Microplastics and the Environmental Impact
Microplastics( MPs), are small plastic particleswith a diameter of less than 5 mm. They appear in various shapes as fragments, fibers, microbeads, forms and pellets. MPs are divided as primary and secondary Microplastics based on their origin. Primary MPs are intentionally producedby designing sizes less than 5 mm and used directly as coarse grains on cleaning products or as a starting material for many plastic products. This class of MPs isused in the cosmetic industry for manufacture of personal care products as facial scrubs, exfoliating hand scrubs, detergents, soaps, toothpaste etc. and also use for blasting thefibers from synthetic clothing are also regarded as primary MPs. Secondary MPs are formed from the degradation and continuous fragmentation of larger plastic components under environmental conditions such as ultraviolet radiation, oxidation, mechanical abrasion etc. Secondary microplastics are more abundant in the environment than primary Microplastics.
Microplastics are not biodegradable. Thus, once in the environment, these microplastics accumulate and persist, mainly in oceans and water bodies. Depending on the density of the polymer, microplastics can float on water and travel far across the globe or sink into sediments.
Apar t from carbon and hydrogen,microplastics consist of other chemicals, including plasticizers, antioxidants, UV stabilizers, lubricants, dyes and flame retardants that were added during manufacturing. These chemical additives leach out of the plastics and enter into the environment.
In addition, MPs have high affinity to adsorb persistent organic pollutants (POPs) such as polychlorinated biphenyls, polycyclic aromatic hydrocarbons, chlorinatedpesticides, heavy metals from the surrounding as well they supply good niches for microorganisms including pathogenic bacteria.
Discharges from factories, households and sewerage add microplastics directly to the environment. Microplastic beads from cosmetics, micro fibers from laundry washing of synthetic clothing containing microplastics are also get added to the environment through sewerage systems. MP used as pharmaceutical and dental carriersin medical field, also end up in the environment through wastewater.
Due to their extremely small size, micro and nano plastics does not get filtered through conventional wastewater treatment processes and will float into rivers, and other fresh water systems and finally to oceans. Micro and nano plastics present in soil are also get into rivers and oceans, through natural erosion. Rivers are the main transport mode of MP into seas and oceans. It is well known fact that the main input of plastic into oceans are from land-based sources that flows through rivers, and only a marginal input is added directly to the ocean from ships, fisheries and water breeding. In a recent study it has shown that Asian rivers present 86% of the global input of MP into oceans, whereas European rivers account for less than 0.5%.
Microplastics are also a source of air pollution, occurring in dust and airborne fibrous particles. Over the last 70 years, the usage of plastics by world population has increased and is still increasing. It was reported in Basel Convention on controlling transboundary movements of hazardous waste and their disposal, plastic accounts for around 10% of the total waste generated and constitutes approximately 90% of all trash floating on the ocean’s surface.
The main concern on microplastic pollution is how it affects the ecosystem and human health.
Once entered to aquatic environment, microplastics could be taken up by wide range of aquatic species, along with their food or ingest mistakenly for food. It was reported almost 700 aquatic species worldwide were adversely affected by microplastics. MPs block the digestive tracts and stuff the stomachs with plastic which leads to starvation and ultimately death. The plastic additives, in microplastics also released to the aquatic environment and cause harm to aquatic organisms.
Microplastics enters to human system through water, contaminated food, inhalation of dust particles, use of personal care products and cosmetics etc. Studies have shown that some adsorbed chemicals on microplastics can interfere withhormone function resulting adverse effects in humans, brain development of fetuses and children, causes cancer or birth defects.
Sri Lanka, once famous for its beautiful beaches is now listed as the 5th polluter with plastic disposals to the ocean. The studies have shown that microplastic pollution is one of the main causes for the decline in fishing harvest along the coast line affecting the earning source of peopling living along the coastal areas. The beaches polluted with debris of plastic makes an unpleasant environment for the tourists visiting the country.
Due to the useful properties of plastics, it cannot completely ban or immediately replace with other alternatives. Even though we do not feel the toxicological and ecosystem consequences at present, it has already occurring harming the environment and human health.
Concern about adverse effects of microplastics several international organizations has initiated programmes onwaste management and mitigation of microplastics.
Sri Lanka realising the consequences of increasing plastic pollution has initiated many programmes for reduced the usage and manufacture of plastic and also to solve waste mismanagement. In 2017, Sri Lanka banned the production of polythene with the thickness less than 20 microns and the single use plastic such as lunch sheets. In 2019, Sri Lanka along with 186 countries agreed on including plastic waste in a legally binding framework in Basel Convention.
Sri Lanka signed a MoU with Centre for Environment, Fisheries and Aquaculture Science (Cefas) UK joining Commonwealth Litter Programme (CLiP) to take action on plastic entering to the oceans. Industrial Technology Institute (ITI) along with Central Environmental Authority ( CEA), Marine Environment Protection Authority (MEPA), National Aquatic Resources Research and Development Agency (NARA) initiated to work with Cefas. on management of marine pollution. Under this collaborationa pioneer research and testing organization; ITI has granted with novel equipment for a fully-fledged microplastic testing laboratory. Addition to that ITI already conducting testing services on MPs in surface water, potable water, sea water, waste water, cosmetics, sand, etc. Testing of MPs in matrices like salt, bottled water, sediments, soil also are potential areas. Not only that ITI has been conducting some research on MPs in personal care and cosmetics. ITI is planning to conduct a baseline study on quantification of MP load in major rivers in Sri Lanka.