title: Biomagnification of persistent organic pollutants along a high-altitude aquatic food chain in the Tibetan Plateau: Processes and mechanisms.
abstract: Biomagnification of some persistent organic pollutants (POPs) has been found in marine and freshwater food chains; however, due to the relatively short food chains in high-altitude alpine lakes, whether trophic transfer would result in the biomagnification of POPs is not clear. The transfer of various POPs, including organochlorine pesticides and polychlorinated biphenyls (PCBs), along the aquatic food chain in Nam Co Lake (4700 m), in the central Tibetan Plateau, was studied. The POPs levels in the water, sediment and biota [plankton, invertebrates and fish (Gymnocypris namensis)] of Nam Co were generally low, with concentrations comparable to those reported for the remote Arctic. The composition profiles of POPs in the fish were different from that in the water, but similar to their food. DDEs, DDDs, PCB 138, 153 and 180 displayed significant positive correlations with trophic levels, with trophic magnification factors (TMFs) ranged between 1.5 and 4.2, implying these chemicals can undergo final biomagnification along food chain. A fugacity-based dynamic bioaccumulation model was applied to the fish with localized parameters, by which the simulated concentrations were comparable to the measured data. Modeling results showed that most compounds underwent net gill loss and net gut uptake; only when the net result of the combined gut and gill fluxes would be positive, bioaccumulation could eventually occur. The net accumulation flux increased with fish age, which was caused by the continuous increase of gut uptake by aged fish. Due to the oligotrophic condition, efficient food absorption is likely the key factor that influences the gut POPs uptake. Long residence times with half-lives up to two decades were found for the higher chlorinated PCBs in Gymnocypris namensis.
authors.affiliation: Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Jiao
authors.initials: J
authors.lastname: Ren
authors.affiliation: Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China. Electronic address: wangxp@itpcas.ac.cn.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Wang
authors.affiliation: Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China.
authors.forename: Chuanfei
authors.initials: C
authors.lastname: Wang
authors.affiliation: Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Gong
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.
authors.forename: Xiruo
authors.initials: X
authors.lastname: Wang
authors.affiliation: Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China.
authors.forename: Tandong
authors.initials: T
authors.lastname: Yao
mesh_terms: D000531:Altitude; D000818:Animals; D059001:Aquatic Organisms / Q000378:metabolism*; D058448:Biota; D004784:Environmental Monitoring; D005399:Fishes / Q000378:metabolism; D020387:Food Chain; D019015:Geologic Sediments / Q000737:chemistry*; D006843:Hydrocarbons, Chlorinated / Q000032:analysis / Q000378:metabolism; D007448:Invertebrates / Q000378:metabolism; D060106:Lakes / Q000737:chemistry*; D010575:Pesticides / Q000032:analysis / Q000378:metabolism; D011078:Polychlorinated Biphenyls / Q000032:analysis / Q000378:metabolism; D017747:Seafood / Q000032:analysis; D018609:Tibet; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000378:metabolism
chemical_list: D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D014874:Water Pollutants, Chemical; C029790:2,2',3',4,4',5-hexachlorobiphenyl; D011078:Polychlorinated Biphenyls
keywords: Alpine lakes; Biomagnification; Dietary uptake; Persistent organic pollutants; Tibetan Plateau