California to issue gasoline clean-up standards
Drinking water regulators are scrambling to determine if an additive that had been credited with helping to clean the nation’s air is a threat to its water supply.
When the petroleum industry developed a fuel additive in the 1970s that boosted the power of gasoline without the use of lead, the additive was hailed as a miracle product. Because of its high oxygen content, the additive – methyl tertiary butyl ether or MTBE – improved engine performance and lowered engine emissions at the same time.
Within 60 days, the California Water Quality Control Board will issue a draft policy that spells out how gasoline spills and leaks are to be cleaned up, a senior control board administrator said at a gathering of water suppliers Tuesday at Stateline.
After the U.S. Geological Survey detected MTBE in shallow aquifers two years ago, local water regulators sought answers to difficult questions, said James Giannopoulos, the assistant chief of the board’s Clean Water Program.
“Was MTBE coming to one of your wells? Were we already drinking MTBE?” Giannopoulos asked.
Since asking water suppliers to test for MTBE last fall, and making the tests mandatory in February, the compound has been found in a relatively small number of wells. Last year, the city of Santa Monica closed half its wells because of contamination from the additive.
State Sen. Richard Mountjoy, R., Arcadia, has introduced a bill to ban the use of MTBE as a fuel additive in California. The bill passed its first committee test, but awaits action in both houses.
Giannopoulos said researchers are trying to determine whether the additive, when leaked or spilled, resembles benzene, a dangerous constituent of gasoline that degrades through biological action when mixed with water.
In the 1980s, when California launched a program to test the 150,000 underground fuel tanks for leaks and possible contamination of water supplies, researchers were afraid that benzene pollution would be widespread. But studies found that plumes of benzene rarely migrated more than several hundred feet in sedimentary soils, Giannopoulos said.
“Once a leaking tank is removed, benzene plumes cleared up quickly,” he said.
Early evidence, however, suggests that MTBE does not degrade as easily as benzene. Far more soluble than benzene, the additive moves almost as fast as the groundwater itself, Giannopoulos said.
“It’s less toxic than benzene, but it is more of a potential problem to water quality because it doesn’t degrade,” he said.
The South Tahoe Public Utility District has already found detectable levels of MTBE in one of its wells, a 150-foot deep well on Tata Lane, said Rick Hydrick, who manages the district’s operations. The level, while still below interim state standards, doubled over a three-month period, Hydrick said.
“We’re obviously at risk from MTBE,” Hydrick said. “We have the same type of sandy aquifer that Santa Monica has, and Santa Monica and Orange County got hit hard.”
But Hydrick said the level of contamination from the Tata Lane well poses no threat to the district’s water supply, because it is treated and then blended with water from other wells.
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