Behavior, Treatability Study And Risk Assessment Of Estrogenic Endocrine Disruptors In Biological Sewage Treatment Process

This study was conducted to investigate the behavior and treatability of the selected estrogenic endocrine disruptors (EEDs) during biological sewage treatment process. After sample pretreatment, LC/MS/MS analysis was applied to detect the concentrations of EEDs. Quantitative structure-activity relationship analysis was performed to study the corelations between sludge-water partition coefficients (Kps) and molecular structure parameters. In anaerobic reactors, linear correlations were obtained upon using the octanol-water partition coefficient and molecular length as individual parameters. When comprehensively analyzing the Kps and removal rates of the EEDs, it was suggested that, biodegradation was the major pathway for the removals of estriol, bisphenolA, daidzein and genistein, while both biodegradation and sludge adsorption contributed to the removals of other five EEDs.To holisticly assess the removal effects and the environmental risk of effluents from different treatment processes, yeast estrogen screen assay (YES) was employed to determine the overall estrogencic activity (estradiol equivalent quantity, EEQYES) of water samples. It was found that upflow anaerobic sludge blanket (UASB) and anaerobic filter (AF) showed the highest removals. Risk assessment of water samples was performed based on USEPA's aquatic criteria for nonylphenol and proposed German environmental quanlity standard (by Hansen, 2007). It was noted that some influents'nonylpehnol equivalent quantity (NEQ) exceeded the EPA standard, while the NEQs of UASB and AF effluents were below its hour average concentration. Concentrations of 17α-ethinylestradiol, BPA, 17β-estradiol and 4-nonylphenol in influents and effluents were above the proposed German standard. However, the concentrations of genistein in most effluents were below the proposed German standard.Additionally, to explore a high-throughput screen method for EEDs based on proteomic techniques, the specified protein expression profile of human breast cancer MCF-7 cell treated with E2 was investigated. More down-regulated proteins were observed than up-regulated proteins. It also provided a new clue to study the action mechanism of EEDs.In general, removal efficiency of EEDs by different anaerobic-aerobic treatments was evaluated in this study. The results showed that the environmental risk of both individual EEDs and overall estrogenic activities in effluents could not be ignored. It was suggested that optimal operation condition of bioreactor and additional treatment etc. are needed to improve the water safety of the effluents. Moreover, the attempt on proteomic study provided an innovative thread to develop high-throughput screen method for EEDs and a scientific basis for relevant environemtal risk assessment.