[Removal of Estrogenic Effect by Typical Domestic Wastewater Treatment Processes].

Targeting at the characteristics of low concentration but high risk of endocrine disrupting compounds in the aquatic environment, the current study investigated the distribution of estrogenicity and E2 level using recombinant yeast estrogen screen (YES) and enzyme linked immunosorbent assay (ELSIA) during domestic wastewater treatment processes. The results showed that the levels of estrogenicity and E2 in influents of wastewater treatment plants were 4.35-7.58 ng·L-1 and 36.95-83.43 ng·L-1, respectively. It was found that biological treatment processes played a crucial role in the removal of estrogenicity and E2, such as oxidation ditch, A2/O and A2/O followed by MBR, where the removal of estrogenicity and E2 was 71.10%-75.54% and 75.88%-80.72%, respectively. The activated sludge, with an estrogencity level of 1.84-2.43 ng·g-1 and an E2 level of 8.45-12.84 ng·g-1, had the function of eliminating estrogenic effect to a certain extent by adsorption. The estrogenic activity in the effluent of domestic wastewater was 1.06-2.19 ng·L-1, which will pose potential risk to the aquatic life in the environment. Last but not least, ELISA had a good correlation with YES assay, which provides a new method for rapid screening and assessment of water environmental estrogen.

[Biological Toxicity Evaluation of Domestic Wastewater Based on A2/O Treatment Processes Using a Battery of Bioassays].

In order to accurately evaluate the comprehensive ecotoxicity of domestic wastewater and the toxicity reduction efficiency of different treatment processes, standardized assays focusing on Vibrio fischeri, SOS/umu test and yeast estrogen screen were applied. Simultaneously, male zebrafish was used to address the mode of action of endocrine disrupting effects of wastewater and reclaim water on aquatic life. Results of this study indicated that the influent was severely polluted:highly acute toxicity, genotoxicity and estrogenicity were observed. After the secondary biological treatment, the above toxicities were significantly reduced, making the water quality improved. However, the estrogencity of secondary effluent was detected at 1.89 ng·L-1, which still posed potential risk on the aquatic life in receiving water. In addition, the up-regulation of estrogen receptor (esr 1) and vitellogenin (vtg 1) in the livers of zebrafish was observed after exposure to 2.5 times concentrated wastewaters, which demonstrated that wastewater modulates hormonal activities of aquatic life by disturbing target genes expression. Moreover, the slight down-regulation of esr 1 was observed in the gonads. These observations reflect that the evaluation of biological toxic effect should be analyzed in different tissues or organs, so that more comprehensive information about the adverse effects of wastewaters on aquatic life can be obtained.