DDTs And HCHs Residues And Pollution Evaluation In The Pearl River Estuary

Abstract：In this study, we sampled water body, surface sediments, fishes from the PearlRiver Estuary in August、November of2010and February, May, August, November of2011, the organochlorine of DDTs, HCHs were selected as research objects, HCHs andDDTs in water body, surface sediments, fishes were detected by GC-ECD respectively.On the basis of this, analysised the special and temporal distribution feature,composition characteristic，contrast to the content of HCHs and DDTs about domesticand foreign waters, and studied the ecological risk assessment of HCHs and DDTs.Themain conclusions were as follows:(1)The distribution characteristics of average content of HCHs, DDTs in the PearlRiver Estuary is Xisi estuaries higher than DongSi estuaries, Among this the averagecontent of HCHs in DongSi is from undetected to0.035μg/L, with the mean of0.025μg/L, DDTs is from undetected to0.03μg/L, with the mean of0.02μg/L; the averagecontent of HCHs in Xisi is from undetected to0.018μg/L, with the mean of0.012μg/L,DDTs is from0.008to0.016μg/L, with the mean of0.013μg/L. the content of HCHsand DDTs in most stations of the Pearl River Estuary may bring low risk to the bottomfeeders and ecological system.(2)The distribution characteristics of average content of HCHs, DDTs in the surface sediment of the Pearl River Estuary is Xisi estuaries higher than Dongsiestuaries, Among this, the average content of HCHs in Dongsi is from undetected to0.68μg/kg, with the mean of0.39μg/kg, DDTs is from undetected to2.12μg/kg, withthe mean of1.67μg/kg; the average content of HCHs in Xisi is from undetected to0.59μg/kg, with the mean of0.39μg/kg, DDTs is from1.68to2.52μg/kg, with the mean of2.04μg/kg. the ecological risk of HCHs, DDTs in the surface sediment from moststations of the Pearl River Estuary is low, may not bring enough effect risk to thebottom feeders and ecological system.(3)The HCHs of the fish in the Pearl River Estuary concentration range fromundetected to3.54μg/kg(wet weight, the same below), with the mean of0.78μg/kg,DDTs content in the range of from undetected to42.73μg/kg, with the mean of6.82μg/kg. In this study, Although both of the two kinds of organic pesticides residue levelsin the examined fishes are also below the recommended maximum residues used forhuman consumption at home and abroad, the high relative amount of p,p′-DDT andγ-HCH implied that there are still new amounts of DDTs and HCHs running into therivers, which should be paid more attention by the local government.(4) the characteristics of HCHs pesticide in the Pearl River Estuary water, surfacesediment are: the α-HCH/γ-HCH ratio is less than3of each channel, explaining most ofthe α-HCH is degraded in study area and Lin Dan is replaced industry HCHs in waterenvironment to the main source of input; Except a few stations, there are new DDTsinput the Pearl River Estuary, the degradation of the environment is mainly in theanaerobic condition, the results were consistent with the results from fishes.(5) Compared to some of the world water, the content of HCHs, DDTs in the PearlRiver Estuary water body, the surface sediment is in the medium level.