Many studies have shown that tiny plastic particles are now spread everywhere on Earth – in the water, food, and air, and even inside the human body, in our blood, lung tissue, and stool. According to a recent cover story published in Chemical & Engineering News, an independent news outlet of the American Chemical Society (ACS), scientists are just beginning to investigate the health and environmental risks of microplastics and nanoplastics, by using lessons learned from nanotoxicology.
Microplastics (plastic particles smaller than five millimeters in diameter) and nanoplastics (particles smaller than one µm) can be made of a variety of materials, and are of different sizes and shapes. Due to their diversity, a proper investigation of their health and environmental effects is a complicated matter.
So far, scientists have mostly used polystyrene beads in their experiments since they are easily accessible. However, these beads are far from being representative of the diversity of microplastics found in the environment: most of these particles are irregular fragments rather than spheres, and environmental factors such as ultraviolet light can change their properties after they are released in the environment. Moreover, polystyrene is not the only polymer found in the environment; fragments of polyethylene, polypropylene, and polyamide are also abundant in our surroundings.
Since there is limited data regarding the effects of exposure to microplastics, making regulatory decisions is challenging. This is a problem that the toxicology community has also faced over the past decade when trying to assess the risks of nanoparticles, so scientists hope that lessons from nanotoxicology could be applied to our understanding and assessment of micro- and nanoplastics.
Currently, researchers are beginning to standardize the various microplastics used in studies, in order to be able to reproduce results and better replicate real-world situations. Moreover, laboratory systems simulating bodily functions are increasingly used to investigate how ingested or inhaled plastic particles could affect human gut and lung cells.
“We really need to launch a micro- and nanoplastic safety consortium similar to what we did with nanomaterials and bring a lot of groups and scientists together to address these fundamental questions,” said Philip Demokritou, an expert in Nanoscience and Environmental Bioengineering at Rutgers University. “Because right now, with a little bit of funding here and a little bit there, we won’t be able to generate the data that risk assessors need.”
The full cover story – written by senior correspondent Britt Erikson – can be accessed here.