The Korea Institute of Ocean Science and Technology (KIOST, President Kang Do-hyung) measured the level of microplastic^* pollution in the sediment of Masan Bay and Jinhae Bay off the coast of Korea along the South Sea and confirmed that the concentration of microplastics has been increasing continuously since the 1970s, with the rate of increase in microplastic pollution, especially since 2000, being about twice as high as that of global plastic production, which is 8%.

* Microplastics: plastic particles 1㎛ to 5㎜ in diameter that are intentionally manufactured to be microscopic or have become microscopic due to weathering during the use of a plastic product or after entering the environment

The research team led by Dr. Shim Won Joon and Dr. Hong Sang Hee of the KIOST South Sea Research Institute has been actively conducting research on microplastics since 2012. Since 2022, they have been conducting the "Research on Inflow, Generation and Environmental Behavior of Marine Microplastics" project as a national research and development project of the Ministry of Oceans and Fisheries to quantitatively assess the level of harm caused by microplastics to marine ecosystems.

The research team used drilling to collect sediment samples with which they could measure the chronology of the sediment in Masan Bay and Jinhae Bay and thus identify the increasing trend of microplastic pollution from the 1970s to the late 2010s. Their findings have been published in international journals.*

* Soeun Eo, Sang Hee Hong, Won Joon Shim, et al., KIOST, Marine Pollution Bulletin, May 2023 (Paper title: Spatial distribution and historical trend of microplastic pollution in sediments from enclosed bays of South Korea)

The study found that the concentration of microplastics in sediment has been increasing over time. The average annual growth rate of microplastics has increased dramatically since the 2000s, with Masan Bay tripling from 5% to 15% and Jinhae Bay nearly doubling from 4% to 10%, which is higher than the annual growth rate of global plastic production of 8%.

In addition, the types of plastics were found to be growing increasingly diverse.^* In Masan Bay, only two types of microplastics, poly(acrylate:styrene) and polyisoprene, were found in 1971, while 20 types of plastics, including polypropylene and polyethylene,^** were found in 2018. In Jinhae Bay, only two types of microplastics, polypropylene and polyester, were found in 1988, while 10 types, including polypropylene and polyethylene, were found in 2013.

* See Plastics Europe, Plastics - the Facts 2022 (link to homepage: Plastics - the Facts 2022 - Plastics Europe)

** Polypropylene and polyethylene are the most common plastics, accounting for about 46% of the world's plastic production.

The types of plastics detected in Masan Bay, an urbanized area, were more diverse than in Jinhae Bay. In the case of Jinhae Bae, home to many aquaculture farms, polypropylene and polystyrene used in aquaculture ropes and buoys were detected in relatively high amounts.

With the emergence of marine microplastic pollution as a global environmental issue due to the increase in plastic consumption, relevant international organizations, including the United Nations Environment Programme (UNEP), have consistently called for action to address microplastic pollution, including risk assessments of microplastic pollution.

KIOST President Kang Do-hyung said, "KIOST is leading the world in research on the analysis, miniaturization, and environmental behavior of marine microplastics and harmful plastic-containing substances, and we are scientifically presenting the need for microplastic management through the environmental risk assessment of marine microplastics." He added, "This research will serve as an opportunity to raise awareness of the impact of marine plastics on marine ecosystems and the importance of the marine environment."