Increased mercury exposure in inhabitants living in the vicinity of a hazardous waste incinerator: a 10-year follow-up.

A hazardous-waste-treatment plant that housed an incinerator began operation in 1984, before which a baseline survey of the surrounding population and environment was conducted; 10 y later, investigators studied the same subjects. Researchers focused on mercury exposure because mercury concentrations were present in the stack emissions, and environmental monitoring revealed mercury concentrations near the plant. In 1984 and 1994 the median hair mercury concentrations were 0.5 mg/kg and 0.8 mg/kg, respectively. During the 10-y period, median hair total mercury concentrations increased by 0.35 mg/kg in workers (n = 11); by 0.16 mg/kg, 0.13 mg/kg, and 0.03 mg/kg in individuals who lived 2 km (n = 45), 2-4 km (n = 38), and 5 km (n = 30) from the plant, respectively; and by 0.02 mg/kg in the reference group (n = 55). In summary, mercury exposure increased as distance from the plant decreased; however, the increase in exposure was minimal and, on the basis of current knowledge, did not pose a health risk.