Marine litter is nothing new but as the extent of the huge volumes of waste polluting the world’s oceans is emerging, international calls for action are becoming ever more vociferous. One of the sites particularly affected is located in the Pacific Ocean, about 1,600 km off the coast of California. People have known about this so-called “Great Pacific Garbage Patch" for years; now US researchers are trying to get right down to the bottom of this “plastics vortex” – a gigantic and ever increasing carpet of waste floating on the ocean. So far, there are no data on the composition of the waste or how many tonnes of it are floating in the oceanic garbage patch.

Scientists from the Scripps Institute of Oceanography (www.sio.ucsd.edu) in California are mounting an expedition to answer these questions. In addition, they want to establish whether it is possible to prevent further growth of the “patch”, which already covers an estimated area of 700,000 km², and, if so, how. “Many people believe it is an interrupted carpet of waste floating on the surface of the water that stretches as far as the eye can see,” says Robert Knox, director of Scripps. “When you are actually in it, you get relatively little idea of its dimensions. All you see are a few large areas of waste,” he explains, indicating just how complex the problem is.

One of the main research foci is how minute polymer particles – known as plastic confetti – impact marine life and what role they play in the food chain. It is extremely difficult to retrieve these increasingly small plastics particles, which often kill seabirds that mistake them for food. Marine turtles are also duped by plastic film floating on the water, which they confuse with their favourite food: jellyfish. Oceanic plastics waste even could enter the human food chain in this way. The research is therefore aimed at finding possible solutions to the problems posed by the growing volume of marine litter.

In a recent blog post from the research vessel Kaisei, Dr. Anthony Andrady also mentioned the risk posed by plastic pellets, which enter the ocean from large shipping vessels during sea transportation. "It is important to note that the team observed only the pellets that float in seawater; likely suspects are: polyethylene, polypropylene, and polystyrene," the senior research scientist wrote. "Other types of pellets, such as nylon or polyester, are denser than seawater and will not be encountered in surface-water collections. Yet, these pellets either remain in mid-water or reach the sea floor; interacting for incredibly long times with the organisms in such regions."

“Marine Litter – A Global Challenge", a 232-page report recently published by the United Nations Environment Programme (UNEP) and Ocean Conservancy (www.oceanconservancy.org) is the first scientific study to shed light on what is clearly becoming an increasingly pressing international problem. The report discusses marine litter in the world’s 12 main oceans. Aside from presenting and analysing the data available from regional programmes to combat marine waste, “Marine Litter” also includes general recommendations on courses of action for the national public, the private sector and international organisations.

The report deals with ecological and health problems as well as the vortex’s economic, social and aesthetic impact. Alongside the maritime ecosystem and the possible consequences for human health, UNEP has identified a range of other – predominantly economic – implications. Mountains of waste on beaches and oceanic garbage patches greatly affect coastal towns, tourism, shipping, fishing, and fish farms (as a result of damage to engines, nets and contamination). Experts believe the rapidly worsening litter problem is linked to a lack of suitable infrastructure, especially in poorer countries, behavioural problems, the failure to establish and enforce suitable global waste management standards and laws, and, last but not least, insufficient financial resources.

The report concludes that, despite the plethora of data and documents, there is still an enormous need for systematic and accurate scientific information on the amount, sources and consequences of maritime waste. Absent effective regional and international action, the problem will only get worse and alleviating the damage will become more complex.

UNEP’s data on the Mediterranean Sea provide a pertinent example of how the plastics industry is inextricably linked to the problem of maritime waste. During a broad investigation covering 1,052 nautical miles of ocean, carried out between February and April 2008, researchers sighted more than 500 kg of waste. The study indicates that plastics make up 83% of the waste floating on the Mediterranean, a popular holiday destination for Europeans. The remaining 17% of waste was comprised of textiles, metals, paper and wood.

Another study of Mediterranean beaches and coastal areas, carried out between 2002 and 2006, revealed a slightly different picture: The data showed that 40% of oceanic waste was smoking-related – with cigarette filters making up the largest share. A further 52% was linked to coastal leisure activities, and mostly included bottles, bags, closures and disposable cups and plates made from plastics, aluminium and glass. While the amount of waste from leisure activities on Mediterranean beaches is in line with the global average, smoking-related waste far exceeds the international norms. That said, a long-term study (1989-2007) reveals that smoking-related waste accounts for almost a quarter of waste particles worldwide.

Nevertheless, the plastics industry needs to pay greater attention to the problem of global marine litter. Due to their durability, plastics products tend to literally catch the eye, severely damaging the image of polymer materials, despite their many ecological advantages. After all, every year around 6m t of plastics products and waste dropped on beaches and in rivers end up in the ocean. Oceana (www.oceana.org), an organisation dedicated to protecting the marine environment, estimates that around 675 t of waste is thrown into the ocean every hour – more than half consisting of polymeric materials.

Solutions suggested by Achim Steiner, UNEP’s executive director, include improving waste management, better efforts at waste reduction and ensuring adequate recycling initiatives. He would like to impose a ban on certain types of plastics, such as ultra-thin disposal bags, which have a disastrous impact on marine life. “There is no justification for continuing to produce these thin films anywhere in the world,” he says.

In fact, many countries have initiated moves to ban these kinds of films. Such bans have already been imposed in many parts of Africa as well as in industrialised countries.

Another UNEP priority is to effect a drastic change in the public’s awareness of this garbage problem and how to address it. Both economic incentives and attractive market mechanisms to encourage recycling and re-use in an effort to counter the prevalent throw-away mentality could help restore the maritime ecosystem. Such efforts could well constitute a basis for initiatives of the plastics industry.

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UNEP report “Marine Litter – A Global Challenge” as a PDF document (6,744 KB)