The Residues Characteristic Of HCH In The Taihu Lake Region

China is a large producer and consumer of pesticides,HCH which is one of major organo-chlorine pesticide is widely used in China,linden(γ-HCH) is the unique isomer for insecticidal activity.As accounted,in the evening of seventy time,the total production and consumption of admixture HCH is around sixty million ton.Account for semi-volatility,fat-soluble,biologic accumulation and persistence,HCH can go with air long-range transportation,and it can exchange in different medium.Although in China, the production and consumption of HCH is banned in 1983,there are higher detectable rate in food,organism,human,air,soil and water for the hard degradation.Taihu Lake Region(TLR) lies in the Yangtze River Delta,is one of paddy rice production with high yield in China,and very important for traditional economic development.It is reported,it provides more than 14%of the gross domestic production (GDP).TLR is one of dense production and consumption area,as reported,in 1980,the average use level of HCH is 9.6429kg/hm² in paddy field.After the degradation for about twenty years,the residual quantity of HCH in TLR has obviously reduced.A field survey is carried out in the TLR.HCH residues in air and soil is investigated.The results indicate that:between 2006 and 2007,the average concentration of the total HCH is 648.05pg.m^-3,range from 54.41 pg.m^-3 to 3148.96 pg.m^-3,has the correspondence level with the Peal River Delta,but has the highest level contrast to some foreign countries;HCH residues in soil with an average of 4.10ng/g, ranges from 0.86ng/g to 7.80ng/g,is 1.3%of this area soil twenty years ago,and has the same order contrast to foreign counties.According to the usage type,the residual level of total HCH is:paddy＞fallow soil＞vegetable soil,individually 1.55ng/g,0.58ng/g, 0.49ng/g.In both air and soil,β-HCH is the highest isomer of HCH,and value ofα/γ-HCH below 3,these results reveal in the TLR,the source of HCH in air is possibly due to out-source,while the major source in soil is possible from the historical residue,and the new source of linden has the secondary role.