Ask Our Help Desk: Are bioplastics and biodegradable plastics really better?

How do you know if the ‘green’ disposable plastic products you buy–marked bioplastic, biodegradable, compostable, or bioplastic–are actually safe for our planet and our health? It’s confusing for well-intentioned people. We’re here to help.

Plastic is made of artificially created chemicals “that don’t belong in our world and don’t mix well with nature.” After we use plastic–sometimes only for a few seconds–we throw it away. These plastics are a big source of pollution, getting into our food and water, creating toxic health hazards for neighboring communities as part of their production and disposal and killing marine wildlife. While public pressure has made companies appear to be more environmentally friendly, most haven’t cleaned up their act. They’ve only created more confusing terms, greenwashing their products to make us feel like we’re acting responsibly.

The bottom line: the best solution is to avoid single-use plastics, no matter what material they are made from. It’s the only real way to prevent pollution and waste. When plastic is unavoidable, it’s vital to understand what the labeling actually means. Biodegradable plastics are very rarely recyclable, and biodegradable does not mean compostable–so they often up in the landfill. Compostable and bioplastic goods can be a better choice than biodegradable ones, but often still end up in landfills unless you can compost appropriately.

Why? There’s an important difference between what makes conventional plastics, biodegradable plastics, and bioplastic–and what happens when we’re done using them.

Conventional plastics are made from products derived from petroleum. The US Department of Energy reports that plastics are mostly produced from from natural gas processing, and feedstocks derived from refining crude oil–these are the ingredients that last forever in our environment. They take hundreds of years to break down and never completely decompose–they just become smaller and smaller pieces that are impossible to remove from the environment. Some plastics are known to be toxic, and as they break down, plastic bits become food for organisms up and down the food chain.

Biodegradable plastics are made from the same materials as conventional petroleum based plastics, but with even more chemicals. These extra chemicals cause the plastic to break down more rapidly when exposed to air and light. Some biodegradable plastics fragment rather than biodegrade, due to the addition of oxidizing agents (found in “oxo-degradable plastics”). By fragmenting, rather than degrading, they break into small pieces which can pollute soils, increase risk of ingestion for animals and end up in our oceans and waterways. These kind of plastics are impossible to recover for recycling and aren’t suitable for composting. The prefix “bio” can be very misleading: plastics do degrade, but not into something biological. It breaks into smaller and smaller pieces of plastic.

Unfortunately, recycling your ‘biodegradable’ plastics isn’t a great answer to this issue. Most biodegradable plastics have a #7 recycling code on them, which places them in the ‘Other’ category of plastics. #7 plastics are generally not accepted for recycling by local municipal recyclers, due to the addition of chemical additives.

Bioplastics and ‘compostable’ plastics tend to be made from plant biomass, such as corn starch, sugar cane or wheat, and should either completely and rapidly break down biologically, or be compostable. This means they are supposed to break down into biological elements, unlike conventional plastics. However, while some bioplastics can be composted and do not harm the quality of compost, others leave toxic residues or plastic fragments behind, making them unsuitable if your compost is being used to grow food. Additionally, the use of plant material for bioplastics causes concern including the use of genetically modified crops, and the use of farmland that could be used to grow valuable food crops, deforestation, use of fresh water supplies, soil erosion, fertilizer use (which comes from petrochemical sources), food security and more.

Bioplastics cannot be recycled with standard plastics as the additives in bioplastics can make the recycled product less durable.

Composting bioplastics is also complicated. Most bioplastics will only compost in commercial (municipal) composters. Commercial composters reach temperatures and humidity levels you would be unable to achieve in a standard garden composter, so your bioplastics may never break down at home. Some commercial composters, like those in Northern California, have to remove bioplastics like compostable utensils because even their temperatures and humidity levels will not break down these products.

So, is sending these items to landfill the best way to dispose of them? In a landfill, they won’t contaminate recycling or compost streams. But for biodegradation to occur, three basic resources are required – heat, light and oxygen. In a landfill site, waste is entombed, creating a complete absence of light and oxygen. If a biodegradable plastic or bioplastic ends up in a landfill site it may never decompose.

It’s clear: we can’t recycle or compost our way out of the plastics issue – and that holds true for new biodegradable plastics and bioplastics. We can make informed decisions and stop waste by buying less, and buying responsibly! Come to our Store for dozens of affordable products and strategies for reducing your reliance on plastic.

Also: check out these Responsible Purchasing Guides for more detailed information on the products mentioned above.


[Photo credit: U.S. Department of Agriculture on Flickr]

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28 thoughts on “Ask Our Help Desk: Are bioplastics and biodegradable plastics really better?

  1. Very interesting! I just wanted to ask what is the impact of bioplastics on the sea and if they are even biodegradable there. Thank you!

    • It needs oxygen, moisture and light. It seems to me like it will dissolve in the ocean but I can’t find that info anywhere myself.

