Influence of environmental zinc on the association between environmental and biological measures of lead in children

Exposure to lead, a common environmental contaminant found at hazardous waste sites, has been associated with adverse health effects to humans. Zinc, a nutritionally essential metal, may influence both the absorption and the toxicity of lead. The purpose of this study was to determine if zinc levels present in the environment affect the association between environmental lead measured in two small communities in the northeastern United States and biological measurements of lead in the residents of these communities. Soil and dust sampled in and around the homes of all participants were tested for lead and zinc. Residents aged 6 months to 14 years (n = 214) provided blood samples for the determination of blood lead concentrations. Soil and dust measurements of environmental lead were positively associated with blood lead, regardless of the corresponding zinc levels in these samples. However, the magnitude of this association was 20% to 46% lower in areas with high environmental measures of zinc. The interactions between environmental lead and environmental zinc levels and blood lead concentrations suggest that zinc may influence the association between soil and dust lead and corresponding blood lead levels.