Water pollution

Sewage and waste dumping

For decades, the Mediterranean Sea served as a dump yard for sewage and a range of agricultural, industrial or military waste; sad to say, but the Mediterranean has always been considered one of the most polluted sea in the world.

The UNEP (United Nations Environment Program) has estimated that 650 million tons of sewage, 129,000 tons of mineral oil, 60,000 tons of mercury, 3,800 tons of lead and 36,000 tons of phosphates are dumped into the Mediterranean each year. Its reports also show that over 50% of the wastewater enters the Mediterranean Sea untreated1.

(Figure 2.1, 70% wastewater enter the sea untreated. Image from Greenpeace.org)

Looking at an aspect of health and hygiene, heavy toxic in seawater is one of the main origins of waterborne diseases. It can lead to eutrophication – increase in chemical nutrients, in this case, nitrogen and phosphorus – and results in excessive plant growth and decay. This may seem like a small problem at first glance, but lack of oxygen and decrease in water quality are all the further effects2.

Oil Spill

Oil spills only make up about 12% of the oil that enters the ocean, but it is still the worst form of ocean pollution, with its effects being immediate, long-term and extremely damaging3. And whilst it being a localised problem, the consequence is catastrophic, as the damages it can do to the local marine species is massive.

It is often caused when large tankers have accidents while transporting their liquid cargo. An oil spill from a tanker is a severe problem because there is such a huge quantity of oil being spilt into one place. The oil spreads rapidly, and forms a thin, film-like layer on the surface, as it cannot be dissolved. The oil slick suffocates fish, gets caught in marine birds’ feathers, and blocks light. With a long-term outcome, oil spills can cause reproductive and growth problems in marine creatures.

The Mediterranean Sea is a major oil transportation route. Approximately 200,000 ships cross the sea annually, releasing up to 650,000 tonnes of oil into the water from accidental spills and insufficient harbour facilities, making the Mediterranean the world’s oiliest sea.

Perhaps the most recent and well-known case is the Lebanese oil spill. July 2006, the Israeli army attacked the Jiyyeh station in Southern Lebanon, resulting 10,000 to 30,000 tonnes of oil been spilled into the Eastern Mediterranean Sea4. The environmental and economical impacts are devastating.

A holiday beach near Jbeil, which is heavily polluted by oil as a  result of the Israeli bombing of the Jiyyeh power plant on the 15th  July 2006

(Figure 2.2 – Oil floating near holiday beach near Jbeil. Image from Greenpeace.org)

(Figure 2.3 – The harbour of Jbeil, which is heavily polluted by oil. Image from Greenpeace.org)

Marine Litter

Marine litter is defined as any solid litter or garbage disposed or abandoned in a marine environment. Despite efforts regionally, nationally or even internationally, marine litter remains a major problem – and clear indications show – growing problem.

It poses a threat to marine animals – sea turtles, seals and birds can be severely injured or even killed by being entangled with or by consuming the garbage. Moreover, most of the marine litter would eventually reach our shores, becoming a major source of aesthetic pollution (also known as visual pollution). As far as human health and safety are concerned, marine litter washed up on our coastline poses risks such as disease transmission from medical wastes, or simply the harm that can be done to us when stepped on pieces of glass and metal.

Some marine litters are able to be decomposed in a short period of time – paper towels take 2 to 4 weeks, orange peels take 2 to 5 weeks. However, plastic bags take at least 10 years to degrade, and 90% of floating marine litter is plastic (see figure 2.4). This allows marine litter to continue over a long period of time.

(Figure 2.4 – Table shows the time taken to decompose various litter. Image from The Ocean Conservancy,
“Pocket Guide to Marine Debris”, 2006.)

(Figure 2.5 – Garbage piled up on a beach in Greece. Image from UNEP Topham Picturepoint)



3Clint Twist, “1000 things you should know about oceans”, Miles Kelly, 2005

pg: 58, 59



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