Air pollution has been of great public concern in China due to its high risks to human health. However, there has been limited information on the atmospheric hexachlorocyclohexanes (HCHs) in rural sites across China. In this study, tree bark was used as a passive sampling medium for atmospheric HCHs. Samples were collected from rural areas across China, and the residue levels of HCHs and the enantiomeric fractions (EFs) of a-HCH were analyzed. The concentrations of total HCHs ranged from 1.19 to 127 ng/g, with the mean value of 6.35 ng/g. The highest provincial average levels of HCHs was observed in Tianjin, and followed by Shanxi, which might be related to the large historical usage of HCHs. Based on the four large regions of China, the residue levels of HCHs decreased in the order of eastern, central, western and northeastern China. The correlation between HCH isomers and site elevation revealed that �-HCH and d-HCH in tree barks tended to accumulate in the tree bark from sites with lower elevation when compared to ?-HCH. It might be related to the different physicochemical properties of individual isomers of HCH, which resulted in their different distribution patterns across China. The results of enantiomeric analysis of a-HCH showed that the value of EFs for most samples were higher than 0.5, suggesting the preferential depletion of (-)a-HCH enantiomer.

Hexachlorocyclohexanes in rural tree bark across China: Distribution and enantiomeric signatures

248th National Meeting (2014)

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