MORGAN HILL
– Olin Corp. must supply continuous bottled water to South
Valley residents whose wells are contaminated with perchlorate.
MORGAN HILL – Olin Corp. must supply continuous bottled water to South Valley residents whose wells are contaminated with perchlorate.
The state agency in charge of cleaning up perchlorate contamination in the South Valley issued the order Wednesday. The state Regional Water Quality Control Board in San Luis Obispo ordered Olin to develop an uninterrupted water supply for residents with wells between 4 and 9.9 parts per billion of the chemical.
An Olin representative said Thursday that the company will appeal part of the order.
In tests performed a year ago, almost 400 wells were contaminated with perchlorate at levels between 4 to 9.9 ppb. The same round of tests showed about 20 wells with levels above 10 ppb. The Water Quality Control Board said these well-owners must be provided with a long-term alternative source of water, such as a well-head treatment system.
The perchlorate comes from 40 years of manufacturing highway safety flares at an Olin Corp./Safety Fusee site on Tennant and Railroad avenues. The chemical was found in January 2003 to have leached through soil contaminated on the site. It traveled southeast through San Martin to north of Gilroy, polluting hundreds of wells.
Olin’s Rick McClure said the company will appeal having to provide bottled water for residents with 4-5 ppb since the California Department of Health Services in March set 6 ppb as the public health goal.
The public health goal is the point at which water consumers must be notified of the chemical’s presence. The 4 ppb level is the lowest that can be detected.
McClure said the company has no problem with providing uninterrupted water for wells testing above the public health goal. Treating fewer wells will save Olin money.
Several dozen wells in the area from Morgan Hill to just north of Gilroy have tested between 6 ppb and 10 ppb while only a few register higher than 10 ppb.
The company can stop distributing bottled water to any resident whose water tests less than 4 ppb, or nondetect, for four straight quarters, though Olin will still need to continue to check the levels in those wells according to the RWQCB order.
The City of Morgan Hill adheres to the 4 ppb standard, closing any well that tests above that level. According to California law, a water supplier doesn’t need to close a well until it reaches far higher levels.
At Wednesday’s City Council meeting, City Manager Ed Tewes announced that the Condit well, long-closed because of perchlorate levels, had tested at 5 ppb, higher than it has for months. It remains shut down. All other city wells, working and closed, tested non-detect, or below 4 ppb.
Perchlorate at a still undetermined level is known to cause thyroid and other health problems.
