UA defends Page Ranch containment system
University and state environmental officials last week expressed confidence in the stability and safety of the Page Ranch landfill's hazardous waste containment system.
A report written by an Oracle research/writer team recently accused the University of Arizona of putting economic concerns ahead of public safety in its management of the closed hazardous waste storage site.
The report states that toxins have been detected in ground water directly beneath the site, and proposed construction in Falcon Valley northeast of Tucson will hasten the spread of contaminants into the aquifer that supplies every community between Oracle and northeast Tucson.
"We don't believe there's any contamination in the aquifer and amazingly enough - neither do the Department of Environmental Quality or the Environmental Protection Agency," said Steve Holland, director of UA Risk Management and Safety.
The Page Ranch landfill consists of roughly three acres of buried chemical and low-level radioactive waste cells located just north of State Highway 77 between Oracle Junction and the town of Oracle.
The landfill officially closed in 1986, and a permanent cap was later installed over the site in 1997.
"The process took too long - I'll be the first to tell you that," Holland said. "It shouldn't take 10 years to close a landfill."
Holland blamed the delay on a number of amendments that were made to the UA's closure and post-closure plans for the landfill.
At the time of closure, the EPA's capping guidelines called for a compacted layer of impermeable clay reinforced with flexible plastic liners to prevent water from permeating the waste cells.
Parton's report states that in order to save money, the UA installed a cap made of clay mixed with earth taken from a nearby cattle pond and without the liners specified in the EPA's guidelines.
Holland said that officials initially considered using a membrane-reinforced cap but later decided against it due to installation concerns.
"Even a pebble sticking up in the wrong place could have punctured that thing," Holland said. "The permeability of the installed cap is equal to or greater than what it would have been with a plastic liner."
The containment system installed in 1997 was designed using EPA software which took into account local factors such as average rainfall, surface evaporation and area geology, Holland said.
Jim Walters, a hazardous waste permits analyst with the Arizona Department of Environmental Quality, also said the site is secure.
"Based on all the computer models we have, there should not be any rainfall going into that landfill," Walters said.
Walters said the landfill's containment system was specifically designed to divert as much water as possible away from the waste cells.
"The perimeters of the waste cells are way overlapped by the cap," he said. "In terms of the cover, the storm water channels, and all the physical features out there - if there's anything that's creating a problem they (the UA), have to go in and repair it."
The Page Ranch landfill report stated that a series of well tests the UA conducted 10 years ago confirmed the presence of a contaminant plume in the aquifer beneath the site.
Holland said the alleged contaminant "detects" cited in the report resulted from flawed laboratory procedures that have since been corrected.
Regina Lynde, an Operations Services Coordinator with the Arizona Water Company that supplies Oracle, said that recent well tests have yielded no evidence of volatile contaminants in the city's aquifer.
The most recent violation of an established maximum contaminant level was in July 1998 for fecal coliform, Lynde said.
Parton has previously stated that aquifer "drawdown" will increase in response to planned development in Falcon Valley and accelerate the spread of the alleged toxins.
"That might be a nice hypothesis, but I don't think it's possible," Walters said. "We don't have any evidence to suggest saturation at the water table."
Holland said that when report co-author Web Parton visited UA risk management to obtain documents, he gave the impression of being more concerned with halting proposed development in Falcon Valley than he was with water safety.
Parton denied the allegation.
"That kind of debate can go on forever, "Parton said. "I think that what's germane here is to look at the bigger issue."
Parton said the UA conspired with the ADEQ and the Arizona Department of Administration to avoid exhuming the Page Ranch site.
"They (the UA) went over their (ADEQ's) head and made it an issue of money," Parton said.
But Holland said there was no such conspiracy.
"The only response I have to that is that regulatory agencies have no incentive to do that," Holland said. "I'm offended that he would suggest that, and I think that regulatory agencies would also be offended."
"We don't have any special exemption or special power," he added.
According to the UA's 1986 estimates cited in Parton's report, exhumation of the Page Ranch landfill would have cost anywhere between $7 million and $10 million.
Holland said ideally, the UA could have removed all the contaminated soil and sent it elsewhere. But the risks associated with unearthing tons of toxic material and the question of how to dispose of it made this an untenable option, he said.
Walters said the UA now has four groundwater monitoring wells at the Page Ranch landfill, which are regularly tested as part of the post-closure plan approved by the ADEQ in 1995.
"There's no detections of anything right now," Walters said. "We're planning to have them conduct soil vapor monitoring from time to time to assure that these containers are not breaking down."
Walters said because the water level lies 620 to 640 feet beneath the site, the only way toxins could conceivably reach the aquifer would be through a crack in the underlying rock. He added that there is presently no evidence which suggests that such a crack exists.
"Obviously we're concerned that those wastes are there - but as long as the cap is maintained and the storm runoff goes around the landfill, I think we'll have a good sense of what's happening there." Walters said.