TEXAS--Dallas Spill Adds to Concern About Fuel Additivegreenspun.com : LUSENET : Grassroots Information Coordination Center (GICC) : One Thread
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Dallas spill adds to concern about fuel additive
Sunday, Mar. 19, 2000 at 01:51 CST By Neil Strassman
FORT WORTH -- When 500,000 gallons of gasoline spilled from a pipeline and flowed toward nearby Lake Tawakoni 10 days ago, Dallas' drinking water supply was threatened by one of the most controversial chemicals in the United States: the gasoline additive MTBE.
Used in about a third of the country's gasoline to cut smog and reduce toxic tailpipe emissions, MTBE -- methyl tertiary-butyl ether -- has created a furor from California to Maine because of how quickly and easily it can ruin a water supply, contaminating lakes and persisting in ground water.
Yet, every 10 gallons of gasoline sold in Fort Worth contains more than a gallon of MTBE. Reformulated gasoline -- a fuel mixture that contains 11 percent MTBE -- is the only gasoline that has been sold in the Metroplex since 1995.
The Tawakoni spill contained more than 50,000 gallons of MTBE.
The event localized the national debate over MTBE issues. Concerns about the benefits and hazards of the chemical intensified among the public and regional, state and federal authorities. Cleanup issues also arose. "Right now, there really is no known treatment for removing MTBE from the water," said Terrace Stewart, director of Dallas water utilities. Some MTBE will escape into the air over time. Tawakoni is the largest water supply lake for Dallas, which can draw as much as 161 million gallons a day, though it usually takes about 100 million gallons daily, Stewart said. The bitter and the sweet of MTBE
Traces of MTBE have been found in the drinking water of Grapevine and Denton but not in measurable amounts in the drinking water of Fort Worth, Arlington or any other Metroplex city, state environmental records show.
It is too soon to assess the damage to Lake Tawakoni, the source of about 25 percent of Dallas' water, state and environmental officials say. The city closed its water intake at the southwest corner of the lake March 10 and does not plan to reopen it until sampling shows that the water is safe, utility officials said.
On Thursday, drinking water was trucked to the small town of West Tawakoni, which depends solely on water from the lake, and state toxicologists are closely monitoring the lake.
Many toxicologists say that the gasoline additive becomes a taste and odor problem in water long before it endangers human health. But other researchers say that MTBE may pose a greater health risk because the water-soluble compound has proved more toxic than first thought, is difficult to clean up and is considered a possible carcinogen.
California, which estimates its initial MTBE cleanup costs at $1.5 billion, banned the chemical as of December 2002, after the chemical was found to have contaminated drinking-water wells, aquifers and lakes across the state. New Hampshire and New York are lowering acceptable MTBE limits. In Maine, which no longer uses gasoline with MTBE, the chemical was detected in measurable amounts in 1,000 private wells and 800 public water supplies, said Ron Severance of the Maine Department of Environmental Protection.
Even so, MTBE will continue to be used in North Texas because of its smog-fighting potential, state and federal officials say.
"It may be a calculated risk we have to take for as long as four years," said Ralph Marquez, the state commissioner responsible for air quality.
The state is under intense pressure from the federal Environmental Protection Agency to reduce ozone smog in the Metroplex by 2007, and reformulated gasoline is an essential part of the proposed clean-air plan.
The federal Clean Air Act of 1990 requires areas with smog problems to use reformulated gasoline that contains at least 2 percent oxygen by weight. MTBE, first used in 1979 to replace lead and to serve as an octane booster, adds the oxygen.
Oxygenated fuels have significantly improved air quality across the U.S., the equivalent of taking 16 million vehicles off the road, according to EPA testimony to Congress on March 2. The EPA is backing away from MTBE because of the water quality problems associated with it, but has not dropped the oxygen requirement in cleaner-burning gasoline.
An EPA advisory panel concluded last year that the use of MTBE in reformulated gasoline should be curtailed. Other oxygenates, such as ethanol, can be used to make reformulated gasoline.
"We wouldn't back off on reformulated gasoline now," said Carl Edlund, the EPA's regional director of planning and permitting.
Vehicles that pollute less and use cleaner-burning low-sulfur gasoline might avert the need to continue using MTBE, but those do not enter the market until 2004, not soon enough to help clean the air in the Metroplex, Marquez said.
"The state does not want to use more MTBE, but it may not have an option, because it is dependent on the gasoline that is available," Marquez said.
Texas refineries produce about 75 percent of the MTBE made in the United States, said Jim Jordan of DeWitt & Co., a consulting firm for the petrochemical industry. Some of it is shipped to California, the East Coast and used in Houston and the Metroplex, he said. Some refineries have said they can produce a cleaner-burning fuel without adding an oxygen-increasing compound, but it would take time and expense to retool the refineries.
Pleasure boating and lake contamination
Nearly all drinking water in North Texas comes from lakes. Other than disastrous events such as the Tawakoni spill, most of the MTBE contamination in lake water is believed to be from boats, personal watercraft and inefficient outboard motors that discharge a third of the fuel unburned. Leaking gasoline storage tanks and storm water runoff also add to the MTBE burden in area lakes.
In Grapevine, drinking water contained 4.7 parts per billion of MTBE on Aug. 9. Denton's water contained 4 parts per billion MTBE in two samples and 3.6 parts per billion MTBE in a third sample on June 23, according to Texas Natural Resource Conservation Commission records.
At three or four times the levels found in Grapevine and Denton, the bitter taste and turpentinelike odor can render water undrinkable.
"It is an issue, without a doubt, but that [4.7] was a spike," said Matt Singleton, Grapevine's assistant public works director. Other quarterly tests on Grapevine water have not shown any MTBE, he said.
