Regulated oil spill is a common practice to prevent the growth of dengue causing mosquitoes and larvae in stagnant water. The larvae face difficulty in breathing, similar is the case when VLCC carrying millions of barrels of crude oil for transportation meets with an accident which results in an oil spill. An oil spill is really dangerous in many aspects. It covers the surface of water having a disastrous impact on marine, wild and human life apart from economic and ecological loss. The most recent is the spill of MV Wakashio near Mauritius that split 1300 tones of crude oil.
Causes of oil spill
The main reasons behind accidental ship’s oil spill are equipment failure, human error which includes collision and environmental factors like a storm, hurricane etc. The causes of oil spills between 2009 to 2018 are:-
1. Organizational factor 45%
2. Human factor 40%
3. Equipment failure or hull failure 13%
4. Environmental factor 2%
Other causes can be a leak from oil refinery, offshore drilling etc. like the Deepwater Horizon spill. This is the reason why we say ‘SAFETY FIRST’. A well trained and responsible crew is also essential onboard a ship.
After effects of an oil spill
Oil flow is hazardous and disastrous, it hampers the ecosystem of the surrounding areas for the coming decades.
1. It harms nature and air, causing breathing problem, headache, burning eye, etc. In some cases, it catches fire and casualties happen.
2. Oil forms a layer on the surface of the water and thus prevent the exchange of oxygen for survival marine life, leading to their death.
3. Shorebirds to catch the fish dive in the water, oil sticks to their feathers, making them unable to fly and also destroys the insulating power and leaving them in a condition called hypothermia due to which they swallow the oil and die.
4. If the amount of oil spill is more, it does not necessarily mean more damage, usually, damage depends on the area and time of the spill. If an oil spill happens in the breeding season like Deepwater horizon (2010), then the birds, aquatic animals as well as their breeding grounds also get hampered.
5. Oil spill mostly kills marine animals, depriving them of breathing and the ability to communicate. Even if they skip the spill, the food chain gets contaminated and consuming them causes various health issues both to marine animals as well as humans.
6. Oil spill also causes stunted growth; impact can be seen even decades later. Example- Exxon Valdez killed 2800 sea otters and 300 Harbor seals and billions of salmon fishes were found dead and their eggs destroyed. This impacted fisheries and took almost three decades to improve.
7. In April 2021, the oil spill from MV Wakashio, near Mauritius affected endangered coral reef and the tourism and hence the revenues.
How to prevent oil spills
1. ‘SAFETY FIRST’ ,so, be more alert, regular maintenance of machinery, valves, inspecting possible leak passage and finding a solution to add extra security and better training are some ways to prevent an oil spill.
2. Oil Spill Prevention Control and Countermeasures program (SPCC) aims to train crew to prevent oil flow.
3. Double hull or thicker hulls can be used that can act as an extra safety layer to prevent an oil spill.
Largest oil spill
The largest marine oil spill in history is the BP oil spill from oil rig ‘Deep horizon’ near the Gulf of Mexico in the year 2010. The reason for this is split was a leak of high-pressure methane gas which eventually caught fire and engulfed the oil rig and caused the oil spill. A total of 94c cew members were rescued, 17 injured and 11 missing. The spill was estimated to be around 4.9 billion barrels or 7.8 lakh tons of oil. It is one of the largest environmental disaster in history from 20th April to 19th September 2010. The Marine and wildlife were seriously hampered the cleaning cost was estimated to be around $65 billion and the Federal community imposed a fine of $4.625 billion on BP.
Cleaning sea after an oil spill
To date, there is no technology developed to completely remove the oil and clean the sea satisfactorily. However, various steps are taken to clean as much as possible. Floating booms are placed around the area of a spill. Since oil floats on water, it serves as a barrier to prevent the spreading of split oil. The oil is then skimmed off. Further, chemical surfactants are spread to speed up dispersion. Controlled in situ burning, or various sorbents like straw, ash etc. are used that absorb oil from water. Some bacteria are also used to clean up the contaminated environment through bioremediation.
Incidents of oil spills
There have been many incidents of oil spill in history, but with the advancement in technologies, implementation of regulations, better training, skilled crew, we witnessed a drastic fall in the number of major oil spills (above 7 tones). The Deep horizon spill in 2010 was the largest and most disastrous due to breeding season.
Out of the 20 major oil spills in history, only 1 was after 2000 that is Sanchi spill in 2018 leaked 136,000 tons of oil in east China sea. Others include Prestige, Exxon Valdez oil spill and many more.
Recent spills include:
1. The Colonial Pipeline gasoline spilt nearly 38000 tones in the USA in August 2020.
2. The Mauritius oil spill of MV Wakashio on 25 July 2020, that ran aground in the coral reef which is a center of tourism.
3. The Norilsk diesel fuel spill on 29 may 2020 nearly spilt 17500 tons of diesel near Russia.