Data shows arsenic levels at Grand Canyon uranium mine are unusually high for the region
Between 1993 and 2025, 40 wells and spring sites in the Grand Canyon region were sampled for arsenic in the Coconino Aquifer. Four wells had average arsenic levels above the U.S. Environmental Protection Agency’s drinking water standard of 10 micrograms per liter. Three of those four wells are monitoring wells at Pinyon Plain Mine, where average arsenic levels are nearly twice the drinking water standard in the south well, nearly three times in the north well, and nearly six times in the east well. These elevated levels are unusually high and uncharacteristic of the Coconino Aquifer.
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