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Removal of chlorpyrifos and its hydrolytic metabolite 3,5,6-trichloro-2-pyridinol in constructed wetland mesocosms under soda saline-alkaline conditions: Effectiveness and influencing factors

Yu, Xiangfei, Zhu, Hui, Yan, Baixing, Xu, Yingying, Bañuelos, Gary, Shutes, Brian, Wen, Huiyang, Cheng, Rui
Journal of hazardous materials 2019 v.373 pp. 67-74
chlorpyrifos, constructed wetlands, decontamination, detection limit, drainage, hydrolysis, lakes, metabolites, nutrients, pH, rivers, slags, stormwater, subsurface flow
Chlorpyrifos (CP) is frequently detected in agricultural effluent worldwide. Both CP and its hydrolytic metabolite 3,5,6-trichloro-2-pyridinol (TCP) can cause serious environment hazards, and require removal before discharged into rivers and/or lakes. The effectiveness and main influencing factors of CP and TCP removal in mesocosm-scale subsurface flow constructed wetlands (SSFCWs) were evaluated. Results indicated that CP in SSFCWs reduced to less than detection limit in 4 d and TCP to 2 μg L−1 in 8 d. Higher influent CP concentrations lengthened the degradation process for both CP and TCP. The presence of co-existing inorganic nutrients restrained the degradation of CP during the hydraulic retention time of 2 h to 2 d. A higher pH resulting from the deterioration of soda saline-alkaline level accelerated the degradation of CP through the hydrolysis process. The SSFCWs with slag operating for another 88 d (i.e., 11 trails with HRT of 8 d for each trial) revealed a better and more stable treatment performance compared with previous studies. The results of this study demonstrated the positive feasibility of using SSFCWs with slag for the decontamination of CP-associated agricultural drainage or stormwater runoff.