EDWARDS WATER TOXIC; NO DRINKING WELLS CONTAMINATED, BASE OFFICIALS SAY.

Byline: Jim Skeen Daily News Staff Writer

A potentially toxic chemical was detected at more than 42 times the level at which state law state requires action in groundwater at the former Jet Propulsion Laboratory site.

Base environmental officials said there are no drinking wells in the area and that they are confident the contamination of perchlorate, a chemical that can impair thyroid function, will not spread off the base.

As a safeguard, the base is installing a series of wells along its northern border that will be used to intercept any contaminated water.

``There are no drinking wells in the area,'' said Robert Wood, manager of the Edwards cleanup program. ``With no pathways you have no risk.''

The perchlorate was discovered as part of the base's multimillion-dollar, years-long effort to clean up contamination that has occurred over Edwards' half-century history and which earned it designation in 1990 as an Environmental Protection Agency Superfund site.

Cleanup efforts have targeted materials ranging from leaked jet fuel to drums of unstable rocket propellant to possible chemical weapons.

Edwards officials said Friday that perchlorate was detected at a concentration of 760 parts per billion in groundwater at a depth of 120 feet. Under state law, the level at which cleanup actions must be taken is 18 parts per billion.

Perchlorate detection limits were lowered last year from about 400 parts per billion to 4 parts per billion after the state Department of Health Services refined its testing methods.

Perchlorate, in the form of ammonium perchlorate, was used in the manufacture of solid rocket propellants.

At Edwards, officials believe the contamination came from an area where solid propellants were ground down. Water used in the grinding process was trapped in a catch basin, but apparently the basin was cracked, base officials said.

JPL began operating on a remote north base location in 1945 as an annex of the California Institute of Technology. Over the years, the site evolved into a 570-acre research facility. As a cost-cutting measure, it was closed down in the mid-1990s.

Base officials are looking at additional studies to determine the extent of the contamination. Plans call for installing five monitoring wells, conducting 20 more water sample tests and 250 soil sample tests. That work is estimated to cost approximately $450,000.

Possible cleanup methods are also being studied.

The nearest community is North Edwards, about two miles away with about 1,300 inhabitants.

Ruby Messersmith, North Edwards' representative on the base's environmental Restoration Advisory Board, said the new wells will keep the contamination from leaving the base.

``The community should be concerned, but not upset,'' Messersmith said.

Ammonium perchlorate has caused problems in other Southern California communities.

It turned up at levels of up to 620 parts per billion at wells at the Rocketdyne's Santa Susana Field laboratory near Simi Valley, and at up to 34 parts per billion in wells near the former Bermite munitions factory in Saugus, records show.

Ammonium perchlorate was once used to treat overactive thyroid conditions, experts say. It interferes with the thyroid gland's ability to take up iodine, which is required to manufacture hormones needed for normal metabolism.