Concentrations of polybrominated diphenyl ethers and alternative flame retardants in surface soils and river sediments from an electronic waste-processing area in northern Vietnam, 2012-2014

We investigated the concentrations of polybrominated diphenyl ethers (PBDEs) and alternative flame retardants (FRs) in environmental samples collected in January 2012, 2013, and 2014 from an electronic waste-processing area in northern Vietnam. During the study period, PBDE and alternative FR concentrations in soils around the electronic waste-processing workshops ranged from 37 to 9200 ng g−1 dry weight (dw) and from 35 to 24,000 ng g−1 dw; the concentrations in soils around the open-burning sites ranged from 1.6 to 62 ng g−1 dw and from <4 to 1900 ng g−1 dw; and the concentrations in river sediments around the workshops ranged from 100 to 3800 ng g−1 dw and from 23 to 6800 ng g−1 dw, respectively. Over the course of study period, we observed significant decreases in concentrations of PBDEs and significant increases in concentrations of alternative FRs, particularly Dechlorane Plus isomers and oligomeric organophosphorus FRs (o-PFRs) in both soils and sediments around the workshops. We also report information on concentrations and environmental emissions of o-PFRs and their low-molecular-weight impurities in the same soils and sediments. The detection of o-PFR impurities around the workshops and the open-burning sites highlights an enhanced breakdown of o-PFRs probably due to weathering during open storage and high temperature attained during the burning of electronic wastes.