A Case Study on the Long-Term Influence of Historical Intensive Usage of Organochlorine Pesticides on Current Ambient Air

Abstract

Polyurethane foam disk passive air sampling was performed to investigate the levels and spatial distributions of organochlorine pesticides (OCPs) in the atmosphere of a typical city (Tangshan) in China where unparalleled amounts of OCPs including dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) were used for sanitary purposes following the 1976 Tangshan Earthquake. This study aimed to investigate the long-term influence of historical intensive usage of OCPs during the earthquake on the current ambient air levels. Sampling was performed at seven sites in Tangshan between July and October 2010. The levels of Sigma DDTs and Sigma HCHs were relatively high, with concentrations ranging from 79-254 pg/m(3) and 117-176 pg/m(3), respectively. The concentration of hexachlorobenzene (HCB) was 69-89 pg/m(3). Technical DDTs and HCHs were sprayed for preventing epidemics mainly in the southern region of Tangshan in 1976. In this study, high levels of DDTs and HCHs were found in the southern region, and levels decreased considerably to the north. Unlike DDTs and HCHs, the levels of HCB are very similar for the different sampling sites. This suggests that intensive usage of DDTs and HCHs following the earthquake had a significant effect on the levels of OCPs. Correlations identified between the enantiomers of the OCPs indicated that p,p'-DDTs and HCHs shared the same source, and that o,p'-DDT and HCB may come from similar sources. The signatures of OCPs suggested that the technical DDTs and HCHs used following the earthquake still contribute to their current levels in the atmosphere of Tangshan city.