Residential metal contamination and potential health risks of exposure in adobe brick houses in Potosí, Bolivia.
Potosí, Bolivia, is the site of centuries of historic and present-day mining of the Cerro Rico, a mountain known for its rich polymetallic deposits, and was the site of large-scale Colonial era silver refining operations. In this study, the concentrations of several metal and metalloid elements were quantified in adobe brick, dirt floor, and surface dust samples from 49 houses in Potosí. Median concentrations of total mercury (Hg), lead (Pb), and arsenic (As) were significantly greater than concentrations measured in Sucre, Bolivia, a non-mining town, and exceeded US-based soil screening levels. Adobe brick samples were further analyzed for bioaccessible concentrations of trace elements using a simulated gastric fluid (GF) extraction. Median GF extractable concentrations of Hg, As, and Pb were 0.085, 13.9, and 32.2% of the total element concentration, respectively. Total and GF extractable concentrations of Hg, As, and Pb were used to estimate exposure and potential health risks to children following incidental ingestion of adobe brick particles. Risks were assessed using a range of potential ingestion rates (50-1000mg/day). Overall, the results of the risk assessment show that the majority of households sampled contained concentrations of bioaccessible Pb and As, but not Hg, that represent a potential health risk. Even at the lowest ingestion rate considered, the majority of households exceeded the risk threshold for Pb, indicating that the concentrations of this metal are of particular concern. To our knowledge, this is the first study to quantify key trace elements in building materials in adobe brick houses and the results indicate that these houses are a potential source of exposure to metals and metalloids in South American mining communities. Additional studies are needed to fully characterize personal exposure and to understand potential adverse health outcomes within the community.
Nicholas School of the Environment, Duke University, Box 90328, LSRC, Durham, NC 27708, USA. Electronic address: mcewen.abigail@gmail.com.
Abigail R
AR
McEwen
Department of Civil and Environmental Engineering, Duke University, Box 90287, Durham, NC 27708, USA. Electronic address: hsukim@duke.edu.
Heileen
H
Hsu-Kim
Department of History, North Carolina State University, 467 Withers Hall, Raleigh, NC 27695, USA. Electronic address: narobins@ncsu.edu.
Nicholas A
NA
Robins
Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, 109 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA. Electronic address: hagan.nicole@epa.gov.
Nicole A
NA
Hagan
Department of Biostatistics and Bioinformatics, Duke University, Box 2717, Medical Center, Durham, NC 27710, USA. Electronic address: susan.halabi@duke.edu.
Susan
S
Halabi
Environmental Health Council, Potosí, Bolivia. Electronic address: mdmbolivia@yahoo.fr.
Olivo
O
Barras
Nicholas School of the Environment, Duke University, Box 90328, LSRC, Durham, NC 27708, USA. Electronic address: drichter@duke.edu.
Daniel deB
DD
Richter
Office of Research and Development, U.S. Environmental Protection Agency, 109 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA. Electronic address: vandenberg.john@epa.gov.
John J
JJ
Vandenberg
D001838:Bolivia; D003252:Construction Materials; D004781:Environmental Exposure / Q000032:analysis / Q000706:statistics & numerical data*; D004784:Environmental Monitoring; D006798:Housing / Q000706:statistics & numerical data; D006801:Humans; D008670:Metals / Q000032:analysis*; D018570:Risk Assessment; D012989:Soil Pollutants / Q000032:analysis*
D008670:Metals; D012989:Soil Pollutants
Adobe; Arsenic; Bioaccessibility; Bolivia; Lead; Mercury