Porphyrin status in aluminum foundry workers exposed to hexachlorobenzene and octachlorostyrene

The possible interference of hexachlorobenzene and octachlorostyrene (i.e., thermal byproducts from hexachloroethane in aluminum degassing) with porph yrin metabolism was investigated in exposed workers. Urine specimens from 9 male aluminum foundry workers (i.e., smelters) at 6 different companies an d from 18 controls-matched for sex, age, residence, and socioeconomic statu s were analyzed for total porphyrins and porphyrin isomers. Workers exposed to hexachlorobenzene and octachlorostyrene had a statistically significant increase in urinary total porphyrins, compared with controls (mean + stand ard deviation: 13.63 +/- 11.13 mu mol/mol creatinine and 6.24 +/- 3.84 mu m ol/mol creatinine, respectively; p = .02). The authors attributed the resul ts mainly to differences in excretion of coproporphyrins-notably coproporph yrin ill. Erythrocyte uroporphyrinogen decarboxylase activity was similar i n both groups. There was a high correlation between levels of hexachloroben zene and octachlorostyrene, respectively, in plasma and urinary excretion o f porphyrins; these findings, however, relied heavily on 1 subject for whom extreme values were obtained. The results indicated that occupational expo sure to hexachlorobenzene and octachlorostyrene in aluminum degassing with hexachloroethane may affect porphyrin metabolism in a manner consistent wit h early secondary coproporphyrinuria-the first recognized step in the devel opment of chronic hepatic porphyria. It was also noted that changes remaine d detectable some years after exposure ceased.