Urinary arsenic, chromium, and copper levels in workers exposed to arsenic-based wood preservatives

Urinary excretion of arsenic, chromium, and copper in workers exposed to arsenic-based wood preservatives was examined to evaluate occupational exposure to these chemicals. Spot urine samples were collected from 89 wood treaters and a comparison group of 232 individuals with no known exposure to arsenicals. The results of urinalysis revealed that the wood treaters averaged 103 micrograms arsenic/L while the comparison group averaged 74 micrograms arsenic/L. The mean urinary chromium and copper levels of the wood treaters were 41 micrograms chromium/L and 191 micrograms copper/L compared with 63 micrograms chromium/L and 221 micrograms copper/L for the comparison group. Covariance analysis of urinary arsenic level between the exposed and comparison groups revealed that the adjusted mean arsenic levels of the exposed population (78 to 122 micrograms arsenic/L) were significantly higher than that of the comparison group (72 micrograms arsenic/L). The adjusted mean urinary arsenic levels of these wood treaters, however, were within published normal limits. Analysis of covariance allowed comparison of group means after statistical adjustments for possible confounding variables such as seafood intake and age. The results indicate that urinary arsenic values can provide a useful index of occupational exposure to chromated copper arsenate wood preservatives, when the effects of dietary arsenic are controlled statistically.