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

Abstract

The results of dioxin blood analyses are presented for three men and four women who were among 231 workers exposed to dioxins at a chemical factory in Ufa, Russia, approximately 25 years prior to blood collection and analysis in 1991 and 1992, respectively. Five of the seven (three male workers and two female workers), were diagnosed with chloracne after manufacturing 2,4,5-trichlorophenoxy-acetic acid contaminated with 2,3,7,8-TCDD (TCDD) between 1965 and 1967 at the Agrochemical complex in that city. This is, to the best of our knowledge, the first reported incident of chloracne in females with elevated dioxin blood levels 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 population pooled sample (N=68) averaged 4.4 ppt. Unlike previous reports of human tissue dioxin levels following exposure to 2,4,5-T, several 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, 1,2,3,4,7,8/1,2,3,6,7,8-HxCDF and 1,2,3,4,6,7,8-HpCDF. We compare the dioxin (PCDD) and dibenzofuran (PCDF) levels and dioxin toxic equivalents (TEQ) of these workers with those of non-exposed Russians and estimate that the workers' total dioxin toxic equivalent levels 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 the workers to have been between 22 and 172 μg using a 5 year half-life of elimination and 4 to 30 μg if the half life was 10 years. We also measured the coplanar polychlorinated biphenyls (CoPCBs) in these workers and found them to range from 81 to 329 ppt lipid for those detected. We believe this to be the first measurement of coplanar PCBs in blood of Eastern Europeans.