METHYL TERTIARY BUTYL ETHER (MTBE)

What is MTBE?

MTBE is added to gasoline to make it burn more cleanly and efficiently. It has been added to gasoline since the 1970's to increase octane levels, but has become more prevalent as an additive to reformulated gas, or RFG.  The U.S. Environmental Protection Agency (USEPA) requires RFG to be sold in areas with the nation's highest ozone and smog rates, including the four-county Dallas-Fort Worth ozone non-attainment area.  MTBE is under study, and at high levels it may pose a public health threat. However, it is not a known carcinogen.

Does Arlington have MTBE in its water supply?

Regular testing done for the Texas Commission on Environmental Quality (TCEQ), formerly the TNRCC, by the Texas Department of Health has not detected MTBE in Arlington drinking water.

There have been very small amounts of MTBE found in limited sampling of two of our three raw water sources. However, no sampling results remotely indicate a risk to human health.  While the estimated health-effect level is 240 ppb (parts per billion or ug/L), the amounts found in Arlington’s supply lakes were only a small fraction of that level.

Has the City of Arlington Water Department participated in any research related to MTBE?

In 1999, the City of Arlington participated in the American Water Works Association (AWWA) Research Foundation project, "National Assessment of Methyl Tertiary Butyl Ether (MTBE) Occurrence in Drinking Water," conducted by the Metropolitan Water District of Southern California, the U.S. Geological Survey, and the Oregon Graduate Institute. A sample of water from Lake Arlington was taken on June 21, 1999 from the boat launch area at the end of Arkansas Lane and sent to the Metropolitan Water District of Southern California Water Quality Laboratory for analysis.

What were the results of the study?

The results of the analysis performed on raw water showed a trace of MTBE (1.4 ug/L). In addition, tests of 65 other compounds showed that none were detected (<0.2 ug/L). A TCEQ water quality sampling project in 46 Texas lakes conducted in the summer of 1999 detected 0.33 ug/L of MTBE in Richland Chambers reservoir, another Arlington raw water source.

Is Arlington prepared to meet additional MTBE challenges?

The Arlington Water Utilities Department has always conducted thorough testing of its water to ensure that contaminants, if present, are effectively eliminated from the water supply. Both treatment plants in the City of Arlington continue to meet or exceed the minimum requirements of all water quality standards and regulations. Recent installation of technologically advanced ozonation and GAC (granular activated carbon) filtration processes at both treatment plants further safeguard Arlington’s drinking water quality.

Arlington Water Utilities will continue to monitor the MTBE issue and work with industry associations and regulatory agencies to ensure the continued safety of Arlington’s drinking water supply.

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