Groundwater Tests Find No Perchlorate

Groundwater wells near Ahmanson Ranch and at the Brandeis-Bardin Institute in Simi Valley tested negative for perchlorate contamination two months after coming up positive for the highly toxic chemical, state officials said this week.

Scientists with the nearby Boeing Rocketdyne Santa Susana Field Lab, where rocket engines have been tested since the 1950s, say the negative readings prove there is no perchlorate in the wells and that the chemical is not spreading from the mountaintop site.

Perchlorate is a solvent used in the formulation of rocket fuel.

“Based on this conflicting data, our conclusion is there is no perchlorate [in the wells],” said Art Lennox, an environmental specialist with Boeing Rocketdyne. “We have committed to do a lot more work to demonstrate that and prove that.”

Lennox said the company was “confident” that future testing would not detect any perchlorate.

Tests conducted by the state Department of Toxic Substances Control of a remote well at Brandeis Bardin in May and June indicated levels of perchlorate ranging from 36 parts per billion to 150 ppb. The state limit for drinking water is 4 parts per billion. The federal EPA has established a safety standard of 1 ppb.

Ron Baker, a director with the state agency in Sacramento, said it stands by its original results.

“We have high confidence that perchlorate was present in the well,” Baker said, noting that different methods of testing could produce varying results.

The Brandeis-Bardin Institute for Jewish studies is about a mile from Happy Valley, an area on the north side of the field lab where perchlorate was stored for rocket-making. The chemical has been found in concentrations as high as 1,600 ppb in the groundwater near Happy Valley and 72,000 ppb in the soil.

But multiple samples taken in a new round of testing at the Brandeis well in July and August showed no traces of the chemical, according to the state Regional Water Quality Control Board, which conducted the tests.

In addition, a well near Ahmanson Ranch showed no contamination despite results of perchlorate last year at 28 ppb.

“That’s good news,” said Tim McGarry, spokesman for Washington Mutual, which owns the Ahmanson property. “The weight of evidence now suggests there is no contamination of groundwater.”

None of the wells where perchlorate was found are used for drinking water. One part per billion is roughly equivalent to a drop of water in a home swimming pool.

Boeing officials said the results showed pollution from the field lab has not migrated off-site and that the earlier positive readings were an aberration, possibly caused by other chemicals that skewed the outcome.

“What we’re finding is perchlorate analysis is not a simple analysis,” Lennox said.

“There are a lot of influences that can make it difficult to determine. What we’ve learned is you have to be really, really careful.”

Boeing submitted a plan this week to regulatory agencies outlining how it would contain and clean up perchlorate at the 2,600-acre field lab. Lennox said the company hoped to begin the process in early October, before the rainy season starts.

Although the contamination has been there for years, it is becoming increasingly urgent to neutralize the chemical as officials have learned more about it and found that it presents health risks at low concentrations, Lennox said.

The fast-moving contaminant is known to cause thyroid dysfunction and has become a national concern as states grapple with the environmental effects of aerospace and defense research.

The cleanup effort would require excavating up to 1,500 cubic yards of soil -- an area roughly the size of a large living room, 3 feet deep -- and treating it with either a citric acid or manure to break down the perchlorate.

The biodegradation process could take up to a year to reduce the chemical concentration to safe levels, according to Lennox.

In doing so, officials will have to be wary of the effect on the Santa Susana tar plant, a species unique to the area that the state Department of Fish and Game wants to protect.

Lennox said that Boeing would have to develop mitigation measures because seedlings were growing close to contaminated soil.