拡充し，「越境微生物の国内での拡散・沈着過程」を理解すると伴に，そ影響を評価する。 黄砂飛来時に日本海側（能登）と太平洋側（関西，関東）の上空500ー2500ｍにおいてヘリコプター観測を行い，高高度の大気粒子を捕集した。また，黄砂・煙霧発生が頻発する春から初夏(4月-6月)にかけて，金沢，鳥取，香川，東京，長野，大阪の観測地において，建物屋上(高さ10m)で長期的に観測した。大気試料のゲノムDNA（環境ゲノム）に含まれる細菌・カビの分類指標遺伝子（16SとITS）核酸塩基配列を解読した。遺伝子解析ソフト(Qiime2)で微生物群集構造を解析したところ，黄砂と煙霧によって細菌は越境しやすく，本国内において真菌と混合する傾向が見られた。感染症（非結核抗酸症）の原因微生物も検出され，潜在的に長距離拡散される可能性も見出した。また分離した真菌株からもカビ毒が検出された。これより，黄砂煙霧とともに国内を拡散する有害種(キーストーン種)の候補に目処が立ちつつある。 こうした研究成果は，環境系の有名学術誌に多数掲載され，書籍「大気微生物の世界」にまとめられた。また，一般からの注目も熱く，大気観測全般を纏めたガリレオXやNHKスペシャルなどの取材を受けた。

本研究は、地域ごとの大気環境中のPM2.5の化学的特性及び肺非結核抗酸菌症（肺NTM症）の90%を占めるMAC菌の特異性を把握することと、これら大気環境中の化学成分とMAC菌との相互作用を検証することを目的としている。大気を介したMAC菌感染症の越境の可能性を検証するため、地上付近数十メートルでの測定を全国5拠点（北海道札幌市、東京都清瀬市、石川県珠洲市、大阪府堺市、福岡県福岡市）にて進めている。頻度としては、季節変動の把握を目的として、年4回のサンプリングを季節ごとで進めている。さらに、高高度での拡散条件の把握を行うために、ヘリコプター、航空機などの活用で、隣国などから越境することの可能性も視野に入れつつ観測を進めている。高高度測定については、大阪府、石川県付近など限られた地点での測定ではあるが、地上でのデータとの比較を目指して、できるだけ同時期に測定することを目指す。これらの測定結果で得られたデータを基に、大気中のバイオエアロゾルの挙動を擬似的に検証できる擬似大気チャンバーを用いて、大気中細菌などのバイオエアロゾル活性保持メカニズムの把握、検証を行う。これらの知識構築にて、肺NTM症などの感染が起こりやすい状況をより明確化し、感染症に対応できる生活環境の整備、又は状況の把握か取り組む予防的な対応にて疾病問題の低減化を目ざす。環境因子と関連した感染症対策は知識が不十分であるため、本研究には大きな意義がありこれらの対応を進めていくことは感染症対策として健康維持に向けた重要な取り組みである。

本研究において福島県の放射性セシウム高汚染地区内の林地に設置した観測サイトを活用し、大気エアロゾル特にバイオエアロゾルのサンプリングを連続的に実施している。そのサンプリングで得られた試料を用い、バイオエアロゾル自体の濃度および微生物や真菌に特有のエアロゾル有機成分濃度と大気セシウム放射能濃度を比較することにより、バイオエアロゾルを介した放射性セシウムの大気再飛散について、より定量的に理解できた。またエアロゾル試料から不溶性放射性セシウム微粒子(CsMP)を検出し、その大気再飛散の影響も考慮した上で、バイオエアロゾルによる再飛散過程の重要性を評価できた。 また、筑波実験植物園林内においても、フィルタサンプリングおよび浮遊菌カウンタによるバイオエアロゾル濃度観測を実施し、その濃度の季節変化や日変化について知見を得ることができた。特に、これまであまり報告例のない日中のバイオエアロゾル濃度増加が見られ、今後その原因について検討していく。 採取したフィルタ試料から林内バイオエアロゾルを構成する真菌胞子やバクテリアのメタゲノム解析を行い、構成種群集の変化との関係を明らかにしつつある。また、同じ林内で採取したキノコの胞子やバイオエアロゾルの氷晶核能について、昇華凝結および内部凍結過程での氷晶化温度により評価を開始し-15℃以上で氷晶化するケースがしばしばみられることが分かった。さらに、ドローンに搭載し森林上空でバイオエアロゾルをサンプリングする装置を開発し飛行試験を実施した。

