The very thing that makes plastic items useful to consumers, their durability and stability, also makes them a problem in marine environments. Around 100 million tonnes of plastic are produced each year of which about 10 percent ends up in the sea. About 20 percent of this is from ships and platforms, the rest from land.
These larger items are the visible signs of a much larger problem. These big items do not degrade like natural materials. At sea and on shore under the influence of sunlight, wave action and mechanical abrasion they simply break down slowly into ever smaller particles.
A single one litre drinks bottle could break down into enough small fragments to put one on every mile of beach in the entire world. These smaller particles are joined by the small pellets of plastic which are the form in which many new plastics are marketed and which can be lost at sea by the drumload or even a whole container load. These modern day “marine tumbleweeds” have been thrown into sharp focus, not only by the huge quantities removed from beaches by dedicated volunteers, but by the fact that they have been found to accumulate in sea areas where winds and currents are weak.