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GESAMP on litter: a more and more serious problem, particularly from tourism

Litter has become more and more serious a problem in recent times. It consists mostly of plastic waste discarded from centres of dense human population and fishing vessels. Another, more localized, source is tourism which is increasing worldwide particularly in tropical developing countries. Litter accumulates on beaches and in shallow water habitats

The thousands of tons of plastics discharged into the marine environment constitute a considerable source of marine contaminants that affect marine wildlife, particularly turtles, mammals and birds, through entanglement and ingestion.

Litter also has repercussions on coastal economic activities, particularly tourism. A variety of land-based and marine activities result in the introduction of debris or litter into the marine environment.

Generally speaking, urban debris is predominant in the vicinity of large cities while ship-generated litter is a major contributor on remote strand lines.

Since the 1970s, studies have addressed the problem of debris in the marine environment mainly in terms of quantitative measurements of abundance and the effects on marine fauna. Most of the data concern floating debris or litter along the coast. Plastics, notably polyethylene and polypropylene, account for the major part because of their poor degradability. Comparisons of the accumulation of marine debris among locations is, however, complicated by differences in the intensities and periods of study and the methods of classifying debris and beach substrate.

Nevertheless, it is obvious that marine contamination by buoyant and neutrally buoyant debris is ubiquitous. Even pristine environments located far from man-made sources, such as the Southern Ocean, are not free of marine debris.

The areas of most concern in relation to litter are shorelines where stranded material can pose risks to human health and cause the aesthetic deterioration of beaches and coastal waters, thus affecting tourism.

Effects on marine organisms are, however, more widespread and extend to the pelagic ocean and other remote areas. High litter concentrations are found in the vicinity of shipping lanes, around fishing areas and in oceanic convergence zones.

Denser solid material can be found littering the seafloor. Large amounts of debris have been encountered on the continental shelf of the Bay of Biscay and around northwestern Mediterranean towns. The presence of debris has also been recorded on the continental slope and the bathyal plain of the eastern and western Mediterranean basins. This further illustrates the ubiquity of litter and the associated risks of damage to marine ecosystems.

Social conditions have a major influence on the types of marine debris found on strand lines. Footwear is, for example, a comparatively large component in Indonesia (hundreds of thousands of flip-flops have been found on the shore of islands located more than 1000 km west of Jakarta), while diverse plastic kitchen and laundry containers, and metal and aluminium cans, are increasing constituents of beach macro-litter in many countries.

Source: GESAMP71:15-26