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/m3 for polybrominated diphenyl ethers (PBDEs) and were 546 ± 547 and 165 ± 144 pg/m3 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 (KP) of PBDEs correlated well with the subcooled liquid vapor pressure (PL(o)) for most sampling events. The varied slopes of log KP versus log PL(o) 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 climate