Date of Graduation

2008

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Committee Chair

Louis M. McDonald

Committee Member

Jonathan R. Cumming

Committee Member

Gregory A. Elmes

Abstract

For many years, lead was used to make the white pigment used in residential paints. Although lead paint was finally banned for residential use in 1978, the environmental legacy of contaminated residences and adjacent soils remains. Lead poisoning continues to be a major public health issue. Those at most risk for lead poisoning are children, especially those who 1) live in low quality housing, or those undergoing unsafe restoration or repainting jobs, that were built before 1978, 2) have parents with lead-based hobbies or occupations, and 3) live near lead mining or processing facilities. Other sources of exposure include inner-city and roadside soils contaminated by lead gasoline emissions, lead soldered pipes, and historically, lead in canned food. More recently, children’s toys and costume jewelry that contained high levels of lead have been swallowed and caused harmful effects, including death in children. In general, lead-based paints, lead in soil, and drinking water are the primary sources and pathways of lead exposure in children. Although it is still controversial, there is enough evidence to consider soil and paint as equally important pathways of human exposure. The interest of this study is the lead from lead-based residential paint that reaches the soil (by peeling or sanding), and that is later released from the paint matrix due to a variety of low molecular weight organic acids (LMWOA) that are found naturally in soils. The first objective was to determine the effect of three simple carboxylate containing LMWOA (citrate, acetate, and formate) on the dissolution rate and steady state concentrations of lead (and zinc) from a lead-based residential paint. Both adults and children can suffer from the effects of lead poisoning, but childhood lead poisoning is much more frequent. An elevated BLL is currently defined as 10 µg dl-1. This level has been reduced by the Centers for Disease Control and Prevention (CDC) from 60 µg dl-1 (before 1970) to 10 µg dl-1 (1991) based on findings linking lead at this level to lowered intelligence and diminished school performance. For this reason, in 1988 the CDC initiated programs to eliminate childhood lead poisoning in the United States. These programs focus on the identification and treatment of children with elevated BLL and the prevention of exposure to lead before children become poisoned. The use of Geographic Information Systems (GIS) could help to pursue those objectives. Thus, a second objective of this study was to identify populations that are likely to be at risk for lead poisoning from lead-based paints by the use of Geographic Information Systems and Spatial Analysis methodologies. Also, although lead poisoning is generally assumed to be a problem of poor, urban areas (inner-city children) and because there is some evidence to show that children living in rural areas are also at increased risk, a third objective was to identify parcels for a study to compare suburban and rural homes for soil lead concentrations.

Download

Share

COinS