The federal government's School Lunch Program is being is urged to phase out purchases of canned tuna because of concerns over exposing children to mercury.

The Mercury Policy Project, an advocacy group that works to to eliminate mercury use and reduce mercury exposure, made the recommendation in a report, “Tuna Surprise,” that conducted tests on canned tuna sold to schools.

“Canned tuna is overwhelmingly the largest source of U.S. Children's methylmercury exposure, and some children's overall mercury dose is clearly high enough to raise substantial risk concerns,” the study's executive summary states. “There is no sound reason why taxpayer dollars should be used to subsidize any part of this risk.”

The report urges schools to find alternatives to canned tuna.

“Over time, canned tuna can be replaced with low-mercury seafood (e.g., salmon, shrimp) and other protein sources,” the study says.

The project tested the mercury content of 59 samples, representing eight brands of tuna sold to schools in 11 states. It concluded that albacore or "white" tuna had much higher mercury levels than did "light" tuna, and mercury levels in both types were highly variable.

“We have to make sure the risks from mercury in tuna don't outweigh tuna's benefits,” says Sarah Klein, staff attorney in the Food Safety Program at the Center for Science in the Public Interest, which co-released the report. “We're urging parents and schools to limit children's tuna consumption and, when they do serve it, to choose lower-mercury options."

The study points out that because tuna is a low-fat protein source popular among children, schools may be tempted to serve it more frequently to meet more stringent nutrition standards for school lunch.

Other recommendations from the Mercury Policy Project:

  • Children should not eat albacore tuna. Albacore or "white" tuna contains triple the mercury level of light tuna.
  • Children weighing more than 55 pounds should not eat more than two servings of light tuna per month.

  • Children up to 55 pounds should consume no more than one tuna meal per month. Because of their smaller body size, an added margin of caution is appropriate for younger children.

  • No child should eat tuna every day.

  • Parents should monitor their children's canned tuna consumption at school and ensure that the total consumed at home and at school does not exceed the recommendations for exposure.