CONTINUOUS MONITORING FOR FLOATING-DEBRIS FLUX IN RIVERS WITH IMAGE ANALYSIS TECHNIQUE

Marine debris with a lot of plastics has become a global and serious environment issue. In particular, a microplastic which is less than 5 mm has been focused over all the world because microplastics with hazardous chemical substance influence on a lot of marine lives. Marine debris are mostly originated from inland and flowed out into the ocean via rivers. Therefore, it is necessary to conduct monitoring of floating-debris flux in rivers. At the first step to improve the plastic waste inputs from Japan, we attempt to estimate annual transport amount of riverine plastic debris in Edo River and Ohori River using a monitoring camera system, and also to estimate an amount of unknown plastic waste in the catchment area of these rivers based on waste management data. The annual transport amounts of riverine plastic debris were 2.83 ton in Edo River and 0.0116 ton in Ohori River, respectively. The annual transport amount of Edo River (Ohori River) corresponds to 0.0098% (0.0005%) of the disposal record of plastic waste.