[Spatio-Temporal Patterns and Environmental Risk of Endocrine Disrupting Chemicals in the Liuxi River].

This study aimed to investigate the occurrence and spatio-temporal distribution of 4-tert-octylphenol (4-t-OP), 4-nonylphenol (4-NP), triclosan (TCS), estrone (E1), 17ß-estradiol (E2), and bisphenol-A (BPA) as endocrine disrupting chemicals (EDCs) in the water of the Liuxi River and to evaluate the risks for estrogenic activity. The results showed that EDCs had been detected at the 14 monitoring sites and the total concentration ranged from 26.07 ng·L-1 to 7109.5 ng·L-1, with the highest contribution rate coming from 4-NP (78.62%), followed by BPA (11.91%), and the other four EDCs (≤ 4.92%). On a spatial and temporal scale, the EDC contents increased longitudinally from upstream to downstream, especially in the heavily-polluted Baiyun section where the water quality was lower than level Ⅴ. The EDC contents in the tributaries were much higher than those in the main channels. Influenced by the monsoon precipitation, the contents of 4-NP, 4-t-OP, and total EDCs in the rainy season were significantly (P<0.05) higher than those in the dry season, while the seasonal changes of E1 and E2 followed the opposite tendency. A Pearson correlation analysis showed that DO was significantly negatively correlated with all the EDCs, suggesting that the EDCs and reductive organic pollutants might coexist. As TN, TP, NH4+-N, permanganate index, and EC were significantly positively correlated with E1, E2, BPA, and TCS but not obviously correlated with 4-NP (P>0.05), we presumed that the pollution source of E1, E2, BPA, and TCS might be the same with nitrogen and phosphorus nutrition, originating from the point source emission of the domestic sewage, industrial, and agricultural wastewater. In contrast, 4-NP and 4-t-OP more likely originated from the non-point source pollution from agriculture. RDA results showed that the variation of the EDCs contents by season was more obvious than that in space (RDA1 56.14%>RDA2 14.20%), which was much more influenced by 4-NP in the rainy season and by BPA in the dry season. As E1, E2, and TCS were positively correlated with the Cu, Zn, cyanide, and fecal coliform, these three target compounds could be used to indicate the multiple pollution components for water quality. Compared with the worldwide reported EDC contents in waters, 4-NP, BPA, and TCS contents in the middle and lower reaches of the Liuxi River were at higher levels, while E1, E2, and 4-t-OP were at the middle and lower levels. The risk assessment for estrogenic activity showed that the RQ values in the middle and lower reaches of the Liuxi River were all greater than 1, indicating that the downstream river sections were under high risk for estrogenic activity. As a result, appropriate precautions are needed to improve environmental management.

[Removal Behavior of Ibuprofen and Diclofenac in Different Constructed Wetlands].

Ibuprofen and diclofenac, two commonly used pharmaceuticals, were studied to evaluate the removal behavior of acid pharmaceuticals in constructed wetlands (CWs) with different flow types, vegetation and seasons. It was shown that flow types influenced the results significantly. The average removal efficiency of ibuprofen in horizontal subsurface flow (HSSF) and vertical subsurface flow (VSSF) CWs (69% and 60%, respectively) was significantly higher than that in surface flow (SF) CWs (26%). For diclofenac, SF CWs (58%) was significantly higher than HSSF and VSSF CWs (49% and 43%, respectively). In addition, the presence of plants improved the efficiency of ibuprofen, while it had no significant influence on the removal of diclofenac. Paired t-test found out that summer and autumn season variety had little impact on the removal. Furthermore, the removal of diclofenac and DO, as well as COD, showed very significant negative correlations. Opposite to diclofenac, the removal of ibuprofen had good positive correlations with dehydrogenase activities. The research indicated that aerobic biodegradation behavior mainly took place in ibuprofen, yet anaerobic biodegradation and photolysis behavior were expected for diclofenac.