Potential health risks of trace elements in adobe brick houses in a historical mining town: Potosí, Bolivia

The objectives of this study were to investigate trace elements in adobe houses and to characterize potential health risks from children’s exposure in Potosí, Bolivia. The city of Potosí sits at the base of the Cerro Rico Mountain, which has been mined heavily for its rich polymetallic deposits since the Spanish Colonial era in the 16th century, leaving a legacy of pollution that is not well understood. In this study, total trace elements were quantified in dirt floor, adobe brick, and surface dust samples from 49 houses. Mean concentrations of total mercury, lead, and arsenic in adobe bricks were significantly greater than concentrations in Sucre, Bolivia, a non-mining town used as a reference site, and exceeded US-based soil screening levels that are protective of human health. Adobe brick samples were further analyzed by simulated gastric fluid (GF) extraction, which approximates bioaccessibility. Mean GF extractable concentrations of mercury, arsenic, and lead were 0.841, 14.9, and 30.0 percent of the total concentration, respectively. Total and GF extractable concentrations of these elements were used to estimate exposure and potential health risks to one and six year old children following incidental ingestion of element enriched adobe brick particles. Although the majority of households have concentrations of total mercury and arsenic that represent a potential health risk, the percentage significantly decreases when GF extractable concentrations are considered. However, even when GF extractable lead is considered, the majority of the households have lead concentrations in adobe bricks that represent a potential health risk to children. This is the first study to quantify trace elements in adobe houses and the results show that the building materials in these houses are a source of exposure to potentially toxic trace elements in South American mining communities. Additional environmental sampling, biomonitoring, and exposure questionnaires are needed to fully characterize sources of exposure and to understand potential adverse health outcomes within the community.