Idaho cattle fall victim to selenium poisoning

Aug 21, 2009
by WLJ

Idaho cattle fall victim to selenium poisoning

Fifteen to 18 head of cattle grazing near the abandoned Lanes Creek phosphate mine in Caribou County, ID, died in early August from suspected acute selenium poisoning, the USDA’s poisonous plant research lab in Logan, UT, reported recently.

Sheep and horses have died from selenium poisoning in the past after feeding on selenium-tainted vegetation in southeast Idaho’s phosphate mining region, but cattle were thought to be less susceptible to it.

Selenium is a byproduct of phosphate that can leach and be absorbed by plants. Trace levels of the element can be beneficial as a micronutrient, but larger volumes can be toxic.

Kip Panter, the Utah lab’s research leader, said the Bear Lake Grazing Association steers were moved into the area on Aug. 2 and died about three days later. They were among about 500 head grazing on pasture and owned by four different partners. Cattle have been grazing there for many years without incident.

"It doesn’t take long. Acute selenium is very toxic. It affects the heart and lungs," Panter said, adding it also can cause hair and mane loss, plus hoof growth. Pigs and humans can suffer neurological damage from it, but cattle and sheep usually don’t because of their rumen.

A range rider provided liver, kidney and blood samples from the cattle which were analyzed by the Utah State Diagnostic Laboratory on the Utah State University campus in Logan. The samples tested positive for high levels of selenium, Panter said.

While water samples from a nearby creek were normal, purple aster showed 4,000 parts per million of selenium, which is relatively high, he said. Large amounts of rain caused vegetation to grow more lush and high this season than normal.

Thirty-six steers from the infected herd ranging from 650 to 800 pounds were brought into the USDA lab, which bought 10 with the highest selenium levels in their blood at market value. It will take weekly blood samples and do monthly liver biopsies for tracking purposes. It doesn’t appear that any other cattle in the herd have suffered acute poisoning.

The lab ironically worked with the Bear Lake Grazing Association at the same Lanes Creek site 10 years ago to monitor poisonous lupine and larkspur affecting grazing cattle, Panter said. Dan Keetch of the association could not be reached for comment regarding the recent cattle deaths.

Chronic and acute selenium levels can be found in Wyoming, North Dakota and South Dakota, Panter said, explaining that there can be excess and deficient amounts of it found side-by-side in soil. Many plants can absorb high levels of it, but some are better indicators than others.

"Our goal is to figure out how animals can handle it. It’s an interesting issue that’s not going to go away soon," Panter said.

Mining at Lanes Creek was begun in 1978 by the Alumet Partnership, which included National Steel Corp. before it filed for bankruptcy in 2002. Alumet sold the property to the Bear Lake Grazing Association in 1997. The J.R. Simplot Co. leases mineral rights but has never mined there. It did process ore from the mine in the 1980s before mining was suspended later that decade. The company has routinely sprayed against weeds in the area.

Simplot spokesman David Cuoio stated: "The area where the 15 to 20 cattle died is not near any present or past Simplot phosphate mining operations."

It was discovered in 1997 that horses and sheep grazing near southeast Idaho phosphate mining operations were dying of selenium poisoning. As a result, Simplot, Monsanto, Agrium, FMC/Astaris and Rhodia each spent $1 million to conduct an area-wide study in conjunction with the Idaho Department of Environmental Quality (IDEQ).

Several horses died near Agrium’s Mabey Canyon Mine in Caribou Canyon on pasture at the base of a mine dump. Hundreds of sheep also succumbed to selenium poisoning near Simplot’s Conda mine, not far from Soda Springs, ID.

IDEQ Regional Administrator Bruce Olenick said his Pocatello office received a telephone call on Aug. 11 from Simplot alerting it to the cattle deaths east of Monsanto’s South Rasmussen Ridge Mine and north of Simplot’s Smoky Canyon Mine. Simplot officials met with grazing association members on Aug. 10.

"Sheep are more susceptible. We always thought cows were more immune and had higher tolerances for selenium," Olenick said, speculating the plants were eaten later in the year when they had more time to mature and gain higher toxicity.

IDEQ officials visited the Lanes Creek mine site on Aug. 13. Olenick said the private land has been reclaimed, describing it as a "big hump of vegetation," but he said he understood cattle were not supposed to be grazing in the area.

Marv Hoyt, Idaho director of the Greater Yellowstone Coalition, an environmental group, said the recent cattle deaths are another indication of continued problems in the phosphate region. He said the kill should be a wake-up call for federal agencies and mining companies.

Forsaken mines that have not been cleaned up are polluting waterways, vegetation and soil, Hoyt said.

"With these old mines spread across the landscape, who knows what the real effects are on livestock and wildlife?" he asked.

Monsanto is seeking permission from the U.S. Bureau of Land Management to open a Blackfoot Bridge Mine to replace its South Rasmussen Ridge Mine phosphate ore in Caribou County.

Simplot is expanding its Smoky Canyon Mine near the Idaho/Wyoming border, not far from Afton, WY. A U.S. magistrate recently gave it the green light to proceed with the expansion after environmentalists filed a request for a permanent injunction against it. Hoyt said the Greater Yellowstone Coalition plans to appeal that ruling to the 9th U.S. Circuit Court of Appeals.— Mark Mendiola, WLJ Correspondent