GILROY
– The latest round of testing performed on the city of Gilroy’s
municipal water system did not reveal detectable levels of
perchlorate, city officials said Thursday.
GILROY – The latest round of testing performed on the city of Gilroy’s municipal water system did not reveal detectable levels of perchlorate, city officials said Thursday.
Results from tests performed March 6 did not show perchlorate in any of the city’s eight municipal wells above 4 parts per billion, which is the reporting level established by the state’s Department of Health Services and currently the level where officials say accuracy can be assured.
“They’ve all come back non-detect,” said Dan Aldridge, operations services supervisor in the city’s water department.
Gilroy upped the testing regimen on its wells to at least once a month after perchlorate contamination was found to be widespread in private wells south of Morgan Hill. Testing of Gilroy’s municipal wells in November and February also came up “non-detect” for the chemical, although the chemical was found at 4.1 ppb in a monitoring well off Leavesley Avenue that officials said is roughly a quarter-mile of a city well at Leavesley and Murray.
The next round of tests on city wells are slated for early April, Aldridge said.
Gilroy won’t be in dire straits even if it has to shut down a well, city officials have said. Its eight wells are tied into a centralized distribution and tank system and are rotated weekly, and individual wells may not run at all for certain periods of time but may be pumping heavily at other times.
The city has enough tank storage that it could shut down a city well and still provide enough supply, although officials said they would want to redrill a new facility.
The chemical has traveled southward 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.
Morgan Hill officials have closed three of that city’s municipal wells to date after discovering perchlorate levels ranging from 4 to 7 ppb.
The chemical is known to cause tumors and thyroid problems.
