Fish feed additive banned in EU found in Tasmanian salmon at levels of concern, researchers say

A fish feed additive banned in the European Union over fears of animal and human health impacts has been found in Tasmanian salmon at worrying levels, experts say which call for stricter regulations.

Dr. Christian Narkowicz, an organic chemist, last year commissioned the National Measurement Institute to test salmon for residues of ethoxyquin.

The compound, a synthetic antioxidant, was developed by Monsanto in the 1950s. It was used to prevent the spontaneous combustion of fishmeal during transport at sea.

The national regulator, the Australian Pesticides and Veterinary Medicines Authority, has set a maximum residue limit for ethoxyquin of 1mg per kilogram of salmon.< /p>

Tests commissioned by Narkowicz found ethoxyquin levels in three brands of Tasmanian salmon were within the maximum residue limits. However, he found that in Tassal and Petuna salmon there were significant levels of ethoxyquin dimer – two ethoxyquin molecules joined together – which forms when the additive undergoes chemical changes.

In the Tassal sample, the ethoxyquin level was 0.34 mg/kg and the dimer level was 1.2 mg/kg, giving a combined rate of 1.54 mg/kg. In the Petuna sample, there was 0.11 mg/kg of ethoxyquin and 0.91 mg/kg of dimer, making a sum of 1.02 mg/kg.

Researchers say maximum residue limits should also take into account ethoxyquin dimer levels.

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"The dimer accumulates to higher levels than ethoxyquin," Narkowicz said.

"Ethoxyquin has a half-life of about a week, but the dimer has a half-life of about 10 weeks. What happens over time [is] most of the ethoxyquin is converted into the dimer."

The dimer is considered to have the same toxic potential as ethoxyquin itself, said Stuart McLean, professor emeritus at the University of Tasmania.

"Ethoxyquin is a parent that produces many other products – a few dozen," McLean said.

"These products form in the fish food itself, but also in the fish, and also in the human eating the fish. Essentially, these other products have been ignored in the safe limit. They only look at ethoxyquin." /p>

The European Commission has suspended the use of ethoxyquin as an animal feed additive in 2017 because "experts could not conclude on the safety of the additive".

The European regulators have also raised concerns that a compound called p-phenetidine, from which ethoxyquin is made, may linger as an impurity in the product.

"P-phenetidine can make up to 3% of ethoxyquin," Narkowicz said. “There are serious concerns about its potential carcinogenicity. There has not been enough scientific data to examine what happens to it in fish or in the environment. studies before EU ban.

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"There are alternatives," McLean said. "It's hard to see why any company would persist in using [ethoxyquin], and regulators really need to review what they're doing with ethoxyquin."

A APVMA spokesperson said ethoxyquin can be legally added to stock foods as an antioxidant, adding that “such uses do not require individual APVMA approval.”

The regulator had not previously undertaken any regulator...