The continuing search of the grounds at Hill Air Force Base and ongoing monitoring of known dump sites has turned up no new hazardous-waste sites on the base since September, according to base officials.
Maj. Portia McCracken, base public affairs director, said the Air Force's ongoing program of identifying and cleaning up hazardous-waste sites is proceeding.More than a dozen former chemical and waste dump sites, some of them dating back to the 1950s and 1960s, have been identified on the base and one has already been sealed to contain groundwater seeping through it.
Three sites on the base's northeast boundary, above South Weber and the Weber-Davis Canal, are leaking chemicals into groundwater off the base, but health officials are aware of the problem and are monitoring it.
No drinking water is in danger, said base environmental engineer Allan Dalpias, who said the contaminated water is confined to a small area.
McCracken said Monday that an ongoing soil gas sampling operation, designed to detect trace amounts of chemicals in the soil that could be leaking from buried waste, has turned up no new sites that need investigation.
"If they found something, we would know immediately and start steps to identify it," McCracken said. "We're still in the process of investigating the known dump sites and formulating procedures to deal with them."
Most of the dump sites contain petroleum-based chemicals used as paint strippers and degreasers for aircraft and other equipment. Many of the chemicals have been identified as cancer-causing.
Before stringent environmental controls on chemical disposal were formulated in the mid-1970s, it was a common practice to dump the used chemicals, usually in drums, in pits on the base and cover them with dirt.
The pits were not marked and as years passed, their locations were forgotten. As the drums deteriorated, the solvents and chemicals began leaking, showing up in groundwater.
The Air Force started its Installation Restoration Program to track down the waste pits, determine their contents and formulate a plan for either containment or disposal of the waste.
A report issued last month by Hill confirms 17 waste disposal sites, some on the base and others at Little Mountain and on the Utah Test and Training Range west of the Great Salt Lake.
The 14-volume report recommends a further investigation to determine how to alleviate the conditions at 14 of the sites, 13 on the base and the one at the test and training range. All the sites are being monitored until a disposal or containment plan is drawn up.
Dalpais said eight sites have been located along the base's northern perimeter bordering South Weber and Riverdale, including the three known to be leaking contaminants off-base. One site, called Chemical Pit 3, is scheduled for cleanup beginning in 1991 and the other sites, which pose less hazard, will follow.
In September, the base announced a low concentration of trichloroethylene, a solvent used until 1979, had been found in a water seep on private land adjacent to the base's north gate.
Dalpais and other environmental specialists said the contamination is not affecting drinking water or culinary water supplies.
A water test showed a concentration of 190 parts of the chemical per billion, said Dalpais. The Environ-mental Protection Agency standard for drinking water is five parts per billion.
As a temporary solution to that problem, Dalpais said the Air Force plans to intercept the subsurface drainage, treat the water and return it to the ground.
In 1987, Hill constructed a hazardous-waste processing and disposal system to treat sludge from its industrial treatment plant. The sludge is filtered and dried, removing most of the liquid and reducing the volume by 80 to 85 percent.
The residue is then trucked to an approved disposal site in conformance with federal and state regulations, said one of the base environmental officers.