High Contaminants in Farmed Salmon

Title: Global Assessment of Organic Contaminants in Farmed Salmon

Journal Source: Science AAAS

Link: https://www.preventivecare.com/shared/pdf/GlobalAssessmentSalmon-Hites.pdf

Salmon consumption has increased by about 40% over the past two decades. And over half of the salmon that is sold globally is farm-raised. Most of the farm-raised salmon is in Northern Europe, Chile, Canada, and the United States. The annual global production of farmed salmon has increased from ~24,000 to over 1 million metric tons.

The health benefits of fish are clear from our previous findings. But, with such an increase in fish production and consumption, there becomes a need to investigate any harmful effects that result is such a large boom.

Since salmon are carnivorous fish, they bioaccumulate contaminants.

The study conducted on wild and farmed salmon did not report on methylmercury, because in a preliminary study, there was no significant difference in methylmercury levels between farmed and wild salmon. However, they did measure different organochlorine contaminants. They focused on PCBs, dioxins, toxaphene, and dieldrin.

In the experiment, they analyzed salmon samples and salmon feed in a gas chromatograph.

Farmed salmon had significantly higher concentrations of contaminants than wild salmon in thirteen of the fourteen tested contaminants. Furthermore, farmed salmon from the Atlantic Ocean (Europe and North America) had higher concentrations of contaminants than farmed salmon from the Pacific Ocean (South America - Chile). Overall, Europe had the highest concentrations of contaminants, followed by North America and South America.

The high concentrations of contaminants in farmed salmon from Europe could be due to the feed the salmon were given. The concentrations in feed purchased from Europe were significantly higher than those in feed purchased from North and South America.

The levels of PCBs and dieldrin in the farmed salmon do not exceed the tolerance levels set by the FDA. However, the FDA does not consider the health risks of exposure to more than one contaminant. This is worrisome since PCBs, dieldrin, toxaphene, and dioxin are all found in salmon and in especially high concentrations in farmed salmon. The EPA, however, has consumption advice of no more than 1 meal per month for all samples of farmed salmon. This consumption advice is based on the potential cancer risks of consuming PCBs, toxaphene, and dieldrin.

Overall, the experiment concludes that the consumption of farmed Atlantic salmon may pose risks that detract from the beneficial effects of consuming fish.