Initially, the EPA’s estimated that 1 million gallons of acidic waste water contaminated with heavy metals (iron, zinc, copper, arsenic, cadmium, lead, manganese) was released from the Gold King Mine. However, the U.S Geological Survey (USGS) used their stream gauges and measured increased flows last Wednesday and calculated that 3,043,067 gallons of contaminated water had actually been released by the EPA. A stream gage is an instrument that measures volume by measuring flow, which is very precise and EPA conceded that the USGS was correct. Oops.
This spill impacted drinking water supplies for Durango and the surrounding area as well as downstream communities. Homeowners along the Animas River near Durango have deluged the La Plata County health department with requests for well tests to see if their drinking water is safe. Many have reported that their well water is discolored. The reservoir in Durango was able to close the intake on the Animas River before the contaminated plume entered the reservoir and are hoping to be able to continue to supply water to the city during the emergency from the water supply on hand. However, pollution seeping into the water table has contaminated rural wells used for drinking, irrigation and livestock, and the river is closed to recreation and water sports that are the lifeblood or the summer tourism industry. Colorado declared a disaster. New Mexico also declared a disaster. California and Arizona water officials are concerned about water supply implications.
EPA deployed a large response team (both technical and community relations) to Durango and Silverton, Colorado and to several locations in New Mexico, Utah and the Navajo Reservation to play both parts as federal regulator and responsible party, coordinate with the affected states, tribes and communities and to address impacts to the environment and water supplies. EPA reported on Monday that aerial and ground reconnaissance showed that the orange plume of waste water had dissipated downstream as it has become diluted by the larger flow of the river. EPA reported that there is no visible leading edge of contamination in downstream sections of the San Juan River or Lake Powell.
However, on Monday EPA officials also posted data showing contamination at 6.13 ppb for cadmium, above a state limit of 5 ppb; 264 ppb for arsenic, above a state limit of 10; 326,000 ppb for iron, above a limit of 1,000; 1,120 ppb for copper, above a limit of 1,000 ppb; and 3,040 ppb for manganese, above a limit of 50. Though, the plume had been diluted, it was still unsuitable as supply for drinking water.
Now that the cave entry has been breached waste water continues to flow out of the mine. EPA has constructed four ponds at the mine site and which are treating water. The pH (acidity) of the water is being raised with the addition of lime and sodium hydroxide solution which also has the effect of increasing the sedimentation of the metals in the ponds. In addition other chemicals are being added to increase the amount of sedimentation. The EPA reports that the treated water that is being discharged to Cement Creek has a pH of 5.5, still slightly acidic. Over the next several days, EPA reports that they will make upgrades to the system to ensure its continued operation.
EPA continues to collect water quality samples from nine locations in the river near intakes for Aztec, Farmington, the Lower Valley Water Users Association, the Morning Star Water Supply System and the North Star Water User Association. Each of these locations will continue to be monitored as the spill makes its way past these areas. EPA has assigned two water quality experts in New Mexico to assist the five drinking water systems.
The river will be closed at least another week. The Colorado Fish and Wildlife Conservation Office, U.S. Fish and Wildlife and the New Mexico Department of Game and Fish are monitoring effects on wildlife and aquatic life in the affected area. The Colorado Department of Public Health and the Environment is assisting with drinking water concerns. The disaster declarations in Colorado and New Mexico will make the state and its residents eligible for federal emergency funds to help deal with any financial damage from the spill.
EPA is taking responsibility for the discharge and impacts to affected communities. Claims can be made by submitting a signed electronic versions of Standard Form 95 to EPA for the Gold King Mine Release via email at R8_GKM_Claims@epa.gov. Claims must be presented to EPA within two years after the claim accrues.