Impacts on people
For a long time, marine litter was regarded as a purely aesthetic problem. Only coastal resorts attempted to tackle the problem by regularly clearing debris from the beaches. However, as the amount of litter has increased, so too have the problems. It is difficult to put a precise figure on the economic costs of oceanic debris, just as it is difficult to quantify exactly how much litter there is in the sea. In one study, however, British researchers showed that marine litter has very serious implications for humans, particularly for coastal communities. The main impacts include:
- risks to human health, including the threat of injury from broken glass, syringes from stranded medical waste, etc., or from exposure to chemicals;
- rising costs of clearing stranded debris from beaches, harbours and stretches of sea, together with the ongoing costs of operating adequate disposal facilities;
- deterrent effect on tourists, especially if sections of coastline are notoriously polluted. This results in loss of revenue from tourism;
- damage to ships, such as dented hulls and broken anchors and propellers from fouling by floating netting or fishing line;
- fishery losses: torn nets, polluted traps and contaminated catches; if nets become choked with debris, the catch may be reduced;
- adverse effects on near-coastal farming: numerous items of plastic waste and other forms of wind-borne marine debris may be strewn across fields and caught on fences; livestock may be poisoned if they ingest scraps of plastic or plastic bags.
Impacts on animals
The presence of such large quantities of debris has a catastrophic effect on marine fauna. Seabirds such as the various species of albatross (Diomedeidae) or the Northern fulmar (Fulmarus glacialis) pick up fragments of plastic from the sea surface, ingest them and then often pass them to their chicks in regurgitated food. It is by no means uncommon for birds to starve to death as their stomachs fill with debris rather than food. Analyses of the stomach contents of seabirds found that 111 out of 312 species have ingested plastic debris. In some cases, up to 80 per cent of a population were found to have ingested debris.
In another study, the stomach contents of 47 harbour porpoises (Phocoena phocoena) from the North Sea were investigated. Nylon thread and plastic material were found in the stomachs of two of these individuals. In other cases, the debris itself can become a death trap. Dolphins, turtles, seals and manatees can become entangled in netting or fishing line. Some of them drown; others suffer physical deformities when plastic netting, fishing line or rubber rings entwine the animal’s limbs or body, inhibiting growth or development.
There is another threat associated with plastic debris as well: almost indestructible and persistent in the environment for many years, plastic items drift for thousands of miles and therefore make ideal “rafts” for many marine species. By “hitch-hiking” on floating debris, alien species can cross entire oceans and cover otherwise impossibly long distances. Plastic debris thus contributes to the spread of invasive species to new habitats, and can even destabilize habitat equilibrium in some cases (Chapter 5). >
- 4.11 > In the Great Pacific Garbage Patch between Hawaii and North America, vast quantities of litter are constantly circulating. Many plastic items are transported thousands of kilometres across the sea before they are caught up in the gyre.