Trash left on beaches in Kanagawa, Chiba and Ibaraki prefectures, together with garbage and natural debris carried in by the tide totaled about 122 tons last summer, according to a recent government study.
The survey, conducted from June to September by the Land, Infrastructure and Transport Ministry, revealed that polyethylene terephthalate resin (PET) bottles and other plastic waste are exacerbating the trash problem.
The statistics were based on garbage collected by about 94,000 local residents from 380 beaches nationwide at 1-km intervals.
Compared with a national average of 6.3 tons per kilometer, the amount of trash collected from 29 localities in the three Kanto region prefectures came to 3.7 tons on average.
The biggest amounts of trash were gathered on two beaches in Chiba Prefecture -- 16 tons at Hiariura Beach in Ohara and 13.3 tons at Kido Beach in Hikari. Yuigahama in Kamakura, Kanagawa Prefecture, came in third with 8.4 tons.
By category, trash left by humans accounted for 39 percent of the total debris found on beaches, when analyzed according to 10-sq.-meter beach samplings.
In the Kanto region, the ratio was 46 percent, with plastic bottles and other plastics accounting for 16 percent, empty cans and metals 7 percent, and glass 5 percent.
Based on these data, the ministry plans to print leaflets for beach visitors to encourage them to stop littering.
PET bottles have become a major source of pollution in the country due to the lack of recycling facilities and the difficulty of processing colored plastics.
Many beverage companies are now opting to use transparent bottles to lighten the load on recyclers.