Farmed salmon consumed in the United States may contain high levels of cancer-causing polychlorinated biphenyl (PCBs), said the Environmental Working Group (EWG). Salmon farming has made salmon the third most popular fish in America-and compromises 22 percent of all retail seafood counter sales, according to the environmental group.

In the meantime, the group recommends that consumers choose Wild Alaskan Salmon instead of farmed salmon.

The group bought and tested farmed salmon from 10 local grocery stores in Washington, San Francisco, and Portland, Oregon, and found seven of 10 fish were contaminated with high levels of PCBs.

“These first-ever tests of farmed salmon from U.S. grocery stores show that farmed salmon are likely the most PCB-contaminated protein source in the U.S. food supply,” the group, a nonprofit organization that investigates environmental matters, said in a statement.

“EWG’s analysis of seafood-industry fish consumption data shows that one quarter of all adult Americans (52 million people) eat salmon, and about 23 million of them eat salmon more often than once a month,” the group said in a statement. “Based on these data we estimate that 800,000 people face an excess lifetime cancer risk … from eating farmed salmon.”

Adults eat enough PCBs from farmed salmon to exceed allowable lifetime cancer risk 100 times over.

“In the case of farmed salmon, you have high-density fish pens off the coast of British Columbia, for example, where you have an environment that is relatively pristine but these fish are fed fishmeal from all over the world,” EWG Vice President for Research Jane Houlihan said in a telephone interview with Reuters.

Often this fishmeal is heavily contaminated with PCBs, Houlihan said. “On top of that, the fish farming industry produces fish with up to twice the fat of wild salmon,” she added.

(via Reuters)