Page 56 - Plastics News August 2024

FEATURE NEWS

nation and bioplastic debris concerns. A February 2024 report by the Composting Con-
sortium found that removing contaminants can
According to voluntary American Society for
Testing and Materials (ASTM) standards, a mate-
rial is considered fully decomposed if more than
90% of it can pass through a 2-millimeter sieve.
But that creates a loophole that allows compost
to be chock-full of microplastics and nanoplas-
tics. Research shows that fertilizers made at bi-
ogas facilities, for example, can have high levels
of microplastics, including so-called biodegrad-
able microplastics.

In an email to Mongabay, a representative of the
Biodegradable Products Institute (BPI) said that,
“Microplastics in compost are coming from con-
ventional plastic contamination, not composta- comprise up to a fifth of a composting facilities’
ble products”. operating costs. Biogas facilities, for example,
remove all plastic wrapping, including bioplas-
However, other research shows that in complex tics, from food waste and landfill it, thus negat-
natural environments, such as oceans or soils, ing the supposed benefit of using compostable
bioplastics often don’t degrade as quickly as foodware in the first place.
their proponents claim.
Meanwhile, consumers, misled by bioplastic la-
“You’ll often have these promises made by beled as compostable, will likely continue toss-
companies that this is going to break down in ing it into the home compost bin.
five years, instead of 50 years, or 100 years, or Hazardous compost can put health at
whatever the comparison is with the tradition- risk
al plastic,” says Susanne Brander, an associate
professor and ecotoxicologist at Oregon State Even if bioplastics break down completely, they
University. “But if you’re thinking about it from can release all manner of toxic additives, includ-
the perspective of an animal that might only live ing PFAS and endocrine disruptors like BPA,
for a couple of years … it’s still going to be ex- none of which are banned from food-contact
posed to all of the breakdown products.” materials by the U.S. Food and Drug Administra-
tion.
According to Ulli Volk, deputy head of waste
management and material flow management at What’s more, photodegradation can lead to new
Vienna Waste Management in Austria, who was toxic chemicals being created, leading the re-
quoted in the Beyond Plastics, bioplastics don’t searchers to conclude that compost containing
add any nutrient value to compost and even compostable bioplastics could be a significant
harm the final product. “What composters really source of environmental pollutants, potentially
want are the food scraps; the bioplastic is col- putting wildlife and human health at risk.
lateral damage,” he said.

58 PLASTICS NEWS August 2024