Organochlorine pesticides and PCBs in fish from lakes of the Tibetan Plateau and the implications Ruiqiang Yang a , Yawei Wang a , An Li b , Qinghua Zhang a , Chuanyong Jing a , Thanh Wang a , Pu Wang a , Yingming Li a , Guibin Jiang a, * a State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing,100085, China b School of Public Health, University of Illinois at Chicago, Chicago, IL 60612, USA Occurrence of POPs in higher-altitude lakes suggests that Tibetan Plateau acts as potential regional convergence zones for long-range atmo- spheric transported contaminants. article info Article history: Received 13 October 2009 Received in revised form 29 January 2010 Accepted 6 February 2010 Keywords: POPs OCPs Long-range atmospheric transport Alpine lakes Indian monsoon abstract High mountains may play significant roles in the global transport of persistent organic pollutants (POPs). This work aims to investigate the levels, patterns and distribution of semi-volatile organoclorine pollutants and to improve the understanding of the long-range atmospheric transport and fate of contaminants on the Tibetan Plateau. A total of 60 fish samples were collected from eight lakes located between 2813 and 4718 m above sea level across the Plateau. Concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) including dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) were measured in fish muscle. The results showed that concentrations of DDT, HCH and HCB were comparable to or lower than those found in remote mountains of Europe, Canada and US, while PCB concentrations in fish were, on average, about 4e150 times lower on Tibet than at other mountain areas. The transport and fate of contaminants in the Plateau are significantly influenced by the unique climatological and meteorological conditions, particularly by the summer Indian monsoon and winter westerly jet stream. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction Persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) are of high concern, not only because of their detrimental health effects but also because they are persistent and semi-volatile, thus able to travel long distances and distribute globally. Long-range atmo- spheric transport (LRAT) is a primary global transport pathway for POPs (Wania and Mackay, 1994). In warm regions, POPs tend to evaporate into the atmosphere, and the transport is often directed towards the colder polar regions where they are efficiently scav- enged from the atmosphere. Similarly, low temperatures in alpine regions could allow high mountains to act as cold condensers and thus influence the global transport of POPs (Daly and Wania, 2005). In Europe and North America, recent research has shown evidence of cold trapping in alpine regions for various airborne pollutants (Daly and Wania, 2005; Blais et al., 1998). The Tibetan Plateau (the Plateau) lies between the Himalayan range to the south and the Taklamakan Desert to the north. With an area of 2.5 million square kilometers and an average altitude over 4000 m above sea level (a.s.l.), the Plateau is the largest and highest plateau in the world. It is characterized by harsh climate featuring dramatic elevational temperature gradient and monsoon affected air movement and precipitation patterns. With sparse human population and minimal industrial activity, atmospheric transport is essentially the only source of POPs to most areas of the Plateau. Recent work showed an increase in some contaminants in conifer needles with increasing altitude along the northern slope of the central Himalayas and the southeast Tibetan mountains (Wang et al., 2006; Yang et al., 2008). These results are in accordance with the observation for the Canadian Rocky Mountains by Blais et al. (1998) and several other studies summarized by Daly and Wania (2005). Such an altitudinal trend can be confounded by other influencing factors such as proximity to sources, directions of diurnal and seasonal airflow, and the topographic feature of the sampling locations. Alpine lakes are unique depositories of long-range transported contaminants. The lakes on the Plateau are generally characterized * Corresponding author. Tel.: þ86 10 62849334; fax: þ86 10 62849179. E-mail address: gbjiang@rcees.ac.cn (G. Jiang). Contents lists available at ScienceDirect Environmental Pollution journal homepage: www.elsevier.com/locate/envpol 0269-7491/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.envpol.2010.02.004 Environmental Pollution 158 (2010) 2310e2316