City officials met with state environmental scientists Wednesday and agreed to conduct more tests to determine the extent of the pollution, according to Steven Thiriot, a Department of Environmental Quality manager.
How long the tests will take and whether the state will require the city to clean up the pollution is not yet clear.
Preliminary tests show pollution in excess of state standards for drinking water, although there are no municipal wells in the area.
The source isn't known, but it could have been auto-repair businesses that operated on or near the property decades ago, leakage from sewage pipes or from nearby underground fuel tanks.
In one test hole on the 1.5-acre site, the concentration of diesel fuel residue was 1,040 times higher than the level at which the state requires action. Soil samples showed high concentrations of benzene, naphthalene, diesel and gasoline, all residuals of petroleum.
The concentration of the solvent tetrachloroethylene (TCE) in the groundwater of one test hole was at 13 parts per billion, more than twice the contaminant level the state allows for drinking water, Thiriot said.
Thiriot, who is manager of site assessment for the state's Superfund program, said the TCE concentration found so far is not a grave concern.
But TCE is heavier than water, so more tests are needed to determine whether the groundwater underlying the future recreation center is seriously polluted.
"If they increase in concentration as we go deeper, then we've got a problem," Thiriot said.
The test holes dug by the city's consultants earlier this summer went only 16 feet deep, and hit groundwater at 12 feet.
Thiriot said the additional tests will go deeper and also will test for metals, such as chromium or lead.
Ogden City, which bought the old Ogden City Mall in 2001 and spent the next few years demolishing it, had hoped to begin construction this summer on what the mayor considers the catalyst for the new mall: an adventure center with a wave pool, climbing wall, wind tunnel and bowling alley.
Potential lenders, however, required the soil and groundwater tests, and when test holes were bored into the ground, the odor of petroleum was unmistakable.
Dave Harmer, Ogden's community-development director, said he hopes the pollution can be handled easily. "I don't think the issues there are all that serious," he said.
The city already watched the project's cost climb by $2 million this summer when it missed a deadline to begin construction. The contractor, R&O Construction of Ogden, agreed to no more cost increases if construction was under way by today.
Now, says Harmer, "We are susceptible to additional cost increases."
The complicated financing the city is relying on for the $18 million project involves two sets of bonds and two lenders.
And because of redevelopment-agency law affecting tax-increment financing, construction must be launched by Dec. 31.
kmoulton@sltrib.com
Chemical health threat
Petroleum and its components can cause organ damage and some have been proved to cause cancer.
The solvent tetrachloroethylene (PERC or TCE) is used for dry cleaning and metal degreasing. Exposure to very high concentrations can cause dizziness, headaches, sleepiness, confusion, nausea, difficulty in speaking and walking, unconsciousness and even death. Research is inconclusive about whether it can cause cancer.
