Occurrence, phase distribution and depositional intensity of dichlorodiphenyltrichloroethane (DDT) and its metabolites in air and precipitation of the Pearl River Delta, China

摘要

Concentrations of dichlorodiphenyltrichloroethane (DDT) and its metabolites (designated as DDTs, the sum of o,p'- and p,p'-DDT, o,p'- and p,p'-DDE, and o,p- and p,p'-DDD) in air and precipitation from the Pearl River Delta (PRD) of China were determined. Total concentrations of DDTs in air (gas + particle) and precipitation (dissolved + particle) were 170 ± 120 pg m-3 and 940 ± 180 pg L-1 for Dongguan (rural) and 240±120 pgm-3 and 790±l40 pg L-1 for Shunde (rural), respectively, while they were 1550 ± 640 pg L-1 in precipitation from Guangzhou (urban). Log-transformed partition coefficients between air and paniculate organic matter (logK'_oa) of p,p'-DDT, p,p'-DDE, p,p'-DDD, o,p'-DDT, o,p'-DDE, and o,p'-DDD were 9.64 + 0.58, 10.07 ±0.56, 9.90 + 0.76, 10.06 ±0.66, 10.02+0.72, and 10.13 ±0.57, respectively; while those between water and paniculate organic matter (log K'_om) were 6.58 ± 0.66, 6.36 ± 0.53, 6.01 ± 0.62, 6.41 ± 0.42, 5.98 ± 0.76, and 5.95 ± 0.66, respectively. Total washout ratios by bulk rainfalls ranged from 4600 for o,p'-DDT to 54,000 forp,p'-DDT. Estimated average dry par ticle and wet depositional intensities in the PRD were 2.1 × 10~6 and 1.6 × 10-6 g m-2 y-1.