Claims that all perchlorate-contaminated water flowed only
southeast from the Olin Corp. site on Tennant Avenue were
overstated, according to a report last week to the Central Coast
Regional Water Quality Control Board.
Claims that all perchlorate-contaminated water flowed only southeast from the Olin Corp. site on Tennant Avenue were overstated, according to a report last week to the Central Coast Regional Water Quality Control Board.
This came as good news to the city, which has been dealing, without any help from Olin Corp., with perchlorate in several municipal wells northeast of the Olin site.
City Manager Ed Tewes said he was encouraged by the report, given its possible positive affect on the city treasury.
“Before, Olin was insisting that the water moved south,” Tewes said.
The company’s investigation of a potential northerly flow was based on merely “asking around for other people’s data,” he said.
“We weren’t convinced that their prior plans were going to lead to anything since they weren’t going to involve any actual testing,” Tewes said.
The situation has changed with the new report.
“We hope this leads to further discussions about Olin’s obligations to pay the city for costs we’ve had in dealing with the problem,” said Helene Leichter, city attorney. “The (Santa Clara Valley) Water District, too, deserves to be reimbursed.”
Rosemary Kamei, Morgan Hill’s representative on the SCVWD board of directors, said Friday she hadn’t yet heard of Olin’s findings but would find it positive.
“That is good news,” said Kamei.
According to the Olin Corp. report to the Regional Board for the third quarter – the board is the lead agency in the perchlorate investigation and cleanup effort – the chemical can migrate north in some gradients or sections after all.
Groundwater is not captured in a single underground pool but is distributed in several reservoirs at different levels going in, apparently, different directions for a host of reasons, geologic and hydrologic.
A series of monitoring wells has been drilled on the Olin site to discover what exactly is going on underground.
The Olin report, submitted to the Regional Board in San Luis Obispo on Thursday, said that during the months of July and August the shallow zone (25.05-28.78-feet) flow moved east-northeast, though southeast in September.
The intermediate zone was monitored at three levels: at 89-99-feet water flowed northeast in July, east in August and southeast in September. At the 134-142-foot depth water flowed east in July, southeast in August and east-southeast in September. At the 175-195-foot level water moved northeast in July, north in August and south-southwest in September.
The deep zone monitoring discovered water moving southwest in all three months at 200-210-foot depths and, at 313-341-foot depths moving northeast in July, August and September. Testing was done by MACTEC Engineering and Consulting.
Representatives of Olin Corp. did not return phone calls on Monday.
The city spent $130,000 to install an ion-exchange perchlorate treatment plant on its Nordstrom well, at Murphy Road and East Dunne Avenue. Olin has, so far, declined to reimburse the city. With the Nordstrom and four other city wells off line, water supplies had been stressed during recent hot weather peak times.
Residents of the Hill/San Pedro road area will take heart, too, since their wells are just as contaminated and their property values just as depressed as those of homeowners south of Tennant, the only area for which Olin had previously taken responsibility.
Olin Corp. and Standard Fusee Corp. had manufactured safety road flares at a plant on Tennant and Railroad avenues for 40 years, until the plant was closed and demolished in 1997. The perchlorate leached into the underground aquifer from a pond on the plant site into which product residue was routinely washed. The practice was not illegal at the time.
It was discovered in January that the chemical, which has been accused of causing thyroid dysfunctions – and worse – in humans and animals, had infiltrated wells in southeast Morgan Hill, San Martin and a few in north Gilroy.
Olin Corp. has taken responsibility for that contamination and has tested hundreds of wells several times over and provided free bottled water to affected residents.
But Olin always held that the chemical could not flow north since groundwater was generally known to flow south, southeast in this area. Until now.
Tewes said Olin had apparently had the data claiming a northeasterly run for some time but its two consultants had not shared the information with each other or with Olin.
Harvey Packard, senior water resources engineer for the Regional Board, said he was being cautious about the meaning of the Olin report.
“This is not proof,” said Packard. “It is only two sampling events where a very small area shows this gradient.”
Packard said the Regional Board would be looking for data to prove or disprove the third quarter report data.
“It will probably affect how we view Olin’s recent workplan for investigating the area,” Packard said. “It may warrant more field work to verify the data in the monitoring report.”
The city and Olin had butted heads earlier in the year over the first casualty of the perchlorate contamination. The Tennant well, located directly across the street – to the south – of the Olin site, was shut down in April 2002 when its water was discovered to have perchlorate levels of well above the 4 parts per billion action level.
The city sent a bill for drilling a replacement well, for which Olin Corp. sent what the city considered partial payment. Not wanting to admit the payment was in full by cashing the check, which Leichter said would be the case, the city sat on the check for several months. The check was finally cashed in August after an agreement was reached between Olin and the city that the check was only partial payment.
