Uranium in Waters of The Southern Colorado Plateau: Implications for the Navajo Nation

Uranium (U) has been observed to be enriched in the waters of the southern Colorado Plateau including waters of the Navajo Nation. The region has naturally occurring U in rocks and a history of mining which may exacerbate U concentrations in waters. Despite past research into the abundance of U in the waters of the Navajo Nation, a regional framework has not been established to understand where U is typically higher and lower. We examined data collected by multiple studies and organizations to establish where and why U is likely to be enriched in waters of the Navajo Nation. Our work shows that U concentrations are related to the presence of U-rich rock bodies, elevation, and the salinity of local aquifers. Additionally, we show that U concentrations in water sources downstream from abandoned U mines are higher than they are in water sources that are not downstream from mines. Our work provides a means for understanding the patterns of U concentration in waters of the Navajo Nation and can act as a guide for local water withdrawal, as well as remediation and mitigation efforts for regional water sources.