      • Old post but for future readers:
        If you’re referring to PLA (polylactic acid polymers) they will never degrade in the sea or naturally under normal conditions. There has been research on leaving PLA underground and in sea water for over a year with no degradation at all. It has to be properly composted at regulated temperatures for approximately 6 months for it to properly degrade. Other biodegradable plastics exist, but so far as I’m aware none are commercially available or even energetically favorable.

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  3. It’s really depressing. The false hope and info companies have supplied us with about biodegradable and bioplastics items, when the truth is the impact maybe even worse. Just tell us plastics and non organic items are not good. If it can’t be recycled then don’t sell it!

  4. So, if I want to not leave plastic all over the planet I have to use paper garbage bags and compost my west green waste to prevent my soggy paper garbage from collapsing. I’m not even sure that garbage pick up will take paper bags only. What a quandary. Corporations should be made legally responsible for the environmental imprint that their packaging makes and not shove the responsibility onto the consumers.

  5. So, if I want to not leave plastic crap all over the planet I have to use paper garbage bags and compost my wet green waste to prevent my soggy paper garbage from collapsing. I’m not even sure that garbage pick up will take paper bags only. What a quandary. Corporations should be made legally responsible for the environmental imprint that their packaging makes and not shove the responsibility onto the consumers.

  6. You may want to check the science on what is required for biodegradation to occur. The article states that “heat, light, and oxygen” are required for biodegradation to occur. This isn’t right. Biodegradation can occur without light or oxygen (we call this an anaerobic condition where nitrogen or sulfate can replace oxygen). Moreover, the majority of the reactions that take place in biodegradation are exothermic – they produce heat as a result of the reaction. This is the reason that solid-waste landfills generate and accumulate heat. The heat generation from landfills is a common issue that municipalities have to deal with – just google ‘landfill heat generation’.

    Please see science direct’s excellent summary based on Tatyana and Alexander Poznya’s publication “Ozonation and Biodegradation in Environmental Engineering, 2019”.

    • Hello,

      I am also curious as to the science of this process! There’s a lot of information out there about how bioplastics are made, but not how they are processed. Could you link me to this summary? All I can find are links to buy the actual book mentioned above.

    • Thank you for this additional information and resource. This gives hope and offers insight for those who need to purchase single use plastics on a regular basis.

      It would be wonderful if zero plastic could be a reality, but there are necessary uses for plastic. Those who are stuck with this impossibility are searching for ways to reduce harms. While in my personal life I’m able to avoid plastics, professionally (working with biohazardous waste) it is necessary to use single use plastics on a daily basis.

    • Hi Douglas,
      We don’t have the expertise to answer your query. We’re not sure who could answer you.

      We believe that there has been some good results with fungal decomposition.

      In any case, biodegradable plastic, is not all the same depending upon the manufacturer, and the base materials they use. Some plastics are formulated differently with different feedstocks and chemistry, resulting in different structural properties. Having no oxygen present may affect one type of biodegradable material and not another.
      Ecology Center Helpdesk

  7. ” Bioplastic” by definition, is an oxymoron. It just like saying “sweet poison” . Plastic is essentially polymer which is a petroleum derivative sourced from crude oil. Therefore, any plastic whether bio or nonbio is basically still plastic, and plastic is neither degradable, nor compostable. In other words the fossil fuels Industry and its ancillary plastics manufacturing industry are trying to fool the public by window dressing the negative and harmful impact on the ecology by gift wrapping ordinary plastic as “bioplastic” and oxobiodegradable plastic” . There is no such thing as an environmentally-, friendly plastic. The people are given a false picture by the fossil fuels’ lobby and PR stuntmen.

    The only long-term viable solution will come, not from the fossil fuels industrry, but from the ordinary consumers who use plastic.
    Here are a few tips that can cut down the alarming volume of plastic waste:

    1. Please take a bag (cotton or Jute or palm) whenever you go for groceries.
    2. Stop consuming carbonated drinks or juices bottled in plastic or PET. Use only glass bottles. Stop buying processed foods like ketchup or soya bottled in plastic. Don’t buy milk sold in plastic pouches.
    3. Stop buying plastic buckets and use clay pots and utensils. Wear clothes unblended with polyester or acrylic.
    4. Stop using UPVC for your doors and windows.
    5. Educate yourself and your children about the dangers and harmful effects of plastic pollution and make sure they understand what would be the world like like when they grow up and do nothing about it.
    6. Apply pressure on your politicians to regulate plastics and pass laws criminalizing the dumping of plastic waste in the environment.
    7. Organize focus groups with your friends and colleagues to discuss and take decisive action at our local level, such as your owt neighbourhood or the company you work for.

  8. I left what was supposed to be a compostable drinking cup in one of my compost bins for at least two years. Today it’s the same cup I put in the bin two years ago.

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  14. Thankx for share this little info about plastic bags. After read this i know that how its better for us. Here i will suggest that please write at also Biodegradable bags .

    Thanks again !!

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  17. This is very focused on landfills and local polution. But I wonder about the climate change comparison. Shifting a buck out of a fossil fuel company is always a good thing, makes the total price for the barrel of oil a little lower.

    But I haven’t seen a full lifecycle analysis

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