Ask Dr. Pete: Are laundry pods and sheets really sustainable?
At Dirty Labs, we're occasionally asked why we don't create laundry pods or sheets. After all, they're very convenient and seem really sustainable and innovative.
So why not?
We asked our chief scientist Dr. Pete to weigh-in and deep dive into this issue. In case you are wondering, Dr. Pete is a product inventor, innovator, and sustainability expert, he’s the brains behind our Bio Laundry Detergent and was a founding member of The Sustainability Consortium. Previously in our The Dirt series he’s covered topics on such things like, Hard Water and How it Affects Our Cleaning, What is Green Chemistry, and How to Remove Balsamic Vinegar Stains.
Ok so what's the deal with pods and sheets?
Unit dose laundry detergents have gained popularity over traditional powder and liquid laundry detergent for several reasons. First off, unit-dose detergents are very convenient. Just grab a pod or sheet, throw it into the washer, and push start – you’re done. Second, marketers behind unit-dose detergents have been promoting the sustainability advantages of pods and sheets. Some of these claims make sense. For example, the weights of the detergents in unit dose forms are only a fraction of a typical powder or liquid detergent. The reduced dosages mean less transportation and storage requirements, which saves substantial amounts of energy required for the laundry detergent industry. However, pods and sheets pose other consumer safety and environmental concerns that they often do not mention.
Our primary concern is that the film in pods and substrate used in sheets is made of plastic. The chemical that allows laundry pods and sheets to “dissolve” is called polyvinyl alcohol - also known as PVA or PVOH. PVOH is a sythnetic, petroleum-based polymeric plastic that "dissolves" in water – breaking down into smaller plastic particles called microplastics.
Once the detergent pods or sheets meet the water in the washing machine, they break down into microplastics and are discharged as part of the wastewater. In previous studies, PVA and its derivatives have been viewed as being harmless and readily biodegradable in wastewater, especially after being treated by water treatment plants.
However, recent studies have seriously challenged the readily biodegradable status of PVA films. Two scientists from Arizona State University reported that the majority of dissolved PVA film in wastewater are not fully biodegraded through the setup of current water treatment plants.
In order for PVA to biodegrade, special PVA-adapted microbes need to be added at high levels and for long durations. Currently, most water treatment facilities do not sufficiently treat PVA in water, and therefore poses a series of environmental and safety concerns.
In recent years, several credited research papers have also challenged PVA’s safety profile and environmental friendliness due to its manufacturing process. Scientists from Ryerson University in Toronto reported their independent product packaging Life Cycle Assessment (LCA) on PVA liquid detergent pods sold in PET containers or flexible pouches, vs. traditional liquid detergents in HDPE plastic jugs. Quite surprisingly, in their load-to-load comparisons, they found that almost all the key human safety and environment indicators of traditional liquid detergents in plastic jugs are much better than the unit-dose liquid detergent pods.
This research indicates that the production of PVA film is quite a polluting process, which involves heavy environmental and safety burdens in carcinogenic toxins, ozone depletion, acidification, eutrophication, and fossil fuel depletion.
Ultimately, the negative impacts from the production of PVA film have greatly compromised the benefit brought in by the less dosage of the PVA liquid pods.
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