Politics threatens FDA mercury assessment.(safe mercury levels in fish debated at Food and Drug Administration)(Brief Article)

A political battle is brewing over whether FDA should lower its mercury "action level" for seafood and tighten its consumer advisories. If the FDA makes those moves, the U.S. market for large predatory fish like tuna, swordfish, sharks and grouper would likely be closed, and more than $1 billion worth of seafood sales would be lost.

Mercury spews into the air each day from factories, power plants and volcanoes and often ends up in water, where microorganisms convert it to methyl mercury. From there it can move up the food chain to fish -- and eventually to humans. Mercury is ubiquitous, but too much is poisonous. The question is: how much is too much?

The EPA says we can safely absorb 0.1 microgram of methyl mercury per kilogram of body weight per day. EPA uses this so-called "reference dose" for environmental regulation, but the gist is that eating fish twice a week can be risky. Others disagree. The Agency for Toxic Substances and Disease Registry has said 0.3 microgram of methyl mercury per kilogram of body weight per day -- three times the EPA standard -- is safe.

Food agencies say it differently. The World Health Organization's seafood guideline equates to five times the EPA standard. FDA takes a similar approach, setting its methyl mercury "action level" for seafood at 1 ppm. In addition, because mercury levels in seafood vary, and some people are more vulnerable than others, FDA advises pregnant women and women of child-bearing age to limit consumption of fish with higher levels of mercury, such as swordfish and shark, to once a month.

State ...