Residues Status And Health Risk Assessment Of Organochlorine Pesticide In Typical Surface Water Of Ningxia Region

Objective To understand the residue levels of organochlorine pesticides of pit water,reservoir water and the Yellow River in south Ningxia, compared to surface water qualitystandard limits,and determine the quality of the measured water;Analysising thecomposition characteristics and degradation speed of organochlorine pesticides in differentwater,and investigate sources of organochlorine pesticides;analysis population health riskvalue caused by organochlorine pesticides through drinking water in sampling region,andpreventing pollution accidents. Methods Selecting five water quality monitoring sectionsfrom Ningxia section of the Yellow River,water sources from the southern mountaincentralized water and17villages from drinking pit water area in2013wet and dryseasons;each sampling point collected6L pit water, liquid-liquid extraction of organochlorinepesticides in water, which measured various isomers of HCH residues in class (HCHs) andDDT class (DDTs) with meteorological chromatography;using the U.S.EnvironmentalProtection Agency (EPA) drinking Water exposure to pollutants on human health riskassessment methods to calculate the value of the health risks.Results (1) HCHs, DDTs weredetected from pit water, reservoir water and the Yellow River water during wet period,inaddition to the Yellow River water, HCHs, DDTs were detected from pit water, reservoirwater and the Yellow River water during the dry season.(2)Three kinds of water HCHs, DDTscontent.①wet period: HCHs content from pit water was in the range of0~5.20ng/L, DDTscontent in the range of0~73.50ng/L, DDTs were higher than HCHs content;HCHs fromreservoir water levels was in the range of0~15.60ng/L, DDTs content was in the range of0~ 31.24ng L,DDTs were higher than HCHs content; HCHs rom Yellow River water content inthe range of0~6.92ng/L,DDTs content in the range0~7.52ng/L,DDTs were higher than HCHscontent.②dry season: the HCHs content from water was in the range of pit in0~8.46ng/L,DDTs was detected at one point only to the content of the3.73ng/L;HCHs content fromreservoir water was range in0~12.51ng/L,DDTs only a point is detected,the massconcentration of0~7.40ng/L;Yellow River water only detected HCHs, HCHs content in therange of0~2.51ng/L.(3)The content percentage of γ-HCH from HCHs in three kinds of waterare highest in a monomer;the content percentage of p,p’-DDE are highest in amonomer.(4)Population health risk assessment of the value of HCHs, DDTs caused by waterways.①wet period: pit water are1.55×10-12/a,3.86×10-11/a;reservoir water are5.92×10-12/a,12.59×10-11/a;Yellow River water were2.63×10-12/a,4.87×10-12/a.②dry season: pit water1.08×10-12/a,0.19×10-12/a;reservoir water are2.38×10-12/a,0.99×10-12/a;health risks causedby the value of the Yellow River water HCHs of0.67×10-12/a.(5)The health risks valuecaused by HCHs, DDTs from three kinds of water were: pit water＞reservoir water＞Yellow River water.Conclusion (1)The HCHs, DDTs residues from three kinds of waterwere in compliance with the limit requirements of centralized drinking surface water through"surface water quality standards" standard(GB3838-2002).(2) HCHs, DDTs residual volumefrom three kinds of water was wet period> dryseason.(3)The residual monomers of HCHs and DDTs in Ningxia surface water are mainly γ-HCH and p,p’-DDE.(4)Use of health risk assessment model calculated,HCHs and DDTs riskis in a lower level to human health in Ningxia typical surface water.