More and more plastic waste in the sea and in food fish - a health risk?

Plastic in the fish - risks for humans?

Every year, tons of plastic waste land in the oceans and therefore also in food fish. Even in freshwater fish microplastics have been detected. Is this also a health risk for consumers? According to experts, this question can not yet be answered clearly.

Plastic waste in all oceans

In recent years, scientific research has shown that plastic waste can be found in all marine regions. Even in arctic waters, plastic waste has already been discovered. Of course, the garbage also lands in the sea dwellers, which is why again and again plastic residues in food fish are detected. How big the impact on fish and the risks to consumers really are, according to experts but so far unclear.

Every year millions of tons of plastic waste land in the seas. About the consumption of fish, the plastic also reaches humans. What impact this has on consumers, according to experts is still unclear. (Image: coffeekai / fotolia.com)

Effects on the human organism

A study by Austrian researchers has recently roused the public: Scientists have found microplastics in humans for the first time.

As the experts wrote in a statement, "the effects of the microplastic particles found on the human organism" - especially on the digestive tract - but "only in the context of a larger-scale study to be explored".

The fact that the effects of plastic on fish and the risks for consumers are still unclear is now also revealed by the Johann Heinrich von Thünen Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries.

Plastic in stomachs of fish

According to a statement from the institute, an estimated 4.8 million tonnes of plastic waste are added to the sea every year.

Plastics of various origins and sizes are driving the oceans - plastic bottles, bags, scraps of fishing nets, but also tiny particles of weathered plastic as well as cosmetics or detergents.

It takes decades to centuries to shred and decompose, but even then they have not disappeared, but are sometimes found in the stomachs of fish and other marine animals, which they perceive as supposed food.

With as little researched impact as the experts write.

Even in freshwater fish, there is microplastic

According to the information, microplastics are found not only in marine fish such as cod, mackerel and whiting, but also in freshwater fish.

This finding and many other new findings were presented at a two-day seminar to which the project group "PlasM: Plastic waste in marine fish" of the Thünen Institute for Fishery Ecology had invited.

How to assess the risks posed by microplastics (particles smaller than five millimeters) is still in its infancy.

So far, it is not known whether the small particles damage the fish measurable. Bringing together the results of laboratory experiments and environmental measurements remains a challenge for scientists.

Assessment is difficult simply because most studies relate to the effects of microplastics on the digestive tract of fish.

This is the place where the plastics are most commonly found in fish - yet these are usually only one or two particles, depending on the species and location, but also on the detection method used.

"Investigations into the effect of plastic particles on the health of fish have so far been neglected", explains Dr. med. Thomas Lang from the Thünen Institute of Fishery Ecology.

Problem for consumers?

Accordingly, it is also unclear whether the consumption of such fish poses a problem for consumers.

Considering that the digestive tract of fish with the exception of some small fish species such as sprat or anchovy is rarely eaten and the number of particles in the fish is low, the risk based on the facts known today, according to the experts, appears low.

It is still unclear, however, whether the small microplastics (smaller than 0.02 millimeters) in particular will pass into the muscle meat of the fish in relevant quantities and fish will land on our plates in the food.

Therefore, these small particles, which escape the eye of the beholder, may pose the biggest problem. The researchers therefore recommend that they devote more attention to smaller microplastics.

Basics for risk assessment

As part of the PlasM project, for example, experiments with small fish are being carried out, in whose feed plastic particles of various sizes and chemical composition are deliberately mixed.

The Thünen researchers then analyze whether the substances are stored in the tissue and whether they can cause damage.

At the same time, robust marine surveillance analytical methods are being developed to obtain reliable data on microplastic pollution of fish and their environment. This includes information on the leaching of the relevant marine areas.

"Our goal is to develop monitoring methods that are fast but still enable accurate statements," says Dr. Ulrike Kammann, chemist at the Thünen Institute.

Such outcomes are the basis for environmental and consumer risk assessment and are ultimately needed for well-informed policy decisions. (Ad)