Residue of PCB, DDT and HCH in fish from lakes and rivers in the world was reviewed from the surveys in the years of 1990's. PCB and DDT concentrations of fish in the Great Lakes of USA and Lake Baikal were higher than those in the other lakes in the world. PCB concentrations of fish in Lake Michigan were about 100 times higher than those in Lake Biwa, but there was a common feature that the PCB concentrations in both lakes were decreasing till mid '80s and have been constant since then. On the other hand, PCB concentrations of fish in the rivers around the Great Lakes of USA and River Seine and DDT and HCH concentrations of fish in River Ganges were higher than those in the other rivers in the world. The use of DDT was presumed in Russia and Kenya from the high percentage of pp'-DDT in the composition of DDT and its metabolites in the several kinds of fish in Lake Baikal and Lake Naivasha. No use of DDT was presumed in USA, Egypt and European countries from the low percentage of pp'-DDT in the lake and the river fish in the countries. High concentrations of HCH in lake and river fish could not be found in this review, but the use of technical HCH was presumed in Japan, China and Russia from the low percentage of γ-HCH in the composition of HCH isomers in the lake and the river fish in the countries. On the contrary, the use of lindane was presumed in USA and European countries from the high percentage of γ-HCH in the lake and the river fish in the countries.

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Despite deep concern of the general public about protection of the natural environment, research on risk assessment of endocrine disrupting chemicals (EDCs) for wildlife as the principle object has been behind still now. Reproductive disorder caused by organochlorine chemicals in wild birds is most representative of adverse effects on wildlife and has been reported from the earliest stages. Avian species seem to be most suitable for evaluating the existence or extent of destruction of the natural environment by EDCs in consideration of extensive habitats of wild birds and high their position in food chains. Fundamental investigation in embryology has gradually explicated the mechanisms of differentiation of the gonad and reproductive behaviors in birds. The results in these studies may be effective in researches on the mechanisms of adverse effects by EDCs and in development of the methods for assessing and screening EDCs.

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This review deals with reaction mechanism of reductive dechlorination of polychlorinated Biphenyls (PCBs) . Characteristic features of PCBs decomposition by (1) gamma ray irradiation, (2) reduction with alkali metal or alikaline earth metal, (3) reduction with transition metal, (4) electrolytic reduction, (5) catalytic hydrogenation, and (6) photolysis are described from a point of view of reaction mechanism and physical chemistry.

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Recently, liquid chromatography-mass spectrometric determination of trace environmental pollutants has been significantly improved by the progress of atmospheric pressure chemical ionization (APCI) and electro spray ionization (ESI) . This review describes the advance of environmental analysis by liquid chromatography-mass spectrometry (LC/MS), based on 336 literatures published from 1995 to 2001. Total number of chemical substances listed in this review is 384, including agricultural chemicals (55%) and others (45%) such as nonionic surfactants and their metabolites, phenols, MX, carbonyl compounds, and estradiol and related compounds. Relationship between chemical structure and sensitivity in LC/MS is discussed and several examples of environmental analysis by LC/MS are also introduced.

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Recent findings in the field of bioremediation, phytoremediation and rhizoremediation were reviewed with emphasis on the introduction of new developing technologies for the remediation of contaminated sites by persistent organohalogen compounds and heavy metals. Bioremediation has been actively studied and entered a new study phase. The number of reports on the monitoring or manegement techniques for the microbial population changes or enzyme activity levels during bioremediation on site were increasing. The phytoremediation and rhizoremediation technologies are being actively developed, and attract much attention since their control is easier than that of bioremediation. Many transgenic plants or bacteria expressing enzymes for biodegradation of pollutants have been created.

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The electrochemical decomposition for several kinds of organic pollutants such as diethylphthalate, naphthalene and ethylenediaminetetraacetic acid, which belong to the groups of endocrine disrupter chemicals, polycyclic aromatic hydrocarbon and artificial organic ligand, respectively, were investigated. The rate of electrochemical decomposition depends on the structure of these compounds and the material of the electrode. The electrochemical decomposition of these compounds with a constant current showed the higher efficiency by using a SnO₂/Ti electrode than by a Pt/Ti electrode. The total organic carbon (TOC) in the solution containing each compound was also removed over 90%. Therefore, these compounds seem to be decomposed to carbon dioxide and water completely. Consequently, it was confirmed that the electrochemical decomposition method could be applied to a variety of organic pollutants under the relatively mild condition and with the higher efficiency.

