Effects of the widely used herbicide diuron on growth of the freshwater green alga, Pseudokirchneriella subcapitata, were investigated in C medium with different nitrate （15, 150 or 1501 μM） or phosphate （1.6, 16.3 or 163 μM） levels at three water temperatures （10, 20 and 30°C） for 144 h. Growth was inhibited by 16 μg L^–1 diuron in all cases. Results from generalized linear model （GLM） analysis showed that the growth inhibition rate by diuron treatment was significantly decreased by increased temperature and decreased nutrient levels. Our result indicated that diuron toxicity may decrease under conditions of high temperature and low nutrients. Therefore, nutrient levels at different water temperatures should be considered in risk assessments to learn the actual impact of diuron in real environmental conditions.

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Perfluorooctane sulfonate（PFOS）is the environmentally persistent compound distributed all over the world. Earlier studies suggested that PFOS is accumulated and give the adverse effects for the organism. Particularly, some studies suggested that PFOS binds to the blood plasma protein. Most of studies performed in vitro exposure experiment not in vivo condition. This study, we conducted in vivo experiments to identify PFOS binding protein in the plasma of rat. PFOS was administered intraperitoneally to Sprague Dawley rat at dose of 1 mg/kg b.w. The plasma obtained was separated by ammonium sulfate precipitation. The highest concentrations of PFOS （1507 ng/mL）and protein（20.7 mg/mL）were found in the 50-55% saturated ammonium sulfate fraction. SDS-PAGE and N-terminal amino acid sequence analysis in the 50-55% saturated ammonium sulfate fraction showed that the rat serum albumin（RSA） was identified as PFOS-binding protein. This is the first report to demonstrate that PFOS is bound to RSA under in vivo condition.

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The toxicological effects of river water on the reproduction of the water flea Daphnia magna were assessed with the standard 21-d chronic test（OECD TG211）at four river sites（St. 1–4）in rural districts of the Kanto Plain（Ibaraki Prefecture, Japan） at monthly intervals from April 2007 to March 2010. Over the 3 years, we recorded the following average numbers of live D. magna offspring after the 21-d tests: 17–233, 14–223, 29–210, and 84–209 in St. 1, 2, 3, and 4, respectively. The average numbers in August 2007, May and September 2008, and April 2009 at St. 1; August 2007 and May 2008 at St. 2, and June 2007 and April 2009 at St. 3 were significantly lower than those of the control（ANOVA, P < 0.01）. The results of the above tests suggest that D. magna may be affected not only by the overall pesticide toxicity in the river water, but also by other factors that were not clarified in the present study. In addition, significant positive correlations were observed at each site between the body length of D. magna and the total number of offspring at 7 d（r² = 0.783）, 14 d（r² = 0.772）, and 21 d（r² =0.931）after the test began on 10 May 2008. These findings suggest that the body length of D. magna might be used to evaluate the toxicological effects of river water, even at 7 d, by using the standard chronic toxicity test.

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The toxic effects of cadmium, zinc, copper, and nickel ions and their pyrithione complexes on Daphnia magna embryos and juveniles were evaluated. Four- to 8-hourold embryos were obtained from the mother’s brood chamber and immediately exposed to various concentrations of each test substance for 120 hours. Embryonic toxicity was determined by evaluating the inhibition of hatching and the immobilization of the embryos after 72, 96, and 120 hours. Juvenile D. magna（less than 24 hours after release by the mother）were also exposed to the test substances for 48 hours. The results of all tests were analyzed and the median effective concentration（EC₅₀）of each test substance was calculated. Cadmium ion exhibited significant toxicity during embryonic development, causing arrested development and immobilization of embryos exposed to a Cd²⁺ concentration of 0.2×10^-7 mol/L（2.2 μg/L）. The 48-hour EC₅₀ value for the immobilization of juveniles was about 10-fold greater than the 120-hour EC₅₀ value for inhibited hatching and immobilization of embryos. Cadmium pyrithione complex had a greater effect on embryonic development than cadmium ion. Analyses of the toxic effects of other metals indicated that D. magna embryos are more sensitive to heavy metals than are juveniles. The 120-hour EC₅₀ values for the heavy metal ions examined were similar to the values at the endpoints of chronic 21-day reproduction tests reported in the literature. These observations suggest that the embryonic developmental test allows for rapid and sensitive early life-stage determination of heavy metal toxicity and is thus an alternative to the 21-day reproduction test.

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