From time to time we're asked questions about the environmental friendliness and safety of Polyvinyl Alcohol (PVA), which is used in laundry strips and detergent pods, among many other applications. Here are our answers to some of the most common questions we receive:
What is Polyvinyl Alcohol (PVA) and how is it made?
Polyvinyl alcohol (also known as PVA, PVOH or PVAI) is a water-soluble synthetic polymer that is odourless and colourless. In simple terms, PVA is made by converting ethylene (a synthetically produced gas like the gas given off by plants that causes the fruit to ripen) into vinyl acetate through a chemical reaction with oxygen and acetic acid. It is then polymerized (a process in which relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer) and then dissolved in alcohol to become a water-soluble polymer - PVA.
Where is PVA used?
PVA can be found in a wide variety of applications, from medications, contact lens solution, food packaging and cleaning products to name a few.
Is PVA safe? I’ve heard PVA has been found in the human body.
We encounter different forms of PVA regularly because it is used in so many applications – including medical devices and procedures due to its highly favorable properties, such as biocompatibility, nontoxicity, non-carcinogenic, swelling properties, and bio adhesive characteristics.
Because PVA is so ubiquitous in our environment it is unreasonable to assume any PVA found in human tissue originated specifically from laundry strips, particularly because the form found in our laundry strips has been proven to biodegrade.
PVA is approved safe by the FDA (Food and Drug Administration) and Health Canada for food packaging as well as in cosmetic, biomedical and pharmaceutical applications. PVA is also considered a GRAS (Generally Recognized as Safe) ingredient by the FDA. And in this review of sub-chronic toxicity and genotoxicity studies it was confirmed that PVA is safe for humans when exposed via numerous exposure pathways in typical daily exposure.
This study verified that “…adequate biodegradability is confirmed by means of ready biodegradation screening tests, across a range of polyvinyl alcohol detergent grade films…Furthermore, their biodegradability ensures there is no concern for persistence or accumulation in the environment.”
I’ve heard PVA is a microplastic, is that true?
Microplastics are recognized as microscopic solid particles made of synthetic polymers that are insoluble in water and are typically resistant to biodegradation in the aquatic environment.
PVA films have some similar properties to many plastics - such as flexibility – but unlike plastics (and microplastics) which are persistent in the environment and do not biodegrade, PVA films fully dissolve in water when used. The dissolved PVA polymers are fully biodegraded by microorganisms in water treatment facilities and the environment.
In the 2021 scientific paper, it concluded that the ready biodegradability data on polyvinyl alcohol films used for detergent applications confirm that highly soluble PVA biodegrades in an aqueous environment. Despite variable biodegradation rates between studies and materials, all films were found to meet the criteria for biodegradability in these stringent studies – which offers definitive and conclusive evidence of their actual biodegradability in the environment.
So no, PVA used in liquid detergent films does not meet any of the definitions of microplastic as:
(1) it is not micro- or nano-sized
(2) it is highly water-soluble
(3) it is biodegradable in the environmental conditions where it is discharged
If you want to learn more about why we made our laundry strips, check out this blog post.