PCAG will ask water district to now study nitrate levels in groundwater
Published in the December 25, 2013-January 7, 2014 issue of Morgan Hill Life
By Staff Report
Levels of perchlorate toxins released for decades by flare manufacturer Olin Corporation into the aquifer in southern Morgan Hill and San Martin have significantly dropped, according to information presented to the public at a Dec. 19 meeting of the Perchlorate Community Advisory Group.
“I would say that 95 percent of perchlorate is at background levels at six parts per billion or less, which meets state levels for water safety,” said Swanee Edwards, a PCAG member representing Morgan Hill. “We have been wildly successful in cleaning up the perchlorate.”
A “very small plume” of perchlorate contamination higher than six parts of billions was monitored in the deep aquifer located below 250 feet and this is at depth below ground level where domestic and farming wells generally do not go, she said. Wells are usually drilled to a depth of 230 feet.
“The information at the meeting shows we’ve been wildly successful,” Edwards said. “Out of 288 domestic wells that were contaminated and homes received bottled water, we only have six left.”
PCAG officials at the meeting held at the Lions Club Hall in San Martin decided to change focus of their group from perchlorate to monitoring the nitrate buildup in the South Valley aquifer.
“We have a lot of nitrate now in our groundwater from farming and we’re going to monitor that nitrate level and approach the nitrate contamination very much like we did the perchlorate,” Edwards said. “We have the infrastructure in place with all of our test wells. We just have to get the Regional Water Quality Control Board and the Santa Clara Valley Water District on board to help us monitor the nitrate levels because we now have all the wells in place at different levels into the aquifer to test the water.”
