Littering has become a global epidemic, as we live in a society that values items less and less and are sold an increasing number of products designed to be used once and then discarded.
But despite looking untidy what are the bigger implications for the environment of our littering habit?
What is the definition of littering?
Littering is defined as the depositing of unwanted items usually on public property without the permission to do so, often leading to a health or environmental concern. Litter is the noun used to describe said items once they are in such an undesirable location.
Litter can range from small items such as bits of paper to much larger items like an old car all of which can affect the environment.
What are the most littered items?
A study of littering in America, which surveyed large areas of the country, estimated that a staggering 37.7% of all litter is from tobacco products. This is the discarded filter at the end of cigarettes that it seems has become socially acceptable to dump wherever people desire.
After cigarette waste, they found the next biggest offenders were plastic waste (19.3%) and paper waste (21.9%). Glass, food, metal and other debris made up much smaller percentages of the overall amount.
Perhaps more shocking though is the change in percentage of certain items over time. Plastic litter for example which have become increasingly common and now seem to be everywhere has increased by 165% between 1969 and 2009!
Main Impacts on the Environment
1) Physical harm to wildlife from plastic waste in rivers and oceans
Over the past few years, more people are becoming aware of the detrimental impacts of plastic pollution in our watercourses and oceans. This is thanks to a number of campaigns and high impact television shows and films that have brought the impact into the public realm.
But still, we continue to leave plastic litter everywhere. On the app ‘Literati’ which encourages users to tag litter they collect, the most commonly tagged item is still plastics by a long way.
How does plastic litter end up in rivers and oceans?
Plastic litter, particularly lighter weight items such as sweet wrappers, packaging or bags easily get caught on the wind and find their way to storm drains where they are washed into sewers and eventually into the ocean in many cases.
How does plastic litter affect the environment?
Plastic is particularly problematic as it doesn’t degrade easily and can last in water for a long time. It is this property along with the fact it can be molded easily into any shape and cheap cost that makes plastic so attractive for all sorts of uses from straws to bags to fast food containers.
Depending on the type of plastic some will float on the water’s surface, such as milk containers, whereas other types are denser (such as polyethylene terephthalate and polyvinyl chloride) and sink hundreds of meters the ocean floor.
How does plastic litter affect wildlife?
So now we know how plastic litter enters our rivers and oceans and why it lasts so long, how does that end up impacting wildlife?
The United Nations (UN) has stated as many as 800 species have been affected by marine debris worldwide of which 80% is plastic debris.
Sea turtles are one species that suffer adverse effects from plastic litter pollution. A sea turtle has to ingest as few as 14 pieces of plastic to have a 50% increased risk of death. But death could result from just a single piece.
This is due to the digestive tract of the turtles and therefore their inability to regurgitate the plastics they consume. This either leads to blockages or internal injuries causing an even slower death.
It was also found that young turtles were much more at risk due to being less selective about what they eat. (1)
Another group of animals that are particularly vulnerable are seabirds which ingest plastic more frequently than any other group of animals. Mistaking the bits of plastic litter for food on the ocean surface or shoreline.
The ingested pieces of plastic can harm seabirds in a number of ways from physical damage and blocking of the digestive tract meaning they are unable to eat. The plastics can also release toxic chemicals once inside the birds which vary in severity depending on the types of plastic.
The Laysan albatross was one species of seabird found to be particularly negatively affected. A study found that 40% of chicks were dying before fledging and examinations of the bodies after death showed the majority filled with plastic waste.
One study in Australia on the flesh-footed shearwater bird revealed that plastic ingestion was impacting the birds kidney function, blood calcium levels, body mass and even size. (2)
Results of studies like this are particularly worrying as most press only relates to birds physically choking on plastics but this shows even small amounts could lead to bird declines.
Even larger mammals are not safe from plastic litter in the oceans. Over 8 years a study in Southeast Alaska and British Columbia revealed 388 stellar sea lions were entangled in marine debris. Which often include plastic packaging bands which entangle the animals.
One whale’s death in Virginia in 2014 was attributed to a fragment of plastic that came from a DVD case! 22% of cetaceans (whales, dolphins etc.) that swallow plastic are at risk of death.
2) Litter can break down into microplastics
Plastic litter doesn’t necessarily stay as one whole piece and although larger pieces of plastic (macroplastics) can have many damaging effects, the impacts of much smaller fragments, typically <5mm, (microplastics) is also a concern.
Microplastics in the oceans can be observed by all sorts of marine life. From the smallest plankton to larger birds and fish. 80% of sampled invertebrates were known to have ingested microplastics. (3)
The toxic nature of some of these small particles has been shown to have an impact. One study of sea urchins found their larvae were less likely to survive due to the toxic effects of microplastics. The study (and others) also showed that the microplastics can transport other harmful chemicals and pollutants such as pesticides, solvents and pharmaceuticals. (4)
Across a variety of studies micropplastics have been blamed for decreased food consumptions, weight loss and decreased growth. (5) (6)
Microplastics aren’t just a concern in water and impacts are being observed on land too. Earthworms were found to make burrows differently when microplastics were present in the soil, affecting their likely survival. (7)
The unknowns for modern-day phenomenons like this are also worrying. Microplastics eventually break down into nanoplastics (<0.1 micrometers) which are so small they can get into human and animal bloodstreams, even crossing cell membranes. Studies are ongoing into the true impact of nanoplastics but behavior change in some fish species has been attributed to nanoplastics in the brain.
