HEXACHLOROCYCLOHEXANE (HCH) RESIDUES IN YA-ER LAKE AREA, CHINA

Ya-Er lake region samples - soil, mud, rice, rice seed grain, sediment, snail and fish - were analysed for alpha-, beta-, and gamma-HCH, according to the standard operating procedure, as used for the necessities of the German Environmental Specimen Bank.(1) The results obtained indicate unexpectedly low concentrations of the HCH-isomers in soil and mud. According to the HCH concentrations in sediment, snail and fish the pollution of the Yanjia lake is significantly higher than the pollution of the Wusi and the Honglian lakes. The bioconcentration factor of total HCH residues in rice seed grain is 0.3, which indicates that HCH residues in soil could probably be the main pollution source for crops after the banning of HCH use. Meanwhile, 1, 4-, and 1, 2- dichlorobenzenes, 1, 2, 4-trichlorobenzene, 1, 2, 3, 4-, and 1, 2, 3, 5-tetrachlorobenzenes were identified by GC-MS as the potential degradation products of HCH residues in field soil.