Feature Article
Fig. 1 Microplastics and Nanoplastics
The problem of Microplastics: Are we under threat? Dr Sajith Edirisinghe Lecturer and Clinical geneticist, Department of Anatomy, Faculty of Medical Sciences, University of Sri Jayewardenepura
T
he term plastic is a generic name given for most of the synthetic and semisynthetic organic polymers which are capable of exhibit plasticity. From our childhood, we have heard of how plastic pollutes the environment. According to the estimated amounts by the year 2017, approximately 6300 million tons of plastic waste had been generated throughout the world. From this huge amount, nearly 20% was recycled or incinerated. In contrast, the remaining 80% was either used in landfills or released without control to natural environments(Geyer et al., 2017). Microplastics(MPs) and Nanoplastics (NPs) refer to the fraction of plastic that is released into the environment, either properly or otherwise, through various environmental or human processes. These MPs particles range from 1 micrometer (10-6m) to 5 millimeters (Figure 01) and those that are smaller than that ( < 1 μm scale) are called Nanoplastics.
How are microplastic/ nanoplastic materials added to the environment?
Fig.2 Primary microplastics in Face Soaps (tiny dark red particles)
Fig.3 Primary microplastics in toothpaste (tiny dark blue particles)
There are several ways in which these MPs/NPs / nanoplastics can be added to the environment. For the study purpose, the MPs/NPs are divided into two parts. These are primary MPs/NPs and secondary MPs/NPs.
Primary microplastics Primary MPs are plastics that are manufactured in sizes less than 5mm and released to the market. For example, small plastic beads used in textiles, tiny plastic beads found in face washes/toothpaste/shower gels, belong to this category(Figure 02 & 03). Without our knowledge, these tiny plastic particles flow through waterways and eventually enter the sea. A recent study have shown that in one wash alone, up to 100,000 MPs/ NPs, molecules are released into the environment(Napper et al., 2015).
Secondary microplastics This category includes plastics
Fig. 4 How Secondary microplastics are produced that are released to the environment after being used once (plastic drink bottles, straws) or several times (plastic pans). These plastics get continuously broken down into very small pieces [eg:- biodegradation ( the action of living organisms – crushing ), photodegradation ( light radiation from sunlight), thermo-oxidative degradation (slow oxidative breakdown at moderate temperature), thermal
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February 2021 | 21
