MORGAN HILL
– Seventeen months after some South Valley residents discovered
a dangerous chemical was contaminating their only drinking water
supply, a picture of the situation underground and possible cleanup
methods have been announced.
MORGAN HILL – Seventeen months after some South Valley residents discovered a dangerous chemical was contaminating their only drinking water supply, a picture of the situation underground and possible cleanup methods have been announced.
And, in another effort to remove perchlorate from the water, Sylvia Hamilton, Perchlorate Community Advisory Group chairwoman, said she has been asked to testify before a House committee reviewing a bill introduced by Rep. Richard Pombo, (R-Tracy), asking for $25 million to help pay for the cleanup.
The contamination was the result of operations at Olin Corp., a flare manufacturing company. Rick McClure, Olin Corp. project manager for the local cleanup, said during a meeting Friday that Olin’s consultants from consulting firm Mactec mapped the underground aquifer and found perchlorate in mostly shallow areas, about 100 feet deep, leaving open the possibility of drilling for clean water in deeper wells.
The Central Coast Regional Water Quality Control Board, the lead agency in the South Valley cleanup effort, required Olin to produce both reports.
Michael Burns, a geologist for Mactec, told the two dozen in attendance that the affected water does not appear to be moving deeper underground, largely because of deposits of clay, a material that does not easily allow filtering, acting instead as a protective barrier.
“I feel we’ve got a pretty good picture of the aquifer,” Burns said.
The chemical ended up in the groundwater after 40 years of being dumped in a holding pond at the Olin Corp./Standard Fusee manufacturing plant at Tennant and Railroad avenues in Morgan Hill. The perchlorate leached down through the soil into the aquifer and has flowed in a southeasterly direction through south Morgan Hill, most of San Martin west of Monterey and, in a lesser concentration, to north Gilroy.
Several hundred private and several municipal wells were contaminated, though most in low concentrations close to levels detectable by tests: 4 parts per billion. A public health goal was set this March by the California Department of Health Services at 6 ppb, the point at which water consumers must be notified of the chemical’s presence.
Mactec’s Don Smallbeck made recommendations for removing the chemical from residential water supplies, a move that well owners, public and private, have been waiting for since January 2003.
The most likely methods involve installing treatment systems at either the point of entry, not unlike a water softener in the garage, or point of use, where the system is installed near the taps, similar to under-sink reverse osmosis systems. Each comes with some difficulties.
McClure was careful to point out that individual well owners would be consulted on – and would have to agree with – the treatment position used on their well.
Smallbeck also discussed the kind of treatment system that might be used for both methods.
Certification by the federal National Science Foundation is pending on several systems and will take at least six months or more, he said.
Potential impediments to installing treatment systems on private wells, Smallbeck said, include getting property owners to agree to the recommended method, formalizing the agreement: deed restrictions, testing and maintenance access agreements, easements and rights of way and city or county permitting.
“I don’t think Olin is averse to maintaining and operating these systems,” Smallbeck said, “because we would want it to be consistent.”
“That’s right,” McClure said. “Olin will monitor and, more than likely, maintain the systems.”
Hamilton, a retired teacher, has paid many costs surrounding the perchlorate fight herself and will not receive any financial help from Pombo’s office or the federal government to cover travel costs.
Gary Shallcross, a member of the Regional Board and an aide to State Assemblyman John Laird, D-Santa Cruz, who represents Morgan Hill and San Martin, suggested after the meeting that the Regional Board or the water district might find money in their budgets.
“But they probably don’t have any extra money,” Shallcross said. “We may have to take up a collection.”
