Environmental and biological monitoring of occupational exposure to 1,1,1-trichloroethane.

Fifty workers involved in various degreasing and cleaning processes using 1,1,1-trichloroethane (1,1,1-TCE) were studied with respect to personal and static exposures. In addition, end-of-shift expired air and venous blood samples were taken for analysis of the parent compound. Urinary samples were also obtained at the same time for analysis of its metabolites-trichloroethanol (TCOH) and trichloracetic acid (TCA). The results show that open/manual degreasing processes generate the highest environmental solvent levels (mean = 819.9 mg/m3; SD = 781.9 mg/m3) followed by jet-spray cleaning (mean = 460.5 mg/m3; SD = 292.4 mg/m3), vapour degreasing (mean = 365.3 mg/m3; SD = 279.9 mg/m3) and ultrasonic degreasing (mean = 134.7 mg/m3; SD = 121.0 mg/m3). Personal exposure levels were well correlated with concentrations of 1,1,1-TCE in end-of-shift expired air (r = 0.81) and venous blood samples (r = 0.88) but only moderately correlated with concentrations of its metabolites in urine (r = 0.49 for TCOH; r = 0.58 for TCA). Static (area) samples were poorly correlated with the biological exposure indices studied.