Biosourced, biodegradable or compostable plastic materials: what are we talking about?
Among the plastic packaging and everyday consumer products on the market, some are described as “biosourced”, “biodegradable” or even “compostable”. Encompassing different notions, these designations can lead to confusion.
- The so-called plastics “biosourced” are made from natural resources such as corn starch, with no minimum natural resource content. Single-use plastics must contain at least 50% of material of natural origin.
- Plastics are said “biodegradable” if they degrade under the action of micro-organisms.
- Plastics « compostable » are biodegradable plastic materials that degrade under specific composting conditions (temperature, humidity), whether industrial or domestic. According to current standards, these materials must degrade to more than 90%, within a maximum period of 6 or 12 months depending on whether it is composting under industrial or domestic conditions.
Even “biodegradable”, these plastics are potential sources of pollution
Even for those claiming to be “biosourced, biodegradable or compostable”, it is not guaranteed that these plastic materials will completely degrade in domestic composters, especially since it is difficult to control their operating conditions. As a result, when an individual spreads compost in his vegetable garden to grow vegetables, for example, contamination of the environment or local cultures cannot be excluded.
« This contamination can come from the different constituents of the materials, or from microplastics resulting from their degradation. The constituents concerned may be polymers, residual monomers, additives or inorganic fillers presenting potential dangers both for human health and for the environment. explains Stéphane Leconte, Expertise Coordinator at ANSES.
ANSES therefore recommends not putting any plastic material, even labeled “biodegradable” and/or “compostable”, in domestic and collective composters.