SALT LAKE CITY - Federal officials are raising concerns about the amount of selenium a new state limit would allow in the Great Salt Lake.

Selenium is a naturally occurring mineral that also turns up in sewage discharge and industrial operations. It builds up in the environment and at high enough levels can cause deformities and other reproductive problems in certain birds.

State officials say the new regulation would protect most birds at the lake from harmful levels of selenium. The levels could lead to mortality in one of 10 mallard duck eggs.

The U.S. Fish and Wildlife Service, in a letter to the U.S. Environmental Protection Agency, says that 10 percent mortality could violate the international Migratory Bird Treaty Act.

The EPA has yet to approve the new standard.