October 2023 • Vol. 29 • Issue 8
T
Biodegradability Considerations for Cosmetic Ingredients …Ben Blinder
he topic of biodegradability has become extremely important in recent years, but still may not be fully understood. The following is a basic overview for formulators and anyone wishing to know more about this critical issue. Note that regulations, definitions, and practical guidelines on biodegradability are continually changing, and the comments in this article are intended to offer general insights, not legal definitions or advice. Simply put, biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi, and once broken down, the byproducts are carbon dioxide and water vapor.1 “Bio” is the key prefix here; the difference between “degradable” and “biodegradable” is that while “degradable” products can be broken down by chemical or biological processes, “biodegradable” materials can only be broken down by biological processes. The concern for biodegradable products began with the issue of microplastics, first detected in the 1970s in the ocean as plastic residue, but not termed “microplastics” until the mid-2000s. A good and comprehensive article on this by Napper and Thompson was published online in 2020.2 Many multinational companies have stopped using microplastics (microbeads) in their formulations and other brands are following, but let’s clearly define what are, and are NOT, microplastics! To qualify as a microplastic, four criteria must be met: • It must be a polymer. • It must be solid (at room temperature). • It must be in particulate form. • It must be under 5 mm in size. To reemphasize, all four criteria must be met. Even if one of these four does not apply, the substance is NOT considered a microplastic. And to complicate matters further, there are many exclusions even if these four criteria are met, including the following: • The material is natural. • The material is degradable. • Its solubility is > 2 grams/liter. • No carbon atoms in its chemical structure. • Its release to the environment is prevented when used. • Its physical properties are permanently modified during end use. • It is permanently incorporated into a solid matrix during end use. Just because your product may be “natural” does not mean it is “biodegradable”. Measurement is key! As mentioned by Dr. Martin Perry, Advanced Development Safety Laboratories at SCS Formulate in 2021: “Although natural content is good (continued on Page 6)
I N D I E
3 6 0 °
•
O C T O B E R
...see page 5-8 for more information.
9 ,
2 0 2 3