ELEVATED DIOXIN LEVELS IN THE BLOOD OF MALE AND FEMALE RUSSIAN WORKERS WITH AND WITHOUT CHLORACNE 25 YEARS AFTER PHENOXYHERBICIDE EXPOSURE - THE UFA KHIMPROM INCIDENT

The results of dioxin blood analyses are presented for three men and f our women who were among 231 workers exposed to dioxins at a chemical factory in Ufa, Russia, approximately 25 years prior to blood collecti on and analysis in 1991 and 1992, respectively. Five of the seven (thr ee male workers and two female workers), were diagnosed with chloracne after manufacturing 2,4,5-trichlorophenoxy-acetic acid contaminated w ith 2,3,7,8-TCDD (TCDD) between 1965 and 1967 at the Agrochemical comp lex in that city. This is, to the best of our knowledge, the first rep orted incident of chloracne in females with elevated dioxin blood leve ls from occupational exposure. The workers were found to have elevated levels of 2,3,7,8-TCDD ranging from 36 to 291 parts per trillion (ppt ) on a lipid basis, with a mean of 185 ppt, where a general Russian po pulation pooled sample (N = 68) averaged 4.4 ppt. Unlike previous repo rts of human tissue dioxin levels following exposure to 2,4,5-T, sever al other congeners were elevated in some workers, including 1,2,3,7,8- PnCDD, and to a lesser extent, 1,2,3,4,7,8/1,2,3,6,7,8-HxCDD, OCDD, 2, 3,4,7,8-PnCDF, 1,2,3,7,8/1,2,3,6,7,8-HxCDF and 1,2,3,4,6,7,8-HpCDF. We compare the dioxin (PCDD) and dibenzofuran (PCDF) levels and dioxin t oxic equivalents (TEQ) of these workers with those of non-exposed Russ ians and estimate that the workers' total dioxin toxic equivalent leve ls in 1967 ranged from 226 to 1,707 ppt assuming a 10 year half-life, and 1,173 to 9,366 ppt assuming a 5 year half-life of elimination for 2,3,7,8-TCDD. We estimate the total body burden of 2,3,7,8-TCDD for th e workers to have been between 22 and 172 mug using a 5 year half-life of elimination and 4 to 30 mug if the half life was 10 years. We also measured the coplanar polychlorinated biphenyls (CoPCBs) in these wor kers and found them to range from 81 to 329 ppt lipid for those detect ed. We believe this to be the first measurement of coplanar PCBs in bl ood of Eastern Europeans.