Littering in National Parks: How It Leads To Various Forms of Pollution

Littering, which is an act of improper disposal of waste products, can happen intentionally or unintentionally. It can take a variety of forms, such as cigarette butts, food wrappers and plastic bottles. Littering can also occur pretty much anywhere in the world. For instance, Mount Everest has been dubbed as the world’s highest rubbish dump. As the number of commercial hikers and mountaineering enthusiasts visiting the peak soar, so too has the amount of trash left behind. This also presents a huge challenge in cleaning up the garbage due to the complexities of bringing them down from high altitudes.

Mount Everest Müll (Getty Images/Afp/Namgyal Sherpa)

Climber clearing empty gas canisters in Mount Everest (Getty Images)

Besides the problems associated with cleaning up the trash, littering can cause serious consequences for the environment too. There are various forms of pollution that are associated with littering. According to Taylor (2018), more than 100 million pounds of garbage are generated by national park visitors in the US each year.  In this blog post, I will be expanding on the topic of littering in the context of national parks, and how it leads to environmental pollution.

How littering results in Water Pollution
Do you know that 60% of water pollution is attributed to litter? This is primarily due to the fact that litter that is thrown on the ground often gets washed into water bodies and freshwater sources such as rivers and lakes, which could eventually end up in storm drains and directly into our waterways. Waterway litter harms and kills marine wildlife, causing the death of at least 100,000 marine mammals worldwide annually. This occurs in various ways, such as marine animals mistaking microplastics as food and subsequently consume them, or the degradation of water quality due to the toxins and chemicals released from litter such as cigarette butts (which contains chemicals such as arsenic and formaldehyde). As mentioned in lecture 5 on the topic of marine pollution, plastic also carries with it toxins known as persistent bioaccumulative and toxic substances [PBTs]. PBTs have the tendency of being transferred to organisms when plastic debris is consumed. An example of this is a study by Ryan et al (1988), which shows great shearwaters (Puffinus gravis), a seabird known to ingest plastic, had PCB concentrations in fat tissues corresponding to the amounts of plastic found in their stomachs (US EPA, n.d.)

A milk bottle being picked up by a litter picker

Plastic bottles being cleared in Snowdonia National Park (Snowdon Society)

Trash and debris in rivers may also result in habitat alteration. As debris accumulates, light levels may be reduced in the benthic zone, which leads to the depletion of oxygen levels as well. Benthic refers to anything that occurs on the bottom of a body of water such as a river, lake or ocean. As a result, the ability of benthic habitats to support aquatic life is undermined. This results in further implications, such as the decline in benthic habitat-forming species and species that are dependent on these habitats for foraging and shelter (US EPA, n.d.)

How littering results in Soil Pollution
Over 400 million tons of plastic are produced globally each year, and it is estimated that one-third of all plastic waste ends up in soils or freshwaters. As plastics are often considered to be one of the most common forms of litter in the world, they also present a threat to terrestrial ecosystems in national parks. This is due to the impact of microplastics in soils and sediments which could have a long-term negative effect on these ecosystems, based on a study done by De Souza Machado et al., (2018).  Microplastics are essentially plastics from litter that disintegrates into particles smaller than five millimetres. They can even be broken down further into nanoparticles, which are less than 0.1 micrometre in size. In fact, terrestrial microplastic pollution is much higher than marine microplastic pollution — an estimate of four to 23 times more, depending on the environment (De Sourza Machado et al., 2018).


Potential Impacts of Microplastic on Terrestrial Organisms (De Sourza Machado et al., 2018)

Microplastics can also interact with soil fauna, affecting their health and soil functions, due to its persistence of more than 100 years as a result of low light and oxygen conditions.  For instance, the earthworm’s fitness and soil function is affected as they have to make their burrows differently when microplastics are present in the soil. Additionally, microplastics could also affect soil chemistry, texture, structure and function, as highlighted in De Sourza Machado et al., (2018).

How littering results in Air Pollution
While littering may not directly result in air pollution, it presents a possibility of wildfires occurring. This is because litter is often composed of flammable materials, which may trigger the start of a wildfire from lighting or a small spark. Another possibility is the accidental lighting up of litter when discarded cigarette butts are not fully put off. When wildfires occur, outdoor airborne particles and gaseous air pollutants such as carbon monoxide, nitrogen dioxide, formaldehyde and acetaldehyde experiences substantial increase. Hence, air pollution may spread over thousands of square kilometres and affect populations living far away from the locale of the wildfire itself.

Smoke from fires in Siberia has blown as far as Alaska, Canada and US cities including Seattle (Credit: Julia Petrenko/Greenpeace)

Heavy smog caused by wildfires (Petrenko)

How littering results in Visual Pollution
Visual pollution is defined as the impairment of the view of an individual due to environmental and man-made factors, although they are most commonly caused by human actions like littering. Visual pollution can have significant effects on health and the well-being of people, as it may result in discomfort and stress for those who experience them. This is especially so for places like national parks, which are often regarded as natural sanctuaries for visitors to relax their mind and enjoy being in the presence of nature. Just imagine yourself walking on a hiking trail, enjoying the sights and sounds of nature, and then coming across a huge pile of trash along the way. Won’t that ruin your mood and experience?

A picture taken by yours truly, on a hiking trail in the Meili Snow Mountain National Park, China

Sometimes, all it takes is an irresponsible individual to start littering.. and others may very well follow suit after that, thus creating a perpetual cycle.

Till next time,


De Souza Machado, A., Kloas, W., Zarfl, C., Hempel, S. and Rillig, M., 2018. Microplastics as an emerging threat to terrestrial ecosystems. Global Change Biology, 24(4), pp.1405-1416.

US EPA. n.d. Impacts Of Mismanaged Trash. [online] Available at: <> [Accessed 9 October 2020].

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