Environment

If you don't want to eat microplastics, sea bass may be the way to go

If you don't want to eat micro...
Although the research was conducted on sea bass (pictured), the scientists believe that their findings could be applied to other bony or cartilaginous fish
Although the research was conducted on sea bass (pictured), the scientists believe that their findings could be applied to other bony or cartilaginous fish
View 2 Images
Although the research was conducted on sea bass (pictured), the scientists believe that their findings could be applied to other bony or cartilaginous fish
1/2
Although the research was conducted on sea bass (pictured), the scientists believe that their findings could be applied to other bony or cartilaginous fish
A microscope image of the microplastic particles, which were mostly excreted but also found in the fishes' bloodstreams
2/2
A microscope image of the microplastic particles, which were mostly excreted but also found in the fishes' bloodstreams

For some time now, there have been concerns that microplastic particles eaten by fish could be passed along to human seafood consumers. According to a new study, though, such may not be the case with sea bass, and possibly not with many other fish.

Currently found in both freshwater and marine waterways around the world, microplastic pollution takes the form of tiny plastic particles that enter the environment from sources such as disintegrating trash, aging tires, synthetic fabrics, and personal care products including shampoo and cosmetics.

Unfortunately fish do eat these particles, which pass through their digestive system and often even enter their bloodstream. It has therefore been surmised that when people eat the flesh of those fish, they may also be consuming microplastics that are present in the tissue.

In order to gauge the likelihood of this happening, a study was recently conducted at Germany's Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research. Led by Dr. Matthew Slater, the scientists started with a lab-based group of adolescent European sea bass (Dicentrarchus labrax), and fed them fish-feed pellets laced with a microplastic powder for a period of 16 weeks.

While the pellets themselves contained fish meal, wheat bran, vitamins and fish oil, the powder consisted of yellow-orange fluorescing plastic particles measuring one to five micrometres in width – this represents the smallest size category of microplastic pollution. It is estimated that each fish ingested about 163 million of the particles over the 16-week period.

The researchers subsequently gutted and filleted the animals, then heated the fillets in caustic potash, causing the muscle tissue to dissolve into a fluid. That liquid was then passed through a filter which captured any plastic particles that might be present. A fluorescence microscope was used to count those particles.

A microscope image of the microplastic particles, which were mostly excreted but also found in the fishes' bloodstreams
A microscope image of the microplastic particles, which were mostly excreted but also found in the fishes' bloodstreams

It turned out that for every five grams of fillet, only one to two particles were present. Even those may have been located in residual blood that was left in the fillet, as opposed to in the actual muscle tissue itself. What's more, even though the fish were exposed to microplastics concentrations far higher than what they would encounter in the ocean, they grew well and were reportedly in perfect health.

"I believe the sea bass results provide some indication of the response of other marine finfish to microplastic ingestion, however this remains untested," Dr. Slater tells us. "Equally, we studied only one type, size and specific shape of microplastic within the study. Microplastics in the marine environment are unbelievably diverse. Our results provide some indication of uptake in the broader marine environment however there are many (many!) other types left to be tested."

It is additionally possible that in the open ocean, plastic particles may absorb pollutants that are passed into the flesh of fish, even if the particles themselves aren't.

A paper on the study, which also involved scientists from the University of Bremen and the IBEN laboratory, was recently published in the journal Marine Pollution Bulletin.

Source: Alfred Wegener Institute

2 comments
minivini
I do worry that “microplastics” will be a significant health threat in 20-40 years. We’re breathing and eating it. Meanwhile, we’re still producing exponentially more of it than we can properly dispose of or recycle.
Robert in Vancouver
Many plastics contain chemicals that continuously off-gass such as flexible or soft PVC. Those gasses collect in the human body and are a known health hazard. So it's logical to assume those gasses collect in fish flesh too.

Soft or flexible PVC materials should not be installed in any hospital, school, or old age homes. But they are installed all the time even though there are alternatives that work as well and cost the same or less.

One significant example is the PVC jacket installed over pipe insulation in schools and hospitals. There's millions of square feet of PVC jacket installed, removed, and thrown away every year. The alternative is canvas jacket (made of 100% unbleached undyed cotton) which does the same job at the same or lower cost than PVC jacket, and is 100% biodegradable.