(CN) – Compostable food packaging seemingly combines
convenience with sustainability, but a study published Wednesday found the
containers are leaching potentially harmful substances into the ground.
In a study
published in the American Cancer Society’s Environmental Science & Technology
Letters, researchers said that the nonstick, biodegradable containers are
leaching man-made, oil-and-water-repellent chemicals.
Biodegradable bowls, cups and cartons can be added to
compost piles, because they are made with materials that degrade relatively
quickly. When mixed with food and yard waste, compostable packages break down
into nutrient-rich matter for soil, reducing the need for chemical fertilizers
and cutting down the amount of waste sent to landfills.
But scientists say they do not know whether putting the
compost on crops is healthy for humans.
Researchers from Purdue University and Seattle-based
environmental consultancy Zero Waste Washington examined the levels of
chemicals in 10 compost samples from five states. Nine samples came from
commercial composting facilities – seven of which accepted compostable
containers – and one sample came from a backyard compost bin which didn’t
contain any biodegradable packages.
The study found all the samples contained traces of
perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). These
substances are “long-chain” per- and polyfluoroalkyl substances (PFAS), which
are known to cause negative health effects because they do not break down and
can build up over time.
The substances, which have been in use since the 1940s, are
widely found in U.S. manufacturing and consumer products due to their
flame-retardant properties and ability to repel oil and water, according to the
U.S Environmental Protection Agency.
The chemicals can travel long distances through the air,
seep into groundwater and move through soil, according to the U.S. Agency for
Toxic Substances and Disease Registry. They are found in compostable pizza
boxes, other food containers, carpets, leather, apparel and textiles.
According to the EPA, these man-made chemicals have been
found in the drinking water in several communities across the country. This
contamination is due to local industrial or firefighting facilities that
produce the materials.
Studies show the chemicals have caused reproductive,
developmental, liver, kidney and immunological effects in laboratory animals,
and have caused tumors in animals.
In the samples from the seven facilities that accepted
compostable food packaging, researchers found higher levels of the chemicals
than in the facilities that did not accept such packaging.
Previous methods of assessing “compostability” of the
biodegradable packages focused solely on physical breakdown of materials in
controlled composting facilities, scientists said in the study, adding new
standards will require container makers to ensure that fluid-repellent
chemicals break down to levels below the established thresholds set by
regulators.
Researchers said the results of the study contributed to the
passage of Washington state’s Healthy Food Packaging Act of 2018, which bans
the use of the chemicals in paper food containers. The ban will go into effect
in 2022.
“This type of law will help prevent the use of products from other countries where PFAS-related bans may not exist because it focuses on the product and not where production occurs,” researchers said in the study. “Other sources of PFAS that may contribute to their presence in commercial compost should be evaluated including Gore cover technology.”
In an email, lead author Linda S. Lee of Purdue University laid out what the packaging industry – and consumers – must do next.
“They will need to invest in finding alternative protective coatings, which at this moment is likely to be a challenge. Also and as consumers realize more about this chemical class, they will start to look to support products that do not contain them,” Lee said. “Many may also choose not to compost their compostable packaging; however, I am not sure how widespread that is with individuals who compost.”
She added: “Based on what I knew at the time about protective coatings on packaging, I was not surprised that PFAS were present.”