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Principal component analysis and multiple regression analysis were applied to profiles of 19 polychlorinated biphenyl congeners (dioxin-like congeners, di-ortho congeners, IUPAC #28, #52, #101, #138 and #153) . Application of principal component analysis to PCB congener profiles of various samples (municipal solid waste, automotive shredder residue, emission gas, municipal solid waste incineration ash, environmental media and Kanechlors) yielded 3 principal components. The first principal component scores were positive for emission gas and ash, and negative for Kanechlors. From this, the first principal component was interpreted as the similarity to incineration congener pattern. Eigenvectors for penta- and hexachlorinated isomers were highly positive on the second principal component, and eigenvectors for heptachlorinated isomers were highly positive on the third principal component. From these, the second and the third principal components were interpreted as the degree of chlorination. To estimate the contributions of each PCBs source (emission gas and Kanechlors), multiple regression analyses with the 3 congener profiles (emission gas, KC-400 and KC-600) as the independent variables and profiles of the samples as the dependent variables were carried out. Results of multiple regression analyses varied with samples. Samples whose first principal component scores are negative and second ones are positive showed positive partial regression coefficients corresponding to KC-400 and KC-600. Samples whose first and second principal component scores are negative showed high positive partial regression coefficients corresponding to KC-400. Contributions of each PCBs source varied with congener. Contribution of emission gas was predominant for congeners #81, #126, #169 and #189, #105, #118, #170, #180, #28, #52, #101, #138 and #153 have a big contribution of Kanechlors.

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Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in sediments (coastal, river, pond) and sediment core from Matsuyama, Japan, were analyzed to evaluate the distribution and historical trend of these compounds. PCDD/Fs concentrations in coastal sediments were relatively higher than river and pond sediments. The PCDD/Fs in atmosphere were mainly originated from combustion process and moved to soil by dry and wet deposition. The PCDD/Fs in soils were then entered into aquatic environment through run off. PCDD/Fs in paddy soil that contaminated from impurities of 2, 4, 6-Trichlorophenyl 4-nitrophenylether (CNP) and Pentachlorophenol (PCP) also flowed out to the sea through the rivers. Then PCDD/ Fs in river and seawater deposited to the bottom sediment.
PCDD/Fs contamination was clearly observed during 1960s-1980s, and ther environmental PCDD/Fs levels have been reduced in recent years.
Accumulation flux and deposition velocity to bottom sediment were calculated based on the data of the Matsuyama. The analytical data show that most of PCDD/Fs in water was bound to particles.

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Chlorine-disinfected sewage effluent poses a risk to aquatic organisms, prompting the need for an innocuous alternative disinfection method. In this study, the toxicity of secondary effluent disinfected with chlorine, chlorine dioxide, ozone and UV irradiation was evaluated by the algal growth test using the green alga Selenastrum capricornutum. Algal growth was significantly inhibited in test media containing 10% chlorinated water. In the chlorination process, about 50% of chlorine remained in the disinfected water as oxidant, while about 80% of residual oxidant was monochloramine (NH₂Cl) . NH₂Cl is the most toxic substance that inhibits algal growth in chlorinated sewage effluent. On the other hand, chlorine dioxide and ozone disinfection apparently did not inhibit algal growth, but the possibility of chlorophyll biosynthesis inhibition was indicated. Effluent dechlorinated with sodium sulfite, which removes residual oxidants such as NH₂Cl, did not inhibit algal growth. Our results have shown that the algal toxicity of the disinfection methods follows this order: chlorine >> chlorine dioxide > ozone. In contrast, UV-irradiated effluent did not harm the algae. This shows that UV irradiation, which is harmless to aquatic organisms, is adequate enough for disinfecting treated sewage effluent.

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Concentrations of tributyltin (TBT) and triphenyltin (TPT) compounds were determined in seawater, bottom sediments and fish and shellfish at various trophic levels in the marine benthic food web collected in Japan Sea to clarify the difference in the bioaccumulation pattern between TBT and TPT in the deep sea ecosystem. TBT was detected in all samples: 0.3-0.8 ng/l for the seawater, 4.4-16 ng/g-dry for the sediment and 1.8-240 ng/g-dry for various kinds of organisms. This deep seawater concentration is lower than the coastal water concentrations. Concentration of TPT in seawater was less than our detection limit (0.9 ng/l), but it was 3.9-12 ng/g-dry for the sediment and 5.0-460 ng/g-dry for the organisms. TPT concentrations of the sediments and organisms were similar to those reported in Tokyo Bay in 1999. TPT concentration becomes higher as the trophic level increases, suggesting the bioaccumulation of TPT through the food web. However, no such trend was observed for TBT. The higher TPT concentration in the benthic organisms than in the sediments implies that TPT can be transferred to benthic organisms from bottom sediments and that the sediments can act as a secondary contamination source of TPT.

