Annual Progress Report, 2012
Mine Cleanups: A Toxic Legacy
Mining has historically pumped up the economy of western states, but left thousands of abandoned mines, some of them releasing toxics into the environment. EPA helps clean up the worst of them.
About 150 miles southeast of San Francisco, Calif., New Idria (pictured above) was North America’s second most productive mercury mine. Though out of sight and out of mind to Bay Area residents, its runoff polluted creeks, wetlands, and even San Francisco Bay.
New Idria’s acidic water flowed over waste rock and tailings, picking up highly toxic, bioaccumulative mercury, and moving it into creeks and wetlands that are a magnet for wildlife in this arid region, including the California Condor and San Joaquin kit fox.
In 2011, EPA re-routed acid mine drainage around waste rock and tailings into a limestone splash pad and retention pond, removing contaminants and acidity. While additional work will be needed, EPA has reduced a dangerous source of mercury pollution in the San Joaquin River and San Francisco Bay.
At Oljato Mesa, near Monument Valley on the Arizona-Utah border, EPA contractors toiled for 200 days in 2011 to move 25,000 cubic yards of radioactive mine waste to a repository near the abandoned Skyline Mine. The site was one of more than 500 abandoned uranium mines investigated by EPA and the Navajo Nation in the past decade. The Navajo Nation made Skyline Mine a priority, since there are homes close by.
Bulldozers scraped radioactive soil into a pile at the bottom of the mesa. A cable yarder – an aerial cable car – moved the waste to the top, conserving energy and preventing air pollution. The repository, a shallow pit, was sealed with high-density polyethylene (HDPE), then covered with local soil and rock.
Island Landfills Meet Disposal Challenges
Trash disposal on islands poses special challenges. EPA oversaw emergency repairs to Oahu’s only municipal landfill, and Guam opened its longawaited, environmentally protective landfill.
Honolulu has only one municipal solid waste landfill – Waimanalo Gulch. On January 12, 2011, the gulch was pounded by 11 inches of rain, and a temporary storm drain system overflowed, washing trash and medical waste downstream. Some of it turned up on nearby beaches. Local officials closed beaches, as well as the saturated landfill.
At the Hawaii Department of Health’s request, EPA worked with landfill managers right away to clean up the waste, make shortterm repairs, and complete a larger, permanent storm drain system. EPA ordered landfill operators to functionally complete the stormwater drainage system and repair the landfill liners before reopening.
Oahu’s trash had nowhere to go, and began piling up. A team of EPA scientists and engineers examined the work at the landfill, and allowed it to reopen on January 28. Heavy rainfall resumed, but there were no more overflows. In November, EPA ordered Honolulu and landfill operators to increase Waimanalo’s capacity to divert stormwater.
Quick action had avoided a potentially catastrophic release of trash-contaminated water. Improved stormwater controls now protect the health of Oahu’s residents, visitors and shoreline environment.
On August 31, 2011, Guam residents celebrated the long-awaited closure of the Ordot dump Superfund site, and the opening of the new, environmentally protective Layon Landfill to receive the island’s municipal solid waste that is not recycled. The Ordot dump had continually discharged leachate into the nearby Lonfit River and sometimes polluted the air when it caught fire. The new landfill meets or exceeds federal and Guam requirements for protecting the island’s environment.
Sun Powers Groundwater Cleanups
Cleanups of toxic sites should not add to other environmental problems, like air pollution. EPA's latest examples of "greener cleanups" are two sites run by solar power near Sacramento, Calif.
For the first time, the sun is providing 100% of the power for a Superfund groundwater cleanup. By installing solar panels on half an acre, the Frontier Fertilizer site in Davis, Calif., reduced energy costs by $15,000 a year and CO2 emissions by more than 54 metric tons a year.
In addition to using solar panels, the site is using an innovative in-place electrical heating system to extract pesticides and fertilizers from the soil and groundwater. This 1-1/2-year treatment will reduce the time for groundwater cleanup by about 150 years. Extraction wells collect gas and liquids generated by the heat, which are then treated with granular activated carbon.
These improvements were funded by more than $2.5 million from the American Recovery and Reinvestment Act.
The largest photovoltaic solar power system at a Superfund site is at the 13-square-mile Aerojet site near Rancho Cordova in Sacramento County, one California’s largest groundwater cleanups.
The latest phase started in September 2011, when EPA ordered a $60 million cleanup of groundwater polluted with rocket fuel. A 27-square-mile swath of groundwater beneath the former aerospace facility is polluted with very high levels of perchlorate – a main component of rocket fuel and a known developmental toxin.Aerojet, under the direction of EPA, will contain the underground plume to prevent it from spreading into nearby rivers and streams, and purify 25 million gallons of groundwater daily to prevent the loss of additional drinking water supplies.
- Mine Cleanups: A Toxic Legacy
- Island Landfills Meet Disposal Challenges
- Sun Powers Groundwater Cleanups
RESTORING GROUNDWATER IN THE SAN GABRIEL VALLEY
Over the course of decades, the huge aquifer underlying southern California's San Gabriel Valley was contaminated by the activities of hundreds of industrial facilities, resulting in several Superfund cleanup sites. The South El Monte Operating Unit is just one of many areas requiring cleanup.
EPA's team of technical experts and attorneys have recovered $23 million from more than 60 parties at South El Monte over the past 10 years to help pay for cleanup of the three-trillion-gallon San Gabriel Basin groundwater aquifer, which serves as the primary source of water for most of the San Gabriel Valley’s one million residents. Through their determined efforts, more than $6 million was recovered from 18 companies in the past year alone.