Oil Pollution Impact

1. The Impact of Oil Pollution

Even if alternate energy sources are being researched, the globe still depends heavily on oil. There are a number of reasons for this: it is relatively easy to store and transport it is easier to extract from the ground than solid materials such as coal it can be made into a number of different products it usually produces less pollution when burnt compared with coal.

Oil is not available everywhere, which presents a problem for the global economy because supplies must be delivered over long distances to buyers. Due to the high demand for oil and the limited supply, individuals who possess reserves have significant economic influence.

Oil is a hazardous substance, and spills can result in significant harm. Crude oil is a sticky, thick substance that is retrieved from the earth. It can also catch fire. An oil leak can have disastrous effects.

The table below lists some of the largest oil spills recorded and their causes.

Oil spill Location Cause of spill Approximate amount of crude oil split (thousand tonnes) Kuwait Oil Lakes 1991 Kuwait War 5000 The Lakeview Gusher 1910 USA Onshore oil extraction 1200

Deepwater Horizon 2010 USE coast/Gulf of Mexico Offshore oil extraction 575 Ixtoc 1 1979 Mexico/Gulf of Mexico Offshore oil extraction 475 Atlantic Express 1 1979 Trinidad and Tobago Oil tanker collision 287 Fergana Valley 1992 Uzbekistan Onshore oil extraction 285 ABT Summer 1991 Angola Oil tanker 260 Amoco Cadiz 1978 France Oil tanker crash 223 The table does not provide the complete picture because the degree of environmental harm is not always correlated with the volume of oil spilled. The oil tanker Amoco Cadiz produced a far lower amount of oil than many of the other spills listed, but because of the dispersion of the oil and the difficulty in cleaning it up, it had a much higher impact. In general, the effects of oil spills at sea are much more severe than those on land.

The three main causes of marine oil spills are:

1. offshore oil extraction, with leakage from the rigs

2. oil pipelines, with leaks in the pipework moving the oil to storage

3. shipping and transporting the oil, with the risk of collision or damage to the oil tankers.

4. How Does an Oil Spill Impact a Marine Ecosystem?

While the table above shows many of the well-known oil disasters, there are other smaller spills, boat washing and cleaning, and seepage from the seabed that cause environmental harm worldwide.

No matter what caused the oil leak, the effects might be profound. Any marine organism that is harmed or removed will have an effect on the local food chain, which may lead to food shortages for animals that depend on the first harmed organism as a food supply or, in the case of predator removal, to an explosion in the number of organisms.

If a species is already severely endangered, the loss of one additional population could result in the extinction of the entire species. Oil spills can lead to the extinction of a species within a certain area.

It is unclear how an oil spill will affect the health of species that consume large amounts of oil in the first generation and in generations to come. Clearly, some organisms will be killed off completely. The table below lists a few of the known effects of an oil spill on several creatures.

Organism or habitat Description Impact of oil Phytoplankton Organisms that are microscopic and can photosynthesise in seawater. They act as food for a variety of larger organisms. Oil covers the water's surface, blocking light from entering. As a result, the phytoplankton cannot photosynthesise and die. Fish The oceans are home to a variety of species, some of which eat phytoplankton and others of which hunt other fish. Both mammals and birds eat them. Food shortage caused by a decline in phytoplankton. Gas exchange is hampered by floating oil on the water's surface. Fish run out of oxygen and die. Fish are directly exposed to the oil, and this damages their gills. Birds Birds are mobile over large distances, feeding on fish, often diving into the water to catch them. Others wade at the coastal edge feeding on fish and shellfish. Food shortage as fish and other animals die. Fish, which can be hazardous, may contain oil, and as animals are foraging for food, their feathers become covered with oil, which affects their ability to fly and their buoyancy. Mammals Marine-based mammals, for example, dolphins and whales, will often travel great distances chasing prey. The effects of the oil lead to a reduction in food supplies. Additionally, when eating, mammals may ingest harmful oil. Their skin, etc., will be affected by an oil covering. Reefs A complex ecosystem; the habitat for a wide community of organisms Photosynthesis cannot occur because an oil slick blocks sunlight from reaching plants and phytoplankton. Other animals will die due to a lack of oxygen. The effect on the whole reef's balance could result in total destruction. The reef may develop oily patches. Beaches A distinct ecosystem supporting a range of land-based and aquatic organisms Oil is often washed in by tides, coating rocks. Organisms living in shallow water and rock pools may be killed by the toxic effects of the oil. Animal food sources will be affected. The local economy of the affected coastal areas will also be impacted by oil slicks. There could be a decline in the fish population, which would have an impact on communities' access to food as well as the livelihoods of fishermen. Many coastal areas rely on the tourism sector, and oil on beaches can affect tourism by making a place less desirable as a vacation spot.Reducing Oil Spills in Marine Environments

