GILROY
– Another 315 private well owners – mostly in Gilroy – have been
told their wells are eligible to be tested for the chemical
potassium perchlorate, as Olin Corp. – the company responsible for
the water contamination – and the state Regional Water Quality
Control Board enter into a fourth p
hase of testing this week.
Residents north of Leavesley Road between Highway 101 and
Foothill Avenue will now join more than 950 well owners who have
had their water sources tested in recent weeks. More than one-third
(317) of those wells contained the dangerous chemical at levels of
4 parts per billion and above.
GILROY – Another 315 private well owners – mostly in Gilroy – have been told their wells are eligible to be tested for the chemical potassium perchlorate, as Olin Corp. – the company responsible for the water contamination – and the state Regional Water Quality Control Board enter into a fourth phase of testing this week.
Residents north of Leavesley Road between Highway 101 and Foothill Avenue will now join more than 950 well owners who have had their water sources tested in recent weeks. More than one-third (317) of those wells contained the dangerous chemical at levels of 4 parts per billion and above.
“There have been detections in the area, so we’re extending our sampling,” said Harvey Packard, senior engineer for the Regional Water Quality Control Board. “We didn’t expect the plume to travel this far.”
Leavesley Road is 7.5 miles from the former Olin Corp. plant at Tennant and Railroad avenues in Morgan Hill, where the contamination began. Olin manufactured highway safety flares in the area between 1955 and the mid-1990s.
Some 80 wells have been tested in the new area, Packard said. Results will not be available for roughly three weeks. Packard said wells in other neighborhoods that have tested positive for perchlorate have typically had less than 10 parts per billion of the chemical.
In the current round of testing, levels below 4 ppb are classified as “non-detect” which is the threshold set by the state of California as an “action level.” Other states allow as much as 18 ppb or as little as 1 ppb.
Tracking the chemical is relatively new and little information is available on long-term effects on people, plants and animals.
Perchlorate is used in the manufacture of the flares (and in rocket fuel elsewhere) and ended up in an evaporation pond on the site where it leached down into the underground water table or aquifer. The resulting plume flowed predominantly southeast and is now found in wells as far south as Leavesley Road.
“There are quite a few from Leavesley Road and north,” said Mike DiMarco, spokesman for the Santa Clara Valley Water District. “The City of Gilroy is constantly checking their water system and most of the wells south of Leavesley are city wells.”
City Engineer Richard Smelser said Monday that the city plans to test its wells at least monthly, if not more frequently. Testing of Gilroy’s eight municipal wells in November and February came up “non-detect” for the chemical, although it has been found in a monitoring well within a mile of one Gilroy municipal well.
“As soon as we heard about this issue, we decided to move on this,” Smelser said. “We are of course monitoring the situation out there.”
The city has enough tank storage that it could shut down a city well and still provide enough supply, he said, although the city would want to redrill a new facility as Morgan Hill did when it closed its contaminated Tennant Avenue well.
“It’s not like the city is in dire straits if we lose a well,” he said.
However, Smelser thinks that scenario is unlikely to happen because the city’s wells are deeper than most private wells that have been affected.
A map of “hits” on the water district’s Web site shows clusters of wells appearing in a southeast swath from the Tennant Avenue source. A few appear west of Monterey Road and east of Center Avenue. No perchlorate has been found in wells north of Tennant Avenue and all City of Morgan Hill wells show “non-detect.”
All water south of Cochrane Road flows south to Monterey Bay; that north of Cochrane travels north into the San Francisco Bay, DiMarco confirmed.
Olin has been providing free bottled water to everyone in the area whose well is scheduled to be tested and will continue to provide the water to those homes whose wells test above the action level. Cleanup methods are under discussion.
In the human body, perchlorate competes with iodide for the thyroid and, if in high enough amounts, will overcome the iodide and cause hyperactive thyroids or even thyroid tumors, as well as other medical conditions just now coming to light.
More than 800 San Martin (and Morgan Hill and Gilroy) residents attended a meeting on Feb. 12 where they told of thyroid-related and other medical problems they attributed to the presence of the chemical in their drinking water. No one knows how long their wells have been contaminated since it was only confirmed to have traveled south of Tennant Avenue in mid-January.
Several residents insisted that a survey of the medical complaints of anyone using the wells, from 1955 forward and later filed a class action suit with the firm of Alexander, Hawes and Audet, requesting such a survey be completed by Olin. The suit also mentions the loss of property values in the area.
“When someone looks at property in San Martin now,” said Fred Threatt, one of the litigants, “they don’t ask what your well’s levels are. They ask where you live.”
At the Feb. 12 meeting the audience also asked the water district to set a date for another meeting, one where a fuller picture on the extent of the problem could be communicated. They also wanted more information on the chemical’s effects and what Olin intended to do about it. The county departments of health and agriculture have been scrambling to collect data and studies.
A mid-April meeting was tentatively set.
“We are waiting to see more test results,” DiMarco said. But he said the meeting will happen.
Reporters Jon Jeisel and Eric Leins contributed to this report.
