GILROY
– The state is on track to certify water filters small enough
for use on a single tap to reduce perchlorate to safe levels.
GILROY – The state is on track to certify water filters small enough for use on a single tap to reduce perchlorate to safe levels.
Similar filters currently on the market cost roughly $1,000.
This development may be a consolation to Morgan Hill, San Martin and north Gilroy residents solely concerned about their home drinking water, but as San Martin resident Bob Cerruti pointed out, he and his neighbors will need perchlorate removed from more than just their taps.
“It may be helpful for those who just want that for their immediate use in the kitchen area, but residents of San Martin have animals, and some have a small vegetable garden like I do, so we really need redemption at the wellhead,” Cerruti said.
Many wells in San Martin have already been treated for perchlorate, a chemical many residents fear could cause an increase in thyroid disorders.
The single-tap filters, which use so-called “reverse osmosis” technology, have yet to be tested for their effectiveness against the controversial chemical.
“Any certifications we do are based on test results,” Terry Macaulay, a sanitary engineer with the California Department of Health Services’ Device Certification Unit, said Tuesday. “I had expected to see some of those test results by early 2004, and I hoped we might have some certifications by early March.
“We’re on track, but we’re not there yet.”
The test standards, already approved, are “very, very rigorous,” Macaulay said; the filters must take in water contaminated with perchlorate at 130 parts per billion and produce water at 4 ppb – the state action level – or less.
Macaulay expects several products will pass the test. A joint committee of stakeholders, including water-product manufacturers, came up with the testing protocols themselves, and Macaulay figured they wouldn’t have approved a test they didn’t think their products could pass.
Reverse osmosis filtering systems for single taps are currently on the market and are certified to remove other contaminants. Culligan, a national water-products company with a regional office in Santa Clara, prices them at roughly $1,000. These products may not, however, be the same as those manufacturers submit for perchlorate certification.
Culligan Water Quality Consultant Jim Osmus doubted that, if his company submits a filter for perchlorate testing, it will be one currently on the market.
“I would be surprised if they were that efficient,” Osmus said of Culligan’s current reverse osmosis filters. “Perchlorate is a tough molecule to get out of the water. … Bringing it from 130 (ppb) down to 4 would be a tough stretch, even for the best (filtering) membranes.”
The Olin Corporation, which once made road flares in Morgan Hill, dumped the perchlorate in the South Valley between 1955 and 1996. Recently, Olin has been providing bottled water to hundreds of households.
It’s unknown at this time whether the state would make Olin supply point-of-use filters to South Valley homes if such items were certified to remove perchlorate.
Perchlorate has spread from Olin through the soil and created an approximately eight-mile plume south from Morgan Hill to Gilroy, plus some northern seepage. About 400 South Valley wells have tested over the state action level of 4 ppb.
Olin is also paying for well treatment. Since August, Olin has agreed to pay about $850,000 to treat the wells of two private San Martin water suppliers that serve roughly 450 homes. One treatment system is being installed; the other has been operating for the past few months. This “ion exchange” technology appears to be working, as those treated already have since tested below 4 ppb afterward, but Cerruti said he’s concerned that the resin beads these ion-exchange machines produce as a by-product are hazardous. He’s intrigued by other technologies in development that he thinks will be cleaner.
Olin is also required to clean up the soil on the site of its former Morgan Hill factory and submitted a plan for this Nov. 21 to the state Water Quality Control Board for the Central Coast Region.
Perchlorate is a white, salt-like powder used in the combustion of rocket fuel, explosives and flares. Tests have shown it can disrupt the thyroid gland’s ability to make essential hormones, though there is great debate in the scientific community over the concentration at which it does so. Researchers from Texas Tech University say it can cause lowered IQ, mental retardation, hearing and speech loss and motor-skill deficits in fetuses, infants and children. On the other hand, scientists at a Perchlorate State-of-the-Science Symposium in Omaha, Neb., concluded Oct. 1 that exposure to low levels of perchlorate, like those found in the South Valley, are not harmful.
In addition to point-of-use treatment, water can be treated for perchlorate at the “point of entry,” meaning where the supply enters a building, or at a well serving multiple buildings.
The ion exchange method is being used at wellheads in San Martin and Morgan Hill, but it is too expensive to be practical for use at a single home or tap, according to Tracy Hemmeter, perchlorate project manager for the Santa Clara Valley Water District.
Likewise, reverse osmosis wouldn’t make sense for point-of-entry treatment because the volume of water that enters a house would probably require the filters to be changed more often than is reasonable, Hemmeter said.
“The more water you’re treating, the less practical reverse osmosis becomes,” Hemmeter said.
