[Water_news] 4. DWR'S CALIFORNIA WATER NEWS-WATERQUALITY-3/12/09

Department of Water Resources

California Water News

A daily compilation of significant news articles and comment

 

March 12, 2009

 

4. Water Quality-

 

 

EPA testing local water to find out if problematic chemical is in drinking supply

Visalia Times Delta – 3/12/09

By David Castellon

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The sidewalk in front of a downtown Visalia law office may seem an odd place to look for environmental contamination.

 

But for years, starting in 1959, long before the Sullivan and Sullivan Law Corp. occupied this West Oak Avenue building, it was Van Dusen's Cleaners, according to a U.S. Environmental Protection Agency report.

 

A group of EPA- contracted workers broke up the sidewalk Wednesday and began pounding stakes into the dirt.

 

They were looking for a not-so-pleasant memento of the former dry-cleaning business — perchloroethylene, or PCE, a chlorinated solvent used for decades in dry cleaning because of its ability to remove stains from clothing.

 

It's also capable — when ingested or inhaled in vapor form — of causing neurological, liver and kidney damage, as well as cancer and other medical problems.

Since the early 1990s, traces of PCE have been found in some of the drinking-water wells beneath downtown and other parts the city. It's potentially a big problem, not only in Visalia but for communities throughout the country where it has shown up in groundwater, often around the sites of current and former dry-cleaning operations.

 

Adding to the problem: Once the chemical is in the water table, it can be difficult to get out.

 

"One of the properties of PCE that make it difficult to detect and clean up is that it is heavier than water," said Chris Skelton, Visalia branch manager for BSK Associates, an environmental consulting firm that has worked on PCE cleanup operations. "PCE that finds its way to groundwater will sink to the bottom of the water-bearing zone and potentially into pockets that may be difficult to find."

 

How the chemical gets into the water can vary.

 

Businesses other than dry cleaners use PCE, mostly as a degreaser. They range from mechanic shops to airports, which use it to clean plane engines.

But the heaviest use remains in the dry-cleaning industry. And dry cleaners are responsible for most of the PCE that gets into the soil, said Mike Vivas, a mechanical engineer and site-contamination cleanup manager for the California Department of Toxic Substances Control.

 

His organization has been conducting studies of PCE in groundwater and wells in Visalia.

 

"At this point, we're determining whether [contamination] exists and whether it can be remediated," he said last week as workers began drilling a series of six small test wells downtown, near the sites of four current and former dry-cleaning businesses.

 

Today, the workers will drop devices to capture groundwater samples into the 90-foot well holes.

 

Jacob Blackburn, whose family operates Blackburn Town and Country Cleaners in Porterville, said his father, 71, told him stories of working in a dry-cleaning business as a 12-year-old. He would dip dirty coveralls into vats of PCE and pull the soaked garments out, dripping the chemical on the ground.

 

Vivas said spills and leaking dry-cleaning machines contributed to the problem. And once it's in the ground, PCE can spend years migrating downward into the water table dozens of feet below.

 

The seepage of oil into groundwater is easier to clean up because oil floats, said Henry Cole, president of Henry S. Cole and Associates Inc., a Maryland-based environmental consulting firm.

 

Once PCE is in the groundwater and settles as far down as it can go, it begins a long process of dissolving into the water. And even though the water under Visalia permeates sand and soil, which acts much like a sponge, it still flows — moving traces of PCE with it, Skelton said.

 

Groundwater here flows toward the southwest and the Tulare Lake basin, he said.

 

Local investigation

Skelton said a previously identified PCE plume in Visalia west of Mooney Boulevard and Walnut Avenue may have come from three dry cleaners that used to operate in the area. He hadn't heard about the PCE that was found downtown until last week, when the EPA drilling began.

 

The California Water Service Company has shut down at least one contaminated downtown well — filling it with concrete — and installed carbon filters in the pump systems of four others to ensure the water meets drinkability standards.

 

The water coming from those wells is safe to drink, as is water from other wells the CWSC operates in and around Visalia, said Phil Mirwald, the company's district manager.

 

But the amount of PCE allowable for water to be considered safe to drink is just five parts per billion. Minor contamination can make drinking-water wells unusable without filters or cleanup.

 

And cleaning up PCE often isn't simple or cheap.

 

"You want to prevent it from getting to the groundwater in the first place," Skelton said.

 

Once PCE chemicals seep into the ground, they can stay in there as heavy vapors, slowly heading downward until they hit the water. And PCE is attracted to water, said Dimitri Stanich, a spokesman for the California Air Resources Board.

 

If high amounts are found in the upper soil, heavy equipment can be used to scoop out the contaminated dirt, Skelton said.

 

On the other hand, if the contamination is deeper than 20 to 30 feet, a common cleanup method is soil vapor extraction, which essentially involves drilling narrow wells and using machinery to suck out the vapors and capture the PCE in air filters.

 

Such a method is being used in Fresno to clean up a more than 2-mile plume of PCE near West Herndon and North Palm avenues. Skelton's company is the environmental consultant on that project, where the cleanup efforts have taken 15 years.

 

Cost of the cleanup in south Fresno will top $10 million. Other cleanup projects could go as high as $30 million, depending on the level of PCE contamination and how far it has spread, Skelton said.

 

Determining levels of contamination and their sources in Visalia are part of the studies now being conducted by state and federal officials.

 

If cleanup is needed, current and former owners of the dry-cleaning sites may be held responsible for at least part of it, Vivas said.

That's enough of a concern that some landowners have hired companies to check for long-gone dry-cleaning businesses where PCE contamination may have occurred, said Blackburn, who also is a regional director for the California Cleaners Association.

 

Another issue to consider is how cleanup might affect the downtown area.

 

"The challenges of working in the downtown area, there is a lot of traffic," Skelton said. "There isn't a lot of space to put in [monitoring or extraction] wells. You're invading a lot of business."#

http://www.visaliatimesdelta.com/article/20090312/NEWS01/903120305

 

 

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