Oil Spills: Causes, Effects and Control.

Hey guys, first of all, I apologize for the long absence. I got caught up in the euphoria of having my graduation from Middlesex University recently and all the excitement. I have always wanted to blog about oil spills though and here you go.
You guys must have heard of the most recent oil spill disaster of British Petroleum at the gulf of Mexico which has been referred to as one of the largest accidental marine oil spills in the history of the Petroleum Industry by analysts. I'll try to discuss the causes and effects of oil spills as well as options for a reduction in its occurrence and control.

Gulf of Mexico oil spill. Source: Boston.com

Oil spill is a type of pollution that occurs mostly on water as well as on land and can have devastating effects on plant and animal life, and the environment. It occurs mainly as a result of human activity (exploration and transport of oil) and is the release of oil/liquid petroleum hydrocarbon into the aquatic environment such as oceans and coastal waters and on land. Spills may occur of crude oil (unrefined oil) from tankers, oil rigs and platforms and oil wells as well as during the transport of the refined petroleum product in vessels and tankers.  
Illegal waste oil dumping into oceans by organisations who do not want to invest in the cost of degrading their waste oils also contributes to increasing oil spills. Natural disasters such as hurricanes and earthquakes can also contribute to oil spills from oil rigs and wells as well as during transport in vessels and tankers. In a country like Nigeria where there is illegal oil bunkering by militants, oil spills occur quite frequently and are a major environmental challenge.

The recent Gulf of Mexico oil spill flowed undiminished for three months in 2010 due to an explosion of Deepwater Horizon drillin rig that was operated by British Petroleum. The explosion killed 11 workers and injured 16 others; another 99 people survived without serious physical injury. The effect of the explosion was that the Deepwater Horizon began to sink which started the offshore (away/at a distance from the land surrounding the ocean) oil spill in the Gulf of Mexico aand which has been reffered to as the seconf largest environmental disaster in the US.

Effects of Oil spills

A bird covered in oil from an oil spill. 

Oil spills largely affect the plumage of birds and fur of mammals by penetrating it and thereby affecting its insulation abilities thereby making them less able to adapt to temperature fluctuations and less buoyant in water. Mammals get hypothermia, which is a reduction in body temperature which may lead to death of both birds and mammals. Oil may reach the mammals liver or lungs poisoning it. Oils may also blind certain animals which reduces their ability to avoid predators and they may this be killed, which can lead to that animal specie being endangered.
When sea birds are covered in oil slick, they become heavy and may find it difficult to fly. The birds then attempt to clean themselves by eating the oil slicks from their plumage which leads to irritation of their digestive tract, altering their liver function, causing kidney damage and eventually leads to death.
Killer whales are also poisoned when they feed on fish that that has swam through the oil. The oil poisons them, and eventually they die. Sometimes, the oil blocks their blowhole (the holes through which they breath) and they die. This has led to killer whales being endangered species.
Plankton, larval fish, seaweed, oysters and bottom dwelling organisms are strongly affected by oil spills because sunlight cannot penetrate through the oil slick to the bottom of the ocean and therefore affects producers. When microscopic plants cannot photosynthesize and manufacture their food, they cannot release oxygen for the bottom dwelling aquatic organisms which leads to their death. When these organisms die, fishes cannot feed on them so they die as well, humans that have fish farming as a means of livelihood have their livelihoods denied them and may have to relocate. The biodiversity of a place where a spill has occurred is greatly affected.

Control of Oil spills
Oil spills occur largely because there is a need/demand for oil has a source of energy. Oil is used in one way or another in our day to day activities. We use oil to fuel our cars/trucks/buses and so on as well as to heat/light up our homes. Oil is used extensively in industries to power large machinery and equipment. Oil is used to tar roads, make plastics, used in inks, paints etc. If less oil is used, there will be a lesser demand on the refining and transport of oil which will lead to less oil spills. If you will walk or ride a bike for short distances, less oil is consumed. If you will turn off your electronic equipment when not in use, less electricity is consumed and less oil is used. In this way, little oil saving measures add up and impact on the demand for oil and can lead lesser spillages.

