You are here:
Meta-Analysis of Lead (Pb) in Multiple Environmental Media in the United States
Citation:
Frank, J., A. Poulakos, AND J. Xue. Meta-Analysis of Lead (Pb) in Multiple Environmental Media in the United States. 2017 ISES Annual Meeting, RTP, NC, October 15 - 19, 2017.
Impact/Purpose:
The U.S. EPA conducts multimedia lead (Pb) exposure modeling to inform the development of health-based benchmarks for Pb in the environment. For this modeling, robust Pb concentration data are needed for developing distributional model inputs. Our goal was to create a database of Pb concentrations measured in multiple media within the USA, and summarize data by media type to refine model inputs.
Description:
Introduction: The U.S. Environmental Protection Agency, Office of Research and Development, conducts probabilistic multimedia lead (Pb) exposure modeling to inform the development of health-based benchmarks for Pb in the environment. For this modeling, robust Pb concentration data are needed for developing distributional model inputs. Objectives: To create a database of Pb levels measured in environmental media within the United States using data from published literature; and to summarize Pb levels by media type to refine model inputs. Methods: A systematic literature search was conducted to identify qualifying articles meeting specified criteria published from 1996 to early 2016. Article screening and database creation were reviewed independently by two researchers. A random effects model was used to summarize data by media type. Preliminary Results (reported as mean ± 95% CI for each single group summary): Residential (RES) soil samples (50±24 ppm) from nonurbanized areas (rural) were ~8x lower than urbanized RES areas (383±74 ppm). RES sites on or nearby Pb Superfund locations were largely classified as rural (8 of 9 sites) with soil Pb levels of 267±56 ppm. Schoolyard and playground soil Pb levels were 54±22 ppm. Community and RES garden soil Pb levels were 160±37 ppm. Soil Pb from non-RES Pb Superfund sites (1316±402ppm) were ~2x lower than soil collected at outdoor shooting ranges (3137±136 ppm). Air Pb reported in the literature for sites classified as rural (0.0035±0.003 µg/m3 ) were ~5x lower than urbanized areas (0.0169±0.014 µg/m3 ). The results for Pb in drinking water for all areas reported in the literature was 2.25±1.79 ppb. Conclusions: The results from this analysis can inform future research and rule-making by providing insight into information gaps and key inputs in Pb multimedia modeling analyses, and by helping to identify potentially vulnerable groups. In addition, this information can be used to assess the effectiveness of remediation.
