The thing about biodegradable plastic

I’ve been seeing a lot of plastic bags around with varying claims of sustainability. Some say it’s compostable, biodegradable, oxo or photo biodegradable or degradable, or bio-based. Some come with the SIRIM logo, MyHijau chop or no information at all.

For context, SIRIM is the Standard and Industrial Research Institute of Malaysia. Its Eco-Labelling certification is awarded by SIRIM QAS International, which it says is Malaysia’s leading testing, inspection and certification body.

MyHijau is Malaysia’s official green recognition scheme endorsed by the Ministry of Environment and Water. It serves as a reference for green procurement, green incentives and green initiatives by the government.

Take these plastic bags for instance. It says its oxo-biodegradable on top. Below, it says its 100% degradable. So, is it biodegradable (two very different things) or not?

Question: How long does it take to biodegrade (if it does), and under what conditions (temperature, moisture etc)?

The one on the left feels like a Styrofoam container. The label says it’s photo-degradable. Technically, that means it will degrade (not biodegrade — which means it will end up as microplastic) in an accelerated process under sunlight. It has both the SIRIM (ECO 001 2016) and MyHijau logo.

Question: Why is photo-degradable plastic under SIRIM’s eco-label and MyHijau? It’s not even biodegradable.

The one on the right doesn’t show any certifications (logos) and only says its biodegradable. Again, under what conditions? Has it been tested?

This bag has the SIRIM (001 2016) and MyHijau logos on it and claims to be both biodegradable and compostable. One good thing, I suppose, is that it states the time needed for it to become compost. But again, under what conditions? Does it need to go to a compost? What kind?

Question: Are any of these plastic bags recyclable? Should you throw it in a recycling bin or regular trash can if you don’t have a home compost?

I find it very disturbing that the labels are inconsistent and there is a lack of information about what one should do with these bags.

Just labelling a bag as compostable, biodegradable or bio-based won’t change the outcomes of using plastic unless consumers know clearly what to do with it at its end of life.

Saying a plastic is compostable doesn’t mean you can just throw it into a recycling bin or landfill. It actually needs to go to an industrial or home compost. Likewise, throwing a biodegradable plastic in the river is not environmentally harmless.

I think this is an important topic to tackle because these alternative plastics figure largely in the Malaysia Roadmap Towards Zero Single-Use Plastic.

I did some research on this topic, which I’m going to share here. Please note that this is just my (personal, incomplete, ongoing) research.

I’ll break it down into:

1. What do the labels mean?
2. What are the limits of these types of plastics currently?
3. What do the certifications or standards mean?
4. What solutions are needed?

Getting the labels right

Plastic: A material consisting of a polymer, to which other additives or substances (stabilisers, colorants, fillers etc) may be added. Typically made from fossil fuels. Since most plastic are made of non-organic materials, it does not decompose easily as microorganisms are unable to break it down. It could, however, be mechanically broken into smaller pieces (microplastic).

Bio-based plastic: Fully or partly made from biological raw materials.

Biodegradable and compostable: Materials that can be broken down by microorganisms into water, carbon dioxide, mineral salts and new biomass within a defined period of time. How long it takes depends on the temperature, nutrients, oxygen, moisture and other conditions.

Biodegradable plastic: Plastics, which could be made from fossil fuels or bio-based materials, designed to biodegrade in a specific medium (water, soil, compost) under certain conditions in varying periods of time.

Compostable plastic: Plastic designed to biodegrade in conditions of an industrial composting plant, which has higher temperatures, or home composters.

Note: International standards specify the exact time period in which the plastic should biodegrade and the conditions it must have.

Non-biodegradable plastic: Plastic that last for a long time and disintegrate into smaller pieces called microplastics.

Oxo-degradable plastic: Plastics with additives that, through exposure to oxygen, disintegrates into microplastics or goes through chemical decomposition. (This is to be banned in the European Union.)

Photo-degradable plastic: Plastics with additives that, through exposure to sunlight, disintegrates into microplastics or goes through chemical decomposition.

Note: Not all bio-based plastics are biodegradable or compostable; biodegradable plastics can also be made from fossil fuel materials.

Sources available in reference list below

https://www.eea.europa.eu/publications/biodegradable-and-compostable-plastics

Limits of each type of plastic

1. There is some research (article) that shows how plastic bags claiming to be biodegradable and oxo or photo degradable still remain intact in soil, marine and regular environments after years. This undermines the supposed benefits of “sustainable” plastics. (Basically, don’t automatically assume that you’re being sustainable when you use biodegradable, compostable or bio-based plastic.)
2. Bio-based plastic is better than fossil-based plastic only in that its source is renewable. But if it’s sourced from crops that are linked to high use of fertilisers and pesticides, or grown in deforested areas and competes with food sources, the benefits are eroded. Also, bio-based plastic is not necessarily compostable or biodegradable.
3. Compostable plastic needs to be composted in an industrial or home compost. Currently, most compostable plastic can only be composted in an industrial compost, of which we don’t have a lot.
4. According to many website and my conversations with recyclers, flexible plastic bags are not widely accepted for recycling. So, I’m not sure what happens when you throw bio-based and biodegradable plastic into the recycling bin. (*Enlighten me if you have information!*)
5. Apparently, in some countries, there are concerns about mixing bio-based, compostable and biodegradable plastics with normal plastics in recycling plants. Separate collection streams are encouraged, so that compostable plastic goes to composting sites, while the rest are recycled (without contaminating normal plastic).
6. If you see an oxo or photo degradable plastic, it just means it’ll break down into microplastics quicker under sunlight and oxygen exposure. Avoid!
7. Some research currently show that oxo or photo biodegradable plastic have not proved biodegradability in any environment sufficiently. This is countered by the product manufacturers, some of whom do test their products according to international standards. Then, there are those that question the mentioned standards. So… use less and if you do need to use it, do your research and ask questions.

