Contribution of Soil Lead to Blood Lead in Children: A Study from New Orleans, LA

In recent years, a significant number of environmental studies have been conducted in New Orleans, LA and surrounding Gulf Coast areas due in part to the occurrence of hurricanes Katrina and Rita. Data collected from studies in the New Orleans area indicate that inorganic contaminants including arsenic (As), iron (Fe), lead (Pb), and vanadium (V); high concentration of bioaerosols, particularly Cladosporium and Aspergillus, and several organic pollutants (PAHs, pesticides, and volatiles) may pose a risk to human health in New Orleans. While many of these results resemble historical data, a current quantitative exposure assessment has not been conducted. We engaged in one such assessment for lead (Pb) contamination in surface soils. We used Pb concentrations in surface soils (<5 cm deep) from New Orleans and quantitative data on soil ingestion using the USEPA terrestrial wildlife model to imitate lifestyle movement (e.g., school to home to daycare) to estimate child exposure to Pb contributed by soil. Our results suggest that Pb exposure from soil could range from 1.4 μg/day to 102 μg/day for our study area within urban New Orleans. These data are concerning because children exposed to >33.5 μg/d Pb may cause their blood-Pb levels to exceed the Centers for Disease Control and Prevention (CDC) threshold for blood-Pb of 10 μg/dL. It has generally been accepted that a more protective blood Pb concentration threshold of 6 μg/dL is warranted. Using the 6 μg/dL threshold puts children exposed to as little as 20.2 μg/day Pb at risk.