Embryonic development assay with Daphnia magna: application to toxicity of aniline derivatives.

An assay system using Daphnia magna embryos was applied to investigate the adverse effects of aniline derivatives. The data were compared with our previous data for chlorophenols. This new assay provides useful information to evaluate the toxicity of chemicals and the differences in sensitivity between the life stages. The effects of 15 aniline derivatives on embryonic development of D. magna embryos were determined. At the start of exposure, 2-6-h old eggs (between stages 1 and 2, round in shape, diameter approx. 400 microm), were used. In control and solvent control groups, embryonic development from an egg to a free-swimming animal proceeded completely within 3 days with more than 90% hatchability. Median effective concentrations (EC50s) to reduce the numbers hatched were determined and gross morphological abnormalities of hatched animals recorded. Anilines induced no obvious morphological abnormalities and no developmental delay although premature deaths occurred. However, they affected the number of embryos hatching in a dose-dependent manner. In addition, this embryo assay was more sensitive to aniline derivatives (except for aniline) than acute juveniles immobilization assay. Ratios of 48-h EC50 (juvenile)/3-day EC50 (embryo) for eight anilines were greater than 5.0. Particularly, the ratios of 4-methyl-, 4-ethyl- and 3-methylaniline were 77, 23 and 11, respectively. EC50s for embryos and juveniles were poorly correlated (r = 0.41). This indicated that the sensitivities of the two life stages were different to the effects of anilines. EC50s were poorly correlated (r = -0.097) with the log Kow (1-octanol/water partition coefficient). These results were compared with previous results for phenols.     

A Mechanical Model for Sieving of Large Deposited Atmospheric Particulates in Surface Soil

A mechanical model for analyzing the sieving of large particulates in soil is proposed and a procedure for assessing soil contamination by airborne hazardous particulates is discussed. The model proposes that deposition of airborne particulates in soil is the results of transport processes of particulates in surface soil. The mechanical sieving of particulates is due to (a) trapping of particulates by the constricted necks of soil pores, (b) adhesion of particulates to pore walls, and (c) suspension in soil water. The probability of particulates being sieved is determined by the cumulative frequency of pore size distribution of the soil. The proposed model indicated that more than 95% of the falling particulates were sieved in the top 5 cm of the surface soil. Furthermore, the model estimated that the unrecorded initial fall of ¹³⁷Cs associated with contaminated particulates was in the range of 2229–2310 kBqm⁻² d⁻¹ and that the unrecorded initial depositions in the 1-cm surface layer were in the range from 129 to 135 kBqkg⁻¹ at a location of about 30 km from the Fukushima nuclear power plant.

     

Monitoring OH-PCBs in PCB transport worker’s urine as a non-invasive exposure assessment tool

In this study, we analyzed hydroxylated polychlorinated biphenyls (OH-PCBs) in urine of both PCB transport workers and PCB researchers. A method to monitor OH-PCB in urine was developed. Urine was solid-phase extracted with 0.1% ammonia/ methanol (v/v) and glucuronic acid/sulfate conjugates and then decomposed using β-glucuronidase/arylsulfatase. After alkaline digestion/derivatization, the concentration of OH-PCBs was determined by HRGC/HRMS-SIM. In the first sampling campaign, the worker’s OH-PCB levels increased several fold after the PCB waste transportation work, indicating exposure to PCBs. The concentration of OH-PCBs in PCB transport workers’ urine (0.55~11 μg/g creatinine (Cre)) was higher than in PCB researchers’ urine (< 0.20 μg/g Cre). However, also a slight increase of OH-PCBs was observed in the researchers doing the air sampling at PCB storage area. In the second sampling, after recommended PCB exposure reduction measures had been enacted, the worker’s PCB levels did not increase during handling of PCB equipment. This suggests that applied safety measures improved the situation. Hydroxylated trichlorobiphenyls (OH-TrCBs) were identified as a major homolog of OH-PCBs in urine. Also, hydroxylated tetrachlorobiphenyls (OH-TeCBs) to hydroxylated hexachlorobiphenyls (OH-HxCBs) were detected. For the sum of ten selected major indicators, a strong correlation to total OH-PCBs were found and these can possibly be used as non-invasive biomarkers of PCB exposure in workers managing PCB capacitors and transformer oils. We suggest that monitoring of OH-PCBs in PCB management projects could be considered a non-invasive way to detect exposure. It could also be used as a tool to assess and improve PCB management. This is highly relevant considering the fact that in the next 10 years, approx. 14 million tons of PCB waste need to be managed. Also, the selected populations could be screened to assess whether exposure at work, school, or home has taken place.     

