The existence of pharmaceuticals and personal care products (PPCPs) in the water environment is an emerging problem. In this study, we investigated the toxicity of eleven PPCPs through bioassays on bacteria, algae, crustaceans, amphibians and protozoa, and compared the toxicology indexes with the concentration of PPCPs in river water for ecotoxiclogical risk evaluation. Toxicity of the eleven PPCPs was observed and the values of EC50 or LC50 were in the order of mg/L. A distinctive finding is that antibacterial triclosan affected all aquatic lives tested. The effects of PPCPs varied according to species of lives. Contamination from PPCPs was detected at observation stations on the river, and the range of concentration was in the order of ng/L far lower than the values of toxicity indexes EC50 or LC50. Ecotoxicological risks posed by PPCPs at the observation stations was evaluated using the concentration in the river water and the NOEC examined by AGI tests. The results revealed that three PPCPs, triclosan, clarithromycin, and azithromycin, posed an ecotoxiclogical risk in rivers where wastewater treatment systems are not yet well developed.
The objective of this study is to evaluate the effect of estrogens on fish endocrine disruption in river water and treated wastewater. Endogenous estrogen estrone (E1), 17b-estradiol (E2), river water, and treated wastewater were used for exposure tests on male Japanese medaka. Vitellogenin induction in male medaka was regarded as the endpoint of endocrine disruption. The effective concentrations of E1 and E2 on vitellogenin induction in medaka were evaluated by breeding medaka for 14 days in tanks with various concentrations of E1 or E2. Vitellogenin induction increased with elapse of time during exposure, with higher estrogen concentrations causing greater vitellogenin induction. According to the test results, the lowest observed effect concentrations (LOECs) of E1 and E2 were estimated to be 31.6 and 5.0 ng ⁄ l, respectively; and the E2 equivalent (EEQ) LOEC value of E1 was 5.2 ng-E2 ⁄ l, derived by multiplying the relative potency of E1 by that of E2 as estimated in this study. In continuous exposure tests using river water or treated wastewater, the estrogenic activity, an index of total estrogenic potential measured by yeast screen assay and expressed as EEQ, varied widely during the exposure tests, and significant vitellogenin induction was observed after several days of high levels of estrogenic activity in water. Vitellogenin concentration tended to significantly increase if EEQ exceeded the level of 5 ng-E2 ⁄ l. The threshold value was substantially the same as the results for E1 and E2 exposure tests of medaka. Consequently, EEQ over 5 ng-E2 ⁄ l was revealed to have the potential to cause endocrine disruption of male medaka. As estrogenic activity exceeding 5 ng-E2 ⁄ l was observed in some rivers in Japan, total estrogenic potential needs to be further decreased at wastewater treatment plants to prevent fish endocrine disruption.
The Bureau of Sewerage, Tokyo Metropolitan Government, has been implementing various measures to reduce greenhouse gas (GHG) emissions. However, measures to reduce Nitrous Oxide (N 2 O) emission from wastewater treatment, which amounts to about 16% of the GHG emission from the Bureau, has been delayed since little is known about its behaviors and factors which affect its emission. The Bureau installed continuous N 2 O analyzer in a wastewater treatment plant (WWTP), and conducted continuous measurement of N 2 O emission for one year. The results showed that N 2 O emission fluctuated significantly and was affected by nitrogen load of influent and nitrification condition in reaction tank.
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