Contaminated ground water near Navajo boundary

Copyright © 2009
Gallup Independent
By Kathy Helms
Diné Bureau

WINDOW ROCK — U.S. Environmental Protection Agency, Region 6, in Dallas will discuss ground water cleanup efforts at the former United Nuclear Corp. mill site May 5 at a community meeting in Pinedale.

In short, cleanup efforts are no longer working.

Contamination from the UNC site — which is in Pinedale Chapter right in the middle of Indian Country — is nearing the Navajo Nation boundary. And though the cleanup remedy at the Superfund site is no longer effective, because no one is drinking the contaminated water, the remedy is still considered protective of human health and the environment.

In addition, this week, officials from U.S. EPA, Region 9, in San Francisco and representatives of General Electric are conducting sampling in the vicinity of the adjacent Northeast Churchrock Mine to determine the volume and location of potentially contaminated materials at that site.

Further characterization of the extent of contamination is necessary to determine the volume of materials that will be excavated once reclamation starts.

It has been nearly two years since U.S. EPA, in conjunction with the Navajo Nation Environmental Protection Agency, began cleaning up radium-contaminated soil at five residential properties near the old mine. Approximately 6,000 cubic yards of radioactive soil were transported to Grandview, Idaho.

Further cleanup at Northeast Churchrock is slated for this spring. Navajo Nation and nearby community residents have said they want clean closure of the site, however, one of the proposed alternatives is to truck the radioactive waste down the highway to the UNC Superfund site and bury it in a lined disposal cell next to existing, unlined disposal cells basically sitting on top of the Pipeline arroyo.

Mark Purcell, remedial project manager for the United Nuclear Corp. site in New Mexico, said EPA Region 6 will report on its third five-year review, completed last year, from 6:30 to 8:30 p.m., at the Pinedale Chapter House.

“EPA is still working with the company, United Nuclear Corp., to get the ground water cleaned up, and that’s been ongoing,” Purcell said Tuesday. “The protectiveness determination was based on the fact that we are not aware of anyone that’s being exposed to contaminated ground water. We know of no one that’s using it in a well or so forth, so there is no exposure and therefore we found it to be protective.”

However, he said, though the remedy has been protective over the years and has done a lot of good, “we don’t think it’s going to get us there. We’ve not been able to stop groundwater contamination from moving. It’s moving toward Navajoland, and that’s a concern which we will talk to the community about next week.”

Stephen B. Etsitty, executive director of Navajo EPA, said recently that many of the cleanup actions that were signed off by other agencies and not the Navajo Nation should be up for review again.

“These sites that have long been thought to have been taken care of, it’s in the best interest to make sure, to do a double check — go back around and see just how secure they are and if the caps and closure plans that were designed and approved decades ago are effectively doing their job, and if not, we need to have them addressed again.”

The remedy for cleanup of ground water at the UNC site — pump and treat — was determined back in 1988 for the three water-bearing zones impacted by the tailings: the shallow alluvium and Zones 1 and 2 of the Upper Gallup Sandstone.

Purcell said contaminants of concern include uranium, thorium-230, radium-226/228, a handful of heavy metals, selenium, vanadium, cobalt, lead, sulfate, and total dissolved solids.

The former UNC mill was demolished in the 1990s. All that’s left is an administrative building and some offices. “What’s also left is their solid waste byproducts from milling, which is what we call tailings,” Purcell said. “They disposed of those tailings into three large bermed areas, or diked areas called cells. Those tailings sit there today.”

The tailings piles were capped under the authority of the U.S. Nuclear Regulatory Commission. “EPA and NRC have kind of divvied up responsibilities at the site. They’ve taken everything on the surface” — the mill and the tailings — and EPA is responsible for cleaning up the ground water underneath, he said. “It’s been a challenge.”

The “treat” portion of the remedy was really just evaporation, according to Purcell. “They’ve got two large evaporation ponds that they’ve built on top of the tailings cells. They evaporate the water. In two of the zones we’ve turned off all the pumping wells.

“The last zone, we’ve had to put new wells in over the years because the contaminants have moved downgradient in the direction of ground water flow. They put in a couple of new wells and they’re pumping two or three of those. We may still put in some additional wells as the slug of contaminated water moves past the existing wells.

“Our problem is we can’t stop it and we can’t get all of it, so it ultimately moves past the wells, and then we’ve got to kind of march downgradient and put some more wells in. They’re getting really close to the Navajo boundary, and so we’re kind of running out of space,” he said.