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Biocides and copper — sustainability in practice

Copper-based net impregnation has been the best-documented tool against fouling for four decades. Here are the facts on how it works and why it's the safest choice for fish, users and the environment.

Did you know that 100% of the biocide in Netwax net impregnations comes from recycled metal? Both the nylon and copper oxide in retired nets can be recycled. See the film for the full story.
100 %
Recycled metalAll biocide in Netwax
95 %
Global antifouling marketUses copper oxide
40+
Years in industryProven and documented
EU
BPR-approvedEU Chemical Regulation
Safe for fish, humans and environment

Approved by the EU — assessed safe

NetKem's copper-based net impregnations are approved under the BPR – the EU Chemical Regulation. That means you can be confident the products have been thoroughly evaluated and assessed safe — for humans, fish and the environment.

How it works

Fact and fiction in the copper story

For four decades, copper-based net impregnation has been one of the most effective tools the aquaculture industry has had to prevent fouling on farming nets. Did you know that all copper in net impregnations is recycled, and that when the net is retired the copper can be reused?

Net impregnation uses copper oxide — a harmless form of copper. The impregnation creates a protective shield around the netting. In contact with seawater, copper ions begin to leach out — this is what prevents fouling.

Copper in ion form is highly reactive. Which is why it works against fouling. But this same property means the ions are quickly — and within a fraction of a millimetre from the netting — converted into other, non-active compounds.

Copper occurs naturally in seawater — making it nearly impossible to distinguish copper from net impregnation from natural copper. Beneath the net, in the sediments, the bioavailability of copper is sharply reduced: insoluble sulphide compounds form and the copper is "deactivated".

In general terms, the vast majority of net particles that end up on the seabed come from high-pressure washing. Any cleaning should therefore be done as gently as possible — and that applies to all impregnation types.

Three options

As operations manager, you have three choices

Each choice has consequences. Here's an honest comparison.

Copper oxide

Well-documented and proven. BPR-approved. Lowest environmental and HSE burden of available alternatives.

Other anti-fouling biocides

Less documentation. Uncertainty around environmental effects, fish health and long-term consequences.

No impregnation

Frequent washing. High operating costs, lower growth, stressed fish and increased microplastic in the sea.

The conclusion

The best-documented option

Despite intensive efforts to find alternatives, copper oxide remains the impregnation method with the lowest environmental and HSE burden. Used correctly, copper-based impregnation is the best-documented — and safest — option.

It's time to separate fiction from fact.

Learn more

Questions about copper and biocides?

We've gathered the most common questions and answers about how copper works, its safety and environmental effects on a dedicated FAQ page.

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