Another 315 private well owners will soon receive a notice that
their wells will be tested for the chemical potassium perchlorate,
indicating another expanded phase of testing by Olin Corp., and
supervised by the state Regional Water Quality Control Board. So
far, more than 950 wells have been tested and the chemical was
found at levels of four parts per billion and above in more than
one-third (317) of those with results to date.
Another 315 private well owners will soon receive a notice that their wells will be tested for the chemical potassium perchlorate, indicating another expanded phase of testing by Olin Corp., and supervised by the state Regional Water Quality Control Board.
So far, more than 950 wells have been tested and the chemical was found at levels of four parts per billion and above in more than one-third (317) of those with results to date.
Four ppb is the amount 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.
In the current round of testing, levels below 4 ppb are classified as “non-detect” which means below 4 ppb, not zero.
Many of the new-to-test wells are in north Gilroy, far south of the southernmost limit of Masten Avenue where the chemical was first thought to have traveled. It started at a former Olin Corp. plant at Tennant and Railroad avenues in Morgan Hill where highway safety flares were manufactured (also by the Standard Fusee Co.) between 1955 and the mid-1990s.
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.”
A map of “hits” on the water district’s website 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.
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 required the water district to set a date for another meeting, one where a fuller picture would be available of the extent of the problem. 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.
The water district’s website, www.valleywater.org is a library of information on perchlorate with the more critical maps, timelines and information available in Spanish.