1.1 MARPOL

The International Maritime Organization, a United Nations (UN) body that oversees the safety and security of shipping, was able to secure consent for the MARPOL treaty only after extensive and prolonged diplomatic negotiations. The International Convention for the Prevention of Pollution from Ships, also known as MARPOL (which stands for Marine Pollution), lays out a variety of rules addressing, among other things, pollution by oil, sewage, trash and poisonous liquids. The 1973 agreement was modified in 1978, and it went into effect in 1983. Prior to MARPOL, ships frequently cleaned their storage tanks or disposed of garbage in the middle of the ocean, with unknown environmental repercussions.

A typical cause of smaller oil spills, the transfer of crude oil from one vessel to another while at sea is now covered by restrictions under the MARPOL regulations. All tankers must be certified in order to demonstrate that they have the necessary processes in place and documentation proving that they have been used. If these rules are broken, the ship risks receiving a steep fine or not being allowed to leave the port until proper systems are installed and certified to be functional.

1.2 Tanker design

Regulations to ensure best practices by individuals transporting potentially harmful substances are important, but the design of ships themselves has also received attention. As was said above, while there may be larger oil spills on land, the damage at sea is far greater due to the capacity of oil to spread on water.

A big oil spill from a tanker is usually the result of hull damage of some kind. It is obvious that a hole in the boat's hull will cause its contents to spill out.

Modern tankers now contain two additional design elements. The first is a growth in the number of compartments the ship's hull may contain; if one portion is damaged, the contents of the entire hull are not lost. Secondly, and more significantly, double-hulled tankers have been introduced. A ship that has two hulls has been created this way so that even if the outside layer (or plate) is damaged, the inner plate will still hold the contents in place.

A cross-section through a single-hulled and a double-hulled tanker. The inclusion of another layer (plate) provides protection for the cargo if the hull is punctured.

Although building double-hulled tankers is more expensive than building a single-hulled ship, the chance of an oil spill is far lower. It has taken 25 years to phase out single-hulled oil tankers due to the high expense of purchasing these new vessels. Although not all spills have been avoided by the deployment of double-hulled tankers, there is evidence of a significant decrease.

2. Minimising the Impact of Oil Spills

Even with careful design and preparation, oil can still spill. In this case, minimising the impact of spillage is the key priority. The method will be heavily influenced by the local weather, distance to land, and the calmness of the sea. There are several widely-used tactics.

• Floating booms: Floating booms can be used to contain an oil spill and stop it from spreading to other places. A boom is a floating barrier. When the spill is contained in a relatively small region and the sea is calm, this procedure works well. While a spill is being cleaned up, it can also be used as a barrier to safeguard environmentally vulnerable places (such as river estuaries). When the sea is choppy and stormy, which is sometimes what caused ship damage, booms do not function very well.

• Sprays using detergents: Detergents aid in breaking down and dispersing the oil slick into smaller droplets. The tiny oil droplets will eventually float away and deteriorate. Detergents work best on minor spills, but a current study indicates they may be more harmful to the environment than crude oil itself. It seems that coral reefs are not very tolerant of detergents.

• Skimmers: these purify the water without affecting the oil's chemical or physical characteristics. The skimmer pulls oil off the surface of the saltwater using a substance that oil readily adheres to, and it is then mechanically scraped off into a container. Once an oil slick has been confined within a boom, this approach is frequently used. Although skimmers are a highly helpful tactic, they are ineffective in choppy or dangerous seas.

The only practical method of cleaning a beach after oil contamination is to manually remove the oil by hand, which is a challenging and time-consuming process. Whatever technique is employed to recover spilled oil, the authorities then have the difficult task of properly and safely disposing of it.