title: Polyhalogenated carbazoles in sediments from Lake Tai (China): Distribution, congener composition, and toxic equivalent evaluation.
abstract: Polyhalogenated carbazoles (PHCZs) have attracted mounting environmental concerns since they were recently discovered in sediments and soil. Current knowledge on their occurrence, environmental behavior and fate remains very limited in general. In the present study, 11 PHCZ congeners were screened in surface sediments of Lake Tai, an important freshwater system located in the Yangtze River Delta, China. Total concentrations of PHCZs (∑PHCZs) ranged up to 15.8 ng/g dry weight (median: 1.54 ng/g dw), rivaling those of polybrominated diphenyl ethers (∑PBDEs, 0.07-15.9 ng/g dw) in the same sediments. The PHCZ congener composition profiles revealed a dominance of 3,6-dichlorocarbazole and 3,6-dibromocarbazole with comparable concentrations. These two dominant congeners differed in spatial distribution patterns in Lake Tai, indicating different sources or origins. Potential toxic effects associated with the levels of PHCZs in the sediments were evaluated via the toxic equivalent (TEQ) approach. The TEQs of PHCZs in Lake Tai sediments ranged up to 1.36 pg TEQ/g dw. As the first report on the occurrence of PHCZs in an Asian waterbody, our findings suggest that PHCZs should be given more attention during environmental monitoring and risk assessments of hazardous chemicals, as they may represent another group of persistent organic pollutants with dioxin-like effects and wide distributions.
authors.affiliation: Cooperative Wildlife Research Laboratory and Department of Zoology, Southern Illinois University, Carbondale, IL 62901, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Key Laboratory of Yangtze River Water Environment (Ministry of Education), College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Yanling
authors.initials: Y
authors.lastname: Qiu
authors.affiliation: School of Environment, Guangzhou Key Laboratory of Environmental Exposure and Health, and Guangzhou Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China; Cooperative Wildlife Research Laboratory and Department of Zoology, Southern Illinois University, Carbondale, IL 62901, USA.
authors.forename: Hongli
authors.initials: H
authors.lastname: Tan
authors.affiliation: Cooperative Wildlife Research Laboratory and Department of Zoology, Southern Illinois University, Carbondale, IL 62901, USA. Electronic address: dachen@siu.edu.
authors.forename: Da
authors.initials: D
authors.lastname: Chen
mesh_terms: D002227:Carbazoles / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity*; D002681:China; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D055768:Halogenated Diphenyl Ethers / Q000032:analysis; D060106:Lakes / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity
chemical_list: D002227:Carbazoles; D055768:Halogenated Diphenyl Ethers; D014874:Water Pollutants, Chemical
keywords: Congener composition; Lake Tai; Polyhalogenated carbazoles; Sediment; Toxic equivalent