Selenium supplements used to meet the nutrient needs of cattle pose no threat to other rangeland species, according to a recently published report by a team of University of California farm advisors. Most commonly known for its toxic effects on wetland wildlife, selenium is also an essential trace mineral for animal growth and reproduction. Because many regions of the United States, especially northeastern California, have comparatively low levels of selenium in the soil, some ranchers provide their cattle with selenium via injections, rumen pellets or salt/mineral mixes. Fish and wildlife officials have been concerened that the selenium supplements perhaps were being excreted and accumlating in the water supply, posing a potential threat to other rangeland creatures. To investigate that possibility, a team of Northern California farm advisors under the leadership of Glenn Nader, Cooperative Extension farm advisor for Lassen County, launched a UC-funded study, examining water, plant and animal life on four ranches in this mountainous region. They discovered no selenium buildup in the aquatic ecosystems of the ranches, strongly suggesting that supplementing cattle diets with selenium poses no threat to the environment. The study was reported in the September issue of the Journal of the American Veterinary Medical Association.