The geologic profile of the western United States lends itself to naturally elevated levels of arsenic and uranium in groundwater and can be exacerbated by mining enterprises. The Navajo Nation, located in the American Southwest, is the largest contiguous Native American Nation and has over a 100-year legacy of hard rock mining. This study has two objectives, quantify the arsenic and uranium concentrations in water systems in the Arizona and Utah side of the Navajo Nation compared to the New Mexico side and to determine if there are other elements of concern. Between 2014 and 2017, 294 water samples were collected across the Arizona and Utah side of the Navajo Nation and analyzed for 21 elements. Of these, 14 elements had at least one instance of a concentration greater than a national regulatory limit, and six of these (V, Ca, As, Mn, Li, and U) had the highest incidence of exceedances and were of concern to various communities on the Navajo Nation. Our findings are similar to other studies conducted in Arizona and on the Navajo Nation and demonstrate that other elements may be a concern for public health beyond arsenic and uranium.
Note: This paper is part of the Special Topic Collection on 30 years of the Nellie Yeoh Whetten Award -Celebrating the Women of the AVS.
Parts of the Southwestern United States report arsenic levels in water resources that are above the United States Environmental Protection Agency's current drinking water limits. Prolonged exposure to arsenic through food and drinking water can contribute to significant health problems including cancer, developmental effects, cardiovascular disease, neurotoxicity, and diabetes. In order to understand exposure risks, water sampling and testing have been conducted throughout Arizona. This information is available to the public through often non‐overlapping databases that are difficult to access and in impracticable formats. The current study utilized a systemic compilation of online databases to compile a spreadsheet containing over 33,000 water samples. The reported arsenic concentrations from these databases were collected from 1990–2017. Using ArcGIS software, these data were converted into a map shapefile and overlaid onto a map of Arizona. This visual representation shows that arsenic levels in surface and ground water exceed the United States Environmental Protection Agency's drinking water limits for many sites in several counties in Arizona, and there is an underrepresentation of sampling in several tribal jurisdictions. This information is useful for water managers and private well owners throughout the State for determining safe drinking water sources and limiting exposure to arsenic.
In the United States, American Indian and Alaska Native (AI/AN) people are frequently under- or misrepresented in research and health statistics. A principal reason for this disparity is the lack of collaborative partnerships between researchers and tribes. There are hesitations from both academic Western scientists and tribal communities to establish new partnerships due to differences in cultural and scientific understanding, from data ownership and privacy to dissemination and project expansion. An infamous example is the mishandling of samples collected from the Havasupai Tribe by Arizona State University (ASU) scientists, leading to a legal battle between the tribe and ASU and ending in a moratorium of research with the Havasupai people. This paper will explore three successful and positive collaborations with a large and small tribe, including how the partnerships were established and the outcomes of the collaboration. In addition, the paper will provide perspective of what needs to be addressed by Western scientists if productive collaborations with tribal groups are to be established.
Concentrations of dissolved uranium (U) and arsenic (As) above drinking water standards in unregulated water sources pose various human health risks. Although high natural background concentrations may occur in some environments (Runnells et al. 1992), anthropogenic contamination concerns are especially troublesome on the Navajo Nation (NN), where past U mining activity may have contaminated water supplies. This research investigated U and As groundwater contamination issues in unregulated wells in the western portion of the NN. Objectives of this research were to provide insights to human health risks by assessing the spatial extent and seasonal variability of U and As concentrations while effectively communicating the potential contamination risks to the local Navajo people. Eighty‐two unregulated wells were sampled in 2018; nine of these sources exceeded the maximum contaminant level (MCL) for drinking water standards for U (30 µg/L), and 14 exceeded the MCL for drinking water standards for As (10 µg/L). U and As levels were highest in the southwest portion of the study area and seasonal variability was observed in a subset of wells, especially shallower hand dug wells and hand pumps. The results were compiled into a report that was presented to NN chapters included in the study as well as the Navajo Department of Water Resources and the NN Environmental Protection Agency. Implications for regional water quality patterns can help to direct policy recommendations for well monitoring, water use, and remediation targets.
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