Following on from the blog of two days ago I took a plastic(!) bag to the Estuary foreshore at South Ferriby and measured (roughly) 100 yards with the intention of seeing how full of litter the bag would be across this distance. In fact the bag was full in less than half way (see picture). So then, with the help of a calculator, assessed the quantity of man-deposited litter along both banks of the Estuary. The total distance along the clay-banks of the north and south banks of the Humber Estuary is 80 miles (approximately) which would equate to 281,600 bags of rubbish using my system above.
Three additional points;
Only the foreshore next to the clay-bank was trawled, the reed-bed stretched another 10+ yards into the tidal water.
A reed-bed would tend to trap flotsam, but with having a large tidal range the litter will settle on any hard surface as the tide ebbs.
About 90 per cent of the stuff in the bag is plastic drinks containers, this has got to be significant.