Tests show increasingly high levels of a cancer-causing solvent in a water well the city relies on in busy summer months.
There is no immediate health risk, and workers are taking steps to combat the problem. But federal regulations likely would require the well to be shut down if the trend continues or worsens, state water quality experts said Wednesday.
In an exceptionally hot summer, that could lead to water rationing.
“I think the human health considerations would override the need for lawn watering,” said Tony Davis of the state Division of Environmental Quality. “With good management, though, the city should be able to hold those (solvent) levels in line.”
An April 15 test of the city’s Hanley Street well - one of five that supply Coeur d’Alene’s drinking water - showed 6.8 parts per billion of the chemical trichloroethylene, a common de-greaser. A subsequent test revealed TCE levels of 7.9 parts per billion.
The well would violate federal standards if levels average more than 5 parts per billion over four successive quarterly tests. The current four-quarter average is 3.99 parts per billion.
TCE causes cancer in laboratory animals, and experts suspect it increases the risks of cancer in humans after long-term exposure to high levels, said Jim Markley, city water superintendent.
Trace amounts of the chemical have been found in the well for more than a year - but never before at these levels. But that doesn’t mean levels will continue to rise.
“This stuff is maddening because the only clear pattern is the more we use the well, the higher the levels are,” said Markley. “It goes up and down.”
The source of the contamination is not entirely clear.
Water experts investigated the area in 1990 after the same compound was found in a nearby community well. By 1992, those traces had risen to five times the legal limit and the well eventually was shut down.
EPA investigators later determined that Deming Industries - a company that anodized aluminum - had disposed of thousands of gallons of degreaser over many years in nearby septic tanks. The practice was not illegal at the time.
The company is in the process of cleaning up the ground near its site.
The city, meanwhile, is trying to limit use of water from that well, believing that will drop TCE levels.
If that doesn’t work, the city will just shut the well down, which creates other problems.
Without the well, water pressure drops too low for fire hydrants and some businesses. So the city would install a $50,000 pump to increase pressure.
But even that won’t help in the worst case scenario.
Hanley, built in 1990, pumps 3,400 gallons of water a minute. Markley can’t say whether the city could make it through July and August - the busiest time of year - without it.
“A real hot summer? Probably not,” he said. “A cool summer? Certainly. A normal summer? I don’t know.”
Regardless, the problem likely will be resolved by 1997, when a sixth well near Honeysuckle Avenue comes on-line.
But if the Hanley well is abandoned, taxpayers - not the polluters - likely will swallow the $500,000 loss.
“There was quite a succession of junkyards and uncontrolled disposals over the years,” Davis said. “It’s not clear how many of them contributed to the problem.
“Would Deming admit they were responsible? I doubt it. Would they help pay for a new well? I don’t know.”
, DataTimes ILLUSTRATION: Map: Contaminated well site