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Gold King Mine Data, August 18, 2015

Data from Gold King Mine Response

The EPA sediment samples collected from irrigation ditches at two locations along the San Juan River have been validated. EPA has done a review of the data which included a comparison to screening levels for exposure during recreational use to determine if the metal concentrations are consistent with pre-incident levels.

The metal concentrations of the irrigation samples were below soil/sediment recreational screening levels. Based upon the sediment sampling results, sediment sample concentrations are trending toward pre-event conditions.


EPA has released additional water quality data from August 12, 2015, on the San Juan River between Farmington, New Mexico and Mexican Hat, Utah.

To assess the impacts of the release at the Gold King Mine, water quality samples have been collected from Navajo Nation at numerous intervals beginning on August 7, 2015. The August 7 data was collected for baseline purposes to understand river conditions at the Hogback, New Mexico monitoring location, prior to the impact of the upstream contaminants from the Gold King Mine release.

To assess the impacts of the release at the Gold King Mine, water quality samples were collected on August 12 at eleven locations for 24 metals. Each surface water sample was analyzed for metals including arsenic, cadmium, lead and mercury.

Due to the highly variable conditions typical of this segment of the river, additional testing will be conducted, and we continue to work closely with the Navajo Nation EPA on assessing drinking water, agriculture, livestock, and other critical water needs.

Water quality data from August 12, 2015, on the San Juan River between Farmington, New Mexico and Mexican Hat, Utah is provided below:

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