氷雲の形成を促す「氷晶核(氷核活性を持つ粒子)」の発生源は不明であり，その粒子密度は気候変動予測での不確定因子となる。その為，近年，分析・観測技術の向上に伴い検出可能となった大気浮遊微生物(バイオエアロゾル)の氷核活性へ学術的関心が集まっている。申請者らは，長年の飛行機観測などで，高度数千mの粒子から氷核活性を持つ微生物を検出しており，その種類から森林由来であると推察してきた。しかし，微生物の森林からの放出量は定かでなく，氷晶核の主要発生源とは断定できない。そこで，本研究では，観測機器を完備した森林観測サイトでの地上観測に，微生物捕集に特化した高高度大気観測を併用することで，森林地表から高高度までの浮遊微生物の鉛直分布を明かとし，氷核活性微生物の森林からの放出量を追究しつつある。 2018年度は，森林バイオエアロゾルの捕集する観測調査を，筑波実験植物園と福島県波江において実施した。大気微生物が増える時期(6月と10月)には，植物園では，ヘリコプターと建物屋上を利用し，それぞれ高度500ｍと10m（樹冠）で大気粒子を捕集し，糸状の真菌が樹冠上まで浮遊し垂直分布していることを突き止めた。また，大気粒子試料から，糸状を形成する真菌が10種程度分離培養され，複数種のカビやキノコの胞子が樹冠外に放出されていることにあたりをつけた。一方，大気粒子から微生物のゲノムDNA直接抽出し（培養を経ない），解析した結果，分離培養された菌以外にも数百種以上の細菌と真菌が，森林内外に浮遊していることが分かった。 こうした風送微生物に関する研究成果への学術的評価は高く，大気科学雑誌JGRに論文発表され，その論文がForbesのサイトにてニュースとして取りあげられた。また，一般市民からの注目も熱く，牧代表が密着取材をうけ，森林観測全般をサイエンスゼロ（Eテレ）にて30分番組にとして放送された。

従来顧みられなかった降水によるエアロゾル発生現象に着目し，里山や都市近郊にて総合観測を実施し，その発生や拡散の実態把握と発生物質の性状解明を狙っている。特に森林生態系由来エアロゾルの評価を目指し研究を進めた。 ・アクセスが容易で，バイオエアロゾル発生源の真菌類観察データのある筑波実験植物園にて観測を実施した。フィルター試料からDNA抽出を行った。また，同時期の植物園内で，きのこ発生状況を調査しDNA抽出も行った。子実体は乾燥し，標本として菌類標本庫に保管した。 ・初夏季，秋季に植物園にて，現場サンプリング，粒子蛍光観測装置，緩和渦集積法によるフラックス観測，ゾンデやヘリコプターを用いた上空までの観測による集中観測を実施した。集中観測時には周辺の基礎気象データを収集した。秋季観測では，担子菌きのこ子実体からの胞子放出現象の野外観測映像を初めて得た。大気エアロゾルの遺伝子配列(16S rRNA，ITS領域)から，氷核活性微生物の同種が，乾燥地や都市部に比べ，森林地帯で頻繁に検出された。 ・蛍光ライダーを335nmレーザー，25㎝径望遠鏡などを基本構成として開発し，生葉クロロフィルやスギ花粉などの日中観測により，動作特性を確認した。観測結果との照合のため，30種類以上のエアロゾル候補物質のEEM特性を計測し，データベース化した。都市上空のライダーと成分組成の同時観測を実施し，強い蛍光が観測された日にCaSO4等，蛍光性の人為起源粒子が多く観測された。 ・浪江町と植物園で夫々，燃焼または，胞子由来の有機マーカーのレボグルコサン，糖アルコールを観測した。植物園では，雨天時にCs濃度が高く，マンニトールが類似挙動を示した。レボグルコサンは晴天時に高く，アラビトールは晴天・雨天時で差はない。浪江町では晴天時にCs濃度が高く，レボグルコサンが類似挙動を示したが，雨天時には検出されなかった。

