Metabolic consequences of exposure to polychlorinated biphenyls (PCB) in sewage sludge

Polychlorinated biphenyls (PCB) were discovered in sewage sludge used for fertilizer in Bloomington, Indiana. The PCB had been discharged into the municipal sewage system by an electrical capacitor manufacturing plant. To study the epidemiology and metabolic consequences of PCB exposure an epidemiologic and clinical survey was conducted. Mean serum PCB levels were 17.4 ppb in 89 sludge users, 75.1 ppb in 18 workers with occupational exposure to PCB, 33.6 ppb in 19 members of those workers' families, and 24.4 ppb in 22 community residents without unusual exposure to PCB. In sludge users PCB levels were associated positively with per cent performance of garden care (p = 0.035) and negatively with wearing gloves while gardening (p = 0.021), but were not significantly associated with the amount of sludge used or the duration of exposure. In no groups were chloracne or systemic symptoms of PCB toxicity noted, nor were significant correlations found between PCB levels and tests of hematologic, hepatic, or renal function. Plasma triglyceride levels increased significantly with serum PCB concentrations in both alcohol drinkers and nondrinkers (r = 0.541, n = 36, p < 0.001 for nondrinkers). These data indicate that PCB may alter lipid metabolism at levels of exposure and bioaccumulation insufficient to produce overt symptoms.