In a cleanup operation that’s not particularly high-tech, the Minnesota Pollution Control Agency is injecting vegetable oil into ground water near Littlefork, a small town just south of International Falls in far northern Minnesota.
The goal is to detoxify a harmful dry-cleaning solvent that has seeped into the water supply, says the International Falls Daily Journal. The vegetable oil solution — which is mostly water and not harmful to humans — provides energy and nutrients to bacteria that can break down the solvent into non-toxic waste products.
The solvent, perchloroethylene (PCE), a toxic carcinogen, was first detected in Littlefork in 1993, when an underground storage tank was being removed at an old gas station site, which also had once been the home to a dry cleaning business from 1950-54.
The vegetable oil process has worked at other PCE-contaminated sites in Minnesota and around the country. Studies show that the vegetable oil continues to break down PCE contamination over a three- to five-year period after which water should test out at below the state’s drinking water standard for PCE.