A Quantitative Comparison of Heavy Metal Concentrations in the Soils on Two Rocky Mountain West tribal Reservations

Native Americans have experienced a long history of environmental injustice, including natural resource exploitation and commercial activity with environmental impacts. A community-based participatory research (CBPR) approach was used to partner with two Rocky Mountain West reservations to conduct pilot-level assessments of potential soil contamination by heavy metals. The Community Advisory Board in conjunction with the research team selected residential areas and community sites for sampling. Samples were obtained, transported to a laboratory for dehydration and sieving, and were analyzed with a handheld X-ray fluorescence (XRF) tool for the presence of 24 heavy metals. Heavy metals concentrations were compared between reservations and were found to be statistically different from one another. Findings were also compared to levels recommended by the Environmental Protection Agency (EPA) and World Health Organization (WHO) to determine possible hazards to human health. Concentration of Sr, Rb, and Th were well above acceptable EPA levels and require further analysis. High localized Pb levels were found in one area, while Hg levels were found close to EPA standards. CBPR was essential to understanding preliminary contamination patterns. In conclusion, even reservations with similar geographies and histories present with unique contaminations and require individualized study to determine possible environmental mitigation.