To investigate the effects of chronic exposure to mercury we studied t
he red cell antioxidant system in mercury-exposed workers through the
evaluation of reduced glutathione, catalase and superoxide dismutase s
ystems. Of these workers, some were being exposed at the time and had
presented urinary mercury levels considered safe for occupational expo
sure for at least 3 months prior to the initiation of this study, and
others had been on leave for at least 6 months because of intoxication
symptoms. Reduced glutathione levels were lower and catalase activity
was higher in the workers which were still being exposed, compared to
those on leave and controls. No differences were observed between the
workers on leave and controls.