Levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin in the serum of U.S. chemical workers exposed to dioxin contaminated products: interim results.
As part of a larger study, a group of subjects who had been employed at a chemical facility between 1951 and 1972 underwent a comprehensive medical exam during which a sample of serum was collected for the analysis of the 2,3,7,8-tetrachlorodibenzo-p- dioxin (1746016) (TCDD). At this site, 2,3,7,8-TCDD contaminated the production of 2,4,5-trichlorophenol (95954) and 2,4,5- trichlorophenoxyacetic-acid (93765). The results of the analyses of 46 of these serum samples for TCDD were presented; the samples were from 27 workers and 19 referents in the cohort. In general, the mean of 8.2 parts per trillion (ppt) TCDD found in the serum of unexposed persons was comparable to levels found in unexposed persons in other industrialized nations. The mean level of 208.2ppt found in the sera of workers greatly exceeded the background levels. The current levels for workers were related to the duration of employment in the production of substances contaminated with TCDD. Since all workers were last exposed prior to 1973, serum levels of TCDD at termination of employment were estimated by assuming a 7 year half life.