Serum concentrations of chlorinated dibenzo- p -dioxins and dibenzofurans among former Michigan trichlorophenol and pentachlorophenol workers JAMES J. COLLINS a , KENNETH M. BODNER a , MICHAEL WILKEN a , SALMA HAIDAR a , CAROL J. BURNS a , ROBERT A. BUDINSKY a , GREG D. MARTIN a , MICHAEL L. CARSON a AND J. CRAIG ROWLANDS a a The Dow Chemical Company, Midland, MI, USA This study examines serum levels of 2,3,7,8-substituted chlorinated dioxins and furans, and PCBs for 375 Michigan workers with potential chlorophenol exposure, 37 Worker Referents, and 71 Community Referents. The chlorophenol workers were last exposed to trichlorophenol and/or pentachlorophenol 26–62 years ago. Employees working only in the trichlorophenol units had mean lipid-adjusted 2378-tetrachlorodibenzo-p-dioxin (TCDD) levels of 15.9 ppt compared with 6.5 ppt in the Worker Referents. Employees working only in the pentachlorophenol units had mean lipid-adjusted levels for 123478-H 6 CDD of 16.1ppt, 123678-H 6 CDD of 150.6ppt, 123789-H 6 CDD of 20.2ppt, 1234678-H 7 CDD of 192.6ppt, and OCDD of 2,594.0ppt compared with the Worker Referent levels for the same congeners of 7.5, 74.7, 8.6, 68.7, and 509.1 ppt, respectively. All furan and PCB levels among workers in the trichlorophenol and/or pentachlorophenol departments were similar to the Worker Referents. The Tradesmen who worked throughout the plant had dioxin congener profiles consistent with both trichlorophenol and pentachlorophenol exposures. PCB levels and levels of 23478-P 5 CDF, 123478-H 6 CDF, and 123678-H 6 CDF were also greater in these Tradesmen than in the Worker Referents. The Worker Referent group had higher levels of dioxins and furans than the Community Referents indicating the potential for exposure outside the chlorophenol departments at the site. Distinct patterns of dioxin congeners were found many years after exposure among workers with different chlorophenol exposures. Furthermore, past trichlorophenol exposures were readily distinguishable from past pentachlorophenol exposures based on serum dioxin evaluations among workers. These data can be used to better assess dioxin exposures in future health studies. Journal of Exposure Science and Environmental Epidemiology (2007) 17, 541–548; doi:10.1038/sj.jes.7500558; published online 11 April 2007 Keywords: trichlorophenol, pentachlorophenol, dioxins, furans. Introduction Production of 2,4,5-trichlorophenol (TCP) and pentachloro- phenol (PCP) may produce polychlorinated dibenzo-p-dioxins and dibenzofurans contaminants. Studies of workers in TCP production report 2,3,7,8-tetrachlorodibenzo-p-dioxin (2378-TCDD) serum levels above background; some of these studies also report elevated 12378-P 5 CDD serum levels (Nygren et al., 1988; Beck et al., 1989; Papke et al., 1992; Piacitelli et al., 1992; Smith et al., 1992; Ott et al., 1993; Littorin et al., 1994; Flesch-Janys et al., 1996; Heederik et al., 1998; Ryan et al., 2000). Workers exposed to PCP often have 123478-H 6 CDD, 123678-H 6 CDD, 123789- H 6 CDD, 1234678-H 7 CDD, and OCDD serum levels above background with some studies also reporting higher 12378- P 5 CDD, 123478-H 6 CDF, and 1234678-H 7 CDF serum levels. (Ryan et al., 1987; Papke et al., 1992; Littorin et al., 1994; Schecter et al., 1994; Flesch-Janys et al., 1996; Schecter et al., 1996; Coenraads et al., 1999). We examined serum dioxin, furan, and PCB levels among former workers in production of TCP and PCP, and compared these levels with workers at the same plant without potential for TCP and PCP workplace exposures. The chlorophenol workers have been studied previously for health effects (Townsend et al., 1982; Bond et al., 1983, 1989; Bodner et al., 2003). This study provides a rare opportunity to compare dioxin body levels of a large group of chlorophenol workers with persons who were not exposed. We will also examine dioxin and furan profiles from TCP or PCP exposures. Finally, specific dioxin and furan blood concentration data have been recently provided that allow us to compare our TCP and PCP workers to a community population in the area. Methods Production of TCP occurred from 1942 to 1979 and PCP from 1937 to 1980 (see Table 1). The total number of workers assigned to either TCP or PCP operations was 2192. On 31 December 2003, the last day of vital status follow-up, 1251 of these workers were presumed living, and addresses were available for 1250 workers. We limited the eligibility to Received 14 August 2006; accepted 20 December 2006; published online 11 April 2007 1. Address all correspondence to: Dr. James J. Collins, The Dow Chemical Company, 1803 Building, Midland, MI 48674, USA. Tel.: þ 989 636 1276. Fax: þ 989 636 1875. E-mail: jjcollins@dow.com Journal of Exposure Science and Environmental Epidemiology (2007) 17, 541–548 r 2007 Nature Publishing Group All rights reserved 1559-0631/07/$30.00 www.nature.com/jes