Gilroy
– Perchlorate-contaminated groundwater in north Morgan Hill will
be tested later this year to determine the source of pollution, but
not by the company that city officials believe is responsible. The
disputed plume will instead be tested by the Santa Clara Valley
Water District as part of a deal b
etween the district, the Regional Water Board and Olin Corp.
Gilroy – Perchlorate-contaminated groundwater in north Morgan Hill will be tested later this year to determine the source of pollution, but not by the company that city officials believe is responsible. The disputed plume will instead be tested by the Santa Clara Valley Water District as part of a deal between the district, the Regional Water Board and Olin Corp.
To the dismay of Morgan Hill City Manager Ed Tewes, the so-called northeast flow was not covered by a final cleanup order issued by the regional board to Olin earlier this month. Wednesday, Tewes reiterated his conviction that Olin should be ordered to clean the city’s groundwater, but said he is pleased with the district’s maneuver.
“Our basic feeling is that there’s ample evidence to deem Olin responsible for the perchlorate in our municipal supply wells, but we want the regional board to finish its fact-finding process as quickly as possible,” Tewes said. “Given they’ve taken that approach, this is a good thing.”
Olin has accepted responsibility for the southern plume, which stretches about 10 miles south of Tennant Avenue in Morgan Hill and east of U.S. Highway 101, but the company contends that it can not be responsible for the northeast plume because the groundwater beneath its former road-flare factory flows south.
Perchlorate, a sodium compound shown to inhibit thyroid function in laboratory animals, was discovered in Morgan Hill two years ago. There are a number of other possible sources of the northeast flow. United Technology Corp. in north Morgan Hill tested rocket engines near Morgan Hill for more than 40 years. Rocket fuel is another known source of perchlorate, as are perchloric acid, used in etching Teflon, and a natural fertilizer that comes from Chile. Some have postulated that perchlorate is produced by lightning.
Sylvia Hamilton, chairwoman of the Perchlorate Community Advisory Group, a group of residents, county officials, water experts and scientists, called the agreement “fantastic.”
“We’ve all been trying very hard to keep this out of the courts, but we’ve got to find the real source,” she said. “We all have our opinions about where the perchlorate came from, but until you have solid data you’re stuck. Olin has done a tremendous job over the last two years and we want to see that keep moving forward.”
In December, the regional board ordered Olin to conduct further testing of the northeast flow, but Olin appealed the order and was to argue its case to the regional board in late March. The order has been stayed.
Thomas Mohr, water district geologist, said the stay was issued because the parties were at loggerheads in regard to the northeast flow. Morgan Hill officials believe the company needs to clean the water that serves nearly all of the city’s population, and Olin believes it’s been unjustly blamed for the contamination. If Olin lost an appeal of the order to the State Water Board, it would have the option of taking the board to court.
“Until these questions are resolved we’re going to be deadlocked,” Mohr said, “and at the moment, we felt like we were assured of going to court unless we found another way.”
The district will test an area substantially larger than the northeast flow. Mohr said the exact parameters have not been mapped out, but they will likely extend as far north as Cochrane Avenue and east of U.S. 101. As part of the agreement, Olin will install a series of piezometer wells – able to track the direction water flows – around the site of its former road-flare factory, which may prove the company is not at fault.
Mohr said that the direction of the groundwater flow is usually given the most scientific weight, but is not necessarily indisputable.
“Ideally, you want to use multiple lines of evidence that everyone agrees on and will be convincing,” Mohr said. “I don’t know if that’s achievable, but I think it’s worth pursuing.”
The regional board had ordered Olin to perform the kind of forensic testing that the water district will conduct. Forensic testing works by distinguishing different characteristics of chemicals. The road flares produced by Olin were made primarily of strontium nitrate and other chemicals that occurred in higher concentrations than perchlorate. Water contaminated with perchlorate from that site may also test positive for strontium nitrate and other chemicals with the same properties as those used in the flares, but Mohr cautioned that forensic testing is not a magic bullet.
“The trick of this kind of investigation is that you don’t know anything until you get in there and take some measurements,” Mohr said. “We have to confirm that possible sources are distinct enough. We have the potential to clarify where we stand, but there is no guarantee that this will answer all of our questions. We’re optimistic, but it remains to be proven.”
One unused road flare on the side of a highway is enough to contaminate more than 300,000 gallons of water with perchlorate to a level above 6 parts per billion, the public health goal in California, Mohr said
The district will apply for a federal grant to finance the testing, which should cost between $100,000 and $200,000. If the grant does not come through, the district will appeal to the regional board for funding. The district has not approached Olin to pay for the testing, but Mohr noted that if the district does not perform the tests, Olin can still be ordered to. Rick McClure, an Olin project manager, could not be reached for comment. Regional board officials also could not be reached for comment.
Mohr said he did not know how long the testing will take, but he expects to begin in eight weeks or so.
Since the perchlorate was discovered Olin has provided bottled water to the worst-affected residents in Morgan Hill and San Martin, and the company is in the process of installing well-head treatment systems on wells that test above 10 parts per billion.
Earlier this month, the regional board ordered Olin to present a final cleanup plan by spring 2006.
