MORGAN HILL
– City officials want to see more testing of water wells to the
north of the Tennant Avenue flare plant where perchlorate entered
South Valley’s groundwater basin – a request that officials with
the state’s Central Coast Regional Water Quality Control Board seem
likely to support.
MORGAN HILL – City officials want to see more testing of water wells to the north of the Tennant Avenue flare plant where perchlorate entered South Valley’s groundwater basin – a request that officials with the state’s Central Coast Regional Water Quality Control Board seem likely to support.
But that could set up a potential conflict with Olin Corp. – the owners of the now-defunct plant – whose officials said they don’t believe the factory contributed to perchlorate contamination in wells north of the site.
At a meeting of the regional water board’s perchlorate community advisory group Thursday, Morgan Hill Mayor Dennis Kennedy said his city would like more testing not only north of Tennant – where the flare plant was located near the intersection with Railroad Avenue – but also north of Dunne Avenue, the next highway exit to the north.
Harvey Packard, a senior groundwater resources engineer with the regional water board, seemed to agree testing is needed in that direction. He noted that three wells to the northeast of the flare site have shown detectable levels of perchlorate.
During March 2003, the city’s Condit and Nordstrom municipal wells and one of two on Dunne Avenue tested above 4 parts per billion for perchlorate – the state “action level” that triggers noticing requirements – and were closed. All are located north of the Tennant Avenue flare plant site.
“We will be asking Olin to look into those areas north and east of the (flare) site to determine if (perchlorate) is there and if they are causing the problem,” Packard told the committee.
Some residents with private wells in the Hill Road area have also reportedly detected perchlorate through private testing.
But informed of Kennedy and Packard’s comments Thursday, an Olin official said there are no plans to sample anywhere else north of the old factory site.
Rick McClure, Olin’s project manager for the South Valley contamination cleanup project, said there would have to be some means of transporting perchlorate north of the flare site in order to justify sampling there. The groundwater flow is to the southeast, he said.
“What that means to Olin in our discussions with the regional board is that the perchlorate detections north of Tennant Avenue are unrelated to the Olin site …” he said. “We are sampling in the southeast direction and taking our environmental responsibility seriously … but a regional investigation of any and all perchlorate is above the call of duty, so to speak.
“Olin is going to do the right thing, but there are limitations. We are investigating perchlorate related to the Olin site.”
Packard said while the groundwater flow in the flare plant area will generally flow to the southeast, with enough wells pumping and the right conditions it could flow to the northeast as well.
“We know Olin is a source of perchlorate,” he said. “In the absence of other known sources, we’re going to assume they are potentially a source to the northeast. We’re going to ask them to check into that.”
Perchlorate was among the chemicals that officials said leaked into groundwater near United Technologies Corp.’s rocket testing and manufacturing center off Metcalf Road in south San Jose.
However, officials with the San Francisco Bay Regional Water Quality Control Board – which regulates water in the UTC area – said they don’t believe that leakage from the UTC plant has any relationship with the current South County plume.
As far as officials know, the contaminants at the UTC site have not left their property,” since industrial solvents were discovered there more than 20 years ago in groundwater and creeks that run through the missile site, said Will Bruhns, an engineer and spokesman with the San Francisco regional board.
The groundwater basin divides near Cochrane Road and generally starts flowing north from that point toward San Francisco Bay, Bruhns said.
Meanwhile, Olin has submitted plans to the regional board to conduct more well sampling in South County, Packard said Thursday. He anticipates the company will sample around Gilroy’s Leavesley Road as well as areas west of Monterey Road.
The company is also working on a long-term monitoring plan with the regional board that Packard said will likely include repeated tests of certain wells for as long as 40 years.
South of the Tennant site, Packard said Olin has proposed to pay for bottled water for any well that tests for perchlorate levels above 2 ppb until such time as the well tests below 4 ppb for four consecutive quarters.
The company will also pay for bottled water for some whose wells do not show detectable perchlorate, but which are physically near other wells that have tested positive. Those wells will likely be identified by Olin and the regional board on a case-by-case basis, Packard said.
