New research shows plastic nanoparticles can end up inside the brains of fish. By tracking the path of tiny plastic particles through marine food chains, scientists found that if the plastic particles are small enough, they can sidestep the blood-brain barrier and accumulate inside a fish's brain.
Researchers found fish with plastic particles inside their brain tended to eat slower and spent less time exploring their surroundings. It was hypothesised that this strange behaviour may be a result of brain damage caused by the tiny plastic beads.
It’s been calculated that 10 per cent of all plastic produced around the world ultimately ends up in the oceans. As a result, a majority of global marine debris is plastic. We’ve all seen the beaches and waterways littered with plastics and the horrendous images of marine life entangled in plastic.
These are the plastics that we can see. What about the tiny nano-plastics that we can’t see? The tiny plastic particles, which are often the result of these bigger plastics breaking down? An analysis of waters around Australia an average of around 4,000 microplastic fragments per square kilometre, with some hotspots recording concentrations of 23,000.
These tiny particles can easily enter the food chain undetected and it’s important to study how they affect ecosystems and the life that live there. While many studies have addressed the impacts of larger plastics on marine life, few have focused on plastic nanoparticles, until now.
In a world first scientists from Lund University in Sweden showed that nanosized plastic particles can accumulate in fish brains. The researchers studied how nanoplastics may be transported through different organisms in the aquatic ecosystem, i.e. via algae and animal plankton to larger fish. The tiny plastic particles in the water are eaten by plankton, which in turn are eaten by fish.
The study demonstrated how plastic of different sizes affects aquatic organisms, but more importantly it provided evidence that nanoplastic particles can cross the blood-brain barrier in fish and thus accumulate inside fish’s brain tissue.
The researchers demonstrated the occurrence of behavioural disorders in fish that are affected by nanoplastics. They ate slower and explored their surroundings less. The researchers believe that these behavioural changes may be linked to brain damage caused by the presence of nanoplastics in the brain.
Another result of the study is that animal plankton died when exposed to nanosized plastic particles, while larger plastic particles do not affect them. Overall, these different effects of nanoplastics may have an impact on the ecosystem as a whole.
The research demonstrated that plastic nanoparticles are transferred up through a food chain, enter the brain of the top consumer and affect its behaviour, thereby severely disrupting the function of natural ecosystems. Scientists concluding that nanoplastic particles are likely have a more dangerous impact on aquatic ecosystems than larger pieces of plastics.
This research will continue as scientists are to determine the effects these nano-plastic particles may pose to the marine environment, to filter-feeders and on to fish which is information urgently needed to help people assess risks of nano-plastics in the marine ecosystem and the steps that need to be taken to mitigate it.
The original paper can be viewed here: