Microplastics are plastic particles less than 5mm in diameter. They contribute to over 80% of the ocean debris. The plastic materials discarded by humans traverse through land and are passed to the oceans by wind or rivers. These plastic materials are broken down to smaller particles by exposure to sunlight or wave action. These smaller plastic particles are called microplastics.
Marine organisms such as fish, crabs and prawns consume these microplastics by misidentification as food. Humans consume these seafood which leads to several health complications. Thus plastic materials discarded by one man ends up on the plate of another man through seafood and sea salt.
Microplastics pose a global problem. However, only 43% of the countries are actively involved in studies on microplastics. This is evidenced in a study entitled “Global distribution of microplastics and its impact on marine environment — a review” published by a team of researchers, inlcuding Nithin Ajith, Surya Pathasarathy, Sathish Manupori and Sivamani Janakiraman, in a leading environmental journal Environmental Science and Pollution Research published by the Springer group.
The review was projected based on the 220 articles published from 2010 to 2019 in peer-reviewed journals. According to the study, microplastics are present on all ocean floors. The analysis highlighted that only 44 (22.9%) countries have engaged in microplastics research. This creates a lacuna of information on microplastic abundance and distribution on a global scale.
Europe (38%) is known to have the highest percentage of studies on microplastics followed by Asia (36%) and North America (12%) and South America (7%). The U.K., Canada, China and India were the front runners in microplastics research. Contrastingly, research in this regard in Africa (2%) and Australia (4%) was scanty, whereas in Antarctica (1%), it was negligible.
With regard to microplastics study in different oceans, numerous research studies have been carried out in the Pacific and Atlantic oceans, while very few have targeted the Arctic and Antarctic oceans. However, there are only a few investigations along the Indian Ocean, where there is a possibility of very high microplastics content.
The article also brings out a number of common seafood such as fish, mussels, clams, crabs and shrimps to have consumed microplastics as evidenced in numerous former studies. In addition to these, some of the earlier studies have observed microplastics in drinking water and table salts. Cosmetics such as face creams and other facial materials also contain microplastics as these are intentionally added to the creams to improve facial gloss. Therefore, the threat of microplastics to man is large with drastic health effects from skin diseases to arteriosclerosis.
The article highlighted that in recent years, research on microplastics has increased; despite that, this information on a global scale is scanty since these studies have been carried out only in certain countries.
The authors suggested that unanimously all the countries need to monitor the microplastics levels off their particular coasts as this will help estimate and understand global abundance of microplastics. The impact of microplastics on the ecologically rich areas such as mangroves, coral reefs, and kelps is not studied well, which needs to be carried out. Numerous organisms have been studied right from microalgae to the whales; however, there are no clear evidence or conclusions on the possible biomagnification or trophic transfer. This aspect has to be studied thoroughly. Yet another area of concern is the degradation of microplastics as it requires several hundred years for degradation to occur naturally.
The article also pointed out that the existing plastic degradation mechanisms such as photodegradation (using sunlight) and biological degradation (using microbes) is ineffective as they only breakdown the microplastics rather than degrading them completely. Hence, a combination of photo and biological degradation systems for effective and complete decomposition of microplastics has been suggested.
In an extended study which is awaiting publication in an indexed journal, the author and his research scholars have observed microplastics in edible fish collected along the Tamil Nadu coast. The fishes include flathead mullet, Indian mackerel, pearl spot, tongue fish and yellow crab. Apart from these, microplastics have been noted in table salt collected from saltpans of Tamil Nadu and in processed salts purchased from supermarkets.
The global problem of plastics will only be solved if all countries and decision-making policies decide to monitor microplastics along their respective coasts and also implement orders to use only biodegradable plastics. In India, both the Central and State governments have implemented several regulations; however the use of plastics have increased day by day and the utilised plastics are not properly recycled or disposed of. Awareness must be created among the common people regarding impact of microplastics.
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