Tainted Ground Water Has Moved Closer to Well Serving 17,000 People

Ground water containing a toxic gasoline additive has traveled closer than previously thought to a well that produces drinking water for about 17,000 homes in Rialto, Fontana, Colton and Bloomington.

“Two existing west San Bernardino County wells are the ones that are the most imminently threatened,” Kurt Berchtold, the assistant executive officer of the regional water board, said Tuesday.

Gasoline has been leaking into the ground from a fuel storage tank terminal on Riverside Avenue near the Rialto-Colton border for about 25 years. Officials from the Santa Ana Regional Water Quality Control Board have been overseeing the cleanup of the site since 1993.

In August, water officials said they believed that a plume of ground water contaminated by the leak stopped a mile north of two municipal drinking wells, one of which is in operation. But water samples about a third of a mile from the wells show that the plume has traveled much farther.

The contaminant, methyl tertiary butyl ether or MTBE, is added to gasoline to reduce air pollution. Some studies have suggested that it causes cancer.

Larry Pierce, a spokesman for Houston-based Kinder Morgan Energy Partners, which owns the major portion of the tank farm, said the samples taken from two test wells last week reveal MTBE concentrations of 12 parts per billion and 4 parts per billion, both of which are below the 13 parts per billion that the government allows in drinking water.

“That means there would not be any danger if someone were to drink it,” Pierce said. The presence of MTBE in the test wells does not mean it is in anyone’s drinking water, he said.

Berchtold said the area where the contaminated plume is located is largely unpopulated.

“We have not identified any other wells in the path of the contamination,” he said.

The general manager of the water district that owns the two threatened wells said that only one is pumping water to the nearly 17,000 homes that the district serves in San Bernardino County.

Anthony Araiza said the district never started using the second well and doesn’t intend to begin operating it until the contaminated plume is contained and cleaned up.

Araiza said the district has hired an expert to study the problem, and district workers regularly test water from the working well to ensure that no traces of MTBE or benzene, another toxic component of gasoline, turn up there.

Araiza said the district’s threshold for MTBE will be much lower than the level allowed by the government, because even at as low as 4 parts per billion, MTBE can make water smell and taste like gasoline.

“We’re not going to take a chance of putting anything that tastes like gasoline in our water supply,” he said. “If we see any trace of MTBE in the well, we’ll shut it down.’

Araiza said he learned about the plume and the threat it posed to the district’s wells from newspaper stories and not from regional water board officials.

“If anything comes out of this, I hope it is better communication between the regulators,” he said.