Effect of Drinking Water Treatment Residuals on the Chlorpyrifos Residues in Paddy Soil
FU Guangyi;XU Youze;PEI Yuansheng;QI Yun;ZHAO Yuanyuan;Key Laboratory of Water Pollution Control Technology of Hunan Province,Hunan Research Academy of Environmental Science;Key Laboratory of Water and Sediment Science of Ministry of Education,School of Environment,Beijing Normal University;
The research has confirmed that drinking water treatment residuals(WTR) as soil additives has great potential to control the migration of chlorpyrifos in agricultural areas, however, the effect of WTR on the chlorpyrifos residues in paddy soil remains to be studied. Therefore, in this study, the residue characteristics of chlorpyrifos and its metabolites TCP in WTR-amended paddy soil aqueous solution system under different application concentrations of chlorpyrifos was investigated using 72 days anaerobic incubatation test. Results showed that the total residual quantities of chlorpyrifos and TCP in the soil aqueous solution system were both enhanced with the increasing chlorpyrifos application concentration and WTR amendment rate(w=0~10%). Within the application concentration of 5~25 mg/kg, WTR has significant effects on the chlopyrifos degradation rate. Compared with the soil aqueous solution system without WTR amendment, the chlopyrifos degradation rate reduced by 6%~19% and the total amount of chlorpyrifos increased by 46%~66% in the soil aqueous solution system amended with 10%(w) WTR. Further analysis shows that this is mainly due to the reduced bioavailable content of chlorpyrifos and TCP caused by WTR amendment. Following 10%(w) WTR amendment, the quantity of bioavailable chlorpyrifos was reduced by 48%~69% under different applying concentrations of chlorpyrifos. Up to 59%~75% of the total TCP existed as the stable residual form in WTR-amended soil, while about 89% of the total TCP existed as bioavailable form in non-amendedsoil. Total soil bacteria abundance was increased by 1.6 times following 10% WTR amendment, indicating that WTR amendment weakened the toxicity of the chlorpyrifos and TCP on soil microorganisms. Overall, reuse of WTR as soil amendment can effectively reduce the ecological risk caused by the migration chlorpyrifos and its major metabolite TCP, but WTR may not be applicable to the rapid bioremediation of chlorpyrifos contaminated soil.
【Fund】： 国家科技重大专项(2013ZX070504-001-01);; 湖南省环保专项(hnhk/hhk-2016-04-320)
【CateGory Index】： X53
【CateGory Index】： X53