Plastic Particles Harm Freshwater Organisms Too

Scientists have become increasingly worried that plastic pollution threatens marine life in the world's oceans, and now new research shows that they have reason to fear it can harm freshwater organisms, too.

"The main sources of plastic are on land, so it is important to also look at the effects of plastic on land," Professor Bart Koelmans, leader of the Wageningen University and the IMARES research group behind the study, said in a statement.

Previous studies have shown that microplastics - microscopic particles of plastic debris - can harm marine life due to their potential physical risks and possible toxicity. But these plastics, as well as plastic nanoparticles, which this recent study focuses on, can impact organisms not just in the seas and oceans but in freshwater bodies, too.

For example, these particles slow the growth of algae, cause deformities in water fleas and impede communication between small organisms and fish, according to the researchers.

This study, published in the latest issue of Environmental Science and Technology, is the first time that such effects of plastic on freshwater organisms have been studied.

The researchers exposed water fleas to various nanoplastic concentrations. Not only did algae growth decline at higher concentrations, but the water fleas were smaller in size after being exposed to the plastic particles, and their offspring displayed various malformations.

"These are the first malformations that have been seen in freshwater organisms and we do not yet know how big the problem really is," said researcher Ellen Besseling.

Not to mention that it seems some organisms, like fish, can send out a sort of warning system to other freshwater species that these particles are present. Fish can emit chemical substances called kairomones that can warn water fleas of a threat. The researchers found it intriguing that the effect of the kairomones appeared to be stronger in the presence of nanoplastic. Researchers believe then that the fish can detect disturbances in the water at low concentrations not easily seen by humans.

And with humans generating 32 million tons of US plastic waste back in 2012, it's important to realize how this pollution may result in changes to the food web in exposed ecosystems over time.