Residue characteristics of HCHs and DDTs in greenhouse soils in Dianchi Lake Distract

The characteristics of organo-chlorine pesticides (OCPs) were studied under greenhouse soil conditions. In the study, hexachlorocyclohexane (HCHs) and dichlorodiphenyl trichloroethane (DDTs) OCPs were analyzed using gas chromatography equipped with ECD detector. Soil samples were collected from 0, 1~5, 5~10, 10~15 and 15~25 years-old greenhouses at 0~20 cm, 20~40 cm and 40~60 cm soil profiles. Based on the study, mean HCHs and DDTs residue significantly increased in soil of greenhouses older than 10 years. HCHs and DDTs residues were not significantly different in 0~10 years-old greenhouse soils. DDTs were main component of OCPs residue. The trend in HCHs residue variation was not significantly different in different soil layers. However, DDTs concentration in the 0~20 cm surface soil was significantly higher than that in other soil layers. β-HCH concentration was higher than other HCH isomers in greenhouse soils. This suggested that the source of soil HCHs was residue of past applications. p,p′-DDT/(DDD+DDE) value in some soil samples was greater than one, suggesting that new DDTs were input in some of the greenhouses.