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The effect of a model humic constituent, protocatechuic acid, on the enzymatic transformation of 3, 4-dichloroaniline (DCA) catalyzed by horseradish peroxidase (HRP) was studied. The presence of protocatechuic acid caused an increase in the rate of DCA transformation, resulting in an 80% transformation after 15 min of incubation, compared with 50% when DCA was incubated alone.
The polymeric reaction products were analyzed by pyrolysis-GC/MS. More than 60% of the pyrolysis products from the DCA alone reaction product were tetrachlorodiazobenzene while this compound was not detected at all in pyrolysis products of DCA in the presence of protocatechuic acid. The major pyrolysis product in the latter case was DCA itself, which appears to have been cleaved from anilinoquinone or enaminone subunits.
In addition to these major pyrolysis products, some minor peaks i.e. formanilide, diphenylamine, phenylpyrrole and isocyanobenzene were also detected. These were consistent with NMR data on the same product and are thought to represent major subunits that are resistant to cleavage from the polymer by pyrolysis.

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This study investigated the concentrations of polychlorinated biphenyls (PCBs) and the specific compositional characteristics in the tidal flat sediments collected from the Ariake Sea. In general, the residue levels were several ten ng/g (dry wt.), which is comparable to those to Japanese coastal waters and lower than those of other Asian countries. In contrast, maximum concentrations of PCBs were found in river sediments (3, 900 ng/g dry wt.), indicating that the large amounts of PCBs discharge occurred. The principal component analysis (PCA) applied to PCB congener compositions in all sediments provided the construction of three different groups. The result implies that the profile of PCBs sources is different among sampling sites. Isomer compositions of PCBs in several sediment samples were compared with those of technical PCBs products, such as Kanechlor (KC) -300, 400, 500 and 600 by using the fingerprint method. The PCB isomer patterns in river sediment was resembled with those in the KC-400, which is indicator of greater di-, tri-, tetra- and pentachloro biphenyls. The Biota-Sediment Accumulation Factors (BSAFs) were calculated from the concentrations of PCBs in oysters and sediments from the heavily contaminated river. The relationship between BSAFs and log Kow suggested that higher chlorinated congeners were likely to retain in the sediment through the river systems.

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We used a pollen culture method to evaluate the in vitro cytotoxicity of trichloroethylene (TCE) and tetrachloroethylene (PCE) in a liquid medium. Cytotoxicity was evaluated for various concentrations of TCE or PCE in the medium, in which pollen tubes of tea were grown. Inhibition of pollen tube growth was observed with the addition of more than 44.2 mg/l of TCE or 2.8 mg/l of PCE.
The IC₅₀ of TCE was about 71.6 to 140 mg/l, and for PCE about 5.9 to 12.7 mg/l This test can be performed easily and quickly and may be useful for in vitro cytotoxicity evaluation of these volatile compounds.

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Carbendazim (MBC) and thiabendazole (TBZ) in river sediments were determined by a liquid chromatograph/tandem mass spectrometer equipped with an electrospray ionization interface (LC/ESI-MS/MS) . A simple and rapid procedure using ultrasonic extraction and solid-phase extraction was evaluated to minimize the ion-suppression. The proposed methodology proved its applicability to sediment samples. Mean recovery of an internal standard MBC-d3, spiked to the ultrasonic extract was 64.0 %, with the relative standard deviation of 6.0 %. The corrected recoveries of MBC and TBZ for sediment spiked at 5 ng/g were 92.9 % and 95.6 %, respectively. Detection limits (S/N =3) of 0.06 ng/g for MBC and 0.07 ng/g for TBZ in sediment have been achieved.

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We have developed a solid-phase extraction method for determination of three pesticides, thiuram, simazine and benthiocarb, in distilled water, river water and industrial waste water by high performance liquid chromatography (HPLC) with ultraviolet detecter (UV) . As a result, good linearity of the calibration curve was obtained in the concentration range from 0.1 mg/l to 1 mg/l. Acetone was recommended for the elution of the pesticides from the solid phases. The recoveries for three pesticides from river water and industrial waste water at a concentration of 0.1 mg/l was 83.3-91.6 %, and coefficient of variation was 4.3-6.0 % by cartrige solid-phase extraction method. This analytical method could be successfully applied to the determination of three pesticides in river water and industrial waste water.

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