Every year, huge quantities of waste and pollutants are dumped into the oceans. Many of these substances did not even exist 50 years ago. Ocean pollution, particularly in coastal waters, comes from activities on land and at sea.
Fertilizers and pesticides used by farms, industrial and nuclear waste, exhaust gases emitted along the roads, used water and garbage are all dumped in waterways and end up in the ocean. Atmospheric emissions from industry and transport are another significant source of pollution from the land. Once emitted, many chemical compounds (copper, nickel, mercury, cadmium, lead, zinc and synthetic organic compounds) remain in the air for weeks, if not more. Carried by the wind, they often end up in the ocean.
Pollutants and garbage are spread around the globe by ocean currents. Marine activities such as the extraction of fossil fuels, transport (including cruise ships) and fishing dump massive amounts of toxic substances in the ocean.
Sound pollution, which profoundly disturbs the behavior of some animals species such as large marine mammals, is another increasingly serious problem.
Oil spills caused by boats colliding or running aground is another issue which has long been a significant international problem, now joined by similar spills of other dangerous, noxious substances.
Once in the marine environment, many pollutants from the land or the sea accumulate in the and form a serious threat to ecosystems, whether along the coast or in deep waters.
According to a recent reportfrom the United Nations Environmental Programme (UNEP), plastics, particularly bags and PET bottles, are the most common marine waste in the world. In many regional seas they make up over 80% of garbage.
Plastic waste accumulates in land and marine environments around the world, decomposing very slowly into small toxic pieces which can consumed by living organisms at all levels of the food chain. Many animals, including marine mammals, birds, fish and turtles, can mistake plastic for something edible. Sea turtles, in particular, confuse the floating bags for jellyfish, one of their favorite foods. A five-year study on fulmars in the North Sea region showed that 95% of the birds had plastic in their stomachs.
Every year, humans use hundreds of billions of plastic bags (100 billion in the United States alone, according to the World Watch Institute). Only a small percentage are recycled, while the rest are used very briefly, usually just for the short trip from shop to home, then thrown out, where they are left to fester in nature for thousands of years.
Plastic bags join with other waste in the oceans to form immense expanses of garbage, effectively giant floating dumps. The most famous, known as the Trash Vortex or the Great Pacific Garbage Patch, is bigger than Texas. This enormous garbage dump has been created by marine currents between Hawaii and the North Pacific. Its infamy has made it a tourist destination.
UNEP Executive Director Achim Steiner: “Some of the litter, like thin film single-use plastic bags which choke marine life, should be banned or phased out rapidly everywhere – there is simply zero justification for manufacturing them anymore, anywhere.”