Trying to deflect blame for the biggest ground-water contamination case in Orange County history, Marine Corps officials denied Wednesday that the military is the only source of a cancer-causing chemical that has fouled a 3-mile-long pool of water lying in part beneath Irvine.
"Before anyone can draw that or any other conclusions, more testing is needed," Marine Brig. Gen. David V. Shuter said. "We are not afraid of embarrassment, and if we are responsible, fine, we will step forward. But at this point, that determination cannot be made."
Toxic Wastes Dumped
The Orange County Water District has blamed the polluted underground water table on the military, which routinely dumped or sprayed toxic wastes, including tricholorethylene, also known as TCE, in landfills at the El Toro Marine Corps Air Station for nearly four decades. The practice was halted in the early 1980s, but by then large quantities of TCE, a carcinogen, had seeped into the water table, contaminating up to 150,000 acre-feet of ground water, water district officials said.
Officials stress that the polluted ground water does not pose any immediate threat to commercial or domestic water supplies in the area.
But Capt. Stan Holm of the Navy's Civil Engineer Corps said it is "premature" to fix blame for the TCE contamination. He said a yearlong, $1.2-million military study made public Wednesday has identified four "separate and distinct" pockets of polluted ground water, including three areas on the El Toro base or along its southern boundary. The fourth "plume," or pool, of contaminated ground water, the military study said, is located about half a mile south and west of base property, extending into the Woodbridge area of Irvine.
Water district officials disagree, however, saying their ground-water samples show that the four separate areas identified by the military are actually one large plume that stretches from the base west into residential Irvine.
The water district and the military also disagree on how rapidly the contaminated water is migrating.
Orange County Water District officials say the plume is moving westward at a rate of one to four feet a day. If unchecked, district officials have said, it could ultimately reach several domestic water wells operated by the Irvine Ranch Water District. The wells are about two miles from the leading edge of the pool of contaminated ground water.
But Holm said the geological characteristics of the aquifer are such that it would take an estimated 63 to 214 years for TCEs generated at the base to travel the distance asserted by the county water district.
"Since the air station has been in existence for only 43 years, it seems highly unlikely that the TCEs could have come from an on-base source," Holm said Wednesday night while discussing the military study with the 10-member OCWD Board of Directors.
To determine the extent of the military's role in contaminating the aquifer, Holm said, a new study must be conducted in the Irvine Spectrum area, which he contends was not tested by either the military or the water district. Results from those tests, he said, should show whether TCEs left the base and moved west into Irvine.
Liability to Be Determined
Determining the size and configuration of the contaminated plume is considered critical to assessing blame and liability for the cost of cleaning up the aquifer.
Meanwhile, Holm said, the military has begun designing a system to pump the contaminated ground water from the aquifer on the base for possible agricultural or landscape use. It is a plan similar to one adopted two weeks ago by the county water district for the Irvine area.
Two weeks ago, the district's governing board approved a $500,000 plan to begin pumping the water out of the aquifer and mixing it with reclaimed water for irrigating crops 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, district officials said.
That cleanup approach has been endorsed by the Irvine Ranch Water District. "At this point, we are more interested in solving the problem than in who is going to pay for it," said Peer A. Swan, president of the Irvine district board. "We can settle that later. Right now we need to get the cleanup started."
Irvine district officials have agreed to pay for the cleanup to get the project under way and halt the migration of contaminants. But district officials say they eventually will seek repayment from the military for both the cleanup and the Orange County Water District's $1-million study.
TCE, a solvent widely used by the Marines for degreasing aircraft and other equipment until the late 1970s, was dumped in at least four major locations and used in 13 more at the El Toro base, military reports show.
Drag Strip Mentioned
But Brig. Gen. Shuter said that TCEs also may have been introduced to the aquifer from Orange County International Raceway, a drag strip along the Santa Ana Freeway, just west of the Marine base, that operated for 17 years before closing in 1983. Also, he said TCEs may have been used years ago in agricultural pursuits in the area.
But Orange County Water District spokesman James Van Haun said a ground-water study by the Irvine Co. 2 years ago showed no TCE contamination on or near the site of the drag strip. He also discounted the possibility of agriculture contributing significantly to the problem.
"We may never know beyond a shadow of a doubt who is 100% responsible for this," Van Haun said. "But is is quite clear that TCEs were used in large quantities on the base since the 1940s. We believe that speaks for itself."