World Environment Day – Plastic Pollution and Rivers

Plastic Pollution and Rivers

The topic of plastic pollution in news and research has often focused on the impact on our oceans. However, less is known about the impact of plastic pollution along the highway to the oceans, and our rivers. Around 70-80% of all plastic in the sea has been transported via rivers and coastlines[1], not all plastic waste does not make it to the ocean, and can be found years, decades, and centuries after entering our river system.

What impact can plastics have on our rivers?

• Rivers support an abundance of species, from brown trout to zooplankton. Over time, plastic can block rivers, preventing migratory fish from reaching their destination[2].
• As plastic breaks down in rivers, evidence suggests that ecosystem productivity and functioning can be negatively impacted, by the altering of key nutrients and growth of primary producers¹.
• Microplastics can impact nutrient cycling, due to the sinking of nutrients bound to plastics, as specific polymers from plastics can promote nitrification/denitrification in sediment, affecting nutrient availability in rivers[3].
• Further issues lie in microplastics as carriers of heavy metals and organic contaminants.
• Rivers can experience blockages due to plastic debris, leading to reduced flow capacity and raised water levels, leading to increased flood risk. Densely populated slums are significantly more likely to have blocked drainage systems, which cause water levels to rise; this is common in areas with less developed infrastructure, due to ease of blockage.

Plastic Pollution and Human Health

Microplastics and nano plastics end up in our bodies through inhalation (urban dust, rubber tyres, and synthetic textiles), ingestion (animal products, food production, leaching from food packaging), and skin contact (through wounds, sweat glands, and hair follicles). However, most of our consumption of microplastics is through kinds of seafood, posing the greatest risk. Much research on the impacts of plastics on human health is still developing.

What do we know about the impact of plastics on human health?

• Research has identified lung inflammation, apoptosis, and leaching of toxic chemicals as potential effects.
• Breathing in plastic particles can also lead to alveoli blockages, subsequently reducing our lung capacity, and leading to lung inflammation.
• Plastics can be carriers of contaminants, such as heavy metals and organic toxicants that subsequently enter our bodies. These can have several effects including increased risk of cancer, acting as hormones affecting our immune system, organ functionality, and reproductive system[4].

Reference list:

[1] Li, W. C. et al, Plastic waste in the marine environment: A review of sources, occurrence, and effects, Science of the Total Environment (2016)

[2] Honingh et al, Urban River Water Level Increase Through Plastic Waste Accumulation at a Rack Structure, Front Earth Science (2020)

[3] D’Avignon et al, Microplastics in lakes and rivers: an issue of emerging significance to limnology, Environmental Reviews (2021)

[4] Campanale et al, A Detailed Review Study on Potential Effects of Microplastics and Additives of Concern on Human Health, Int J Environ Res Public Health (2020).