Draft report for Herman Pit available soon
A feasibility study concerning cleanup of the Sulphur Bank Mercury Mine Superfund site could be available for public review by the end of April or early May. Rick Sugarek, remedial project manager for the Superfund site, presented the Lake County Board of Supervisors with a project update on Tuesday.
For the Herman Impoundment Pit and adjacent waste rock and ore piles, the Environmental Protection Agency (EPA) is looking at an option that could cost between $39.3 and $47.5 million total, depending on the level of treatment to wastewater. "Level 1 would simply neutralize the acidic waters," Sugarek explained. It would eliminate most metals but it wouldn't address boron concentrations, nor sulfate concentrations. The cost of this procedure alone would be about $10 million.
"Level 2 would cost $15 to $20 million," Sugarek added. "It would remove some of the sulfate. And Level 3 treatment, with reverse osmosis, would cost about $30 million."
The elevation of fluids in the Herman Impoundment Pit would be regulated with pumping. Treated water could be diverted to the Southeast Geysers Effluent Injection System project, and a letter from Mark Dellinger with the Geysers Joint Operating Committee is scheduled to come before the board of the Clearlake Oaks County Water District, 10 a.m. Wednesday, March 17 at the district office, 12952 East Highway 20 in Clearlake Oaks.
As a last resort, treated impoundment pit water could be discharged into Clear Lake. Solid residue would be treated with a combination of soil covers or membranous "caps."
"We think this is the most protective alternative and it is the one we prefer," said Sugarek.
Sulphur Bank Mercury Mine waste poses a hazard in two ways. The first is through direct contact with contaminated wastes. The length and level of necessary exposure depends upon a subject's age, with young children being most susceptible.
The more significant risk, however, is posed by "bioaccumuation" of mercury in plants and animals that make up the the food chain. The state has issued an advisory against eating fish from Clear Lake, due to their levels of mercury.
"High concentrations of mercury have been noted all the way back to the 1970s," Sugarek noted on Tuesday. "The current advisory, by the California Department of Fish and Game, limits adult consumption to one pound per month of largemouth bass. Pregnant women, nursing mothers and children 6 and younger should not eat fish from Clear Lake."
The Herman Impoundment Pit, with its contamination of ground water, is merely one aspect of the Superfund cleanup project. Other aspects include the elimination of chemicals from the bottom of Clear Lake and the addressing of contaminated materials at the Elem Indian Colony. According to Sugarek, mine wastes were used to pave roads in the Elem community. Waste materials were also used in the foundations of houses.
On Tuesday, Sugarek presented a timeline of previous remediation efforts at the Elem colony. In 1997, the EPA removed contaminated soil from around colony houses. "They did not remove the metal, but they capped it with a soil cover," Sugarek added. "They did not address the mine wastes in the gravel roads. There is an ongoing study, with additional action to be taken in the Elem area."
A feasibility study for Herman Pit clean-up activities is currently in the hands of representatives from agencies that participated in a technical advisory. "It should be out for public comment at the end of April or early May," Sugarek said on Tuesday. "This opportunity for agencies to comment will provide extra input into the document that the public will see."