Study on residues of organochloride pesticides in soils of Anhui Province

Surface soil samples from 119 sites in the watersheds of the Yangtze and Huai Rivers and around Chaohu Lake in Anhui Province were collected from May to June,2004.The samples were extracted by accelerated solvent extraction(ASE) and analyzed by GC/MS to quantify organochloride pesticides including hexachlorobenzene(HCB),Chlordane,∑DDTs,Aldrin,Dieldrin,Endrin,Heptachlor and Mirex.HCB and ∑DDTs were detected in 100 percent and 99.2 percent respectively of all soil samples,while the concentrations of Aldrin,Dieldrin,Endrin,Heptachlor and Mirex were below the detection limit.The total amount of organochloride pesticides was 58.2 μg·kg-1.∑DDTs was the primary organochloride pesticide in the soil samples,representing 86.2 percent of the pesticides present.High concentrations of DDT,some of exceeded the control criterion,were found in the soils near a pesticide factory and in cotton fields.Although HCB was detected widely in the soil samples and it is considered one type of Persistent Organic Pollutant(POPs),its concentration was so low and thus poses little harm to the soil quality in Anhui Province.