National | Regional voices: Chubu

Massive increase in concentration of microplastics seen on beach facing Japan's Ise Bay

Chunichi Shimbun

Some 60,000 particles of microplastics per square meter — meaning one particle per 16 square millimeters — are estimated to exist at Nasanohama beach on Toshi Island in Toba, Mie Prefecture, a study by Yokkaichi University professor Satoshi Chiba has revealed.

Although the beach is known as a place where heavy concentrations of marine waste from Ise Bay wash up, there has been no research done on microplastics at the beach near the mouth of the bay.

Chiba, who specializes in coastal and marine environmental studies, and his students at the university in Mie Prefecture conducted the survey in February. They collected microplastics — plastic particles with a diameter of 5 mm or less — at 11 locations on the beach, each measuring 900 square centimeters on the surface and up to 5 cm deep.

They found 60,386 particles at the locations. Sixty-eight percent, the largest percentage of the particles, were fragments of Styrofoam, followed by controlled-release fertilizer pellets, accounting for 18 percent, and rigid plastics at 7 percent.

Others included plastic resin pellets — small cylindrical granules or spherical industrial raw materials used to manufacture plastic products — as well as artificial turf and plastic film.

The total number of particles is equivalent to 60,994 per square meter.

Students of Yokkaichi University examine microplastic particles on Nasanohama beach on Toshi Island in Toba, Mie Prefecture, in February. | CHUNICHI SHIMBUN
Students of Yokkaichi University examine microplastic particles on Nasanohama beach on Toshi Island in Toba, Mie Prefecture, in February. | CHUNICHI SHIMBUN

In 2008, a Kagoshima University research team collected microplastics at 33 locations on the coastline of Ise Bay, and the average density was 4,038 per square meter. Although a simple comparison cannot be made since the survey methods differ, the density on Nasanohama beach was 15 times higher.

“Waste is believed to originate from land areas and also sea areas where aquaculture and fishing are widely conducted,” Chiba said. “Microplastics are washed away and concentrated just like other marine waste. It is necessary to come up with measures to first reduce the kinds of waste that are produced in large quantities.”

It is said that some 12,000 tons of waste flow into Ise Bay a year mainly from Mie, Aichi and Gifu prefectures, much of which washes up on Nasanohama beach. Cleanup activities are conducted regularly on the beach, but they fail to keep up with the accumulating waste.

Microplastic pollution in oceans has become a global problem. In a declaration issued by the leaders of the Group of 20 major economies in June following a summit in the city of Osaka, they endorsed an implementation framework for actions on marine plastic litter.

Also in June, the government released its 2019 white paper on the environment with a new chapter assessing efforts to reduce plastic waste, reflecting increased public awareness of the issue.

The white paper estimates that some 8 million tons of plastic waste flow into oceans worldwide every year and mentions reports that microplastics are found at the North and South poles.

It also introduces the government’s plan to reduce domestic discharges of disposable plastic waste by 25 percent by 2030 and efforts to recycle plastic products, as well as to replace plastics with other materials.

Park Hye-sook, a professor of environmental geography at Mie University, said the issue of microplastics “has already been known, but the fact that it was included in the white paper on environment will offer an opportunity for every one of us to feel responsible for producing and using (plastics) and start making efforts in our everyday lives to make it into a big movement.”

This section features topics and issues from the Chubu region covered by the Chunichi Shimbun. The original article was published on Nov. 10.