Extensive Pollution of Ground Water Determined in Study

A cancer-causing chemical has polluted a vast pool of underground water stretching more than 3 miles from the western edge of the El Toro Marine Corps Air Station to the heart of residential Irvine, a study released Wednesday by the Orange County Water District showed.

Ground-water contamination near the military base has been suspected for several years, but the breadth of contamination--more than 2,900 acres--had not been identified until the water district recently completed its yearlong, nearly $1-million study.

The report, presented Wednesday to the district’s 10-member Board of Directors, blamed the tainted ground water on the military, which routinely disposed of toxic wastes, including cancer-causing tricholorethylene, also known as TCE, at the base for nearly four decades before the practice was halted in the early 1980s.

No Immediate Threat Posed

The result, the study concluded, has been widespread contamination of up to 150,000 acre feet of ground water. (About five adults use the equivalent of about an acre foot of water a year.)

Water district officials stressed that the polluted ground water does not pose any immediate threat to commercial or domestic water supplies in the area. The nearest domestic water wells operated by the Irvine Ranch Water District are 2 miles away from the spreading contamination.

“There is absolutely no threat to any domestic water supplies,” district spokesman James Van Haun said.

Levels of TCE in water analyzed from some agricultural and test wells located between North Lake in Irvine and the western boundary of the Marine base were, in some cases, 10 times the allowable limit for safe drinking water, the report concluded.

The pocket or “plume” of contaminated water, the report stated, is about 3 miles long and half a mile wide and is moving in a westward direction at a rate of 1 to 4 feet a day. Since 1985, when the water district first detected TCE traces in the ground water, officials estimate the plume has “migrated” west about a mile, to a point halfway between Jeffrey Road and Culver Drive in the Woodbridge area of Irvine.

While there is no present health threat, water district General Manager William R. Mills warned that the plume, if left unchecked, eventually could reach the Irvine Ranch Water District’s domestic water wells. In time, it could also threaten an area near Irvine Center Drive, where the Irvine Ranch district is contemplating sinking several new domestic water wells.

As a result, the Orange County Water District board agreed Wednesday to negotiate with the Irvine Co. and the Irvine Ranch district to begin pumping the contaminated water out of the aquifer and mixing it with reclaimed water used for irrigating corps and landscape. Once the tainted water is exposed to air, the TCEs “volatilize” and dissipate into the atmosphere, greatly reducing any health or safety risk to plant life or humans, Van Haun said.

But even if the cleanup approach is implemented, it would only remove about 2,000 acre feet of contaminated water a year.

“It would not solve the problem overnight,” Mills said. “But at least we might slow the migration of the plume.”

The only wells now affected by the contaminated water are used for agricultural purposes, but Van Haun said that could change. As rapidly growing Irvine continues to urbanize, it may need to convert those wells for commercial or domestic use.

“But that would be impossible unless the ground water is cleaned up,” Van Haun said.

The cost of the Orange County Water District study, including drilling of four new wells to test for contaminants, was close to $1 million. District officials contend that the military should eventually reimburse the agency for the cost. Any cleanup costs, including the proposed pumping out of the aquifer, should also be paid by the military, Mills said.

Military ‘Unconvinced’

But military officials, who are nearing completion of their own $1.2-million ground-water study within base boundaries, believe they may not be entirely responsible for the contamination.

Capt. Stan Holm of the Navy’s civil engineer corps said Wednesday that the TCE contamination could have come from the Orange County International Raceway, a drag strip that operated for 17 years before closing in 1983 along the Santa Ana Freeway, just west of the Marine base.

“We know we have some (TCE) hot spots that have moved off the base that we have to address,” Holm told the water board.

But during a break in the meeting, Holm said the military remains “unconvinced” that it is to blame for all the contamination.

The TCE-contaminated ground water--as well as three on-base landfills containing solid wastes--prompted the U.S. Environmental Protection Agency last June to add the El Toro facility to its Superfund hazardous-waste cleanup list.

Most of the toxic waste produced at the base, including TCEs, stems from maintaining jets and helicopters. For example, each year the El Toro base disposes of 166,000 gallons of used motor oil and hydraulic fluid and 281,000 gallons of waste fuel, according to county health records.