Uranium mining’s legacy

Copyright © 2009
Gallup Independent
By Kathy Helms
Diné Bureau

GRANTS — Data reviewed by an independent team of scientists and engineers contracted by U.S. Environmental Protection Agency to evaluate the remediation system at Homestake Mining Co.’s uranium mill site has raised a number of issues.

William Thompson, senior hydrologist for Environmental Quality Management Inc. of Cincinnati, said the Remedial System Evaluation team looked at what Homestake was doing right, and what it might be doing wrong in its cleanup of the Superfund site.

With regard to the tailings pile, water is injected to flush contaminants out of the rock strata, then collected and drained in wells. “The question is, how effective is this process,” Thompson told a group of concerned residents during a community meeting conducted Wednesday evening in Grants by EPA and the New Mexico Environment Department.

“The information that we’ve gotten and have seen from their reports indicate that they have calculated almost half a million pounds of contaminants have been removed from the large tailings pile to date. We don’t know how many pounds are ultimately there.”

Thompson explained that Homestake utilizes a system of wells and trenches to emplace water of better quality. About 1,200 gallons per minute of water is taken from the San Andres aquifer to help them isolate the most contaminated water in the immediate vicinity of the tailings pile.

“The injection is operated in conjunction with a series of extraction wells to allow them to establish a balance between the migration of the water and the contaminants throughout the system. That’s in the Alluvial aquifer. In the Chinle aquifers they’re doing an injection program and a pumping program as well,” he said, which is expected to continue until 2017.

As part of the program to clean up the groundwater Homestake generates water that needs to be treated. The most contaminated water from the Alluvial aquifer and some water from the large tailings pile is taken through a water treatment system frequently termed “reverse osmosis,” though a little more complex, to remove contaminants, Thompson said.

Homestake then reinjects that water in close proximity to the large tailings pile to isolate the contamination. Evaporation ponds also are used. “Not only do they use the ponds themselves to evaporate water, but water is sprayed into the atmosphere and allowed to evaporate that way.” A third treatment component is an irrigation system.

After reviewing data on these processes and making a site visit, the team came up with a series of issues. One is that work on the tailings pile contaminant reduction might not be completed by the target date of 2012.

A more difficult question, he said, is how did the Chinle aquifer become contaminated. While the Alluvial aquifer was contaminated principally by direct infiltration, the Upper, Middle and Lower Chinle aquifers were contaminated when contaminants in the Alluvial aquifer migrated to points where they came into contact with the Chinle.

“There was contamination in the Alluvial aquifer and it was able to be drawn down into the Chinle aquifer,” Thompson said. “As a second mechanism of contamination of the Chinle aquifer, there are a lot of wells that are in operation at the site by the residences in the area and those can serve as conduits from which the contamination can migrate downward from the Alluvial aquifer to the Chinle aquifer.”

While residents may have reasons to keep those wells operating, Homestake is going to have to evaluate a program that is going to allow a balance, he said.

“The easy answer, which you don’t want to hear, is turn it all off. Take away that driving force. I know that’s not something that anybody wants to do, and I’m not saying specifically that it has to be done, but it’s going to have to be very carefully considered as part of their remedial program.”

Resident John Block questioned whether there had been any effort made to try to understand what might be concentrated in the soil that’s being irrigated with water from the treatment process. “You did indicate there is a contamination level of some kind in the liquid they’re applying. I’m wondering if you keep applying it for say, 25, 30, 40 years, does the uranium or other materials in there at a low level slowly concentrate into the soil and actually become a cumulative hazard of some kind?”

Thompson said that, too, was identified as an issue. “The question is what is the accumulation of metals.” He said the information they reviewed showed that currently the concentrations do not present a potential health risk, however, “we recommend that Homestake undertake the necessary studies to better understand what that concentration is, and if necessary, implement a remedial program for soils contaminated as a result of that process.”

Johnnie Head, a resident of Murray Acres, told agency representatives, “I think what you’re not facing is the only way you’re going to cure the problem is to move that tailings pile and get it out of there, because it’s going to continue to seep and contaminate and spread, and that’s just a fact.

“And the other thing that I really don’t understand — and I realize I don’t have a degree — but I do not understand how you can in good conscience set our standard of water above what should be good drinking water — even what it was when you first said it was bad; and now we’re going to have a higher level of contamination. How can you in good conscience do that?

“The standards are being raised to suit something that you can’t seem to think you can bring it down to where it should be. I don’t understand why we should feel better about that.”

Alan Cox of Homestake said the Nuclear Regulatory Commission set the background standards about three years ago and the other agencies agreed to the change. “In relationship to the objective that we ought to be cleaning the site up to where there’s drinking water standard water in the ground downgradient from the site when we are done at the end of the day, it’s not appropriate,” he said.

Water monitoring samples upgradient from Homestake “show that that water is above drinking water standards, whether you want to talk about federal drinking water standards or state drinking water standards, and that’s one of the things that’s so contentious here. People downgradient of the site have the expectation that they should have drinking water standard groundwater,” he said.

Milton Head told the group that when EPA first announced in 1975 that there was contamination in the Alluvial aquifer, there were no monitoring wells to develop background data.

“So, let’s go from there. They tell us in ’75 that we’ve got this pollution that’s halfway into Broadview Acres, it’s into a portion of Murray acres, and it’s clear across the site. In our discussions with NMED and EPA at that time, we suggested some options,” he said, including that monitoring wells be put in ahead of the contaminant plumes to develop background data.

“We’ve asked for it hundreds of times since, and even today we don’t have monitoring wells to develop background data ahead of the plume down there close to Milan. They’ve never put one in.”

Laura Watchempino from the Pueblo of Acoma Haiku Water Office asked whether the construction of Homestake’s wells was investigated to determine whether those might also be spreading the contamination.

“The other thing you mentioned was other aquifers besides the Alluvial aquifer that was contaminated. Nobody has mentioned any water samples or studies done on the San Andres aquifer that is being used, or is proposed to be used for part of this remediation. ... I think it’s really critical that samples be taken right now to see what background we can get from that before it’s used as part of the remediation.”

Chris Shuey of Southwest Research Information Center took issue with Thompson’s statement that the contaminant plume is getting smaller. “There are several thousand acres now that have contaminant plumes under them, and that’s hugely different from 1961 and 1975. So, in fact, it has gotten bigger. It has gotten huge; and it keeps getting huge.”

He also questioned Thompson’s statement that the remediation system is preventing contaminant plumes from reaching residences, stating that a report from the Environment Department issued in June stated that 18 of 24 residential wells in the Alluvial aquifer exceed safe standards for uranium. One out of two Upper Chinle wells also exceed, as do six out of 10 Middle Chinle wells, three out of 13 Lower Chinle wells, and one out of three San Andres wells.

“We don’t want contamination to reach the San Andres. We don’t want to have to wait until you get monitoring data that says, ‘Oh, it’s contaminated’. We want to prevent contamination. That’s a hallmark of our water quality act.”