Diesel detected at city test well

Wells that normally handle about 20 percent of Spokane’s drinking water supply have been shut down because of concerns about potential contamination with diesel.

City officials stress that diesel has not been found in the drinking water, and state and local administrators say evidence so far shows that it would be safe to keep the wells in operation. However, two tests found diesel in a separate monitoring well about two blocks from the pumping stations that were closed.

“I don’t think that these very low detections of diesel pose a significant health risk,” said Rob Lindsay, Spokane County’s water resources manager.

Two water pumping stations near Hamilton Street and North Foothills Drive were shut down Monday after the county reported results of a test it performed at the nearby monitoring well, located near Marietta Avenue and Denver Street, said Lloyd Brewer, the city’s environmental program manager. A second analysis confirmed the presence of diesel at the monitoring well, but tests at the drinking water wells haven’t found the chemical.

The state Department of Ecology will investigate the site next week to determine if a cleanup is necessary, said Keith Holliday, supervisor of the toxics cleanup program.

The well that had the diesel is only three blocks from where a fire engulfed the Whitley Oil Co. on July 23, but officials caution that they are uncertain that the Whitley fire is the source of the contamination.

In response to the fire, the county added the examination for diesel in a set of water quality tests the county performs regularly at the well, Lindsay said. Samples were taken around Aug. 1. Results, which showed diesel levels registering at 341 parts per billion, were received Monday. On Tuesday another test was performed that showed 130 parts per billion.

“At this level, we’d like to see some more samples and figure out what’s going on,” Holliday said.

Holiday said a level of 500 parts per billion would require cleanup.

Frank Triplett, the city’s acting water director, said as long as temperatures remain out of the 90s, the city has plenty of water without using the wells near Hamilton and North Foothills.

“If I need them, I’m going to turn them back on,” Triplett said.

On Monday, city and county officials will discuss what other tests should be completed. Since the fire, the affected pumping station has been tested weekly for volatile organic compounds. Triplett has since ordered weekly tests for petroleum.

The state Department of Health enforces Environmental Protection Agency contamination-level regulations for drinking water, but there is no standard for diesel in water, said Jeff Johnson, assistant regional manager of the state health department’s Eastern Washington drinking water office.

Brewer, the city’s environmental program manager, said the levels appear safe based on other EPA drinking water standards.

Rachael Paschal Osborn, a local water attorney, said the presence of diesel displays the lack of protection in place for the aquifer.

“Once you have contamination like petroleum present down there it is incredibly difficult to get it back up,” she said.