Heavy Metal and Chemical Toxicity
Minefield Out There
Minefield Out There
By Kate Ramsayer / The Bulletin
Published: March 23. 2008 4:00AM PST
What are the risks?
If someone is exposed to too much mercury, it can case a variety of neurological problems, including cognitive defects, inflammation of the nerves and tremors, as well as neurological damage to a developing fetus . If people hold it in their hand, however, it’s not very likely to be absorbed through the skin unless the skin is wet. The biggest danger, said Christopher DiGiulio, a doctor with Cascade Occupational Medicine, is inhaling it in gas form or drinking water from a contaminated supply. “If it’s not in gaseous form, and you’re just walking on it with boots, it’d be very hard to get poisoned,” he said.
Mercury mines and the DEQ
The DEQ is eyeing some of the mines in its database for cleanup. Of those are four major ones:
1 – HORSE HEAVEN MINE
Horse Heaven Mine, which operated between 1934 and 1958, produced 17,216 flasks of mercury. (A flask is 76 pounds of mercury. ) At its peak, the mine employed so many people that it had its own post office east of Madras. A mercury-removal project is under way at the mine.
2 – INDEPENDENT MINE
About 30 miles east of Prineville, the Independent Mine extracted cinnabar — the main ore of mercury.
3 – MOTHER LODE MINE
About four miles from the Independent Mine, the Mother Lode operated on and off between 1906 and 1972. Canyon Creek runs by the site, and sediments in the stream were contaminated with mercury when they were tested in the 1990s.
4 – BLUE RIDGE MINE
Blue Ridge Mine was first developed in 1930, and over the next several decades, miners produced between 271 and 301 flasks, according to the DEQ.
Though not a hazard to hikers or campers anymore, mercury deposits left along the Ochocos pose a serious threat to nearby waterways. And for the DEQ, cleanup often is a matter of funding.
The mercury miners dug into the slopes of the Ochoco Mountains in the early 1900s, searching for ore rich in the heavy metal.
Once they got a hold of the mineral-rich rock, they heated it in special ovens, extracting and then cooling the vapor to get drops of liquid mercury.
Although the mining stopped decades ago, some mercury traces remain at sites scattered across private and federal lands.
The Oregon Department of Environmental Quality, the U.S. Forest Service and others have done cleanup work at the worst spots that posed an immediate threat. For people hiking or riding in the Ochoco National Forest, the amount of the metal, a neurotoxin, in the dirt surrounding most of the old mines shouldn’t pose a health concern.
Still, there are about a dozen sites where officials would like to see potentially contaminated soil tested and removed so the mercury hasn’t spread into nearby waterways, harming aquatic ecosystems.
But in many cases, getting the work done is a matter of funding.
“There’s mines everywhere, and it’s very competitive on what people want to spend their money on,” said David Anderson, eastern region mine coordinator with the DEQ. “Our goal is to reduce the human health issues, and primarily it’s been on fencing signs, closing the adits (mine shafts) and physical hazards rather than chemical hazards.”
The DEQ is working on a report about how the mining history in the region could impact the ecosystem, though, and could use those results to get funding for additional projects.
The mother lode
Mercury mining picked up in Central Oregon in the 1930s, said Steve Lent, an assistant director at the Bowman Museum in Prineville.
“Prior to that, everyone was looking for gold and silver,” Lent said. “But in the process, they did find a lot of cinnabar deposits, which is where they got mercury deposits from.”
The big mines were in the Ochoco Mountains, like the Mother Lode Mine and the Horse Heaven Mine east of Madras. Horse Heaven even had a post office because there were so many miners working there, he said.
The mercury was collected, drop by drop, in a flask — the unit of measurement for the liquid metal, each one weighing 76 pounds — and was used in the gold- and silver-mining process, he said.
“A lot of those guys didn’t take much precautions — they were probably breathing in a lot of mercury fumes,” Lent said. “It definitely left contaminants as a result of those operations.”
The mining operations started slowing down around the 1950s, he said, as alternatives to the metal were found.
And in the mid-1980s, the Forest Service started looking into abandoned mines, and their potential for chemical contamination, said Bob Fujimoto, group leader for minerals and geology with Region 6 of the Forest Service, which includes Oregon. With the state geology department’s help, the Forest Service located about 500 mines.
