Gold King Mine Data, August 28, 2015

Today EPA is posting additional sampling data results from the San Juan River in the Navajo Nation. Surface water and sediment samples were collected at 11 locations and analyzed for 24 metals, including arsenic, cadmium, lead and mercury. Concentrations of iron and other metals in San Juan River water in the Navajo Nation peaked during the week of August 10^th as the mine release moved through the Navajo Nation, but have since trended to pre-release conditions.

Based on the comparison of pre-event data with data collected over the past two weeks, the pre-event sampling data show that concentrations for all 24 metals in surface water have trended to pre-event conditions, well below Recreational Screening Levels (RSL). The metal concentrations of the samples were also below soil / sediment recreational screening levels. Based upon the sediment sampling results, sediment sample concentrations are trending toward pre-event conditions as well.

Open or download the data file: r9_sediment_0817_and_0818(1 pg, 61 K)
Open or download the data file: r9_surfacewater_0817_and_0818-eu(1 pg, 107 K)

EPA sediment samples collected on August 15-22 and Aug 24, 2015, at locations along the Animas and San Juan Rivers 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-event levels.
The metal concentrations of the samples were below soil / sediment recreational screening levels. Based upon the sediment sampling results, sediment sample concentrations are trending toward pre-event conditions.
EPA surface water samples collected August 12-22, 2015, at locations along the Animas and San Juan Rivers have been validated.
Based on surface water sample results, surface water concentrations are trending toward pre-event conditions.

Open or download the data file: r6_sediment_08272015_1700(1 pg, 232 K)
Open or download the data file: r6_surfacewater_08272015_1700(1 pg, 429 K)

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