GILROY
– The city wants to see more action from the company responsible
for contaminating nearby groundwater with perchlorate.
GILROY – The city wants to see more action from the company responsible for contaminating nearby groundwater with perchlorate.
City officials and the Regional Water Quality Control Board are asking Olin Corp. to more closely monitor the southern extent of the contaminant plume and determine the risk to Gilroy’s water supply.
“We want the definition of their plume,” City Administrator Jay Baksa said. “Meaning, how far south is it?”
The city is asking Olin to address three major issues:
• Provide all water level, perchlorate concentration, water quality and well-screening information for private wells that Olin has sampled or has results for, south of Buena Vista Avenue.
• Conduct ongoing monitoring and a work plan to address perchlorate groundwater contamination in the vicinity of three city wells.
• Install and monitor a network of sentry wells to provide the city with warning of contamination moving towards its wells.
“Olin has not provided the Regional Water Quality Control Board or the city with sufficient information regarding the perchlorate plume in the vicinity of, or past our wells,” Baksa said.
So far, no Gilroy city wells have tested positive for perchlorate.
A letter to Olin from the regional water board notes a lack of information about the spread of perchlorate in the area around three city wells that supply nearly 60 percent of Gilroy’s water supply. The city is asking for at least 10 new testing locations that are monitored regularly and tested more often than what is currently being done.
“We just wanted to find out what the plume is doing in relation to these supply wells,” said David Athey, an engineer with the Regional Water Quality Control Board.
The city first asked the regional water board and Olin back in September for data regarding the southern edge of the plume. The board is now asking Olin to provide a written response on how they are, or are planning to, address the issue.
During the monthly meeting of the Perchlorate Citizens Advisory Group last Friday, Gilroyans with private wells were encouraged to allow Olin to test for perchlorate.
For reasons unknown, according to Tom Mohr of the nta Clara Valley Water District, one in three north Gilroy residents contacted by Olin to have their private wells tested have refused.
