A study conducted at the University of Lund (Sweden) revealed that plastic nanoparticles reduce the survival of zooplankton and penetrate the fish brain, causing behavioral disturbances. This pioneering study was published in the journal Scientific Reports, last month.
The increase in the production of plastic material in the last decades around the world has turned plastic waste into a major problem in the oceans. About 60-80% of all marine litter is made out of plastic, affecting at least 660 marine species (the ones we know so far), showing that this material is a serious pollutant for aquatic environments. Through physical-chemical and biological reactions caused by environmental conditions, the plastic material is divided into smaller and smaller pieces, reaching the size of nanoparticles. Being so small is a dangerous characteristic because the plastic nanoparticles are able to overcome biological barriers, penetrating tissues and accumulating in organs, thus affecting the behavior and the metabolism of the organisms.
One of the things this study shows is how plastic nanoparticles strongly affect an aquatic food chain from the zooplankton Daphnia magna to the top consumer, the freshwater fish, Crucian carp (Carassius carassius), which is a species common in anthropogenically affected waters. The researchers showed that amino-modified polystyrene nanoparticles were transferred through a three-level food chain, algae-zooplankton-fish, directly affecting the brain of these fish, modifying their behavior in terms of activity, feeding time and distance they need to swim to consume the food provided.
The authors suggests that the effects caused by plastic nanoparticles to the biota depends on both concentration and size of particles, therefore they specifically appeal to plastic manufacturers to adjust the nanoparticles production to sizes that are less dangerous for the metabolism of organisms, so that from a wider perspective, the top consumers, humans, will not come to be affected by their own garbage.
By Thiago Guerra
Mattsson et al. Brain damage and behavioural disorders in fish induced by plastic nanoparticles delivered through the food chain. Scientific Reports 7:11452.