Investigation of environmental contamination of mono-isopropylnaphthalene, di-isopropylnaphthalene and tri-isopropylnaphthalene in Hyogo in Japan

Di-isopropylnaphthalene (DIPN) has highly persistent and bioaccumulative properties, and a large amount of DIPN is used as a PCB substitute in Japan. However, DIPN in the environment has not been thoroughly investigated. In addition, mono-isopropylnaphthalene (MIPN) and tri-isopropylnaphthalene (TIPN), which are the homologues of DIPN, have similar properties to DIPN. In this study, simultaneous analytical methods for MIPN, DIPN, and TIPN for air, environmental water, sediment, and biological samples were developed, and the resultant contamination caused by each in the environment was investigated. DIPN was detected at 1.1?±?0.38?ng/m³ in air and between <?1.9 and 9.8?ng/L in river water, but MIPN and TIPN were not. In Lateolabrax japonicas (Japanese sea perch), TIPN was detected from only females at between 0.65 and 1.4?ng/g-wet. DIPN was detected from all perches at between 1.2 and 3.4?ng/g-wet. DIPN and TIPN isomer fingerprints in females were different from those in the reference standard stock solution ones. In sediments, MIPN, DIPN, and TIPN were detected at between <?0.16 and 8.6?ng/g-dry, between <?1.1 and 4400?ng/g-dry, and between <?0.83 and 500?ng/g-dry, respectively. The contamination trend of DIPN in the sediments was similar to that of PCBs.     

Sources,spatial variation,and speciation of heavy metals in sediments of the Tamagawa River in Central Japan

Subsurface geochemical behavior of As(V) with Fe(II) was studied under strict anoxic conditions. Abiotic reduction of As(V) (0.1 mM) to As(III) by aqueous Fe(II) and sorbed Fe(II) in pH range 5.0–7.0 and Fe(II)_aq concentration (0.6–1.2 mM) was investigated along with the effect of As(V) on the oxidation of Fe(II) by dissolved oxygen (DO). Although the reduction was thermodynamically feasible for homogeneous chemical conditions, practically no As(V) reduction by aqueous Fe(II) was observed. Similarly, no sorbed As(V) reduction was observed under the heterogeneous experimental conditions by sorbed Fe(II) onto synthetic iron oxide (hematite, α-Fe₂O₃). Experimental results on Fe(II) oxidation by DO in the presence of 0.1 mM As(V) showed a significantly slower Fe(II) oxidation, which might be due to the formation of Fe(II)–As(V) complex in the aqueous phase. The results of this study demonstrate that As(V) is relatively stable in the presence of Fe(II) under subsurface environment and interfere the oxidation of Fe(II).     

Effectiveness of an air cleaner device in reducing aerosol numbers and airborne bacteria from an enclosed type dairy barn

Environmental Science and Pollution Research - There is growing pressure to find technically feasible and economically viable solutions in reducing emissions of pollutants from various occupational...     