Certifications and standards

A company can claim that their product is compostable, biodegradable or bio-based. But how would you really know? In Malaysia, seeing the SIRIM or MyHijau logos could provide you with some assurance, I suppose. But you’ll have to find out what the standards mean and how the products were tested.

I haven’t found a lot of information about the MyHijau standard MyHP00161/16 that was on the plastic bags. (*Let me know if you have more information*)

As for SIRIM, there are 6 eco labels corresponding to biodegradable and compostable plastic. I’ll just mention a few below:

1. SIRIM ECO 074:2019 Oxo-biodegradable plastic
2. SIRIM ECO 001:2018 (replaces SIRIM ECO 001:2016) biodegradable and compostable plastic and bioplastic
3. SIRIM ECO 075:2019 photodegradable plastic

You can read about the details here. You can buy the reports to find out more details. Since the plastic bags featured above have the SIRIM ECO 001:2016 label, which has been replaced by SIRIM ECO 001:2018, I bought this report for RM50.

A few interesting things from the report:

1. The plastic and bioplastic are meant to be segregated and disposed in a controlled facility
2. The plastic or bioplastic must comply with these classifications: Biodegradation shall be > 90% in total or > 90% relative to reference substance within 180 days (test method: ISO 14855–1 and ISO 14855–2)
3. For Compostable plastic: Aerobic composting shall be < 10% of its original dry weight remains after sieving through a sieve of < 2 mm after 84 days in a controlled composting test (ISO 20200). No adverse impact on the ability of compost to support plant growth (OECD 208).
4. The content of heavy metals, toxic and hazardous substances has to be tested.
5. The product/packaging shall be clearly and indelibly marked: biodegradable or compostable. The symbol for products in contact with food is stated MS 2453.

Question: If these plastic bags must be disposed of in controlled facilities, would it be more more effective to state that on the bag, and tell consumers where are such controlled facilities?

Also, I still don’t know the conditions in which the plastics with this standard require to biodegrade or compost. So, if this plastic is left out in the air, will it biodegrade in 180 days?

Another thing: can these plastic bags be recycled like regular plastic products? Can I put it in the recycling bin?

I looked abroad at how they certify or label their plastic. The three major standard-setting bodies in this context are: the ISO, ASTM International (American Society for Testing and Materials) and CEN (European Committee for Standardisation), whose standards begin with “EN”.

This report by Consumers International and the UN Environment Programme highlights the strengths and weaknesses of different labels for plastics.

Bio-based plastic: The best labels make a distinction between sustainably-sourced biomass from those that are not. It must also be differentiated from compostable and biodegradable plastic. Verification of these claims with international standards like ASTM D6866 make the claims more reliable.

Compostable plastic: The best standards make it clear that this plastic can only be composted in specific composting infrastructure, and it references compliance with a certification standard. (i.e. AS 5810 is for plastics suitable for home composting, TUV AUSTRIA Belgium requires home composting with at least 90% degradation in 12 months at ambient temperature. EN13432 requires 90% disintegration within 12 weeks in an industrial compost).

Biodegradable plastic: There are specific requirements for good standards. For instance, EN 13432 requires at least 90% disintegration after 12 weeks, 90% biodegradation in 6 months, including tests on ecotoxicity and heavy metal content.

https://www.consumersinternational.org/media/352255/canirecyclethis-finalreport.pdf

Solutions (my personal opinion)

1. Create better labelling and awareness campaigns so people don’t think that compostable, bio-based and biodegradable plastic can be littered in the environment or thrown into the rubbish bin.
2. Educate consumers on what should be done with biodegradable and bio-based plastic. Should it be recycled? Where?
3. Set up a process and infrastructure to collect compostable plastic and place it in industrial or home compost.
4. Avoid bio-based plastic made from materials that compete with food sources, involve deforestation or heavy use of fertilisers and pesticides.
5. Avoid oxo and photo degradable or oxo and photo biodegradable plastic for now. Otherwise, go read up more about the product’s standards and testing methods.
6. Call for more transparency in the certification standards of bio-based, biodegradable and compostable plastic.
7. Reduce is the still the best option!

Sources (excluding those linked above):

1. https://www.eea.europa.eu/publications/biodegradable-and-compostable-plastics
2. https://op.europa.eu/en/web/eu-law-and-publications/publication-detail/-/publication/0c0d6267-433a-11eb-b27b-01aa75ed71a1
3. https://ec.europa.eu/environment/topics/plastics/bio-based-biodegradable-and-compostable-plastics_en
4. https://docs.european-bioplastics.org/publications/fs/EUBP_FS_Standards.pdf
5. https://www.consumersinternational.org/media/352255/canirecyclethis-finalreport.pdf