[Show abstract][Hide abstract] ABSTRACT: In this study, Dechlorane Plus (DP) concentrations were analyzed in marine sediments (depth: ~ 10 cm) from two Korean industrial bays. Two sediments were fractionated into 5 sizes by using gravitational split-flow thin fractionation technique and DP distribution was investigated in different particle size fractions. Elevated DP levels in surface sediments were observed at the site closest to land and industrial area. The highest concentrations of DP were detected in the finest grain-size (< 10 μm, 451.2 and 149.9 pg/g dry weight for the two bays). The fraction of anti-DP to the total DP (fanti) in the two fractionated samples increased with reduced grain-size and significantly correlated with organic carbon content (OC), which can be caused by preferential adsorption of anti-DP or higher biodegradation rates of syn-DP in the fine particles. To provide insight into such mechanism, simulated experiments were conducted using activated charcarbon (ACC) to adsorb DP dissolved in methanol and molecular descriptors of both isomers were estimated using Gaussian 03. The adsorption results revealed that syn-DP was preferentially adsorbed by ACC, suggesting syn-DP is more hydrophobic than anti-DP. The preferential adsorption of syn-DP by ACC also supported the hypothesis that the enrichment of anti-DP was more likely due to preferential biodegradation of syn-DP in the sediment. Molecular characterization of anti-DP and syn-DP showed that syn-DP had a higher dipole moment, slightly larger Van der Waals volume, but smaller maximal diameter, which might explain its higher uptake rate in biota.
Science of The Total Environment 05/2014; 481(1):114–120. DOI:10.1016/j.scitotenv.2014.01.082 · 4.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A highly chlorinated flame retardant, Dechlorane Plus (DP), was measured in five fish species collected in 2008 from 22 river sites across South Korea. The sites consisted of 15 urban-industrial areas, three rural-industrial areas, and four rural rivers. Both syn- and anti-DP isomer were consistently detected in all fish samples regardless of sampling sites and fish species. DP has become a widespread environmental pollutant in South Korea. Concentrations of summation operatorDP isomers ranged from 0.61 to 126ngg(-1) lipid, with a mean concentration of 24.5ngg(-1) lipid. The mean summation operatorDP concentrations in the 15 urban sites (36.1+/-35.3ngg(-1) lipid) were approximately 25 times greater than those measured in the rural sites (1.4+/-1.0ngg(-1) lipid). The summation operatorDP concentrations in this study exceeded those determined in fish from the Great Lakes. DP exposure to fish is related to urbanization activity. Specific urban areas could be significant source areas of DP exposure, even in the absence of a local DP manufacturing facility. Concentrations of syn- and anti-DP isomer ranged from 0.17 to 30ngg(-1) lipid and 0.44 to 97ngg(-1) lipid, respectively. The anti-DP isomer was dominant in all samples. However, the mean f(anti) value for urban-industrial samples (0.67+/-0.060) was significantly lower than that of the technical DP standard (f(anti)=0.75; p=0.032). This observation supports that DP isomers exhibit different bioaccumulation behaviors and that syn-DP isomer more easily accumulates in biota samples than anti-DP isomer does.