What is MTBE?

MTBE(methyl tertiary-butyl ether) is a member of a group of chemicals commonly known as fuel oxygenates. Oxygenates are added to fuel to increase its oxygen content. It is produced in very large quantities (over 200,000 barrels per day in the U.S. in 1999) and used in gasoline throughout the United States to reduce carbon monoxide and ozone levels caused by auto emissions. It replaced the use of lead as an octane enhancer in 1979.

How Does Methyl Tertiary-Butyl Ether Get Into Groundwater?

While these air quality benefits have been welcome, it has been controversial due to its contamination of groundwater. Unfortunately, gasoline storage tanks that leaked in the past released this and other chemicals into groundwater.

MTBE travels farther and faster and is more resistant to breakdown than other gasoline ingredients. This has led to detections of it in private and some public wells near tanks that have leaked. It may also enter groundwater from gasoline spills on unpaved portions of your yard, such as when refueling a lawn mower or doing auto repairs. Any that evaporates may join with moisture in the air to form trace levels of methyl tertiary-butyl ether in rainwater.

According to the Environmental Working Group it has been detected in 1,861 water systems in 29 states, serving more than 45 million Americans.

What are the Health effects?

It can be adsorbed through the skin but the process is slow. The majority of exposure studies have been health effects through inhalation. Limited research to date has been done from ingestion or topical exposure of it in drinking water.

Immediate or acute symptoms from consumption may include nausea, dizziness, shortness of breath, and diarrhea.

Long term health effects from exposure through inhalation and possibly consumption may include gastrointestinal irritation, liver, and kidney damage.

Additionally, cancer and nervous system effects have developed in laboratory rats and mice by exposure through inhalation of vapors and topical application of high concentrations of MTBE using oil. However, evidence to date is inconclusive on the cancer-causing or nervous system effects of consuming or bathing in methyl tertiary-butyl ether contaminated water.

Good news is that evidence has also shown that intake by humans and animals does not stay in the body long, but is metabolized or eliminated from the body within hours.

There are a number of effective technologies that can remove it from drinking water. The most common treatment technologies are 1) air stripping and 2) adsorption using granular activated carbon (GAC).

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