Researchers have detected trace amounts of tralopyril, an antifouling agent, in farmed salmon fillets during a laboratory test.
Tralopyril is used to replace copper in fish farming net pens, and this is the first time it has been found in salmon. The detected levels are extremely low, just above the measurable threshold, according to Bjørn Einar Grøsvik, a scientist at the Norwegian Institute of Marine Research (Havforskningsinstituttet).
Although the concentrations are minimal, Grøsvik calls the discovery concerning due to the lack of data on the impact of tralopyril, which is not naturally occurring and has no established safety limits for food products or animal feed.
In addition to salmon, tralopyril has been found in species such as blackmouth catshark, mussels, and krill. Grøsvik compares it to other treatments used in the aquaculture industry, such as sea lice medications, which have regulated safety levels, noting that tralopyril lacks such guidelines.
A 2023 EFSA risk assessment highlighted knowledge gaps, with only one rat study available for comparison. The levels found in salmon were significantly lower than those that caused health effects in the study.
