A road flare manufacturer has reinstated free shipments of
bottled water to 42 homes in Morgan Hill and San Martin after
discovering elevated levels of contaminants in drinking water
supplies, according to state water regulators.
Gilroy – A road flare manufacturer has reinstated free shipments of bottled water to 42 homes in Morgan Hill and San Martin after discovering elevated levels of contaminants in drinking water supplies, according to state water regulators.
Last July, Olin Corporation discontinued shipments of bottled water to roughly 1,200 homes along the edges of a 9.5-mile perchlorate plume extending southeast from its former Tennant Avenue factory. The move hinged on water samples showing that the contaminant, which can cause thyroid dysfunction, had dropped below levels deemed dangerous by state environmental regulators.
Of the 530-plus wells that no longer triggered requirements for free water, 21 have since climbed back into the range of concern set by regulators, according to regulators at the Central Coast Regional Water Quality Control Board.
“There are natural fluctuations in the groundwater concentrations that occur,” said Thea Tryon, a hydro-geologist at the water board. “There are some that are increasing, some that are decreasing, but in general the (perchlorate) plume looks stable.”
In May 2005, the State Water Resources Control Board ruled that Olin could discontinue water shipments to homes with water supplies found to have perchlorate levels of 6 parts per billion or less over four straight quarters. One part per billion is roughly equivalent to one drop of ink in a lane of a public swimming pool. Tryon said the concentrations of perchlorate in the 21 wells ranged from 6.1 to 8.4 ppb, though the majority were less than 6.5 ppb.
The timing of the samples, groundwater flow rates and a range of other factors could have caused the increases, Tryon said, adding that “it’s actually a pretty small number” when compared to the number of wells that remain within the public health goal.
Residents concerned that perchlorate levels may have risen in their wells since the date of Olin’s last test can perform their own well samples, according to Sylvia Hamilton, chairwoman of the Perchlorate Community Advisory Group, which is monitoring the company’s efforts to clean up the contamination.
Even as it continues supplying bottled water to hundreds of homes, Olin is working on long-term plans to clean up the area’s groundwater.
“We’re very grateful that (residents using those 21 wells) have bottled water again,” Hamilton said, “but the reason the long-term clean-up is so critical is that they’ll be able to go back to the tap, turn it on and use it and feel safe.”
Olin spokesman Rick McClure could not be reached by press time.
For information on how to sample your well, visit the San Martin Neighborhood Alliance at www.smneighbor.org.
