Improving Children’s Lead Risk Modelling in a Rural and Active Mining Community and an Evaluation of Risk Communication in a Rural Mining Community

Abstract

Lead exposure has been shown to be harmful to humans in various settings. Lead is particularly harmful to children, in whom it can cause neurological problems, low IQ, developmental delay, and other health issues. There are no safe levels of blood lead in children. At the ASARCO Alternative Superfund site in Hayden-Winkelman, Arizona, lead exceedances in air and soil have been measured in the past 20 years. An important question is whether these lead levels can be expected to affect the health of children in the community, since those age seven and under are particularly vulnerable to the effects of lead. Over 140 children under age 11 live in Hayden and Winkelman. The majority live within a quarter mile of the smelter. In the main portion of the thesis, I used the U.S. Environmental Protection Agency’s Integrated Exposure Uptake Biokinetic (IEUBK) model to estimate Hayden-Winkelman children’s (age 6 months--7 years) blood lead levels using site-specific lead concentrations measured in indoor and outdoor air, soil, indoor dust, and water. Values used by the Arizona Department of Environmental Quality’s airborne lead risk forecast were also evaluated in the IEUBK model to determine whether their forecasting program is useful in determining risk for children in the community when coupled with other measured lead exposures on the site. The results demonstrate that lead in dust is the major contributor to estimated blood lead levels in a simulated population of children at this site, while lead in the air does not contribute greatly to risk. In the second portion of the thesis, an analysis of the Arizona Department of Environmental Quality ’s Air Lead Risk Forecast as a risk communication was performed and suggestions for further evaluation were given.