The bad, the bad and the ugly
It can start with a tiny leak in an underground fuel storage system, or from someone overfilling a car’s tank, or from a person spilling gas on the lawn while filling up a mower.
Then, a whole gang of bad stuff – including benzene, which is known to cause cancer, and toluene, which can cause birth defects – goes into the soil.
However, one chemical stands above the rest as being a threat to drinking water – MTBE.
It’s not that MTBE is more deadly; many of its health risks are still unknown. MTBE has many other qualities that make it an insidious problem.
One of the big reasons MTBE is such a bad character is that it’s fast. Once it hits the groundwater, MTBE leaves benzene, toluene, xylene, ethylbenzene and the rest of the gasoline gang in the dust.
At 98 percent solubility, MTBE moves at the same rate as the groundwater. And in a place like the south shore of Lake Tahoe where shallow drinking water wells have been punched in the ground all over town, that underground water can move extremely fast.
Lisa Dernbach, associate engineering geologist of the Lahontan Regional Water Quality Control Board, said a good example of that is the U.S.A. Gasoline station at South Lake Tahoe’s “Y.”
The station, which had gasoline contamination problems since 1983, was required to start testing for MTBE in 1996, and the then-not-so-controversial fuel additive was discovered.
By 1997 officials realized a plume of MTBE had traveled 1,500 feet to the South Tahoe Public Utility District’s Tata Lane well. Benzene had only made it 300 feet.
STPUD continued using the well, because it was connected to an air-stripping tower that had successfully removed the MTBE. However, contamination levels continued to grow, and STPUD shut the well off in July 1998.
“They turned off their well, and what happened was the other wells in the area were still pumping,” Dernbach said. “Then they realized it was getting bigger and shut off all the wells. Then it was being carried by natural groundwater, moving toward the “Y.”
Today the MTBE plume is 2,300 feet long, 1,800 feet wide. It is by far the biggest MTBE contamination site in the Tahoe Basin. USA officials have spent millions on cleanup so far.
The second biggest plume, from the Meyers Beacon station, traveled 1,500 feet, ruining two STPUD wells. When those wells were turned off in 1997, the MTBE swung 100 degrees, turning with the natural flow of groundwater. Now another plume is headed in the opposite direction, moving toward Lake Baron.
There are so many contaminant plumes in the Tahoe area that Lahontan, charged with protecting the water quality of the region, earlier this year created a new branch specifically to address such problems. The state agency has fined numerous gas stations for recalcitrant cleanup efforts. Lahontan also is the only water quality control board in the state that has taken over cleanup at gas stations where the owners have run out of resources.
MTBE has other problems besides its solubility, though. It is difficult to clean up, and it does not break down.
“It’s different with alcohol or benzene,” Dernbach said. “They breakdown or dilute. You’ll test for it a few times and see it. Then it goes away. That’s not the case with MTBE.”
Another problem with MTBE is that it contaminates water at extremely low levels. At 5 parts of the additive per billion parts water, it can render water undrinkable by making it smell and taste like turpentine. What that means is a soda can full of MTBE can ruin the water in an Olympic-sized swimming pool. And, with MTBE constituting about 11 percent of the state’s fuel, nearly every tank of gasoline sold in California has enough MTBE in it to fill a soda can.
The U.S. Environmental Protection Agency classifies MTBE as a possible cancer-causing agent.
However, Dr. Myron Mehlman said he believes it won’t be long before that “possible” is deleted from the sentence.
Mehlman, the director of toxicology for Mobile Oil from 1977 to 1989, has completed several studies on the health effects of MTBE.
He said people, whether exposed to it through water or through the air, can experience disorientation, nausea, shortness of breath, diarrhea, rashes, inability to sleep and depression.
It is especially a risk to pregnant women, infants, the elderly, people with respiratory illnesses such as asthma and those with heart problems.
MTBE can also lead to leukemia, lymphoma, lung disease, kidney cancer and testicular cancer, said Mehlman, a New Jersey resident who has testified at numerous hearings on MTBE, including ones held early last year in California.
“Eventually we’re going to get it out,” Mehlman said of MTBE. “It will probably cost billions of dollars, and there will be lawsuits.
“It’s unfortunate. It never should have been allowed in gas.”
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