Tim Fisher, assistant manager of the Denton water utility, said there is "a little concern about how representative [the MTBE level] is of our system," which more often has shown no MTBE or traces below two parts per billion. As in Grapevine, quarterly tests have not shown elevated levels of MTBE, he said.
Traces of MTBE in drinking water do not pose a health threat, said Richard Beauchamp, a Texas Department of Health toxicologist.
"If the levels are three or four parts per billion, it would probably be well below the level of concern," he said. Texas has a taste and odor limit of 15 parts per billion MTBE in water but has not set a concentration limit for drinking water. California has a drinking water limit of 13 parts and New York is proposing 10 parts.
Heidi Klein, 37, of Denton, the mother of 4- and 8-year-old sons, said she is concerned about the MTBE in Denton's water.
"We're being told the levels are safe, but at what point is it no longer safe?" said Klein, a professional singer and voice instructor.
Denton, which draws its water from heavily developed Lake Lewisville, is in a dispute with the U.S. Army Corps of Engineers over further development at the lake, which has nearly 30 boat-launching ramps and more than 2,300 slips.
"At some point you have to address recreation vs. water issues," Fisher said. "It's tough to know where to draw the line. We are in negotiations."
In written comments responding to the corps' environmental analysis of future development at the lake, the utility said the corps failed to adequately address water quality.
Denton would like to restrict boat access to "Party Cove," a narrow inlet just northwest of the Interstate 35E bridge, because its drinking water intake is there. On holidays and in the summer, dozens of boats gather in the cove.
State law prohibits boats from coming within 200 feet of a drinking water intake and forbids marinas within 1,000 feet of an intake. But the boating limit can be hard to enforce.
"Whoever owns the intake structure is responsible. We have no way to enforce that," said Ron Ruffennach, a corps spokesman in Fort Worth.
Water quality was addressed according to state and federal standards, he said, and the levels of MTBE in the lake are not high enough to take action.
A University of North Texas study of MTBE levels at Lake Lewisville, conducted by professor Ken Dixon and graduate student Ann Lee, found concentrations of MTBE in lake water as high as 16 parts per billion. They sampled monthly, beginning in February, then sampled weekly when boat traffic was highest, between May and September.
MTBE was found in greater amounts around the holiday weekends when the most boats were on the lake, Lee said.
The U.S. Geological Survey measured MTBE levels at more than 40 Texas lakes last year and found concentrations averaging about 2 parts per billion MTBE.
But northwest of Austin, the Lower Colorado River Authority found MTBE levels of 45 parts per billion when it measured near marinas at the Highland Lakes over the Labor Day weekend. Sampling four days later found levels of 9 parts per billion MTBE, said Suzanne Zarling, manager of water resource protection.
Ron Beardon, a public drinking water official with the Texas Natural Resource Conservation Commission, said that it is difficult to replicate test results because the level of the chemical is not constant in lakes.
"You go back to re-collect samples, and [MTBE] is not there anymore," Beardon said. "A detection of MTBE does not mean that level is in the water all of the time, but, at some point, there has been gasoline exposure to the water."
Extent of MTBE's danger is still debated
The federal government says that MTBE can cause cancer in animals and possibly in humans. In laboratory tests the chemical was shown to cause cancer in two animal species. However, the levels found in North Texas drinking water samples are thousands of times lower than levels that caused adverse health effects in the tested animals.
The EPA says that it expects to set a limit for the amount of MTBE allowed in drinking water by year's end.
Some medical researchers and clean-water advocates say that may not be soon enough to protect the public health.
Young children and pregnant women should avoid drinking any contaminated water, said Dr. Myron Mehlman, the former head of toxicology for Mobil Oil and an adjunct professor of community medicine at Robert Wood Johnson Medical School and Mt. Sinai School of Medicine.
"MTBE should never have been put in gasoline," Mehlman said. "The data did not support the safety, and it will cost billions to clean up."
One of the problems with MTBE is that it moves through water 30 times faster than benzene or toluene, two of the most toxic chemicals in gasoline, toxicologists say.
"The toxicity of MTBE is somewhat greater than we thought," said Dr. Kenneth Rudo, a leading expert on MTBE and a toxicologist with the North Carolina Department of Health. In the body, MTBE metabolizes into formaldehyde, a probable human carcinogen, he said.
Klein, the Denton mother, says the boats that idle over the city's water intake at Party Cove should be moved.
The state, though, says that it has no plans to change the 200-foot rule.
"As it is now, it is safe," Tom Kelley, a spokesman for the Texas environmental agency, said of the 200-foot rule. But because MTBE is water-soluble, it can easily get into water inside the buoyed-off area around a water intake. Water intakes in many of Tarrant County's drinking water lakes are marked to keep boats away, said Woody Frossard, manager of environmental services for the Trinity Regional Water District, which oversees many North Texas lakes.
"If it becomes apparent that increasing the distance from the intakes is a public benefit, we would do that," Frossard said.
As for Lake Tawakoni, state officials say that they have recovered about two-thirds of the gasoline spilled, and sampling of water there continues. The officials say that they are concerned about Greenville and many small towns in the region that take water from the lake.
By three days after the spill, MTBE levels were about 1,000 parts per billion. They dropped to around 100 parts Tuesday, but climbed two days later to 271 parts, officials said.
Dallas water official Stewart said that he is unsure when the city will be able to use the lake's water again.
"Just because the gas has been cleaned up doesn't mean the MTBE isn't still there," Stewart said. "We need to do additional testing. "
But Dallas is fortunate. Stewart said Lake Ray Hubbard, which belongs to the city, is nearly full.
Neil Strassman, (817) 390-7657
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