Analysis of U.S. soil lead (Pb) studies from 1970 to 2012.
Although lead (Pb) emissions to the air have substantially decreased in the United States since the phase-out of leaded gasoline by 1995, amounts of lead in some soils remain elevated. Lead concentrations in residential and recreational soils are of concern because health effects have been associated with Pb exposure. Elevated soil Pb is especially harmful to young children due to their higher likelihood of soil ingestion. The purpose of this study is to create a comprehensive compilation of U.S. soil Pb data published from 1970 through 2012 as well as to analyze the collected data to reveal spatial and/or temporal soil Pb trends in the U.S. over the past 40 years. A total of 84 soil Pb studies across 62 U.S. cities were evaluated. Median soil Pb values from the studies were analyzed with respect to year of sampling, residential location type (e.g., urban, suburban), and population density. In aggregate, there was no statistically significant correlation between year and median soil Pb; however, within single cities, soil Pb generally declined over time. Our analysis shows that soil Pb quantities in city centers were generally highest and declined towards the suburbs and exurbs of the city. In addition, there was a statistically significant, positive relationship between median soil Pb and population density. In general, the trends examined here align with previously reported conclusions that soil Pb levels are higher in larger urban areas and Pb tends to remain in soil for long periods of time.
Oak Ridge Institute for Science and Education, Environmental Media Assessment Group, National Center for Environmental Assessment, U.S. Environmental Protection Agency, Mail Drop: B243-01, Research Triangle Park, NC 27711, United States. Electronic address: Datko-Williams.Laura@epa.gov.
Laura
L
Datko-Williams
Adrien
A
Wilkie
Jennifer
J
Richmond-Bryant
D002947:Cities; D004787:Environmental Pollution / Q000266:history* / Q000706:statistics & numerical data*; D005843:Geography; D049673:History, 20th Century; D049674:History, 21st Century; D007854:Lead / Q000032:analysis*; D011156:Population Density; D012989:Soil Pollutants / Q000032:analysis*; D014481:United States
D012989:Soil Pollutants; D007854:Lead
Pb storage; Population density; Soil lead; United States; Urbanized area