Levels and Isomer Profiles of Dechlorane Plus in Chinese Air NANQI REN, † ED SVERKO,* ,‡ YI-FAN LI, †,§ ZHI ZHANG, † TOM HARNER, § DEGAO WANG, | XINNAN WAN, ⊥ AND BRIAN E. MCCARRY ‡ International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, Heilongjiang, China, Department of Chemistry, McMaster University, Hamilton, Ontario, L8S 4M1 Canada, Science and Technology Branch, Environment Canada, Toronto, Ontario, M3H 5T4 Canada, IJRC-PTS, College of Environment Science and Technology, Dalian Marine University, Dalian, Liaoning, China, and IJRC-PTS, Chengdu University of Technology, Chengdu, Sichuan, China Received February 15, 2008. Revised manuscript received June 10, 2008. Accepted June 13, 2008. The highly chlorinated flame retardant, Dechlorane Plus (DP), was measured in air across 97 Chinese urban and rural sites. DP was detected in 51 of these sites, with a mean air concentration in urban centers (15.6 ( 15.1 pg m -3 ) approximately 5 times greater than those measured in rural areas (3.5 ( 5.6 pg m -3 ). These DP levels were likely attributable to local sources rather than trans-boundary influences. Elevated urban levels were measured along the southeastern coast and in south- central China; the highest concentration was observed in the city of Kunming (66 pg m -3 ). Few of the urban samples (7%) and a majority of the rural samples (62%) were below the method detection limit, notably areas in rural central and northeastern China. The mean fractional abundance of the syn- DP isomer ( f syn ) in all samples was 0.33 ( 0.10, values indistinguishable from that of a commercial mixture ( f syn ) 0.35). This paper represents the first report on DP levels in Chinese air, together with isomeric ratio profiles from urban and rural sites. Introduction Persistent organic pollutants (POPs) are chemicals which bioaccumulate, may be toxic to humans or wildlife, and degrade slowly in the environment. The Stockholm Conven- tion (1) was initiated to restrict and regulate these chemicals, with the intention to reduce their potential deleterious effects. To effectively monitor and establish levels of POPs in the environment, the Stockholm Convention included air as one of the main environmental compartments in which these compounds are measured. One of the recent approaches used to determine POP air levels is the global atmospheric passive sampling study, utilizing polyurethane foam (PUF). Passive air samplers (PASs) are useful as a cost-effective means to measure airborne contaminants, especially in areas where electricity is unavailable. The first global-scale deployment of PASs was reported by Pozo et al. (2). Results were used to determine local and transboundary influences from sources including com- pounds such as polybrominated diphenyl ethers (PBDEs), which are in a chemical class known as brominated flame retardants (BFRs). The fate and occurrence of BFRs in the environment have been a primary focus for scientists during the past decade (3–5). Furthermore, the Stockholm Conven- tion considers PBDEs as a candidate for inclusion to its list of target compounds. Notably, the penta- and octa-BDE formulations have been discontinued through legislative restrictions due to concerns related to their toxicity and bioaccumulative properties (6, 7). While policy makers consider further restrictions on these currently used BFRs, Dechlorane Plus (DP), a chlorinated flame retardant (C18 H 12 Cl 12 ) manufactured for over 40 years, has only recently been reported in the environment (8). Annual production of DP is estimated to be as high as 10 million pounds. This formulation is used primarily in products such as cable coatings, plastic roofing materials, and hard connectors in computers and televisions (9). The United States Environ- mental Protection Agency (EPA) has classified this flame- retardant additive as a high production volume chemical. As such, the manufacturer (OxyChem, Niagara Falls, NY) is obliged to conduct certain toxicological and chemical tests, reporting the results in the form of a Robust Summary (10). OxyChem’s submission suggested that DP had little to no toxicity. However, the report suggested that sediment-bearing organisms may be affected by DP because of its adsorptive properties. DP is also on the Canadian Domestic Substances List but not ranked highly in terms of risk for bioaccumulation because of its high molecular mass (648 Da) and high log Kow (9.3). However, recent research by Tomy et al. (11) demon- strated the biomagnification properties of DP for certain trophic relationships in food webs within Lake Winnipeg and Lake Ontario, Canada. On the basis of these data, the bioaccumulation potential of DP may need to be re-evaluated. DP is sold worldwide, including in Europe and the Far East. In a European Union (EU) report, annual importation of DP into the EU was estimated to be 1.1 million pounds (12). Existing data on global ambient environmental con- centrations of DP are sparse; current information stems primarily from studies located in North America. Recently, measurements of DP in tree bark provided the first data on DP levels in the Asian and European continents (13). In an effort to further determine DP concentrations beyond the North American continent, a study was initiated at the International Joint Research Centre for Persistent Toxic Substances (IJRC-PTS) centered at the Harbin Institute of Technology, Harbin, to analyze samples collected using a network of PASs deployed across China. In this paper, we present DP levels in ambient air, together with isomeric composition in urban and rural areas of China. Materials and Methods Sample Collection. PASs using PUF disks were deployed in 97 sites across China for approximately three months between mid-July and mid-October, 2005. A map of the sample IDs and longitude/latitude data are available in the Supporting Information. PUF disks were precleaned by Soxhlet extraction for 24 h (acetone/hexane, 1:1 v/v) at the IJRC-PTS laboratories located at the Harbin Institute of Technology and at Dalian Maritime University, China. The cleaned disks were trans- ported to sampling locations using sealed, solvent-rinsed * Corresponding author e-mail: ed.sverko@ec.gc.ca. † Harbin Institute of Technology. ‡ McMaster University. § Environment Canada. | Dalian Marine University. ⊥ Chengdu University of Technology. Environ. Sci. Technol. 2008, 42, 6476–6480 6476 9 ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 42, NO. 17, 2008 10.1021/es800479c CCC: $40.75  2008 American Chemical Society Published on Web 07/24/2008