Water Sampling Results in the Navajo Nation

EPA is investigating if and to what extent abandoned uranium mines (AUMs) on the Navajo Nation have impacted groundwater and surface water.

EPA and the Navajo Nation agreed to assess potential impacts on water resources at four types of AUMs: surface mines, underground “dry” mines above groundwater, underground “wet” mines below groundwater, and “leach” mines where acid was used on site to extract ore.

To better understand potentially impacted water resources, in 2016 the United States and the Navajo Nation agreed to complete studies of two AUMs to determine if groundwater or surface waters have been affected by those mines.

Subsequently, in 2022 the U.S. and Navajo Nation agreed that these two water studies will be carried out under the newly created Phase 2 Expanded Trust Agreement (pdf) (753.67 KB, February 14, 2022) by the Phase 2 Expanded Trust (More information on the Phase 2 Expanded Trust can be found at Trust Mines). To this end, detailed surface water and groundwater studies are being conducted at Claim 28 mine in the Tachee-Blue Gap chapter and the Saytah/George Simpson 1 Incline mine in the Tolikan chapter by the Phase 2 Trustee, Derrith Watchman-Moore.

Separately, EPA is conducting a study to investigate potential impacts to surface water and groundwater from underground mines at the Northeast Church Rock/Quivira mining complex in the Church Rock chapter.

Finally, EPA will conduct a comprehensive investigation of potential impacts to surface water and groundwater in the Cove chapter as part of the Lukachukai Mountain Mining District remedial investigation and feasibility study.

Though these studies are ongoing, they are helping EPA to better understand the potential impacts to groundwater and surface water and to ensure that cleanup options implemented at abandoned uranium mine sites are protective of surface water and groundwater.

The following documents provide more information about EPA's work to provide safe drinking water to communities affected by uranium contamination.

• Contaminated Unregulated Water Sources (pdf) (33.1 KB, November 13, 2012)
  This is a table with the results of testing of water sources in the Navajo Nation.
• Final Report: Church Rock Mine (NECR) Water Well Sampling (pdf) (3.92 MB, April 21, 2011)
  Final residential water well sampling report by Ecology and Environment Inc. Superfund Technical Assessment and Response Team (START) in the vicinity of the former Northeast Church Rock Mine located in the Church Rock Chapter of the Navajo Nation.
• Navajo Nation Water Well Sampling: Church Rock Chapter Navajo Nation (pdf) (2.68 MB, April 20, 2011)
  Ecology and Environment Inc. Superfund Technical Assessment and Response Team (START) with technical assistance relating to residential water well sampling in various regions of the Navajo Nation. The purpose of this sampling event was to generate additional data to measure the impact of the former uranium mines on wells within the adjacent areas. April 20, 2011
• Navajo Nation October 2009 Unregulated Water Source Sampling Results (pdf) (132.5 KB, August 2010)
  Final report of the October 2009 Unregulated Water Source Sampling Project, which sampled 36 unregulated water sources on the Navajo Nation in the Eastern Agency and chapters in the South Central and North Central areas of the reservation.
• Navajo Nation Drinking Water Source Sampling Report (pdf) (9.39 MB, August 28, 2008)
  Report on water sampling performed between February and March of 2008 at locations on the Navajo Nation to investigate potential radioactivity related public health issues.