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Fish contaminants - Example 2: Organic pollutants in salmon"A recent study published in the magazine Science reported on 'Global assessment of organic contaminants in farmed salmon'. Concentrations of 14 chlororganic compounds in farmed and wild salmon were examined. Each of these compounds is thought to cause cancer. The study revealed that all the substances tested were present in higher concentrations in farmed salmon than wild salmon. This applied in particular to fish produced on European farms. Although the levels found were consistent with results from earlier surveys and official controls, the researchers concluded hastily that consumers should tightly limit their consumption of farmed salmon and suggested that anyone who does not want to additionally increase the risk of getting cancer should restrict consumption of one portion of farmed salmon to a maximum of once every two months. On the basis of the identified concentrations of toxic substances, the authors of the study then calculated the portion sizes for wild and farmed salmon that could be consumed without increasing the risk of cancer. The recommended quantities fluctuate strongly depending on the salmon’s origins. Whereas, for example, eight portions (227 g) of salmon from Kodiak (Alaska) could be consumed per month, consumers should not eat more than one portion of Chilean farmed salmon per month, no more than one portion of Norwegian farmed salmon every two months, or one portion of farmed salmon from Scotland or the Faeroe Islands no more than every four to five months. It is these calculations that caused a big stir. The model used for the calculations is highly disputed among scientists and is not specifically intended for calculations on commercially produced fish; it had been developed by the US EPA to estimate how much of their catches could be eaten by anglers who regularly fished in contaminated inland waters. By contrast, commercial products should be evaluated according to the FDA criteria. To refute the model, researchers calculated that on the basis of the PCB contamination levels cited in the study, after 70 years of regular consumption of 200 g of salmon per week the risk of developing cancer for the high-risk group (pregnant women, children, nursing mothers) would be one-hundred-thousandth higher – equal to a rise in risk of 0.0001 percent. By comparison, the risk of dying of a cardiovascular disease by eliminating fish completely from the diet can be as high as 30 percent! It is therefore understandable that the recommendations made by the authors of the Science study to limit salmon consumption met with strong objections in Europe, the United States and elsewhere. Food control and health authorities reacted by announcing that its findings did not raise new food safety issues as the levels were consistent with results from other surveys and official controls. They encouraged consumers to continue eating salmon and other fish, the health benefits of which had been proven beyond all doubt in over 5 000 scientific studies. Unfortunately, the study had already alarmed the consuming public, and retail orders of farmed fish fell by 20–30 percent in countries such as Ireland, Norway and Scotland. A great deal of time and effort were required to restore consumer confidence." Source:
FAO "The State of World Fisheries and Aquaculture, 2004" |
