Solutions elusive to mercury problem

Solutions elusive to mercury problem

Dec 8, 2001

By Janelle Holden
Journal staff writer

Killing predatory fish in McPhee and Narraguinnep reservoirs would help solve the reservoirs’ mercury problems a lot faster than reducing the amount of mercury settling into them.

That’s what Janice Sheftel, attorney for the Dolores Water Conservancy District, told state and federal environmental health officials at a stakeholders’ meeting in Dolores on Thursday.

"If you take the several hundreds of thousands of dollars spent on the study to get rid of the fish, you’d get rid of the problem," said Sheftel.

Sheftel’s solution was just one of many proposed by the crowd of over 60 who gathered to hear officials present the scientific support for developing a Total Maximum Daily Load for Mercury in McPhee and Narraguinnep.

According to a recent Environmental Protection Agency study of the reservoirs, 3,049 grams of mercury per year settles in McPhee, and 78 grams per year settles in Narraguinnep.

The inorganic mercury is then converted to dangerous methyl mercury by bacteria and fungi, and "bioaccumulates" in fish through the food chain.

Mercury has been a long-standing problem in the reservoirs. The Colorado Division of Wildlife began posting fish-consumption warnings in the early 1990s after high levels of methylmercury were found in fish tissue samples.

The warnings, devised by the Colorado Department of Public Health and the Environment, don’t recommend avoiding fish altogether, but urge recreationists to limit, on a monthly basis, consumption of northern pike, walleye, channel catfish, largemouth bass, black crappie, Kokanee salmon, and rainbow trout.

Older and larger predatory fish contain higher amounts of mercury, and are more dangerous to consume than smaller fish

At greater risk are pregnant and nursing women, children, and women of child-bearing age. Not only should these women watch their intake of fresh-water fish from the reservoirs, but the U.S. Food and Drug Administration has advised them not to eat shark, swordfish, king mackerel, and tilefish.

Methylmercury is a possible carcinogen, and poisoning can result in kidney failure, stillbirths, early abortions, decreased conception, personality changes, decreased muscle coordination, memory difficulties, tremors, and other nervous system failures.

High levels of methylmercury in fish do not mean water from the Dolores River or the reservoirs also have high levels of mercury.

Mercury levels in the water are under the state standard, and Greg Brand, the Durango district engineer for the state Water Quality Control Division, reassured the crowd that Dolores, Cortez, and Montezuma Water Company have not detected any mercury in their potable-water systems.

But because of the mercury in the fish, McPhee and Narraguinnep are listed by the state as impaired waters.

And as a result of a recent settlement agreement following a lawsuit by Earthjustice, an environmental group, the state is required to come up with a TMDL document by June 30, 2002.

The document will not only list how much elemental mercury can safely settle into the reservoir, but will also point a finger at the source — both point and non-point sources.

Pointing fingers at non-point sources of pollution is what had many members of the audience concerned, including members of the water conservancy, who fear the EPA and/or the state would shut off tributaries to the Dolores River or prohibit the transfer of water from McPhee to Narraguinnep in order to reduce mercury-loading.

According to Phil Hegeman, the TMDL coordinator, the state and the EPA do not have the authority to regulate non-point source pollution, change land-use practices, or change flows between McPhee and Narraguinnep or into McPhee. The only thing the state can regulate is permitted point-source pollution.

Hegeman said once the source of the problem is found, the state is hoping for voluntary compliance and Good Samaritan cleanup.

Steve Harris, the water district’s engineer, pointed out that the language of the technical study that is being used as a scientific basis for developing a TMDL document is misleading and should be changed to clarify that water transfer from McPhee to Narraguinnep will not be hindered.

The initial technical study was completed by environmental consultants Tetra Tech, Inc., this fall, who studied mercury levels in the reservoir, in reservoir fish, and in the watershed in 1999.

"There’s not one smoking gun," said Jon Butcher, from Tetra Tech. "There’s not one big source that we can go out and focus on, unfortunately."

Hegeman agreed, admitting earlier, "We don’t have nearly as much data as we would really like before we finalize the TMDL."

But, he said, the TMDL would be done in phases, and if the funding comes through, more studies would be completed before it is finished, and before health officials request a reduction in mercury pollution from specific sources.

For right now, TetraTech’s study says several things contribute to mercury in McPhee: a history of mining in the watershed, natural geology, transfers of mercury from McPhee to Narraguinnep, and mercury deposited from the air and in snow packs.

"I think we can say with a great deal of confidence that there is a component that is human-induced as well as a component that is natural," said Hegeman.

"It’s clear that the geology here does contribute to the mercury (levels)," Butcher said.

Other sources of mercury could come from watershed hot springs, and forest fires.

Members of Citizens for Accountability and Responsibility, a group opposed to gravel pits along the upper Dolores River, asked if mercury in the flood plain— especially if it is disturbed, could contribute to the overall mercury-loading.

Butcher said the study did not include floodplain mercury, but it could contribute to the overall problem.

Although not technically a permitted point source, the only point-source pollution that could be cleaned up is tailings from the Rico Argentine mine, on the Upper Dolores River.

But the mining point sources don’t appear to be a significant source of the mercury-loading in the reservoir, so cleaning it up won’t really make a marked difference, said Butcher.

The San Juan and Four Corners power plants also put out nearly 500 kilograms of mercury per year, but it’s "not clear that those plants are continuing on any large-scale mercury deposits in the area — maybe some, but not big contributors because mercury is in its elemental form," said Butcher.

Elemental mercury can travel long distances in the air — from as far away as China and Russia.

The uncertainty of the study is what bothers the water-conservancy district and Sheftel, who think it’s unfair to act on the TMDL in June before the study is not complete.

They, and many others, also believe that most of the mercury may be coming from natural geologic sources rather than human pollution and thus will be impossible to reduce.

Sheftel said on Friday that if the large, predatory fish were eliminated from the reservoirs, perhaps through a bounty that the water-conservancy district would offer, the state would have to lift the impaired-water listing for McPhee and Narraguinnep and thus would have more time to complete the study before the TMDL was implemented.

For right now, however, the state is planning to complete the TMDL and start addressing the mercury problem.

Hegeman said the Phase 1 TMDL document will likely be completed in February and a 30-day public-comment period will follow.