研究目的：黄砂や煙霧とともに微生物群(バイオエアロゾル)がアジア大陸から日本へ風送され，その環境影響に学術的関心が集まっている。しかし，黄砂の主要発生源であるゴビ沙漠(モンゴル:蒙)での調査は手薄であるとともに，沙漠由来の風送微生物と汚染大気との混合状態についても不明な点が多い。本申請では，日中韓蒙で，ゴビ砂漠を含めた東アジアを網羅する集中観測を行い，大気微生物の発生源と越境輸送ルートを理解する伴に，生理学実験・疫学的調査によって，その生態・健康影響の解明に取り組んでいる。 実施内容：黄砂発生地から飛来ルートを網羅する日中韓蒙の観測サイト(11箇所：特にモンゴル、中国甘粛省、能登半島)において，気球，ヘリコプターおよび山岳積雪を使った集中大気観測を実施し，黄砂煙霧の発生に同調させながら，環境データ収集と大気粒子の採取を行った。培養を経ない遺伝子分析法によって，大気粒子に含まれる微生物叢の群集構造を系統分類学的に解析できたため、現在，環境データと照合して，大気微生物の発生源と越境輸送ルートを考察しつつある。未知微生物種の集積培養では、長距離輸送される可能性のある真菌株を入手でき，動物・培養実験によって、気管支炎やアレルギー症状の誘発を実証するに至った。黄砂に含まれる氷核活性微生物が、春の氷雲形成への関与する可能性も見出し，気候変動への影響も示唆された。 成果：本研究成果は，申請者らが主催するバイオエアロゾルシンポジウム(2018年で第11回)で発表し，異分野研究者及び行政関係者と交流した。また，異分野研究(医・農・薬・社)分野にまたがり，種々の学会，招待講演や市民向けシンポジウムで頻繁に研究発表し，学術論文も国内外の専門学術誌に報告した。また，展望があり話題性の高い研究として，テレビ報道でも取り上げられ，内容を一般向けに咀嚼し，社会への情報公開にも努めている。

本研究では、アジアダストの発生とそれに関わる環境レジームシフトのメカニズムを解明するために、平成26-28年度JSPS研究拠点形成事業「アジアダストと環境レジームシフトに関する研究拠点の構築」(コーディネーター：甲斐憲次)で整備した研究拠点ネットワークを活用して、前年度同様、発生源地域のモンゴル草原・ゴビ砂漠および風下側の北海道・能登半島等で集中観測(IOP-2017)を実施した。 IOP-2017では、名古屋大学の甲斐・河合、金沢大学の牧、酪農学園大学の能田は、モンゴル気象環境監視庁（NAMEM)および情報・気象水文環境研究所（IRIMHE)と協力して、ゴビ砂漠中央部に位置するダランザドガド気象台でアジアダストの集中観測を行った。さらに、ウランバートルからダランザドガドまでの600kmを自動車で移動観測して、ダストと気象要素の水平分布を観測した。酪農学園大学の星野のグループは、サインシャンドおよびホスタイ国立公園で植生調査を行った。長期間の植生分布と降水量の変動の解析から、レジームシフトが発生している地域を特定した。 東アジアの広域にわたる地域で大規模なダストイベントがIOP2017期間中の5月に発生した。5月7日には日本全国でアジアダストが観測された。ひまわり8号DUST RGBと研究拠点ネットワークを活用して、このダストイベントの発生と輸送のプロセスを解明した。 アジアダスト・バイオエアロゾル・環境レジームシフト(A-B-E)に関する国際ワークショップを11月3日－5日、名古屋大学環境総合館で開催した。活発な研究発表が行われ、最終日のビジネスミーチングでで、A-B-Eに関する専門書の出版計画が合意された。

我々は黄砂とPM2.5発生時に能登半島でバイオエアロゾルを捕集し、またゴビ沙漠でも捕集した。バイオエアロゾルから微生物を分離・培養して遺伝子解析を行った結果、生体影響の可能性が高い真菌類が能登半島で16株、ゴビ沙漠で15株得られた。これらのうち8株についてマウスに単一、黄砂と併用曝露を行い喘息誘導の強さを比較した結果、単一曝露ではコニオサイリュウムが最も強く、フィアロセファラとクラドスポリウムがこれに続いた。併用曝露ではミリアンギュムが最も強く、コニオサイリュウムがこれに続いた。発生源はコニオサイリュウムとミリアンギュムは能登半島の森林、フィアロセファラとクラドスポリウムがゴビ沙漠であった。

