Narrator: This is Science Today. Mercury is similar to lead in that high exposure causes neurological problems. Mercury poisoning can also impair brain development in fetuses and young children, leading to learning deficits and other problems. Russ Flegal, a professor of environmental toxicology at the University of California, Santa Cruz, says the toxic effects of mercury have been known for quite a while.Flegal: The Mat Hatter in Alice in Wonderland was mad because they used mercury in making felt hats and so the history of mercury as a toxin has been known for hundreds of years. But the magnitude of mercury s a neurotoxin has only been recognized at the low levels within the past decade.
Narrator: Because of this, there's been a lot of concern about eating fish with higher levels of mercury - such as swordfish, shark and tuna. Federal agencies suggest eating these fish no more than once a week. Yet Flegal says people shouldn't feel they need to stop eating fish altogether.
Flegal: Fish is a terrific source of protein and so to say that people shouldn't eat fish, the disadvantages of that may outweigh the advantages of getting that protein source.
Narrator: For Science Today, I'm Larissa Branin.