Dec. 18, 2008 -- Actor Jeremy Piven has ended his role in the Broadway revival of the David Mamet play Speed-the-Plow after being diagnosed with a "high mercury count." Mercury is an element found throughout the environment. High levels of exposure to mercury can harm the brain, heart, kidneys, lungs, and immune system of people of all ages, especially fetuses, according to background information from the Environmental Protection Agency (EPA). WebMD spoke with Carlon Colker, MD, FACN, FACSM, who is treating Piven. Colker is the chief executive officer and medical director of Peak Wellness Inc. in Greenwich, Conn., and Beverly Hills, Calif.

Does Piven have mercury poisoning? "The word poisoning implies some surreptitious act, like we poison rats," Colker tells WebMD. "The proper term is mercury toxicity. And the answer is 'yes' to mercury toxicity." Colker says Piven's original mercury level was "shockingly elevated" at nearly six times the upper tolerable limit and the highest Colker had ever seen in his practice. "You can imagine how stunned I was," Colker says.