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Swimmers at chemical risk near salmon farms

Report flags hydrogen peroxide as a possible risk to swimmers near salmon farms on Scotland’s north and west coasts. Salmon Scotland argues that risk is “worst-case scenario”
12 May 2022 , Katie Coyne

Concerns have been raised over the safety of wild swimmers after a report surfaced highlighting the dangers of hydrogen peroxide use in salmon farming.

Salmon Scotland commissioned environmental consultants WCA to carry out the report, published at the end of last year, which was picked up by investigative website the Ferret, and the i newspaper.

The report looked at several chemicals used to treat lice in farmed salmon, but only the hydrogen peroxide was flagged as a possible risk.

It noted that, in high concentrations, the chemical can cause respiratory irritation, skin irritation, severe skin burns and eye damage, and is harmful if swallowed.

But Salmon Scotland insisted the reports looked at an “absolute worst-case scenario, which would not occur in real life”.

“Someone would have to be swimming in the same concentration for more than two hours for the risks to be realised."

A spokesperson continued: “Someone would have to be swimming in the same concentration for more than two hours for the risks identified in the report to be realised.

“This is near impossible given the location of salmon farms on Scotland’s rugged north and west coasts and the fact that hydrogen peroxide rapidly disperses and dilutes after use and breaks down into water and oxygen.

“Hydrogen peroxide is used by environmental agencies to re-oxygenate polluted rivers and is an eco-friendly way of protecting fish from potentially harmful organisms.”

However, the report based its findings on a “standard” 71.8 kg – 11 stone – person, wearing a wetsuit. The effects upon smaller swimmers, including women and children, and those that don’t wear a wetsuit was not considered.

The Scottish Environment Protection Agency (SEPA) did not comment directly on this observation when asked but welcomed the report and said it was awaiting the outcome of a review of the work by environmental experts.

Peter Pollard, Head of Ecology, SEPA said: “All marine finfish farms require a permit from SEPA to discharge medicine residues or other matter into the marine environment and include conditions designed to protect it. Farm operators must comply with these conditions and SEPA independently verifies that they are doing so. Where there is a non-compliance, appropriate and proportionate action is taken.

“As Scotland’s environmental watchdog, SEPA believes that the long-term success of finfish [bony fish] aquaculture sector depends on the protection of the environment being foremost in all the sector’s plans and operations, working together with other users of the marine environment. As scientific understanding of environmental risks improves, it is important this is reflected in how we regulate to protect the environment. We continue to analyse the latest science and apply this to our risk assessment framework for bath medicine discharges.”


Image credit: Shutterstock

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