How pollution reaches the sea
All too often, harmful waste matter is put deliberately into the sea – sewage, oil, chemicals and plastic articles are dumped from ships, oil rigs and even aircraft. Products such as agricultural pesticides from farms may be carried into the sea by rivers, and other substances fall from the atmosphere in the form of heavy metals. Lead, for example, originates in vehicle exhausts, yet is found in the sea. In small enclosed seas such as the Wadden Sea, these pollutants are trapped and build up in the bodies of fish and other marine life, with greater concentrations found in animals at the top of the food chain. In the open ocean, pollution may be carried thousands of kilometres by currents and tides and it may take a long time before the poisonous effects are discovered. In Antarctica, several species of wildlife contain pesticides that have never been used in the Antarctic.

What the law is doing
There are a number of laws and regulations designed to control marine pollution, directives which apply to European Union countries and international conventions such as OSPAR – the Convention for the Protection of the North East Atlantic. However, enforcing and policing these controls is a problem. There are also a number of organisations set up to control pollution such as the Environment Agency, the OSPAR Commission and the International Maritime Organisation (IMO).


Current threats & problems

Rubbish
Until it became illegal in 1989, ships would dump up to six million tonnes of rubbish into the sea every year, including plastic, glass, tin, wood and food waste. Lost nylon nets as well as rope and plastic waste helped kill two million seabirds, 100,000 marine animals and huge numbers of turtles and fish every year. Hospital waste has
also found its way into the oceans, as has waste from port and harbour dredges.

Legal steps have been taken to prevent these practices continuing – but they still happen and the problem, in the form of almost indestructible plastic, is already there.

Sewage
millions of litres of sewage are dumped in coastal waters each day – much of it untreated or given very basic treatment. It is unsightly and unpleasant and can contain harmful bacteria and viruses which cause diseases such as hepatitis. Industrial waste including man-made chemicals discharged into sewers finds its way into the sea and will build up, eventually killing fish and other animals.

Agricultural waste
oxygen is used up by farming chemicals and nutrients which are washed into rivers and eventually reach the sea. These include poisons to kill pests and nutrients to increase the productivity of the land. DDT, an insecticide that has been banned in some parts of the world for many years, is still found in high concentrations in birds that hunt by the sea.

Industrial waste
some of the industrial waste reaching the sea can comprise fats and carbohydrates from the food industry or cellulose from paper mills. This is biodegradable waste, which means it will be broken down by natural chemical processes – but even this action is harmful because it consumes large amounts of oxygen, leaving less for marine life. The process may also create toxic products.

Industrial waste is very damaging. It kills, causes distorted growth in shellfish and slows down the breeding rate of sea creatures. The most dangerous waste includes heavy metals such as mercury
and cadmium, biocides from the special paint used to prevent barnacles growing on ships' hulls, and various man-made chemicals including polychlorinated biphenyls (PCBs), now banned but still entering the environment from historical use. Significant levels of PCBs have been found in seals on the north coast of the Netherlands and pollution may account for the reduced number of dolphins seen around UK coasts.

Oil
tanker accidents grab the headlines, but they account for less than five per cent of the oil pollution which gets into the sea. The main sources are from shipping and oil refineries. Although ships are now banned from discharging oily ballast or washing out their tanks at sea, the main areas of oil pollution do happen to coincide with main tanker routes. Oil also reaches the sea from rivers where industry lines the banks. It kills seabirds, fish and other marine life and can damage whole communities that rely on fishing and tourism. Oil does eventually break down, but it can take a long time and even when a slick has disappeared, the oil dissolved in the water can slowly poison life in the sea.


What WWF is doing

WWF has been given observer status at many international frameworks which aim to reduce marine pollution and enforce pollution controls. This allows us to press governments and industry to introduce stringent measures controlling marine pollution from industry, agriculture and shipping. We also work with governments, industry, scientists, biologists and other organisations to ensure our marine heritage gets the protection it deserves.