Source of water contamination eludes agencies - Monterey County Herald | 11/20/2004 |

MTBE is a gasoline additive used since 1990...is found contaminating drinking water supplies across US...

Source of water contamination eludes agencies

By VIRGINIA HENNESSEY

Herald Staff Writer

Contamination of two Salinas water wells has become the center of a perplexing mystery baffling two Central Coast water agencies.

For more than two years, the Central Coast Regional Water Quality Control Board and the California Water Service Co. have been searching for the source of MTBE contamination in two of the company's water wells at Pajaro and Bridge streets in Salinas.

Typically, sources of the carcinogenic gasoline additive are tracked down quickly once the contamination is identified, said John Goni, water resource control engineer for the regional board. But in this case, both Goni and officials at California Water are stumped.

About 50 potential leak sites have been tested in a one-mile radius around the wells. While several MTBE leaks were detected, Goni said, none was significant enough to account for the contamination at the company's wells.

None of the contaminated water was or is being delivered to customers without being treated, he stressed. But somewhere out there, a gasoline storage tank is leaking a significant amount of the suspected cancer-causing agent, and authorities have been unable to find it.

MTBE, or methyl tertiary butyl ether, is a gasoline additive used since 1990 to meet requirements of the federal Clean Air Act. It was outlawed last year after it was found to be contaminating drinking water supplies across the country.

On Friday, the Associated Press reported that hundreds of MTBE-tainted wells had been found in Maryland. In California, serious contamination cases have been reported from Sacramento and South Lake Tahoe to Cambria and Santa Monica.

In addition to fouling the taste of water, the chemical has been shown to cause cancer in laboratory rats at high doses, though the health effects of low levels in humans are unknown.

California Water detected low levels of MTBE in the two wells in early 2002. By June 2003, the levels had jumped from an acceptable but worrisome level of 3.9 parts per billion to 39.9 ppb in one well and 120 ppb in the other. The maximum allowable concentration is 12 ppb in drinking water. Read More....

Monterey County Herald | 11/20/2004 | Source of water contamination eludes agencies