An environmental engineering firm advised the city to be careful to protect its deep aquifer and to prepare to jockey for position as discussions on how and how much to clean up the Murray smelter site continue.
Steve Glaser and Carl Anderson of the Salt Lake City firm Montgomery Watson told the council Tuesday that ASARCO, the state Department of Environmental Quality and the federal Environmental Protection Agency will probably take different positions on how much the smelter site should be decontaminated.Most likely ASARCO, the company that owns the site, will push for a cleanup that will translate into a cancer risk of one in 10,000, Anderson said. DEQ will want the site to have a cancer risk of no higher than one in a million.
"The EPA will probably be in the middle," Anderson said.
City Attorney Craig Hall said the issue for the city will ultimately be how to protect the deep aquifer.
"The question will be what's it worth to protect that," he said. "It's going to be an economic decision."
Because groundwater is difficult to clean up, restoration of the contaminated shallow and intermediate aquifers at the site to drinking water quality may be "economically impractical," Anderson noted. Drilling restrictions may have to be implemented in and around the site, and those who build there may be required to store contaminated soil under or near their buildings.
Anderson said ASARCO had proposed cleanup levels much higher than federal drinking water standards, with suggested levels for arsenic at 700 mg/kg and for lead, 4000 mg/kg. In comparison, cleanup levels at the old Sharon Steel site in Midvale were 70 mg/kg for arsenic and 500 mg/kg for lead.
However, the two sites are different in that the Sharon Steel site was developed into a residential community and plans for the Murray smelter site do not currently include residential development - although the planned Main Street extension project will pass through contaminated areas of the site.
"The proposed soil levels are based on industrial land use," Anderson said.
Another problem facing city planners is the hazard to workers constructing a proposed police training center at the site. Anderson said lead contamination may be a problem for workers as they dig to clear a foundation and lay pipe. Current plans are to excavate soil near the proposed facility and store it there indefinitely. New fill dirt will be brought in on which to build the training center.
One area of cadmium pollution in excess of standards has been located in the intermediate aquifer, Anderson said. Contrary to earlier reports, some evidence indicates the contaminants have already reached Little Cottonwood Creek, but other surveys have not shown contamination, Glaser said.