Evoked potentials are modified by long term exposure to trichloroethylene

Two groups of New Zealand albino rabbits were respectively exposed to 350 and 700 ppm of trichloroethylene (TRI) 4 hrs/day, 4 days/week for 12 weeks. Weekly, visual evoked potentials (VEP) recordings were obtained under mesopic condition. Blood samples were also collected weekly to determine the concentration of TRI and its metabolites. Recordings from the 350 ppm group showed a significant (p less than 0.001) decrease in the amplitude of VEPs, while a significant (p less than 0.001) increase was observed in the 700 ppm group. Both effects were reversed to baseline values within six weeks after the last exposure. The observed modifications in VEP amplitudes were related to blood level of trichloroethanol. These results thus confirm the neuro-ophthalmotoxicity of TRI and support the hypothesis that trichloroethanol is a reliable marker of the effective neurotoxic dose of this organic solvent.