Over recent years since the advent of “plastics”, there has been a consistent annual increase in its global demand. In 2018 alone, global plastic production surpassed 360 million tonnes. A few years ago, it was estimated that approximately 6,300 metric tonnes of plastic waste had been generated, out of which around 9% had been recycled, 12% incinerated, and a staggering 79% used in landfills or dumped into the sea.
Plastics that eventually end up in the environment get weaker over time, leading to fragments that are less than 5 mm in size, which are then called microplastics. These are not a particular type of plastics as many believe, but rather are smaller fragments of any type of plastic material. They can be produced due to environmental degradation or by intentional manufacturing such as in the cosmetic industry, be it as tiny beads in exfoliants or in other consumer processes such as clothing and industrial processes where they are called primary microplastics. The vast majority of materials used to make plastics, such as ethylene and propylene, are derived from fossil hydrocarbons. None of the commonly used plastics are biodegradable and their accumulation in the environment leads to human exposure.
[caption id="attachment_88085" align="alignleft" width="200"]
Dr. Sajith Edirisinghe[/caption]
To understand its long-term impact on human health and disease, we spoke to an avid educator on the harmful effects of microplastics, Dr. Sajith Edirisinghe, who is a lecturer at the Department of Anatomy of the Faculty of Medical Sciences at the University of Sri Jayewardenepura (USJ).
The local situation is not poles apart. We are among the top five countries that mismanage plastic use. This is estimated to be 300 g of plastic waste per person living in Sri Lanka per day. The preliminary results show that waters on the west coast are more polluted with microplastics compared to the east coast, with the highest abundance in the north west (0.85 particles/m3). The central east is slightly more polluted (0.27 particles/m3), compared to the north east (0.18 particles/m3) and the south east (0.25 particles/m3).
Microplastics found in the southern waters were as low as 0.12 particles/m3. The overall average abundance of microplastics in Sri Lankan waters was estimated to be 0.31 particles/m3 of surface water. The majority of microplastics were fragments whereas the second and the third most abundant contaminants were thread-like microplastics from fishing nets and foam, respectively. Microplastics are now found in our oceans, rivers, soil, and air, and most importantly are contaminating the food we consume. Its ubiquitous nature hasn't left any stone unturned. As a result, we have been exposed to microplastics through ingestion, inhalation, and skin contact over many years, thus leading to eventual internal toxicity if we don’t take steps in the right direction.
PHOTO ©Abdul Halik Azeez, 2020[/caption]
Dr. Sajith Edirisinghe[/caption]
To understand its long-term impact on human health and disease, we spoke to an avid educator on the harmful effects of microplastics, Dr. Sajith Edirisinghe, who is a lecturer at the Department of Anatomy of the Faculty of Medical Sciences at the University of Sri Jayewardenepura (USJ).
The local situation is not poles apart. We are among the top five countries that mismanage plastic use. This is estimated to be 300 g of plastic waste per person living in Sri Lanka per day. The preliminary results show that waters on the west coast are more polluted with microplastics compared to the east coast, with the highest abundance in the north west (0.85 particles/m3). The central east is slightly more polluted (0.27 particles/m3), compared to the north east (0.18 particles/m3) and the south east (0.25 particles/m3).
Microplastics found in the southern waters were as low as 0.12 particles/m3. The overall average abundance of microplastics in Sri Lankan waters was estimated to be 0.31 particles/m3 of surface water. The majority of microplastics were fragments whereas the second and the third most abundant contaminants were thread-like microplastics from fishing nets and foam, respectively. Microplastics are now found in our oceans, rivers, soil, and air, and most importantly are contaminating the food we consume. Its ubiquitous nature hasn't left any stone unturned. As a result, we have been exposed to microplastics through ingestion, inhalation, and skin contact over many years, thus leading to eventual internal toxicity if we don’t take steps in the right direction.
Birth of microplastics
Plastic waste takes aeons to decompose – an estimated 400-650 years or more. As a result of their longevity, they are exposed to various environmental conditions such as heat, rain, UV radiation, and mechanical degradation. These processes contribute to its fragmentation and the eventual birth of secondary microplastics, which are visible to us. However, they can be further broken down into microscopic pieces. [caption id="attachment_88086" align="aligncenter" width="800"] PHOTO ©Abdul Halik Azeez, 2020[/caption]
Microplastics and the ecosystem
Owing to its versatility and low cost, most conventional materials such as glass, metal, and paper were replaced with plastic alternatives. However, its derogatory nature only came to light many years later. Nearly a third of all plastics are converted into consumer packaging material including disposable single-use items commonly encountered as beach debris (Figure 1). It is estimated that 80% of the seabeds in the Western Province of Sri Lanka is heavily polluted with this type of single-use plastic waste. However, it is not surprising that 80% of this pollution originates on land. Our monumental overuse of plastics has a devastating impact on the ecosystem. Since the oceans are the world's largest sink for microplastics, the biggest impact is seen here. This has now become a persistent pollutant one that is difficult to remove and is distributed widely across the globe. Research has shown that this particulate matter has toxic effects on freshwater plants, invertebrates, and several species of fish and when we consume these marine animals and plants, it can have an impact on us. Microplastics found in agricultural soil, dust, and groundwater may contribute to its toxic effects as well. In a recent study, a quarter of the marine fish sampled from markets in Indonesia, California, and the US were found to have plastic debris. Fibres from textiles in their guts are the best example of a “plasticised food chain”. The effects of microplastics include toxicity, oxidative stress, and inflammation. Inflammation may lead to cancers and may contribute to a disruption of immune function and neurotoxicity. Besides seafood, emerging evidence shows that the microplastics, especially synthetic fibres, have been detected in a variety of food including drinking water, beer, honey, sugar, and table salt. These microplastics are also found freely floating in the air. When inhaling the polluted air, the microplastics might enter the human body. According to the study conducted by the University of Newcastle, Australia, currently each human consumes 5 g of plastic per week (irrespective of age and gender). In reality, it is the size of an ATM card, stated Dr. Edirisinghe.