The U.S. Environmental Protection Agency unveiled its conclusive cleanup strategy for a drinking water aquifer situated within the Tohono O'odham Nation. This effort will establish the groundwork for the responsible utilization of groundwater, guaranteeing the security of future drinking water supplies, according to an Aug. 3 news release.
“Ensuring access to clean and safe drinking water is one of EPA’s most important missions,” EPA Director of Region 9 Superfund and Emergency Management Division Michael Montgomery said in the release. “Today’s announcement is an essential step in reducing the burden on communities in the region, including the Tohono O’odham Nation.”
The EPA finalized its plan for the remediation of the Cyprus Tohono Mine Site Basin Fill Aquifer, located on the Tohono O’odham Nation in Arizona, under the Comprehensive Environmental Response Compensation and Liability Act, commonly referred to as the Superfund law, the release reported. The recently issued record of decision outlines the cleanup approach, which involves employing reverse osmosis treatment to purify groundwater contaminated with perchlorate, uranium and sulfate.
The goal of this cleanup effort is to restore the polluted groundwater to a state suitable for use as drinking water, ultimately benefiting the local community, according to the release.
The Cyprus Tohono Mine Site, situated near the village of North Komelik, experienced groundwater contamination due to mine waste, which was removed in 2008, the release reported. However, a substantial stretch of groundwater, about four miles long, remains polluted with perchlorate, sulfate and uranium in the Basin Fill Aquifer.
This aquifer, once a drinking water source, currently necessitates the supply of alternative drinking water to nearby residents due to its compromised state. The chosen cleanup strategy involves the extraction and treatment of contaminated groundwater using reverse osmosis technology, which employs pressure to filter out contaminants through a semipermeable membrane, the release said. The treated water will either be reinjected into the aquifer or repurposed for other beneficial uses. The plan also encompasses ongoing site monitoring to ensure successful contamination eradication.
While the selected cleanup plan prioritizes expediency, the EPA estimates the comprehensive remediation process will span approximately 30 years, followed by an additional 20 years of monitoring. This cleanup falls under the Superfund Alternative Approach program, the release reported.
The Cyprus Tohono Mine site's contamination traces back to copper mining activities dating back to the 1880s, with subsequent mining operations further contributing to the pollution, according to the release. The site's complex history of mining operations and contamination necessitates this extensive cleanup and restoration effort.
