Fish Bones, Manure Help Rid Groundwater of Perchlorate

Companies cleaning contaminated sites also have used molasses
and road salt
Gilroy – Toss some fish bones on a pile of potato peels, manure, lemon juice and mushroom compost and you’ve got one very effective perchlorate-cleaning mess.

Researchers at New Mexico Sate University’s College of Engineering have announced that fish bones have shown a knack for cleaning everything from heavy metals, like lead and uranium, to organic materials, like perchlorate, from groundwater.

“They’re really excellent for contaminated water,” said James Conca, director of the Carlsbad Environmental Monitoring and Research Center. “You just get a bunch of bones, 100 tons of bones, dig a ditch in the ground in front of the oncoming groundwater, the water will leach through them [and remove the perchlorate].”

White fish works best. In theory, homeowners could use the remnants of a Friday night cod dinner on their private wells, but there is a catch. Water cleaned by fish bones tends to smell – and taste – like fish.

“You really want to do it on a larger scale,” Conca said. “It’s not something you want to drink right afterwards.”

Perchlorate, which has been shown to inhibit thyroid function, has contaminated the groundwater in Morgan Hill and San Martin, as well as numerous sites across the country. Fish bones clean perchlorate by stimulating growth of bacterial microbes that feast on the sodium that was used by the Olin Corp. to make road flares in Morgan Hill.

Tom Mohr, a geologist with the Santa Clara Valley Water District, said the fish bone research is just one component of the quickly evolving science surrounding perchlorate contamination, a national problem caused in large measure by companies producing military equipment for the U.S. Dept. of Defense.

He said that companies cleaning contaminated sites across the country also have used molasses, road salt and steer manure.

“All have worked remarkably well,” Mohr said.

Rick McClure oversees the South County cleanup effort for Olin Corp. He said the company believes installing ion-exchange systems on wells is the best way to ensure safe water and clean the groundwater basin, but won’t rule out other methods. At the site of its former factory, for example, Olin has used citric acid from lemons.

“It’s very important as we continue to address the drinking water supply that remediation systems be mature in technology,” McClure said. “Ion-exchange leads the way, but that doesn’t mean we won’t evaluate fish bones.”

Ion-exchange systems work by cleaning water as its pumped out of the well. It’s the technology the city of Morgan Hill uses on its municipal wells and Olin has installed seven similar systems on private wells in South County.

The California Department of Health Services has approved the systems for large-scale municipal use and is in the process of approving smaller-sized contraptions for home use.

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