Biodegradability - Rate and Testing

Current knowledge on microplastics, while growing, is still early with much to be understood. This leaves our approach to designing a competition that promotes conventional plastic alternatives in a dark place; in order to mitigate the potentially destructive characteristics of alternative materials, we need to test for microplastics and ultimately understand how things break down within a reasonable timeline for a competition.

Considering existing bio-based materials, what would be the best-in-class timeframe for complete biodegradation (aka, complete mineralization: water and gas) ? We are particularly interested in hearing more about the following environments:

Deep Sea
Surface of the Sea
Freshwater
Beach
Desert
Soil – surface
Soil – lightly buried
Landfill
Industrial composting
Home composting

Can you recommend relevant standards/guidelines for testing?

Here is our new topic on bioedegradablity @eakinyi @LHanson @Joanne @Utobou @Thanku @AustinClowes @iduaolunwa @AKB @kjbradford @marsxr @bngejane @renskelynde @kcamphuis @ricardoyudi @NoraEatREAL @neillk @jcoonrod @FranckSaintMartin @Olawale @LaurenTurk @barbswartzentruber @yusuke and @janetlee - any recommendations or thoughts you have around biodegradation in general and these environments!

@NickAzer that’s an interesting topic.
Here’s one perspective; the one that involves rapid processing of biological materials: consumption by animals (of a wide variety of species). In other words, if an alternative material is edible by a range of species then this might lead to its rapid removal from the environment.
(This assumes all components of the material meet this requirement.)

@NickAzer here’s some information that may be of interest:

Biodegradable and compostable alternatives to conventional plastics

Degradation Rates of Plastics in the Environment
[They use half-lives to express the degradation rate.]

Introduction of Environmentally Degradable Parameters to Evaluate the Biodegradability of Biodegradable Polymers
[They established the rates of biodegradation for 15 commercial biodegradable polymers over a 2-week test period, in soil.]

Biodegradability standards for carrier bags and plastic films in aquatic environments: a critical review
[They argue that current standards and test methods are insufficient to predict biodegradability in aquatic environments, and do not involve toxicity testing or account for the potentially adverse ecological impacts.]

Great resources @akb ! Tagging my teammates @Eti and @Caroline in case they have more questions for you. I’m personally super keen on reading the degradation rates review!