Wednesday, 31 August 2022
Monday, 1 August 2022
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