Exposure of Russian phenoxy herbicide producers to dioxins

Russian workers who manufactured phenoxy herbicides and related compounds i n the 1960s in the city of Ufa, Bashkortostan, a republic of the forme Sovi et Union, were studied for exposure to polychlorinated dibenzo-p-dioxins (P CDDs) and dibenzofurans. Sixty whole blood samples were drawn in September 1992 and analyzed by gas chroma tography-mass spectrometry. Thirty-four wor kers who manufactured the herbicide 2,4,5-trichlorophenoxyacetic acid (2,4, 5-T) had median blood lipid 2,3,7,8-tetrachlorodibenzo-p-diozin (TCDD) conc entrations of 166 ng per kg (parts per trillion) and 1,2,3,7,8-pentachloro- p-dioxin (PnCDD) levels of 52 parts per trillion with several TCDD values g reater than 500 ng/kg. These 1992 values are 10 to 30 times greater than co ntemporary normal or background blood levels from the Baskortostan region o f Russia and were at least 10-fold higher 25 years earlier in the late 1960 s. Six workers who produced the herbicide 2,4-dichlorophenoxyacetic acid al so had elevated levels in 1992, with 1,2,3,7,8-PnCDD blood lipid levels hig her than 2,3,7,8-TCDD. Even children of some of the workers and factory adm inistrative personnel had blood levels of TCDD higher than most general pop ulation groups from other parts of Russia or from other countries. The patt erns of the PCDDs and dibenzofurans (as defined by the specific congeners a nd their relative amounts) were distinctive for the type of chemical produc ed, with notable contributions to the TCDD toxic equivalents from the 2,3,7 ,8-TCDD and 1,2,3,7,8-PnCDD congeners. No correlation was found between chl oracne status in 1965 to 1967 and TCDD or toxic equivalent blood lipid conc entrations in 1992. These Russian phenoxy herbicide and related chemical pr oducers have some of the highest occupational exposure to dioxins of any co hort studied to date and seem to be unique with respect to the presence of appreciable amounts of 1,2,3,7,8-PnCDD.