[Investigations on neurotoxicity of chemical substances at the workplace. III. Determination of the motor and sensory nerve conduction velocity in persons occupationally exposed to trichloroethylene].

We studied 31 employees (26 men, five women) from three firms, between the ages of 16 and 56 years, who had been exposed to trichloroethylene (TRI) from 1 month to 35 years, mean 7 years. To objectify the actual solvent-exposure we performed "biological monitoring" and determined TRI- and the metabolites trichloroethanol (TCE) and trichloroacetic acid (TCA) in blood- and/or urine-samples. The following concentrations were found in the urine-samples: TCE 19.0-357.0 mg/g creatinine, median 90.0; TCA 2.0-201.0 mg/g creatinine, median 48.0; TTC (TCE + TCA) 31.0-416.0 mg/g creatinine, median 112.5. Additionally three results of former urine-analyses in the period 1978-1980 from 10 workers were obtained to calculate "time-weighted-average (TWA)"-levels (TWA-TTC in urine: 53-640 mg/g creatinine). Nerve conduction velocity (NLG)-measurements of motor and/or sensory fibers of the ulnar and median nerve were performed to test peripheral nerve function. Seven employees were excluded. They had possible competitive risks of peripheral neuropathy, or were of less than 10 months exposed. For controls we examined 24 healthy persons of identical sex and age (matched pairs), but without known risks of a peripheral neuropathy. In comparing the nerve conduction velocities there were no significant differences between TRI-exposed and non-exposed persons. Correlation analyses and the individual assessment of the data concerning exposure/dose and effect revealed no signs of a "dose-effect-relationship".