熱帯低気圧「台風」は、熱帯地域で発生し、日本に大雨・暴風など被害を及ぼす気象現象としてよく知られている。本研究は、台風によって長距離輸送される大気バイオエアロゾルについての実相調査を実施した。大気バイオエアロゾルは生物粒子のことで、ウィルス、細菌、カビ、キノコ、その胞子・芽胞や花粉などを含む。サンプリングは、徳島大学と弘前大学で、2017年日本南岸に上陸した台風3号、5号、18号が通過する時に行った。DNA濃度や種組成が台風の接近と通過とともに激しく変化することが明らかになった。

近年，中国沙漠地帯から飛来する黄砂とともに真菌や細菌(バイオエアロゾル)も長距離輸送され，その生態・健康へ与える影響に強い関心が集まる。そこで，砂塵（黄砂）による微生物の越境輸送を解明し，その生体影響評価に取り組んだ。黄砂発生源（敦煌）と飛来地（日中韓）において，高高度（1000m-3000m）の大気粒子試料を採取する大気観測（係留気球，ヘリコプター併用）を実施した。採取した試料に含まれる微生物群のゲノムDNAを解析することで、東アジア一円を拡散する大気微生物の群集構造と特性を明らかとした。さらに、動物実験によって、黄砂に付随する真菌がアレルギーおよび気管支炎の発症に関わることを突き止めた。

中国大陸から越境輸送されるエアロゾル（黄砂・汚染粒子）に含まれる化学成分は、海洋へと沈着すると、海洋微生物の栄養となり，その増殖を促す。現在，大気海洋研究が、モデル計算で進められるのが国際的に主流な中，申請者らは，山岳積雪に蓄積した越境エアロゾル試料を捕集し，海水に添加する洋上培養実験を施行することで，海洋微生物が受ける動態変化を直接検証した。その結果，貧栄養海域では，大気粒子（特に汚染粒子）から溶出する硝酸と有機物が，植物プランクトンの増殖を促進させ、海洋細菌群の群集構造も変化させた。海洋と気象の条件が揃えば，越境エアロゾルが一次生産者を大きく変動させる潜在的な影響力があると言える。

現在、大気汚染物質の広域監視システムが注目されている。大気に含まれる生物粒子（風送バイオエアロゾル）の中に、強い感染力はないものの日和見感染症原因菌などが存在しており、風送バイオエアロゾルによる健康影響が危惧されつつある。これまでに我々が培った黄砂バイオエアロゾル研究における経験から、大気環境監視項目としての風送バイオエアロゾルの定点観測を提案する。風送バイオエアロゾルに関するサンプラー、最近の遺伝子工学を駆使した大気DNA分析手法、気象情報としてのバイオエアロゾル濃度経日計測を試みる。このデータは、健康影響のみならず、日々の国民の多方面にわたる生活データとして生かされる。

初期の放射性Cs放出には従来想定されていた水溶性サブミクロン粒子に加え，直径数μmの不溶性粗大球状粒子が存在することを初めて明らかにした。 典型的な里山では再飛散由来のCs濃度は，都市部での結果と異なり，夏季に上昇し，冬季には低かった。夏季のCs担体は大部分が生物由来であることを初めて見出した。 放射性Csの再飛散簡略スキームを開発し，領域エアロゾル輸送モデルを用いて森林生態系からの生物学的粒子による再飛散，ならびに事故サイトから継続する一次漏えいも含め，フラックス定量化－収支解析を行った。その結果、他のプロセス同様、再飛散は、地表に沈着したCsの減少や移動にほとんど寄与しないことがわかった。

本研究では黄砂発生源地の一つであるタクラマカン砂漠の東端にある敦煌市と石川県上空において、エアロゾル（大気浮遊物質）を採集後、DNA抽出し、DNA濃度から微生物濃度を明らかにした。また、rRNA遺伝子や組み換え遺伝子の配列解析により微生物の多様性や同定を行なった。その結果、大気中のDNA濃度は黄砂飛来時には高くなること、地上付近になるほどDNA濃度は高くなること、生物の多様性は上空になるほど低くなる傾向が見出された。

つくばサイトに於いて、各種エアロゾル測定・採取装置、雲核計、氷晶核計を用いて通年観測を継続実施した。エアロゾルの物理化学生物特性および雲核・氷晶核活性化スペクトルの季節変化について明らかにした。 大気エアロゾルの主要構成要素である、黄砂粒子・バイオエアロゾル・種々の人為起源エアロゾル（標準粒子）を対象とした雲生成チェンバー実験や雲核計・氷晶核計を用いた測定結果と詳細雲微物理モデルの結果に基づき、その雲核能・氷晶核能を種々の気象条件下で調べ定式化した。その結果を用いて非静力学モデルなどに用いるエアロゾル（雲核・氷晶核）・雲・降水を統一的に取扱う新機軸のパラメタリゼーションを開発した。

