Biological monitoring to determine worker dose in a butadiene processing plant

Abstract

Butadiene (BD) is a reactive gas used extensively in the rubber industry and is also found in combustion products. Although BD is genotoxic and acts as an animal carcinogen, the evidence for carcinogenicity in humans is limited. Extrapolation from animal studies on BD carcinogenicity to risk in humans has been controversial because of uncertainties regarding relative biologic exposure and related effects in humans vs. experimental animals. To reduce this uncertainty, a study was designed to characterize exposure to BD at a polymer production facility and to relate this exposure to mutational and cytogenetic effects. Biological monitoring was used to better assess the internal dose of BD received by the workers. Measurement of 1,2-dihydroxy-4-(N-acetylcysteinyl) butane (M1) in urine served as the biomarker in this study. M1 has been shown to correlate with area monitoring in previous studies. Most studies that relate exposure to a toxic chemical with its biological effects rely on exposure concentration as the dose metric; however, exposure concentration may or may not reflect the actual internal dose of the chemical.