“Since there are so many, and since there are limited funds, we thought, ‘How can we prioritize?’” he said.
In the Ochocos, the mercury mine that got first priority was the Mother Lode, where the Forest Service did cleanup work in the late 1990s.
“We knew there was mercury in concentrations in the soils that is potentially harmful to humans if they were recreating in the area,” he said, noting that there was a popular trail that went by the mouth of the mine.
But “the sites that are left, you would have to be living in that dirt, and not washing your hands and eating” to get sick, he said.
In addition, there was mercury in the water nearby, which eventually drained into a reservoir.
Sampling at the site found up to 22,000 milligrams of mercury per kilogram of soil, Fujimoto said. The standard for what it should be to protect campers at the site is 500 mg/kg, and the standard for folks just walking through is 11,000 mg/kg.
The agency cleaned up the site so there wasn’t more than 2,000 mg/kg, he said, and also removed some of the old equipment that had been used to mine the mercury.
More work needed
DEQ also looked at what was left behind from numerous historical mine sites, starting its testing with the mines that produced the most mercury or were closest to people or sensitive fish populations.
In the areas where miners had processed the ore — heating and then cooling and then collecting the metal — samplers found the highest concentrations, Anderson said. And that’s where the cleanups were focused.
“Those primarily have been addressed,” he said, noting that two in Southeast Oregon are scheduled to be cleaned in the next couple of years. “The level of risk is reduced by 90 percent.”
The Forest Service and Bureau of Land Management conducted several of the Central Oregon mine cleanups, and a company is working on a mercury-removal project at the Horse Heaven Mine as well, he said.
The Forest Service actually got lucky, said Carrie Gordon, a geologist with the agency, because there aren’t many sites where ore was actually processed in the Ochoco National Forest, compared with other areas.
Cleaning up the concentrated mercury is an important thing to do, said Tim Lillebo, with the conservation group Oregon Wild, because if the chemical makes its way into small streams it can really play havoc with the ecosystems there. Still, he said he did not know of any instances in the Ochoco Mountains where mercury contamination from mining activities had caused significant damage to the watersheds.
The agency is now working on a project to clean up an old gold mine in the area, Gordon said, and is considering taking another look at the Mother Lode Mine as well to make sure the original work got the job done.
There are 10 to 15 sites that could either use more sampling to identify potential trouble spots or more cleanup, Anderson said, and some are on private land. In those places, the problem is often that water passes through the site, potentially spreading mercury contamination into aquatic habitats.
At the Maury Mountain Mine, for example, where 181 flasks of mercury were produced, mercury-contaminated soil could be eroding into surface water, and the area is next to redband trout habitat, according to a report in a DEQ database.
Or at the Byram Oscar Mine, some of the soil had mercury at 3,600 parts per million, and there was a pathway between the site and a creek, according to the DEQ database.
“It does have a problem and needs more work; we just don’t have the money,” Anderson said of the Byram Oscar Mine.
There’s also an old mercury mine on Barnes Butte, he said, but a voluntary cleanup program agreed to by developers interested in building near the site has been put on hold until the housing market picks up.
The cost for testing or cleaning up a mine varies, he said. Sampling can cost a couple thousand dollars or $50,000, and the cleanup can range from hundreds of thousands of dollars to several million dollars for major efforts, he said.
The DEQ is currently working on a study that will take a look at the overall effect of mercury mines in the Ochoco Mountains.
It’s hard to tease out whether mercury is present because miners dug it up and concentrated it on the surface, he said. And if the watersheds are damaged, it’s hard to tell what might be from mercury and what might be from other environmental problems, he said.
But Anderson said he hopes the report will help bring funding to projects that would do things like measure the mercury levels in the Ochoco Reservoir.
And the return of salmon and steelhead to the Crooked River, planned as part of the relicensing of the Pelton Round Butte dam complex, could help with funding to clean up the sites as well, he said. There are groups that are focused on improving habitat for those fish species, which might be able to help with the projects.
“In my mind, I hope we would get to them,” he said of the remaining mines and prospecting sites. “I think we’ll eventually get to them. What eventually means in years, I don’t know … There’s always going to be something that needs money.”
Kate Ramsayer can be reached at 617-7811 or firstname.lastname@example.org.