By Cecily Barnes
After nailing down ways to detect and treat water contaminants such as lead, aluminum and copper, water officials have been faced with a new, previously unknown chemical that has infected parts of Santa Clara County's water supply. The culprit is methyl tertiary-butyl ether (MTBE), a synthetic chemical used to reduce carbon monoxide emissions from burning gasoline in vehicles.
Little is known about the health effects of MTBE, but Santa Clara Valley Water District officials aren't waiting to find out. At their April 22 board of directors meeting, board members approved a plan aimed at eliminating MTBE from Santa Clara County's water supply.
"The board expressed its gratitude to staff for taking a proactive stance toward MTBE and gave us carte blanche authority to monitor and research [the chemical]," water district spokesman Mike DiMarco said. "They made it real clear that they are worried about MTBE's presence in Santa Clara County and are concerned that [it] could invade our drinking-water supplies."
The MTBE action plan is a five-part process which will treat infected water, monitor the reservoirs, prevent future contamination, research health risks and assure that all information is communicated to other water districts. The district will also ask the state Water Resources Control Board to identify infected water sources and offer guidance regarding prevention and treatment. Portions of the district's action plan have already begun.
"The plan has already been started," DiMarco said. "About a dozen of us from different disciplines in the district have been working together on an informal basis, sharing research."
MTBE became known to the Santa Clara Valley Water District after the chemical contaminated nearly 40 percent of Santa Monica's water supply last June. Fearful of a similar catastrophe, officials began testing local reservoirs for the compound.
"When last June they [experienced] water contamination, we immediately started testing our drinking water supplies," DiMarco said.
Initial screenings of Anderson, Coyote and Calero reservoirs showed no traces of MTBE. However, the same three reservoirs tested positive during follow-up screenings at different times.
"The highest reading found was nine parts per billion, which is very, very minute," DiMarco said. "The state and federal governments are looking at enforceable action levels between 35 and 70 parts per billion. [Anything less than that] is not expected to cause any adverse effects over a lifetime of exposure."
But no matter how minuscule the levels, officials are committed to fixing the problem, especially since the chemical's effects on health have not yet been determined.
The Environmental Protection Agency classifies MTBE as a possible carcinogen, but nothing is conclusive. Tests in the 1970s found that although MTBE is present in the atmosphere, inhaling it isn't dangerous, according to the Environmental Protection Agency. However, water district officials do not know the effects of MTBE particles when, through precipitation, they are carried into streams and ground water.
The chemical can also reach water through gasoline spills. Hence, EPA officials are working to determine the chemical's effects when ingested through water.
Until more is known, the Santa Clara Valley Water District says it is committed to keeping homes and businesses free of water that tests positive for MTBE. DiMarco says the district has plenty of uncontaminated water from other sources, including imported water and water from aqueducts, to adequately supply the county. Someday the county could run out of water that is free of MTBE, but it is highly unlikely, according to DiMarco.
"If water has MTBE in it, it's not making its way into homes and businesses," DiMarco said. "But we want to be as proactive as we possibly can."
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This article appeared in the Los Gatos Weekly-Times, May 7, 1997.
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