MICROPLASTICS

 

Microplastics are small plastic particles smaller than 5 mm, and plastic particles smaller than 1 µm are defined as nanoplastics. Microplastic particles exist in water, are consumed by living things, and can affect human health. Currently, microplastics are detected in various areas, such as streams, rivers, seas, drinking water, and even food in the world. Microplastics can be divided into two parts: primary microplastics and secondary microplastics. Primary microplastic is defined as plastic made of 5 mm or less according to a specific purpose, and it is often included in toothpaste, face wash, cosmetics, industrial abrasives and 3D-printer particles. Secondary microplastics were large at the time of production and manufacturing, but the large plastics were crushed or degraded through physical, chemical, and biological weathering, due to the environment, and became microplastics, such as straw foam and mulching vinyl. As such, pollution from microplastics are becoming a serious problem around the world, and many studies on microplastics such as distribution, toxicity, analysis, and removal are being conducted by many researchers. Among the 192 countries of the world, 44 countries have carried out research regarding microplastics; the studies looking at the impacts on organisms have mostly targeted fish (38%), whereas few studies on other highly affected organisms, such as turtles (1%), have been conducted. The main sources of microplastics in flash water are from domestic and industrial sewage, sea littering, and runoff water. Household sewage contains many microplastic particles in cosmetics and detergents used in everyday life, which is mainly introduced into sewage when washing faces or showers. Industrial sewage mainly flows from the plastics industry, such as plastic pellets and abrasives used in the manufacture of plastic products.

Many countries around the world treat their sewage using adequate water treatment methods. The sewage treatment plant removes many microplastics contained in sewage, but nano-sized microplastics still remains in the treated sewage water. Therefore, microplastics are continuously discharged into the surface water by domestic, industrial, and agricultural processes. Microplastics exposed to surface water are mainly introduced into the sea through rivers or streams and accumulate downstream or in sediments, mainly showing a high degree of microplastic pollution. In seawater, plastic fragments are worn out by extreme environments, such as waves and salinity, and are absorbed in various ways by marine creatures and salt, etc., and are finally swallowed by humans