title: Mediated distribution pattern of organic compounds in estuarine sediment by anthropogenic debris.
abstract: Natural organic matter and grain size are considered as important parameters dictating the transport and fate of organic compounds in sediment. However, increasing evidence suggested that manufactured debris may alter the underlying mechanisms for biogeochemical cycling of organic compounds. To examine this assumption, estuarine sediment and embedded debris were collected from a fishery base in Guangdong Province of South China and analyzed for organophosphorus flame retardants (OPFRs), phthalates (PAEs), organotin compounds (OTs) and dichlorodiphenyltrichloroethanes (DDTs). Coarse-size debris (>200μm) were heterogeneously distributed in sediment, and most abundant near the boat maintenance facilities, aquaculture zone and shipping channel. The median concentrations of OPFRs, OTs, PAEs and DDTs in debris were 11, 0.2, 11 and 3.9μgg(-1) dry sample weight(-1), respectively, 1 to 3 orders of magnitude greater than those in bulk sediment (19, 60, 240 and 570ngg(-1) dry sample weight(-1), respectively). Furthermore, OPFRs, OTs and PAEs were mostly (>99%) enriched in coarse-size (63-2000μm) sediment, and there was no significant correlation (p>0.05) between the concentrations of OPFRs, OTs and PAEs in bulk and size-fractioned sediment samples and total organic carbon or grain size, similar to the distribution pattern of DDTs reported previously. When distinct debris were removed from the light-density (<1.7gcm(-3)) fraction of coarse-size (200-2000μm) sediment, the concentration levels of OPFRs, OTs, PAEs and DDTs declined by 84%, 59%, 55% and 7%, respectively. Obviously, debris irregularly distributed in sediment can alter the sediment sorption capacity for OPFRs, OTs and PAEs, and thus may undermine the significance of organic matter and grain size to the distribution of organic chemicals in sediment. Finally, commonly used procedures for preparing sediment samples and screening of debris may disturb the grain size distribution or underestimate the abundance of heavy-density debris, resulting in flawed sediment quality assessment.
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: School of Environment and Guangzhou Key laboratory of Environmental Exposure and Health, and 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 and Guangzhou Key laboratory of Environmental Exposure and Health, and 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; D004784:Environmental Monitoring / Q000379:methods; D063366:Estuaries; D005398:Fisheries; D019015:Geologic Sediments / Q000737:chemistry*; D007220:Industrial Waste / Q000032:analysis*; D009930:Organic Chemicals / Q000032:analysis*; D010316:Particle Size; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D007220:Industrial Waste; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical
keywords: Anthropogenic debris; Organophosphorus flame retardants; Organotin compounds; Phthalates; Size and density distribution in sediment; Sorption capacity