3) Transport of ‘alien’ species
Alien or invasive species are species that are introduced to a location where it does not naturally occur. This ranges from exotic pets that are imported from other countries and are then released or escape to sea creatures transported in the ballast water of ships. But there are also studies to show that some invasive species are reaching new locations by ‘hitchhiking’ on our litter too.
Floating pieces of litter in the ocean can act as a raft which certain species can attach to. As these pieces of litter float across the sea they offer an excellent means of transportation potentially for thousands of miles.
A study in 2018 in Sweden on the Baltic Sea showed how litter is used by non-native species as a transport mechanism. Litter was collected at 8 sample sites and around 92 species of organism were found. Of these species 4 non-native species were found in high numbers. This was compared to natural substrates such as rocks where only 2 non-native species were found. (8)
This impact can be higher in extreme events such as after the Japanese tsunami when lots of litter was washed into oceans. 30 invasive species were found up to 5 years later washed up on the shores of the USA. (9)
4) Toxic chemicals into soils and water
Additives in plastics can leach into soils and cause damage. Phthaltes and Bisphenol A have been observed to leach out into soils and are known to affect wildlife by disrupting hormones.
One increasing source of litter is e-waste. As computers and other electronics come down in price, people are increasingly fly-tipping electronics too. These items are full of toxic compounds from mercury to arsenic. These chemicals leach into the soil and don’t break down easily. This can lead to the deaths of vital microorganisms in the soil.
Nicotene from cigarette butts wash away in rainwater and end up in rivers and streams. Studies have shown they pose a threat to drinking water quality. (10)
Why do people litter?
A real lack of empathy is shown amongst people when littering is concerned. With 81% of observed littering acts in one study being intentional.
But why do people litter?
Perhaps unsurprisingly, the distance between trash cans was a strong predictor of littering likelihood. So increasing the frequency of bins will help. This is a pattern we see for a lot of environmental behaviors, people do care and are even aware of the issues a lot of the time.……just not enough to go significantly out of their way. (11). People will engage in pro-environmental behaviors if there is a personal benefit but rarely if there is only an environmental benefit. (12)
Also interestingly the presence of existing litter increased the likelihood of people littering. Showing how as a species we are still susceptible to social cues and nudges. This is known as social proof. A series of studies back in 1990 found that when just one or two pieces of litter were present up to 90% of people used litter bins whereas this when this increased to three or more visible pieces of litter only 59% of others used bins. (13)
Make it easier not to litter
After exploring the reasons why people litter, one key solution to reducing it is to make things as easy as possible for people. Ensure there are enough trash cans in public places and make sure they are easy to find.
But at the same time as making it easy we must continue to educate people, particularly younger generations. Studies have shown engaging kids at an early age in the problems and then the positive solutions understanding and therefore concern increases. (14)
Apps to put pressure on the producers of the litter
It wouldn’t be a Innovate Eco blog article without at least one innovative solution to the issue at hand. One of my favorite innovations that aims to tackle the issue of litter is the app ‘Litterati’.
The basic premise of the app is that when you find a piece of litter you take a photo of it and then tag the photo with various things such as ‘plastic’. This then gives a georeferenced piece of data which helps contribute to the bigger picture. Because you are able to tag specific brands, this gives campaigners data to back up claims that certain brands are responsible for a significant portion of litter.
There have been some interesting success stories so far from the app with campaigners winning a court battle with cigarette companies in San Francisco to kids successfully banning plastic straws from a school.
To hear more about the app check out Episode 22 of the podcast on any podcast platform or below:
Nudging is a concept of behavioral science that attempts to influence the behavior of individuals by making subtle suggestions.
In Denmark for example footprints were printed on the ground leading up to bins. An experiment was run around this found that 46% reduction in littering thanks to this nudge.
Subtle nudges can also be applied in language and framing. It has been found that focussing on what a person is rather than just the act has more of an effect as people care about their reputation. Calling someone a ‘litterbug’ for instance may have more impact than saying ‘please don’t litter’. (15)
Work towards a circular economy
Litter does not look aesthetically pleasing, it costs a lot of money to clean up and it has an increased chance of ending up in rivers and oceans. But by singling out litter we aren’t getting to the heart of the problem.
Even if people carefully dispose of single-use plastic items in a bin it still has to go somewhere.
This disconnect between what happens to our rubbish after it goes in the bin is still there even though the problem is highlighted more frequently now.
We need to work towards more of a circular economy model, and away from the current model of buy and throw away.
