Urinary 2-Thiothiazolidine-4-Carboxylic Acid as a Biological Indicator of Exposure to Carbon Disulfide: Derivation of a Biological Exposure Index

Abstract

Abstract The current American Conference of Governmental Industrial Hygienists (ACGIH) Biological Exposure Index (BEI) for carbon disulfide (CS2) is 5 mg of 2-thiothiazolidine-4-carboxylic acid (TTCA)/g creatinine in a urine sample collected at the end of the workshift. The BEI, based on studies of viscose rayon workers, corresponds to an 8-h time-weighted average (TWA) inhalation exposure at the 1991–1992 Threshold Limit Value (TLV) (ACGIH, Cincinnati, Ohio) of 10 ppm CS2. Reduction of the CS2 airborne permissible exposure limit (PEL) from 20 ppm to 4 ppm in 1989 by the Occupational Safety and Health Administration, coupled with new experimental human-exposure studies from the published literature, prompted us to reexamine the literature and derive a new BEI. This reexamination led to the following observations: (1) Inhalation exposures of humans at rest, under laboratory conditions, to 10 and 4 ppm CS2 8-h TWA, produced urinary increases of 2.7 and 1.1 mg TTCA/g creatinine, respectively. (2) Viscose ray...