E. Idaho scientists double check groundwater test results

IDAHO FALLS, Idaho – Down a gravel road south of U.S. Highway 20, amid sagebrush and grasses, a small encampment had been set up Wednesday morning.

Jeeps, pickup trucks and a pop-up tent were positioned in a circle around a 1,100-foot-deep well. Several scientists and technicians had gathered to try and solve a bit of a head-scratcher: Why were traces of the chemical tetrachloroethylene showing up in recent tests of the groundwater here?

“It’s a mystery,” said Roy Bartholomay, a U.S. Geological Survey hydrologist who heads up the agency’s Idaho National Laboratory project office.

It was especially odd because tetrachloroethylene, a clear liquid, is commonly used for dry cleaning and as a metal degreaser. There was no obvious explanation for why it would be found in the aquifer at this particular location, miles from any nuclear research or cleanup facilities.

“There’s not much out here,” said Jeff Forbes, a hydrogeologist with the Idaho Cleanup Project.

Forbes and other officials with cleanup contractor CH2M-WG Idaho, or CWI, discovered the chemical – which at higher concentrations can be dangerous for human consumption – during routine groundwater sampling at the well in November. It showed up again during a follow-up test in March, though at lower and safer levels.

So employees with the Geological Survey, the Idaho Department of Environmental Quality and Forbes, who now works for Fluor Idaho, gathered Wednesday to withdraw more water from the well. The samples were later shipped to three different labs for testing to find out if the tetrachloroethylene was still present, or if the earlier findings may have been a false positive.

This type of work is essentially the definition of Geological Survey’s job on the U.S. Department of Energy’s desert site. The agency monitors 142 well sites positioned throughout the 890-square-mile site. It measures fluctuations in the Snake River Plain Aquifer, and keeps an eye on groundwater contamination left behind from years of nuclear research and cleanup operations.

The agency, which employs 11 in its INL office, is constantly taking samples at various wells or analyzing the data. Bartholomay and other USGS officials are midway through compiling a report examining groundwater trends over the last four years, detailing which areas are getting cleaner, and any areas that may need more testing or remediation work.

But Wednesday, the focus was on this one well, and why a strange chemical had apparently shown up.

There was conjecture that some of the well equipment leaked some degreaser during the previous tests, contaminating the samples. Or perhaps the lab that handled the samples for the cleanup contractor had made a mistake.

Regardless, Bartholomay, Forbes, and the DEQ’s Jack Rainey figured they would get to the bottom of the mystery by collecting even more samples, and testing them at three separate labs.

“Until we get some more data, we’re just speculating a lot right now,” Bartholomay said.

Pulling water samples out of a well hundreds of feet deep is slow work. Hydrologic technicians Jayson Blom and Amy Wehnke operated a cable pulley system that lowered slender, steel water bottles into the well hole. At varying depths, they would stop the bottles, remotely fill them up with water, and slowly bring them back up to the surface.

In a nearby camper trailer, hydrologist Neil Maimer prepared small sample bottles to fill with the water, which would eventually be shipped off for testing at the labs.

Bartholomay said he expected lab results to be back in about a month. If tetrachloroethylene is once again present in all three tests, he said the Geological Survey will likely start testing for the chemical at other nearby well sites, too, in an effort to figure out how it might be getting in the groundwater.

“We’re going to try to answer it,” he said.