This could work in a number of ways from food containers that decompose safely. To new businesses that can find a use for litter, such as several fashion brands making clothes from plastic waste.
Generating a sense of communal pride
Studies have shown that people will make ‘self-sacrificial’ choices when they are made aware of the benefits for the group. Instilling a sense of local community and pride is key but this is an increasingly tricky problem.
We live in an increasingly mobile society, where it is much more unusual for a person to be born in one place and live there for their entire lives. This creates problems around generating a sense of local ‘pride’.
I’m still yet to come across a solution for this one but let me know in the comments if you have any ideas!
Tackling other issues such as poverty
It is a sad reality that some of the worst areas for litter are in poor neighborhoods. In these areas littering is a relatively minor issue when you might be worried about how you can afford your next meal. As we’ve already discussed once the litter starts to appear it can exponentially get worse as others see it as normal.
There are many ways to tackle this and we must work towards a more equal society where people can afford to worry about issues like litter more. But governments and local councils can also do more to help out these communities. Increasing litter pickups in these areas can help these people out and act as a morale builder.
As we’ve seen littering isn’t just an issue of untidiness and aesthetics, litter can affect the environment too.
But as discussed here but this must not obscure vision of the true causes of the issues. We can educate and nudge people to not litter but what would help much more is if big corporations took more responsibility and stopped producing single-use non-degradable waste in the first place.
Innovation will help as the cost and options in biodegradable packaging comes down and we have better ways to utilize waste in a circular economy model.
But that still relies on us disposing of waste correctly and littering does not do this. There is no use in us inventing a t-shirt made from recycled plastic bottles when those plastic bottles are at the bottom of a river or ocean.
So for now, if you are reading this. Try not to litter, and maybe even pick up someone else’s because the impact may be more significant than you think.
(1) Wilcox, Chris, et al. “A quantitative analysis linking sea turtle mortality and plastic debris ingestion.” Scientific reports 8.1 (2018): 12536.
(2) Jennifer L. Lavers, Ian Hutton, Alexander L. Bond. Clinical Pathology of Plastic Ingestion in Marine Birds and Relationships with Blood Chemistry. Environmental Science & Technology, (2019);
(3) Lusher, A. L., et al. “Sampling, isolating and identifying microplastics ingested by fish and invertebrates.” Analytical Methods 9.9 (2017): 1346-1360.
(4) Nobre, C. R., et al. “Assessment of microplastic toxicity to embryonic development of the sea urchin Lytechinus variegatus (Echinodermata: Echinoidea).” Marine pollution bulletin 92.1-2 (2015): 99-104.
(5) Besseling, Ellen, et al. “Effects of microplastic on fitness and PCB bioaccumulation by the lugworm Arenicola marina (L.).” Environmental science & technology 47.1 (2012): 593-600
(6) Wright, Stephanie L., et al. “Microplastic ingestion decreases energy reserves in marine worms.” Current Biology 23.23 (2013): R1031-R1033.
(7) Anderson Abel de Souza Machado, Werner Kloas, Christiane Zarfl, Stefan Hempel, Matthias C. Rillig. Microplastics as an emerging threat to terrestrial ecosystems. Global Change Biology, (2018);
(8) Garcia-Vazquez, Eva, et al. “Leave no traces–Beached marine litter shelters both invasive and native species.” Marine pollution bulletin 131 (2018): 314-322.
(9) Carlton, J. T., J. W. Chapman, J. B. Geller, J. A. Miller, D. A. Carlton, M. I. McCuller, N. C. Treneman, B. P. Steves, and G. M. Ruiz.. Tsunami-driven rafting: Transoceanic species dispersal and implications for marine biogeography. Science (2017) 357:1402–1406.
(10) Green, Amy L. Roder, Anke Putschew, and Thomas Nehls. “Littered cigarette butts as a source of nicotine in urban waters.” Journal of hydrology 519 (2014): 3466-3474.
(11) Schultz, P. Wesley, et al. “Littering in context: personal and environmental predictors of littering behaviour.” Environment and Behavior 45.1 (2013): 35-59
(12) De Dominicis, Stefano, P. Schultz, and Marino Bonaiuto. “Protecting the environment for self-interested reasons: Altruism is not the only pathway to sustainability.” Frontiers in psychology 8 (2017): 1065.
(13) Cialdini, R. B., Reno, R. R., & Kallgren, C. A.. A focus theory of normative conduct: Recycling the concept of norms to reduce littering in public places. Journal of Personality and Social Psychology, (1990) 58(6), 1015–1026.
(14) Hartley, Bonny L., Richard C. Thompson, and Sabine Pahl. “Marine litter education boosts children’s understanding and self-reported actions.” Marine pollution bulletin 90.1-2 (2015): 209-217.
(15) Bryan, C. J., Adams, G. S., & Monin, B.. When cheating would make you a cheater: Implicating the self prevents unethical behavior. Journal of Experimental Psychology: General, (2013) 142(4), 1001–1005.