title: Significance of antifouling paint flakes to the distribution of dichlorodiphenyltrichloroethanes (DDTs) in estuarine sediment.
abstract: Recently published literature indicated that dichlorodiphenyltrichloroethane (DDT)-containing antifouling paint flakes were heterogeneously distributed within estuarine sediments. However, the significance of antifouling paint flakes in the fate and transport of DDT compounds and other organic pollutants in estuarine sediment is yet to be adequately addressed. To fill this knowledge gap, estuarine sediment and paint flakes from cabin and boat surfaces were collected from a fishery base in Guangdong Province of South China and analyzed for DDT compounds. Coarse fractioned samples collected from the vicinity of boat maintenance facilities contained appreciable amounts of colorful particles, which were identified as paint flakes by Fourier transform infrared spectroscopy. The highest concentrations of DDXs (sum of DDTs and its metabolites) occurred in the heavy-density (>1.7 g cm(-3)) fraction of coarse-size (200-2000 μm) sediments from near the boat maintenance facilities, suggesting the importance of paint flakes in the distribution pattern of "hot spots" in estuarine sediment. Moreover, the desorption rates of DDT compounds from paint flakes and the heavy-density fraction of coarse-size sediment were both extremely slow. Apparently, unevenly distributed paint flakes in sediment can artificially inflate the sorption capacity of heavy-density sediment for DDT compounds, and therefore can substantially change the environmental fate and behavior of hydrophobic organic chemicals in estuarine sediment. Finally, commonly used source diagnostic indices of DDT compounds were mostly grain-size and density dependent in sediment, as a result of the occurrence of paint flakes, which may strongly compromise the outcome of any source diagnostics efforts.
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Chen-Chou
authors.initials: CC
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; School of Environment, Guangzhou Key Laboratory of Environmental Exposure and Health, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China.
authors.forename: Lian-Jun
authors.initials: LJ
authors.lastname: Bao
authors.affiliation: Laboratory of Earth Surface Processes, College of Urban and Environmental Science, Peking University, Beijing 100871, China.
authors.forename: Shu
authors.initials: S
authors.lastname: Tao
authors.affiliation: School of Environment, Guangzhou Key Laboratory of Environmental Exposure and Health, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China. Electronic address: eddyzeng@jnu.edu.cn.
authors.forename: Eddy Y
authors.initials: EY
authors.lastname: Zeng
mesh_terms: D002681:China; D003634:DDT / Q000032:analysis / Q000737:chemistry*; D003633:Dichlorodiphenyl Dichloroethylene / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D005398:Fisheries; D019015:Geologic Sediments / Q000737:chemistry; D010150:Paint / Q000032:analysis*; D012767:Ships; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D014874:Water Pollutants, Chemical; D003633:Dichlorodiphenyl Dichloroethylene; D003634:DDT
keywords: Desorption; Dichlorodiphenyltrichloroethane; Estuarine sediment; Hot spot; Paint flake