Homovanillic Acid (HVA) and Manganese in Urine of Workers Exposed in a Ferromanganese Alloy Plant

Forty workers occupationally exposed to manganese in a ferromanganese alloy plant and twenty-five controls were investigated in order to assess the validity of urinary homovanillic acid (HVA) as a potential indicator of early effects of manganese intoxication. None of the exposed workers showed signs and symptoms of typical manganese intoxication, but most of them reported subjective symptoms which may be related to a prodromic phase of manganism. Urinary HVA levels were not significantly different among the groups under study. On the other hand, mean urinary manganese levels were higher in the exposed group (compared with the controls). A negative correlation between urinary HVA and duration of exposure to manganese was found.