What is plastic? How does its degradation affect ecosystems?

  • Plastikos
    • Plastics: thermoplastics and thermosetting materials
    • PET
    • PE, PP and PS
  • Microplastics in the Mediterranean
    • Zooplankton and microplastics
  • UV and plastic degradation
  • River Cleaning system

 

Plastikos

The term Plastics comes from the Greek “Plastikos” which means “suitable to be molded”. Plastics have in fact had a great success, and a wide diffusion, from ‘900 to today precisely because of their advantageous characteristics, compared to many other less performing materials, which allowed many uses in the most varied sectors.

Plastics: thermoplastics and thermosetting materials

Plastics can be divided into two macro categories: thermoplastics and thermosets. Thermoplastics become malleable with the action of heat and can be recast and then recycled and reused. Thermosetting plastics can be melted and shaped, but once solidified with the desired shape, unlike thermoplastics, they cannot be recast and then reused.

PET

PET, for example, is a robust yet lightweight, water-resistant and unbreakable plastic. PET is recyclable, however, much of the 26 million tons produced each year ends up in landfills or is dispersed into the environment[1] and often flows into rivers and then into the sea (where it takes hundreds of years to degrade).

PE, PP and PS

Other widely used plastics, and therefore the first sources of marine microplastics, are PE, PP and PS. In several marine areas studied, the most abundant floating plastics are fragments of polyethylene (54.5%), polypropylene (16.5%) and polyester (9.7%) and with high probability, many of them come from the continent by river[2].

Microplastics in the Mediterranean

According to a recent study[3], it has been observed that the microplastics found along the Mediterranean coasts are generally roundish in shape, small (~1mm) and light: all characteristics that suggest a state of advanced deterioration and therefore a long stay in the marine environment. It often happens that marine organisms eat the plastic floating on the marine surface.

Zooplankton and microplastics

Zooplankton is also able to eat microplastics and expel them through faecal pellets. This path thus generates an aggregate of particles of organic origin (faeces) and mineral origin (plastics) which, in addition to the additives that make up the microplastics, can bring toxic compounds into the trophic chain (metals, organic pollutants and others) or even invasive species and pathogenic organisms into marine waters.

UV and plastic degradation

The process of combining plastics with zooplankton feces could also facilitate the deposition and accumulation of microplastics in the seabed, an environment away from solar ultraviolet radiation. UV radiation[4] is a factor that allows the degradation of many widely used plastic compounds. UV rays are therefore on the one hand a benefit in the disposal of plastic waste, on the other hand a problem for objects that must remain intact for proper functioning without the risk of degradation by releasing dangerous microplastics.

River Cleaning system

Prolonged exposure of plastic devices to UV radiation accelerates the generation of microplastics that can be ingested by many aquatic organisms, effectively entering the food chain of rivers, lakes and seas. It is therefore very important that this additional source of pollution be prevented.

To deal with this problem, the River Cleaning patent is designed to be coated and composed of highly wear and UV-resistant plastics. Avoiding the degradation of materials is important in order to not create further pollution and, above all, to not compromise the primary function of the modules: the collection of plastic waste from the rivers preventing its arrival at sea.

Protecting river and marine systems is a priority and responsibility for River Cleaning to safeguard the future of the planet and humankind.

 

If you are interested in learning more about the project or if you want to know more about it, write us here, in any social channel, on our website or at info@rivercleaning.com.

 

 


If you are interested in learning more about the project or if you want to know more about it, write us here, in any social channel, on our website or at info@rivercleaning.com

[1] Rorrer et al. Combining reclaimed PET with bio-based monomers enables plastics upcycling. Joule, 2019 DOI: 10.1016/j.joule.2019.01.018

[2] https://rivercleaning.com/2020/06/plastics-the-urge-to-stop-the-path-to-the-sea/

[3] William P. de Haan, Anna Sanchez-Vidal, Miquel Canals. Floating microplastics and aggregate formation in the Western Mediterranean Sea. Marine Pollution Bulletin, 2019; 140: 523 DOI: 10.1016/j.marpolbul.2019.01.053

[4] Zhu L., Zhao S., Bittar T.B., Stubbins A., Li D., 2020. Photochemical dissolution of buoyant microplastics to dissolved organic carbon: Rates and microbial impacts, Journal of Hazardous Materials 383, (2020), https://doi.org/10.1016/j.jhazmat.2019.121065

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