The activities of ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, monodehydroascorbate reductase, and ascorbic acid and glutathione contents increased in response to mercury accumulation in E. crassipes . This enhancement in the glutathione-ascorbate Cycle components was observed in response to mercury in solution up to a concentration of 100 μg l^-1, whereas, at a concentration of 1000 μg l^-1 the enzyme activities decreased. Roots accumulated maximum amount of Hg, and there was a significant positive correlation between Hg accumulated and components of the glutathione-ascorbate cycle in E. crassipes , during phytoremediation of mercury.

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Concentrations of natural estrogens such as 17β-estradiol(E2)and estrone(E1)in the water collected from sewage treatment plant(STP)were determined by ELISA. The concentration of natural estrogen in treated water decreased gradually through the treatment processes, but the concentration in the effluent water of final sedimentation tank (after activated sludge treatment)was still high. The residual ratio of the concentration of estrogens in the water of final sedimentation tank to those in the water of primary sedimentation tank(100%)ranged 25.9 - 50 %(E1)and 65.8 - 90.9 %(E2).However, the levels of estrogens in the water after stone contact oxidization(treatment process using biofilm on the surface of sgravels)decreased markedly, and the residual ratio ranged 3.5 -5.1 %(E1)and 10.7 - 12.1 %(E2). Degradability of estrogens by the microorganism in biofilm on surface of gravels was investigated using gravels collected from stones contact oxidization of sewage treatment plant, and in Muko River, Hyogo Prefecture. E2 and E1 were degraded within 2 - 3 days, and ethynylestradiol(EE2)being synthetic estrogen was degraded after about 10 days by the gravels of STP, whereas E2 and E1 were degraded within 5 - 6 days and 8 -9 days, respectively, by the gravels collected from Muko River, and it took 10 days more for the degradation of EE2. The biodegradation capability of E1 by biofilm on the surface of gravels in STP was superior to those in Muko River.

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In order to evaluate genotoxicity of water samples such as river water and tap water by the umu-test, improvement of ISO 13829 method and an efficient solid phase extractionconcentration method for pretreatment of water samples were studied. A quantitative measure of DNA-damaging potential, GA(Genotoxic Activity) was proposed to compare the strength of genotoxicity among various water samples. Then, temperature and duration of the first bacteria culture were modified from 37 °C, 8-12hr to 30 °C, 16-18hr to improve the performance of the ISO method, and the concentration of dimethylsulfoxide (DMSO) in the test solution was increased from 4.5% of the ISO method to 12% based on no growth inhibition of bacteria. As a result, sensitivity of the method is suggested to be improved 2.67 times compared with the ISO method. A high performance porous polystyrene resin, Sep-pak plus PS-2 cartridge, was used to enrich genotoxicants in water samples. By comparison with 7 other volatile organic solvents, DMSO was proved to be most effective to desorb genotoxicants from PS-2. One PS-2 cartridge was able to adsorb genotoxicants from 1.5l of water samples those DOC are under 10mg/l, and the adsorbed genotoxicants could be completely desorbed with 1.5 ml of DMSO. It was confirmed from the applications to various water samples, such as tap water, river water and treated sewage water that the genotoxicity could be evaluated quantitatively by the developed method.

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A program for presenting quantitative structure-activity relationship(QSAR) was developed and named PAS(Platform for Assessment from Structure). Though this development is still continuing, the efficiency of PAS is ascertained. I herein provide an outline of PAS and the know-how acquired. The disclosure of details of PAS can be a help for people who are interested in QSAR presentation. In Part 1, the extraction method of the component from the SMILES notation is discussed.

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