A group of German and Norwegian researchers have concluded that “bio-based and/or biodegradable materials available on the market are just as toxic as conventional plastics with regards to the chemicals they contain. This highlights that the positive connotation of ‘biological’ or ‘sustainable’ materials does not extend to chemical hazards.”
Plastics contain a complex mixture of known and unknown chemicals, some of which can be toxic. Bioplastics and plant-based materials are marketed as sustainable alternative to conventional plastics. However, little is known with regard to the chemicals they contain and the safety of these compounds.
To test levels of toxicity the researchers tested 43 everyday bio-based or biodegradable products covering mostly food contact materials made of nine material types. The researchers combined in vitro bioassays with high resolution non-target mass spectrometry to characterise the toxicity and chemical composition of bio-based and biodegradable materials. The results indicate that two-thirds of bioplastics and plant-based products contain toxic chemicals as well as a large number and diversity of compounds (>1000 chemical features each in 80% of the samples).
Two-thirds (67%) of the samples induced baseline toxicity, 42 per cent oxidative stress, 23 per cent antiandrogenicity and one sample estrogenicity.
The study demonstrates that most bioplastics and plant-based materials contain toxic chemicals. Cellulose and starch-based products induce the strongest in vitro toxicity, while most samples contain >1000 chemical features; the maximum is 20,000 features. The material type does not predict toxicity or chemical composition.
The researchers said, “Our study demonstrates that bio-based and/or biodegradable materials available on the market are just as toxic as conventional plastics with regards to the chemicals they contain. This highlights that the positive connotation of ‘biological’ or ‘sustainable’ materials does not extend to chemical hazards. Accordingly, our findings imply that in order to develop bio-based/biodegradable materials that indeed outperform conventional plastics, sustainability and chemical safety aspects must be addressed alike. One way to promote this is to integrate chemical toxicity into the life cycle assessment of materials.
“On a positive note, we show that safer products are already at the market that can be used as best practice examples. Additionally, the chemical safety of materials can be further optimised using green chemistry to ‘design out’ toxicity during the development of new bio-based and biodegradable materials. Besides these human health aspects, the carbon, energy, water and land footprints need to be minimized to create truly better plastics or plastic alternatives and avoid regrettable substitutions.
Read the research, Are bioplastics and plant-based materials safer than conventional plastics?