Harmonizing methods to monitor microplastic pollution

Writer: Ning Liu, Editor: Anna Manikowska D.G., Reviewer: Yegor Volovik, Nancy Groves   The global production of plastics has increased between 1950 and 2017 at an average of 9 percent per year, reaching about 350 million tons in 2017. Natural weathering processes convert larger plastic products into much smaller pieces of plastics, micro- and nanoplastics. Besides, microfibers from clothing, microbeads, and plastic pellets used in cosmetics, as well as in cleaning products—currently extensively used—also enter the environment. In recent years, the negative impacts of microplastic pollution have drawn the great attention of scientists as a global issue. In the Northwest Pacific region, a group of scientists from China, Japan, the Republic of Korea, and Russia gathered together in Dalian, China, in September 2019 to discuss ways harmonize monitoring methods of microplastics pollution in the region. Daoji Li, Director of the Plastic Marine Debris Research Center from the East China Normal University, introduced a monitoring network of 48 survey stations along the coastline of China established by his team. In July 2019, the team conducted a comprehensive microplastic study in the Yangtze Estuary for the full tide and whole depth of the water. Following this exercise, in August 2019, the research was extended to an additional 15 main estuaries in China. Sang Hee Hong from the Korea Institute of Ocean Science and Technology highlighted the importance of adequate quality assurance and quality control practices for this kind of research. Such practices need to include some measures to avoid contamination of samples during storing and analysis, use of unique materials for sample handling and processing, application of special step-by-step procedures, and availability of certified laboratories and equipment. Atsuhiko Isobe, Professor at the Research Institute of Applied Mechanics of the Kyushu University in Japan, presented a "Numerical particle tracking model for predicting microplastic abundance in the Pacific after 50 years". According to his forecasts: "The high concentrations (of marine plastics) in the upper ocean are remarkable in boreal summer in the Northern Hemisphere, owing to the relatively calm oceanic conditions, and owing to the concentration denser than the Southern Hemisphere." In boreal summer, a heavy precipitation belt slowly moves from the equatorial Indian Ocean to south Asian monsoon regions on a time scale of two or to six weeks, which affects extreme weather events over Asia. Nikolai Kozlovskii, from the Pollution Monitoring Regional Activity Centre of the Northwest Pacific Action Plan, emphasized that some institutions in Russia had undertaken an initial assessment of microplastic contamination in the Baltic Sea coastal area and the Far East. Sampling in the rivers was carried out in spring, summer, and autumn months from 2016 to 2018. During discussions at the meeting, the scientists from China, Japan, the Republic of Korea, and Russia agreed to continue working on a project proposal to harmonize the monitoring methodologies for microplastics in the marine environment in the Northwest Pacific region. In order to succeed, pollution criteria of microplastics in the marine environment will be studied, such as the contents of microplastics in the water column, sediments, aquatic organisms, as well as the detection ratio in the various media and biota.