南極域の風送バイオエアロゾル(生物粒子)は、南極アイスコア微生物、大気循環による長距離輸送などから注目されている。黄砂バイオエアロゾル研究で培った手法・経験を応用し、南極域上空の風送バイオエアロゾル実相調査を世界に先駆けて行った。研究代表者の小林は、第54次日本南極地域観測隊夏隊同行者・公開利用研究（バイオエアロゾル）として南極に行き、2013年1月3日に、係留気球を用いて昭和基地Cヘリポート上空の採集を実施し、地上採集も昭和基地やラングホブデ等で行った。南極海上のバイオエアロゾル調査として南極観測船(砕氷艦)しらせ船上採集も実施した。帰国後、次世代シーケンサーなどを用いて生物分析を行った。

黄砂とともに風送される微生物群(黄砂バイオエアロゾル)を、黄砂発生地(タクラマカン砂漠)および飛来地(珠洲、立山等)の高度1000m-3000mで採取した。分離培養法および遺伝学的分析手法を駆使して、黄砂バイオエアロゾルに優占する種を突き止め、優占種が飛来地に沈着するとともに、ヒト健康影響および生態系の動態に関わっている可能性を明からにした。ただし、優占種以外の微生物種(非優占種)には、数百種が含まれることが分かり、その生態学的および生理学的特徴は推測に留まる。

タクラマカン砂漠での気球観測では上空に浮遊する黄砂の約10%が微生物と合体していた。黄砂が偏西風帯にまで舞い上がった時点ですでに微生物を付着させている可能性が高い。 能登半島での観測は、黄砂濃度上昇時に微生物濃度が上昇し「黄砂とともに大気圏を移動している」ことを強く示唆した。 立山山頂付近の積雪の黄砂層の微生物多様性はタクラマカン砂漠のものと高い類似性があり、砂塵発生源地からの長距離移動・拡散を示唆した。

黄砂とともに微生物群(黄砂バイオエアロゾル)が中国大陸から日本へ運ばれ,生態系やヒト健康へおよぼす影響に社会的かつ学術的関心が集まりつつある。これまで,中国敦煌および日本珠洲の上空1000mで係留気球による大気調査を実施し,耐塩細菌の長距離輸送を実証した。さらに,細菌分離株の遺伝子情報を駆使して,輸送細菌株の病原性の解明や輸送細菌の遺伝識別検出系を構築した。

金属を高レベルで吸収・蓄積する植物(金属集積植物)を用いて、ヒ素の汚染環境を浄化する技術(ファイトレメディエーション)の開発に取り組んだ。今年度は、有機金属の無機化細菌(分解細菌)が植物の有機ヒ素集積を促すことを、土壌栽培法を用いて実証した。化学物質による汚染事例のうち、国内でもっとも件数の多い物質はヒ素である。従って,ヒ素に関する成果が得られた意義は大きい。以下に成果を示す。【I有機ヒ素分解細菌の探索】環境試料(湖沼)中において,粒子物質が有機ヒ素の分解にかかわることを突き止め、有機ヒ素分解細菌を多数分離した。【II金属集積植物体内の金属定量】植物体内の金属定量法のみならず土壌中のヒ素濃度の定量法を確立する必要が生じ、連続ヒ素抽出法を考案し、酸抽出画分および水抽出各分の定量を可能とした。これによって土壌ヒ素の浄化量を評価しやすくなった【III金属集積植物の生理機能の解明】ヒ素化学種が植物のヒ素集積に及ぼす影響を明らかにした。土壌栽培においても、モエジマシダは,無機ヒ素に較べ,メチルヒ素を1/20程度と少量しか集積せず,有機ヒ素の浄化量も少なくなった。【IV細菌による植物のヒ素集積の促進】土壌栽培したモエジマシダに,有機ヒ素分解細菌株を接種した結果,植物のヒ素集積が約10倍に促進された。また、実汚染サイトでのファイトレメディエーションの実施を見据えた野外実験を行ったところ、細菌による植物のヒ素集積の向上およびヒ素浄化促進を実証した。