It is widely known that microplastics are significant polluters of the ocean. Recently, microplastics were discovered in human lungs, breastmilk, blood or human's womb. But have you heard of microplastics in soil?
Why is it important to study microplastics in soil?
Microplastics can enter the plants and migrate to their edible parts
So we eat the microplastics directly or indirectly through the grazing animals
Also, microplastics can get from the soil into groundwater – and we drink the water
I researched the distribution of plastic microfibres in soil in the Isle of South Uist in the Outer Hebrides, Scotland – both their quantity and the processes behind it.
Despite its remote location, relatively pristine nature, and low population, way more microplastics than in China were found!
Why are so much more microplastics further from the coast?
Plastic microfibres have their origin mostly in synthetic clothes and fishing ropes. They get to the land from the sea by tides and wave action in general. Once they are on the beach, they can be easily transported further to the inland by wind. So why aren't there more microplastics near its source – the coast?
It has something to do with soil texture, organic matter content, and vegetation and its roots.
Sandy soil is more prone to wind erosion. There is less organic matter that would "glue" the grains and microplastics together, and there is very sparse vegetation and roots. This kind of environment cannot prevent the soil and the microplastics from deflation.
Once the microplastics get to the inland soils, which are more loamy, with more vegetation and denser roots, they easily incorporate into the soil. Irrigation, terrain depressions, or seaweed fertilisers help them. This kind of soil is less susceptible to wind erosion.
Simply, a lot of microplastics get to the beach, but they are quickly transported elsewhere. By contrast, microplastics tend to accumulate in the inland, vegetated soils. And in the future, the gap between the two environments will grow.
Why should you care when you live in an inland country or just far away?
The world is connected by the atmosphere and watercourses – and the rivers are full of microplastics
Thus, we all contribute to the microplastics pollution in the South Uist, at least by wearing and washing synthetic clothes
We still don't know all the impacts microplastics can have on humans' health
By researching the soil far away, we get more knowledge about the problem and it's applicable even in your local soil
I am the author of the map showing the modelled distribution of microplastics.
The model is based on following data: Fick & Hijmans (2017), The James Hutton Institute (2016),
European Environment Agency: EU-DEM, CORINE
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