This could give consumers a lot more confidence in what they are buying. In recent months, a number of states have recommended that pregnant women, women planning to get pregnant within a year and children under 6 years old limit their intake of canned tuna, fresh tuna, swordfish and shark. These fish contain enough toxic mercury to cause developmental and learning problems in children. Most of the mercury that enters lakes, streams, rivers and oceans comes from power plants that burn coal and municipal and medical waste that contains mercury-tainted trash. Fish absorb mercury through their gills or through their digestive systems when they feed, and the poison builds up in their tissue.
Many fish continue to swim chemical-free.
If consumers or members of the industry can test seafood before it hits the dinner table, health threats can be greatly reduced. Kim Janda is a chemistry professor at Scripps Research Institute. Current methods for testing mercury are costly and time-consuming. Janda's four-step method requires only a few hours. The test uses enzymes to separate mercury from the flesh of the fish.