“I eat rubbish!”, the notice fixed to it claims that it collects 40 tons of rubbish every year; the equivalent of 800,000 plastic bottles. Called a “passive debris collector”, nine of them have been bobbing along the river for the past five years. Each captures tons of floating litter; bottles, cans, and plastic, that otherwise would have flowed out to sea and killed fish and birds. It was initiated by Thames21, an environmental charity…