Blood lead levels in Noranda children following removal of smelter-contaminated yard soil.

In 1979, children two to five years of age living in Rouyn-Noranda, QC, in an urban district located within 1 km from a copper smelter had mean (geometric) blood lead levels (BLL) of 21 micrograms/dL. Afterwards, stack emissions were lowered. In 1989, mean (geom.) BLL were reduced to 11 micrograms/dL; 50% of the district children had BLL less than 10 micrograms/dL. In 1990-91, a $3 million top soil removal operation took place; residential lots having more than 500 ppm soil lead were decontaminated. In 1991, BLL were reduced to 7 micrograms/dL; 75% of the children had less than 10 micrograms/dL. Geographic analysis of the 1991 results showed that children with the highest BLL lived nearest to the smelter, where atmospheric dustfall to the ground reached 36 mg/m2/month. Follow-up pediatric blood lead campaigns are planned in 1993 and 1995, to evaluate the effects of an ongoing program for further reduction of atmospheric smelter emissions.