REVERSIBLE COLOR-VISION LOSS IN OCCUPATIONAL EXPOSURE TO METALLIC MERCURY

Color vision was evaluated in twenty-one mercury exposed workers and r eferents matched for sex, age, tobacco smoking, and alcohol habits. Th e Lanthony 15 Hue desaturated panel (D-15 d) was applied. In the worke rs, mean urinary Hg (HgU) was 115 +/- 61.5 mu g/g creatinine; in all b ut one the values exceeded the biological limit (BEI) proposed by the American Conference of Governmental Industrial Hygienists. A dose-rela ted subclinical color vision impairment was observed in Hg-exposed wor kers compared to the referents. Just after the survey, working conditi ons were improved. Twelve months later the workers were reexamined. Me an HgU was 10.0 mu g/g creatinine and in no subjects was the BEI excee ded. Color perception was significantly improved compared to the first examination and, furthermore, no differences were observed between ex posed workers and referents. The results add evidence that the color v ision loss observed during the first part of the study was related to Hg exposure and, moreover, show that this effect is reversible. These data indicate that metallic Hg can induce a reversible impairment in c olor perception. This suggests that color vision testing should be inc luded in studies on the early effects of Hg, The possibility of applyi ng the D-15 d as an early effect index in the biological monitoring of Hg exposed workers should also be entertained. (C) 1998 Academic Pres s.