Biodegradable bags can hold a full load of shopping after 3 years in the environment

[OnlinePoker]

Biodegradable and compostable plastic bags are still capable of carrying full loads of shopping after being exposed in the natural environment for three years, a new study shows.

Researchers from the University of Plymouth examined the degradation of five plastic bag materials widely available from high street retailers in the UK.

They were then left exposed to air, soil and sea, environments which they could potentially encounter if discarded as litter.

The bags were monitored at regular intervals, and deterioration was considered in terms of visible loss in surface area and disintegration as well as assessments of more subtle changes in tensile strength, surface texture and chemical structure.

https://eurekalert.org/pub_releases/2019-04/uop-bbc042519.php

[applegrove]

1. I gave out biodegradable bags at a campus bookstore when I worked there.

They were shoulder bags that could hold a pile of textbooks. I don't see why grocery stores don't sell them. I'm sure people would be willing to buy them for 25 cents on the occasion they don't have their regular reusable bags with them. They could easily be made in a smaller size. They had handles.

[nitpicker]

2. From The Guardian

https://www.theguardian.com/environment/2019/apr/29/biodegradable-plastic-bags-survive-three-years-in-soil-and-sea

(snip)
The research for the first time tested compostable bags, two forms of biodegradable bag and conventional carrier bags after long-term exposure to the sea, air and earth. None of the bags decomposed fully in all environments.

The compostable bag appears to have fared better than the so-called biodegradable bag. The compostable bag sample had completely disappeared after three months in the marine environment but researchers say more work is needed to establish what the breakdown products are and to consider any potential environmental consequences.

After three years the “biodegradable” bags that had been buried in the soil and the sea were able to carry shopping. The compostable bag was present in the soil 27 months after being buried, but when tested with shopping was unable to hold any weight without tearing.
(snip)

The research showed that the way compostable bags were disposed of was important. They should biodegrade in a managed composting process through the action of naturally occurring micro-organisms. But the report said this required a waste stream dedicated to compostable waste – which the UK does not have.

Vegware, which produced the compostable bag used in the research, said the study was a timely reminder that no material was magic, and could only be recycled in its correct facility.
(snip)

[muriel_volestrangler]

3. "waste stream dedicated to compostable waste - which the UK does not have" - that's odd

For over 20 years, my UK council has been collecting compost weekly from a dedicated bin, and has always said you should wrap it either in newspaper or compostable bags. Compostable bags were hard to find, but we used to get a free local paper once a week, so that was plentiful. But this shows that some parts of the UK have had such a stream for years.

And a few weeks ago, one supermarket I use started using compostable bags for loose fruit and veg - made in Austria, they seem to say. They specifically say use as a "food waste caddy-liner" or in a compost bin, but do not put it in a recycling bin.