By Jim-Rex Lawson MOSES

The importance, uses and overall benefits of petroleum otherwise known as rock oil can not be overemphasized. From factories, machineries and transportation to electricity generation, crude oil has become a major source of energy that affects all sectors of any nation and its economy.

But important as this natural resource may be, spillages of this product on the environment especially marine, which could be caused through carelessness, natural disasters like weather conditions and earthquake, vandals, terrorists, etc., could be sometimes very disastrous, depending on the volume of the oil spill which could affect the fishing industry, resorts and recreation areas, water supplies for drinking and industry amongst others.

What is an oil spill?  According to the encyclopedia of Earth, an oil spill is the accidental petroleum release into the environment. On land, oil spills are usually localized and thus their impact can be eliminated relatively easily. In contrast, marine oil spills may result in oil pollution over large areas and present serious environmental hazards.

The primary source of accidental oil input into seas is associated with oil transportation by tankers and pipelines (about 70%), whereas the contribution of offshore drilling and production activities is minimal (less than 1%). Wikipedia, the free encyclopedia, an oil spillis defined as the release of a liquid petroleum hydrocarbon into the environment, especially marine areas, due to human activity, and is a form of pollution.

Response Techniques
Going by history and study of oil spillages, no two oil spills have been found to be the same because of the variation in oil types, locations, and weather conditions involved. But, broadly speaking, there are four main methods of response.
Leave the oil alone so that it breaks down by natural means. If there is no possibility of the oil polluting coastal regions or marine industries, the best method is to leave it to disperse by natural means.

A combination of wind, sun, current, and wave action will rapidly disperse and evaporate most oils. Light oils will disperse more quickly than heavy oils.
Besides the method described above, other three possible clean-up techniques which must be adopted by response teams… depending on the volume of the spill should include; Dispersant of chemicals, Bioremediation and In-situ burning.

Oil spill

Dispersant Chemicals:
They are chemicals which enhance the natural dispersion of oil. It is the most common method employed for oil slicks, especially when mechanical recovery seems impossible. These dispersant chemicals are used to reduce the extent of damage that could be caused by the floating oil. However, there are some limitations on these chemicals as they can cause damage themselves if they are not controlled.

These chemicals work by increasing the rate of natural dispersion. When the dispersant is sprayed onto the oil slick the oil forms droplets of variable size (thereby dispersing them), the larger droplets float and the smaller droplets remain in suspension. Dispersants have two main components, a solvent and a surfactant.

How they are applied: workboats can be used for small spills in confined areas of water, but for the larger, off-shore oil slicks large aeroplanes are used and for small oil slicks near the shore small aeroplanes and helicopters are used. A spray of “rain drop” sized droplets is used in order not to lose too much in wind drift.

Limitations: chemical dispersants have little effect on oil with a high viscosity as the chemicals run off the oil before the solvent can work. Oils that the dispersants have an initial effect on become resistant after a while because the viscosity increases as the more volatile oils evaporate.

In-situ burning:
The name in-situ burning is the name given to the burning of spilled oil while it is still at sea. Technically this seems like a good method which will remove most of the oil, but in reality, there are a number of problems associated with this technique which include: production of a lot of smoke, formation of residues, ignition of oil, and safety concerns.
Smoke: when oil burns, large clouds of thick black smoke are produced which react with the normal clouds and causes oily rain which contaminates farm crops and animals.

Residue: the residues formed by in-situ burning are heavily viscous and are very hard to remove from the sea and the shorelines. Residues of this nature affect fishing gear, boats and the shoreline. Some of the residues also sink and can poison the sealife and is almost impossible to recover.

Ignition: the time it takes for the ignition and fire safety devices to be set up many of the lighter fractions of the oil will have already evaporated making ignition more difficult. Ignition can be done by different methods, from simple petrol or diesel soaked cloths to sophisticated devices like a flamethrower attached to a helicopter otherwise known as a helitorch.

Bioremediation:
Biodegradation is the name for the two processes used in promoting the natural biodegradation process oil spilled oil. The two processes are bioaugmentation (application of microbes to degrade oil) and biostimulation (addition of nutrients).

Bioaugmentation: this process is used in many waters (both sea and fresh) to degrade waste such as oil as well as raw sewage and industrial discharges. Microbes are added to the water to feed on these wastes. The species of microbes added will not compete with the naturally occuring species so that degradation is as efficient as possible.

Biostimulation: for the microbes to work efficiently there has to be enough phosphorus, nitrogen and carbon available. In the case of an oil spill, the carbon level escalates and the nitrogen and phosphorus levels are too low to allow the microbes to work at optimal efficiency. Fertilisers containing these two elements are added to enable microbes degrade the oil.

Limitations: despite how attractive these processes seem, they cannot be taken at face value. If bioremediation is used on oil floating on the surface, the materials added will quickly dilute and be lost. Oxygen is also required, which is not present in the oil itself, only at the water/oil interface. Bioremediation is therefore not suitable for the removal of large volumes of oil. The processes of bioremediation and bioaugmentation currently available are too slow to prevent the majority of the oil from reaching the shoreline. They can be physically and biologically harmful in some habitats such as salt marshes.

Prevention
Since cleanup after an oil spill is so ineffective and so difficult, and does not always fully rehabilitate affected areas, prevention is most important. Effective prevention plans should include:
*Improved piloting; training of ship and tanker crews
*Training of storage and pipeline facility crews
*Enforcing pollution rules at sea
*Building more spill-resistant vessels
*Maintaining vessels and pipelines
Preparing for spill response through effective training, planning (contingency planning), and practice drills.
Oil Spill Containment: