Effects of transient flow conditions on colloid-facilitated release of decabromodiphenyl ether: Implications for contaminant mobility at e-waste recycling sites.

Polybrominated diphenyl ethers (PBDEs) are ubiquitous contaminants, especially in the soil and groundwater of contaminated sites and landfills. Notably, 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209), one of the most frequently and abundantly detected PBDE congeners in the environment, has recently been designated as a new pollutant subject to rigorous control in China. Colloid-facilitated transport is a key mechanism for the release of PBDEs from surface soils and their migration in the aquifer, but the effects of hydrodynamic conditions, particularly transient flow, on colloid-facilitated release of PBDEs are not well understood.

Preferential association of polycyclic aromatic hydrocarbons (PAHs) with soil colloids at an e-waste recycling site: Implications for risk of PAH migration to subsurface environment.

Polycyclic aromatic hydrocarbon (PAH) contamination at e-waste recycling sites poses high ecological and human-health risks. Of note, PAHs in surface soils can be mobilized through colloid-facilitated transport, and may migrate into the subsurface and pollute groundwater. Here, we show that the colloids released from the soil samples at an e-waste recycling site in Tianjin, China contain high concentrations of PAHs, with total concentrations of 16 PAHs as high as 1520 ng/g dw.

Key factors controlling colloids-bulk soil distribution of polybrominated diphenyl ethers (PBDEs) at an e-waste recycling site: Implications for PBDE mobility in subsurface environment.

Accumulation of polybrominated diphenyl ethers (PBDEs) in surface soils at elevated concentrations is common at e-waste recycling sites. Even though highly insoluble, migration of PBDEs into the vadose zone and groundwater is possible, due to their association with soil colloids. Here, we show that upon equilibration with artificial rainwater surface and subsurface soil samples collected at an e-waste recycling site release significant quantities of colloids, with the total concentrations of 14 PBDE congeners as high as 990 ng/g dw.