During this Plastic Free July, we decided to bring attention to the ever-growing popularity of pods and encapsulated detergents and cleaners. Pods are extremely convenient because they give a precise dosage needed to get the cleaning job done and aid in not using excess product.The pods do not melt easily in your hands and are puncture resistant, yet, when plopped into water they dissolve even in cold temperatures. The magic of this is in the material used to create these pods. This material is called PVA, PVOH or polyvinyl alcohol. It is claimed to be a biodegradable material that breaks down into inert particles that eventually get turned into carbon dioxide and water. Although several studies show impressive biodegradability statistics on this material, upon further investigation, actual biodegradability of PVOH becomes questionable.
Here are some important points to know about PVOH:
- PVOH is a plastic. Some companies claim that their film is plant based, but that is not possible. This is a fully synthetic product made from reacting polyvinyl acetate and methane in the presence of yet more chemicals.
- PVOH is a petrochemical product. Ethylene, which is a petroleum-based product, is reacted with acetic acid and oxygen to make vinyl acetate monomer, which is then processed to make polyvinyl alcohol.
- PVOH was able to slither away from being called a microplastic because it does not break down into smaller parts, rather it dissolves. This film is modified to be water-soluble, but this does not mean that it stops being plastic due to this ability. What this means is that PVOH pollution can be overlooked or ignored when samples are taken for testing from the environment because it is not considered a microplastic.
- Biodegradability is not so clear cut with PVOH. The definition of biodegradability is that a substance is biodegradable if it can be broken down by bacteria or other living organisms. In the case of PVOH, only certain strains of bacteria can break down this substance, and they are not common to the environment. These bacteria are specialised cultures that grow and acclimatise in the environment where there is exposure to PVOH. As an example, these bacteria are found in sewer water treatment plants and environments that have been exposed to PVOH pollution. Pristine environment will take longer to degrade this type of plastic as they do not have the means. Therefore, this begs the question- is it biodegradable? In addition, biodegradability of pod films depends on how soluble they are in water. The more soluble, the more complete the biodegrading process. However, not all PVOH is made to be completely soluble in water and so, some ends up persisting in the environment. Polyvinyl alcohol was found at some of the deepest sea trenches, according to research done by Newcastle University.
- PVOH is not necessarily tested for in wastewater treatment plants before discharge. We have specifically investigated a 2020 report of Drinking Water Analysis Summary for Toronto plants and found no PVA or PVOH testing done. In fact, Toronto’s Sewer By-law does not require testing for PVA/PVOH before discharging water into the sewer system or storm drain. Do you know if your water is tested for PVOH?