Human UDP-glucuronosyltransferase isoforms involved in bisphenol A glucuronidation

Bisphenol A (BPA) is one of a number of potential endocrine disruptors which may affect normal hormonal function. In this study, human UDP-glucuronosyltransferase (UGT) isoforms involved in BPA glucuronidation were studied by kinetic analyses using human liver microsomes and recombinant human UGTs expressed in insect cells (UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A9, UGT2B4, UGT2B7, UGT2B15 and UGT2B17). BPA glucuronidation was catalyzed by UGT1A1, UGT1A3, UGT1A9, UGT2B4, UGT2B7 and UGT2B15 as well as by human liver microsomes. Among these UGTs, UGT2B15 showed the highest activity of BPA glucuronidation at low- (1.0 microM) and high- (20 microM) substrate concentrations. Kinetic analyses of BPA glucuronidation were performed by constructing Michaelis-Menten and Eadie-Hofstee plots. The kinetic profile of BPA glucuronidation by pooled human liver microsomes and UGT2B15 was monophasic, the K(m) and V(max) values were 6.39 microM and 4250 pmol min(-1)mg(-1)protein for pooled human liver microsomes, and 8.68 microM and 873 pmol min(-1)mg(-1)protein for UGT2B15, respectively. The K(m) values for BPA glucuronidation by pooled human liver microsomes and UGT2B15 were similar. These findings demonstrate that BPA is mainly glucuronidated by UGT2B15 in human liver microsomes, and suggest that this UGT isoform plays important roles in the detoxification and elimination of BPA.     

Screening of climatic impacts on a country’s international supply chains: Japan as a case study

Industrial activities are linked through international supply chains, and the impacts that one country experiences can easily influence other countries. Climate change has made it essential for countries to review their supply chains and to prioritize introducing concrete adaptation actions. Therefore, this study aims to demonstrate a method of screening imported products that are highly vulnerable to the impacts of climate change by assessing all imported products in a consistent manner throughout the global supply chain to support a country’s adaptation strategy planning. The study focuses on the potential impacts on land use and human health of climate change effects such as floods and heat waves. Japan was selected for a detailed analysis of its imports. A life-cycle assessment technique was applied to evaluate imported products through their supply chains. In Japan’s case, land use results show that agricultural products imported from the United States of America (US) are highly vulnerable to climate change impacts. In relation to imported meat products, feed production processes are most vulnerable. The human health results show in addition to agricultural imports, electronics and textile imports are also vulnerable. The study recommends that the relevant stakeholders impacted by these products scrutinize their supply chains. Especially, Japan is recommended to collaborate with the US, China, and Southeast Asian countries for increasing resilience to climate change. The results include uncertainties due to limitations of data availability and methodology; however, this method is also applicable to assessing the global trade activities of any country and to supporting global adaptation strategies.     

Dehydrochlorination behavior of polyvinyl chloride and utilization of carbon residue: effect of plasticizer and inorganic filler

The dehydrochlorination behavior of plasticizer (DOP) and inorganic filler (CaCO₃) contained in PVC samples and the properties of the activated carbons produced from those carbon residues have been investigated. In the dehydrochlorination process, both additives contributed not only to a decrease in HCl yield but also to the prolonged evolution of HCl. Part of the Cl species were observed to be stabilized as CaCl₂ by reaction with calcium ions when CaCO₃ was added. More than 80% of chlorine removal was achieved in all samples at 533 K. The use of potassium as an activation agent led to the production of activated carbon with a specific surface area greater than 1000 m²/g at the low temperature of 1023 K and assisted also in the elimination of residual Cl species by the formation of KCl during activation. Chemical Feedstock Recycling & Other Innovative Recycling Techniques 6     

Ultra-High Efficiency Photovoltaic Cells for Large Scale Solar Power Generation

The primary targets of our project are to drastically improve the photovoltaic conversion efficiency and to develop new energy storage and delivery technologies. Our approach to obtain an efficiency over 40% starts from the improvement of III–V multi-junction solar cells by introducing a novel material for each cell realizing an ideal combination of bandgaps and lattice-matching. Further improvement incorporates quantum structures such as stacked quantum wells and quantum dots, which allow higher degree of freedom in the design of the bandgap and the lattice strain. Highly controlled arrangement of either quantum dots or quantum wells permits the coupling of the wavefunctions, and thus forms intermediate bands in the bandgap of a host material, which allows multiple photon absorption theoretically leading to a conversion efficiency exceeding 50%. In addition to such improvements, microfabrication technology for the integrated high-efficiency cells and the development of novel material systems that realizes high efficiency and low cost at the same time are investigated.