SAN MARTIN
– As South County citizens, farmers and animal lovers continue
to press for information about health effects from potassium
perchlorate contamination in San Martin, government officials say
they’re searching for answers to many of the same questions.
SAN MARTIN – As South County citizens, farmers and animal lovers continue to press for information about health effects from potassium perchlorate contamination in San Martin, government officials say they’re searching for answers to many of the same questions.
Officials stressed this week that they’re concerned about the situation, but are limited in what they know about perchlorate’s effects on both humans and animals. Low amounts of the chemical – a naturally occurring salt – have reached the underground aquifer that supports private wells in the primarily agricultural south part of Morgan Hill and San Martin.
“So much is unknown,” said Greg Van Wassenhove, Santa Clara County agricultural commissioner. “We are trying to find out some answers – if there are any – but more research needs to be done …
“Little is known about the indirect effect on humans through crops and animals.”
According to the federal Environmental Protection Agency, it’s unclear whether lettuce – a local crop – or other vegetables accumulate the chemical from irrigation water. However, tests on crops irrigated with highly polluted water have shown concentrated levels of perchlorate.
Van Wassenhove acknowledged his department has received quite a few phone calls from farmers and ranchers about perchlorate, but not the overwhelming numbers the Santa Clara Valley Water District has attracted.
“I’m doing my best as ag commissioner to get the right agencies in line to work with the water district, the county and health officials,” he said.
At a community meeting water district officials attended Thursday in San Martin, several residents asked for more information on how perchlorate – which can cause thyroid problems – would affect them and their families, as well as animals who drank it and non-drinking uses such as agriculture, gardening and bathing.
“The doctors are overwhelmed,” said Louise Helland. “They don’t have the information. If there’s information, we want to know.”
District officials said they’re working to get answers from university researchers and medical experts. Part of the problem is that science and technology are advancing rapidly, said district spokesman Mike DiMarco. State-mandated “action levels” of the substance have dropped repeatedly in recent years, he noted.
“There are all of these studies going on right now,” he said. “We’re looking for the exact same answers you are.”
San Martin veterinarian Pete Keesling said UC Davis toxicologists told him most animals don’t live long enough to develop levels of exposure high enough to cause harm.
“You can put that worry probably on the back burner,” he said.
Testing continued this week to discover which, if any, of the 450 private wells in south Morgan Hill and San Martin show contamination by potassium perchlorate.
The affected wells are located in an area bordered by Tennant Avenue, Monterey Road, Masten and Center Avenues. All are privately owned; city wells are free of the chemical so far.
The water district is testing privately owned wells. DiMarco said the agency is testing 36 wells a day and expects to continue for the next five to six weeks. Results generally take three weeks, he said, so it will be nine weeks until we really know what the picture looks like.
“We were one of the first labs in the country to test for this,” he said. “If we are overwhelmed, we will contract out.”
The district announced last week that testing had shown perchlorate in 12 of 100 wells; one showed a level of 98 parts per billion, two showed levels of 32 ppb and all others were at 4-10 ppb or lower. The SCVWD notified the public, arranged for the tests and for bottled water to be available free to any well-owners in the affected area. The state-mandated action level is 4 ppb.
The chemical has traveled in a “plume” through the underground aquifer from a Tennant Avenue industrial site owned by the Olin Corp., which manufactured safety flares there along with Standard Fusee Co. from 1955 to 1997. Perchlorate is a by-product from the manufacture of flares, matches, fireworks and, in larger amounts, solid rocket fuel.
Ground and water samples showed that perchlorate had leaked down into the water table.
There were a few minutes of concern last Friday at San Martin-Gwinn Elementary School, which is within the noticed boundaries. The school, however, gets its water from the San Martin Water Co., not from a well. Principal P.J. Foehr sent a letter home to parents assuring them that the most recent test of water from the District showed no perchlorate.
