Scientists are warning that salmon from European fish farms is so contaminated by cancer-causing chemicals that, in the worst cases, it should not be eaten more than three times a year. The research, published in the US magazine Science, was co-authored by David Carpenter, director of the University of Albany’s Institute for Health and the Environment.
American and Canadian researchers took samples from 700 wild and farmed salmon purchased from shops in North and South America and Europe. The fish were tested for levels of 14 toxic chemicals known to be carcinogens, such as polychlorinated biphenols (PCBs), dioxins, dieldrin and toxaphene. These are among the so-called "Dirty Dozen" of persistent industrial pollutants, outlawed by an international treaty signed in 2001, that linger in the environment and build up in the fatty tissues of fish and marine mammals.
In the wild, salmon eat smaller prey in the sea, but in commercial farms this is substituted with pellets containing oil and fish meal manufactured from wild fish - which adds to the stock depletion problem. One tonne of farmed salmon requires four tonnes of wild fish.
Salmon farming is now a worldwide industry, and the consumption of the fish, once a luxury food, has increased 40 times in the past 20 years. The annual growth rate is 14% in the EU and even higher in the US. At the same time prices have plummeted, putting salmon alongside herring as the cheapest fresh fish in most shops.
Food safety officials have emphasized that the health benefits of eating oily fish, such as salmon, twice a week outweigh the concerns of toxins. Fishing industry sources also reject the criticism, stating that the toxins in salmon were within safety levels set by the EU and the WHO. Guidelines set by the US Environmental Protection Agency have been reviewed recently and become stricter.
University of Albany News Release, ’First Global Study Reveals Health Risks of Widely Eaten Farm Raised Salmon’.
