Subtopic 2: The impact of plastic pollution on the flora

The majority of researchers affirm that plastics and microplastics are a major concern for the flora, because they reach the soil and the water sources thus leading to the decrease of species living below the surface – such as mites, larvae and other tiny creatures – (Microplastics negatively affect soil fauna but stimulate microbial activity: insights from a field-based microplastic addition experiment), to having less fertile soil and land, to releasing harmful chemicals into the soil, such as the Bisphenol A (BPA), which disrupt the hormone systems of vertebrates and invertebrates and alter soil’s composition and chemistry, and, finally, to hinder the photosynthesis capacity. However, on the other hand, a consistent part of researchers affirms that determining the exact impact of plastic contamination in the soil is a difficult challenge which cannot be seen by the naked eye’s scope. On this matter, some authors have argued that plastic may not be as harmful to plants like it is to animals because soils are rich in particles and plants only absorb what they need from the soil. On the other hand, it has been highlighted by research that any change in soil chemistry causes a domino effect on all the plant life dependent on the soil, thus negatively affecting the growth and productivity of flora, impacting the metabolic effect on plants and increasing the possibility of drought.

Figure 9 – Source: repurpose.global – What is the Effect of Plastic in Forests and Widlife?

In addition to that, as a consequence, the food growing in the soil and the wildlife and humans consuming this food are more likely to be contaminated with microplastics. According to Greenpeace (3 Everyday Foods that contain Microplastics), fruit like apples and pears have an average of 195,500 and 189,500 particles of plastic per gram respectively, whereas vegetables like broccoli and carrots average more than 100,000 plastic fragments per gram. Other studies have demonstrated that one of the worst scenarios is the case of plastic penetrating and getting absorbed by plant roots of lettuce and wheat, which both humans and animals highly consume. Surprisingly, studies carried out by the Hong Kong’s Consumer Council have found microplastics in over 90% of 39 sampled salt brands sourced from 21 countries.

Figure 10 – Source: plasticsoupfoundation.org – New Studies: Microplastics found in Fruit and Veg.

A research conducted in Germany (An underestimated threat: Land-based pollution with microplastics) has demonstrated that the impact of plastic and microplastics in soils, sediments and water has a detrimental long-term negative effect on ecosystems and humans. It is due to the sewage systems and wastewater disposals that microplastics are distributed in the soil and the water, and in particular garment plastic fibres from our clothing (acrylic, nylon, spandex and polyester) persist in the sludge because get shed every time we wash our clothes. To investigate more on this issue, the clothing company Patagonia commissioned a study in 2016 to the University of California, Santa Barbara, (Microfiber Masses Recovered from Conventional Machine Washing of New or Aged Garments) whose shocking result was that a synthetic jacket being washed released an average of 1.7 grams of microfibers into the environment.

Figure 11 – Source: orbmedia.org – Invisibles. The Plastic Inside Us – https://orbmedia.org/the-invisibles

As a consequence, plastic reaches water (including tap water) and causes diseases to both the organisms and the environment. For example, earthworms build their burrows in a different way if microplastics are present in the soil, thus affecting their wellbeing and reproduction.

More specifically, plastic changes the composition of the soil, it leads to an increase of water evaporation, which dries to soil, it leads to an accumulation of toxic elements, and it impacts plants’ roots and then prevents these from growing and flourishing.

Figure 12 – Source: Shahid Iqbal, Jianchu Xu, Schaefer Douglas Allen, Sehroon Khan, Sadia Nadir, Muhammad Saleem Arif, Tahira Yasmeen, “Unraveling consequences of soil micro- and nano-plastic pollution on soil-plant system: Implications for nitrogen (N) cycling and soil microbial activity”, Chemosphere, Volume 260, 2020, 127578, ISSN 0045-6535, https://doi.org/10.1016/j.chemosphere.2020.127578.