Brominated Flame Retardants in the Atmosphere of E-Waste and Rural Sites in Southern China: Seasonal Variation, Temperature Dependence, and Gas-Particle Partitioning

The recycling of electrical and electronic waste (e-waste) in developing countries has attracted much attention as a significant source of brominated flame retardants (BFRs). Gaseous and particle-bound BFRs were measured in the atmosphere at e-waste and rural sites in southern China during 2007-2008. The annual average concentrations in the air were 3260 +/- 3370 and 219 +/- 192 pg/m(3) for polybrominated diphenyl ethers (PBDEs) and were 546 +/- 547 and 165 +/- 144 pg/m(3) for non-PBDE BFRs at the e-waste and rural sites, respectively. PBDEs had unusually high relative concentrations of di- and tribrominated congeners at the e-waste site. The Clausius-Clapeyron (CC) plots showed that the gaseous concentrations of less brominated BFRs (di- through hexa-BFRs) were strongly controlled by temperature-driven evaporation from contaminated surfaces (e.g., e-waste, soils, and recycled e-waste remains) except for winter. However, weak temperature dependence at the rural site suggests that regional or long-range atmospheric transport was largely responsible for the air concentrations. Gas-particle partitioning (K(p)) of PBDEs correlated well with the subcooled liquid vapor pressure (P(L)degrees) for most sampling events. The varied slopes of log K(p) versus log P(L)degrees plots for the e-waste site (-0.59 to -1.29) indicated an influence of ambient temperature and atmospheric particle properties on the partitioning behavior of BFRs. The flat slopes (-0.23 to -0.80) for the rural site implied an absorption-dominant partitioning. This paper suggests that e-waste recycling in Asian low-latitude regions is a significant source of less brominated BFRs and has important implications for their global transport from warm to colder climates.