Short- and Medium-Chain Chlorinated Paraffins in Air and Soil of Subtropical Terrestrial Environment in the Pearl River Delta, South China: Distribution, Composition, Atmospheric Deposition Fluxes, and Environmental Fate

Research on the environmental fate of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) in highly industrialized subtropical areas is still scarce. Air, soil, and atmospheric deposition process in the Pearl River Delta of South China were investigated, and the average SCCP and MCCP concentrations were 5.2 mu g/sampler (17.69 ng/m(3)) and 4.1 mu g/sampler for passive air samples, 18.3 and 59.3 ng/g for soil samples, and 5.0 and 5.3 mu g/(m(2)d) for deposition samples, respectively. Influenced by primary sources and the properties of chlorinated paraffins (CPs), a gradient trend of concentrations and a fractionation of composition from more to less industrialized areas were discovered. Intense seasonal variations with high levels in summer air and winter deposition samples indicated that the air and deposition CP levels were controlled mainly by the vapor and particle phase, respectively. Complex environmental processes like volatilization and fractionation resulted in different CP profiles in different environment matrixes and sampling locations, with C10-11 Cl6-7 and C-14 Cl6-7, C10-12 Cl6-7 and C-14 Cl6-8, and C11-12 Cl6-8 and C-14 Cl7-8 dominating in air, soil, and atmospheric deposition, respectively. Shorter-chain and less chlorinated congeners were enriched in air in the less industrialized areas, while longer-chain and higher chlorinated congeners were concentrated in soil in the more industrialized areas. This is suggesting that the gaseous transport of CPs is the dominant mechanism responsible for the higher concentrations of lighter and likely more mobile CPs in the rural areas.