Assessment of exposure to carbon disulfide in viscose production workers from urinary 2-thiothiazolidine-4-carboxylic acid determinations

The follow‐up of environmental carbon disulfide (CS2) exposure and urinary excretion of 2‐thiothiazolidine‐4‐carboxylic acid (TTCA) among 20 operatives over a 4‐day working week in two viscose producing factories confirmed earlier observations that TTCA is a sensitive and reliable indicator of exposure to CS2. Exposure to as low as 0.5–1.0 ppm (1.6–3.2 mg/m3) of CS2 (8‐hour time‐weighted average [TWA]) was associated with detectable amounts of TTCA in end‐of‐shift urine. Moreover, the excretion of TTCA, relative to estimated CS2 uptake, appeared surprisingly constant in the studied work force. Approximately 3% (range 2–6.5%) of absorbed CS2 was detected in urine as TTCA. The proportional TTCA excretion did not show dose dependency in the estimated CS2 dose range which varied by about 20‐fold. TTCA elimination exhibited both a fast (T 1/2 6 hour) and a slow (T 1/2 68 hour) phase. The slow elimination is compatible with a high lipid solubility and reversible protein binding of CS2. Consequently, urinary excretion of TTCA, relative to CS2 exposure, increased by about a third during the workweek. Urinary TTCA concentration of 4.5 mmol/mol creatinine in a postshift sample corresponded to a TWA exposure to 10 ppm CS2 towards the end of the working week. © 1992 Wiley‐Liss, Inc.