Cleanup Chemical Plume That Contaminated Drinking Water Wells. Cleaning up the seven-mile long plume of perchlorate, a chemical linked to thyroid disorders that has contaminated at least 235 private drinking water wells in southern Santa Clara County, can be done, experts say.
But it will take decades and tens of millions of dollars, according to private consultants and government regulators familiar with such cleanups.
The leading technologies already being used in a handful of similar cleanups, involve either breaking down the underground pollution with benevolent bacteria, or pumping it through tanks full of tiny resin beads.
Either way, billions of gallons of water will have to be treated, San Martin residents will almost certainly have to be provided with an alternative drinking water source, and the overall project won’t be finished until many of the experts now studying cleanup options have retired.
“It could take 30 or 40 years,” said Kevin Mayer, regional perchlorate coordinator for the U.S. Environmental Protection Agency in San Francisco. “It took 40 years to get contaminated, so chemically, it will probably take longer to get it out.”
How did it get there?
The pollution seeped from a factory that made highway flares from 1955 to 1996 in southern Morgan Hill at Tennant and Railroad avenues. The plume now stretches nearly to Gilroy and affects more private wells than any of the other 19 major perchlorate plumes in the state, affecting 2,000 residents of San Martin.
Since the perchlorate issue became public in January, Olin Corp., the Norwalk, Conn., company that claims responsibility, has given free bottled water to San Martin residents whose wells are contaminated.
Perchlorate cannot be ingested through the skin, so the water is safe for bathing, health experts say. But residents are worrying about the long term. They need a reliable source of drinking water, which could mean hooking San Martin up to a city water system, such as Morgan Hill’s. And they worry about how the water situation and decades of cleanup work will affect property values.
“Either somebody is going to perpetually provide them the water, or they are going to get hooked up to the surface water system,” said Mike Kavanaugh, vice president of Malcolm Pirnie, an environmental engineering firm in White Plains, N.Y. “From that standpoint, there would be little impact in terms of property values,” he said. “You’re dealing with perceptions, but there are lots of people around the country who are connected to city water systems and have contaminated water below their property. It’s not the end of the world.”
Things could be worse. Unlike some companies that avoid cleanups because they’re no longer in business, Olin remains viable and says it will pay for the job.
“Olin is an environmentally responsible company,” said Rick McClure, Olin’s project manager for San Martin. “We have been for 100 years. We are working on this. Our goal is to address the groundwater situation and clean it up.”
In fact, that process already has begun.
Work To Be Done
The state agency in charge of the cleanup, the Central Coast Regional Water Quality Control Board in San Luis Obispo, has given Olin until March 31 to submit a cleanup plan for the soil and groundwater on the former factory site. Work there is expected to begin by this fall, said John Mijares, an engineer with the water board. The buildings have been removed and plastic sheeting spread on the site to prevent rainwater from causing more perchlorate to seep through the soils.
Later in the year, Olin will submit a cleanup plan for the entire San Martin basin. Construction is expected to begin as early as 2004, Mijares said.
Crews from Olin and the Santa Clara Valley Water District continue to test wells to determine the size and shape of the plume. To date, they have tested 607 of about 900 wells in San Martin. Of those, 235 had perchlorate levels above four parts per billion, the amount for which the state Department of Health Services requires public notification. In addition, two municipal wells in Morgan Hill have tested positive for the chemical and been shut down.
“You need to define the extent of the contamination,” said the EPA’s Mayer. “Not all the water is contaminated. Some is just fine.”
The most important step will be setting a cleanup standard, which will be up to the regional water board. The key question: How clean is clean?
Because perchlorate concerns began only in the late 1990s, there is no state or federal drinking water standard for the chemical, which has slowed other cleanups statewide. Of 19 California sites with major perchlorate pollution, only five have cleanup systems up and running, according to the U.S. EPA.
In the interim, California has set 2 to 6 parts per billion as a recommended safety level for drinking water. At any level higher than 40 parts per billion, the state tells water systems not to serve the water.
A permanent, enforceable standard is on the way. California’s Department of Health Services is required by law to set the standard by Jan. 1, 2004. The EPA has recommended a preliminary standard of 1 part per billion, but a final federal standard isn’t expected for at least three years.
If other cleanups are any guide, Olin will drill dozens of wells across the South County and pump the groundwater to one or more central sites. There are two leading cleanup methods after that.
The first is to run water through tanks filled with tiny resin beads. When perchlorate touches the beads, perchlorate ions, or charged particles, stick to the resin and pick up chloride. Known as “ion exchange,” the system is used now at several California sites, including in the San Gabriel Valley.
But to wash the perchlorate off the beads afterward, a brine solution is needed. Disposal of that can be a problem. In Southern California it is washed into the ocean, but state law will ban that practice by 2006. Instead, resin beads can be shipped away and incinerated.
Success in south state
In the San Gabriel Valley area of Baldwin Park, rocket testing by AeroJet in the 1940s and 1950s created an eight-mile plume. The cost of the cleanup was $90 million, with at least $10 million a year in operating costs. The treated water is served to the public to drink, with perchlorate levels below 4 parts per billion, said Charles Drewry, regional sales manager for Calgon Carbon, the company that built the ion exchange system there.
That cleanup could take as long as 25 years, he said.
The other leading cleanup method, known as “biological reactor” treatment, pumps water into tanks and uses “good” bacteria, fed with ethanol, molasses or citric acid to consume it. The water is then chlorinated and filtered, making it safe to drink. Cheaper and newer than ion exchange, the method is used at an AeroJet site in Rancho Cordova, near Sacramento, but some regulators are concerned about public perceptions.
“We don’t have a preferred method here at the moment,” said Jim Crowley, who heads underground cleanup programs for the Santa Clara Valley Water District. “We are doing an independent assessment to see if there is something else out there.”
Cost estimates are preliminary, but because of the job’s size, Olin’s cleanup bill may top eight figures.
“I can easily see this exceeding $100 million,” said Tom Mohr, solvents and toxics cleanup liaison for the Santa Clara Valley Water District.
Some San Martin residents already have sued the company, seeking a 50-year health study and mitigation for medical costs and lost property values.
Other residents say they are pleased so far with the response by the company, the water district and the state.
“We want all the time, energy and money going to solving the problem, not causing communication to stop or padding the pockets of lawyers,” said Sylvia Hamilton, a retired school teacher and president of the San Martin Neighborhood Alliance.
But Hamilton said residents remain concerned about their health, animals and crops.
“People in this community love their wells,” she said. “They have a right to use them. We want the groundwater cleaned up.