Uranium in Grand Canyon Spring Water – the Potential for Contamination and Aquifer Disruption From Mining Activities

Mining activities near Grand Canyon National Park have the potential to damage the quantity and quality of Grand Canyon springs, and the plants and animals that depend on those springs.  The lands in question include the Tusayan Ranger District and Federal land managed by the Bureau of Land Management in the vicinity of Kanab Creek and in House Rock Valley.  The springs support a rich diversity of animals, birds, insects and plants, and provide water for backcountry hikers and Native Americans.  Uranium concentrations in water from various springs in the Grand Canyon are high, including Horn Creek (below the site of the abandoned Orphan Uranium Mine on the Rim) which has shown levels as high as 92.7 ppb, which is above the EPA Maximum Contaminant Level Goals (0 ppb), and in excess of the EPA Maximum Contaminant Levels (30 ppb).  High uranium concentrations provided part of the impetus for the Park Service to clean up the Orphan Mine site under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), also known as Superfund.  The cost for remediation of the Orphan Mine's surface area is estimated at $15 million (Phase 1), but costs to remediate contamination in the underground portion of the mine and in Horn Creek are unknown.  Activity ratios of uranium 234 / uranium 238 show abnormal ratios below the Orphan Uranium Mine Site, which is supportive evidence of mining impact.