Oils spill clean ups can be carried out using a variety of approaches, depending on the type of oil spilled, layout of the spill area, the temperature of the water (which affects evaporation and bio degradation)etc.
Some bacteria such as Sulfate reducing bacteria which are anaerobic (can survive without oxygen) can be used to clean up oil spills are they are oil consuming bacteria. This is called a bio-remediation approach because it entails the use of micro organisms to biodegrade/eat up the oils.

Controlled burning at the Gulf of Mexico oil spill site. Source: usgs.gov

Controlled burning is also another approach that has been used to clear out oil spillages but it brings about air pollution issues.
Bio-remediation accelerator is another approach which entails using chemicals to chemically and physically bond the hydrocarbon oil molecules. What this does is to cause the oil molecules to aggregate and float towards the surface of the water column. Undetected hydrocarbon molecules can be aggregated in this way. The accelerator creates a bloom of indigenous hydrocarbon consuming bacteria that bio degrade the hydrocarbon into water and carbon dioxide. Other times the oil can be separated from the water and burnt, but like i said, this creates air pollution issues.

Dispersal agents have been used on oil spills as well, this prevents the oil suspension from forming clumps or settling, thereby rapidly dispersing the oil over a large surface area from which water soluble micelles are formed and are rapidly diluted. The downside of this approach is its toxicity to fishes. several other methods employed include dredging; when the degree of spill is not extensive, skimming and solidifying. Solidifying entails using hydrophobic (having little affinity for water) polymers to clean up spills. Solidifiers change the physical state of the oil droplets into more solid/semi-solid substances and thus can be quite easily separated from the water column and removed. They have been tested to be non toxic to aquatic organisms as well.
The use of a centrifuge has been commonly employed and works by sucking up oil and water after which the oil is separated from the water and the water pumped back into the ocean. The separated oil is then broken down / biodegraded in special treatment plants. The downside of this approach is that some oil may be pumped back into the ocean along with the water.
Finally, and thus may shock you, the best approach may be to do nothing and let nature take its course. This is actually a remediation approach and is regarded to as natural attenuation. This is particularly ideal in certain ecologically sensitive areas where the use of micro organisms may significantly affect the balance and biodiversity of the environment, such a wetlands.

Preventing Oil spills.
In the United States, Congress passed the Ocean Pollution Act in 1990 which laws include:

1. Emergency response plans. This entails that oil transporters/tankers have detailed written plans on what actions they will take if a spill occurs. This plans must have been written out before transporting oil
2. Double hulls: The law states that all ships transporting hulls must have double hulls before 2015. Double hulls reduce the possibility of oil spills during transport by 60% has compared to single hull ships.
3. Spill funds: This law specifies that Oil companies pay certain amounts to the government so that in case of a spill, The government can pay for a clean up.
4. Navigation: The law states that the Coast Guard (they protect the United State's water bodies) must know where oil tankers can navigate through without a spill occurring and enforcing it.

In a country like Nigeria, the Government should pay more attention to the activities of militants engaged in oil bunkering as some of the spills in the oil rich region occur due to this. In addition, Government should ensure that regulatory bodies have the authority to sanction oil companies who spill oil in the region. More and stricter laws with stiffer penalties should be passed so that oil companies are more mindful of their activities and the spills that they cause. Nigeria is highly dependent on oil as a means of foreign exchange and revenue. The government is unlikely to want to discourage the presence of foreign oil companies that drill for oil in the oil rich region despite the spills that their activities cause. A shift from the dependence on oil to other  sources of revenue such as agriculture will make it more likely for stricter laws and stiffer penalties for organisations guilty of oil spills to be implemented.

There you go guys, I hope you learnt a thing or two about oil spills.