Oil Pollution: Meaning, Causes, Effects, Preventive and Control Measures

Introduction

Pollution of every kind is harmful to nature. Oil pollution in particular is a kind of water pollution, and a dangerous one at that. Oil does not dissolve in water and hence oil usually floats on the surface of water. Thus, oil pollution due to any cause greatly affects the quality of natural water bodies and is classified under pollution.

Definition and Meaning

Oil Pollution is the resultant contamination of environment due to the introduction/presence of oil in excessive quantity.

Oil pollution is most common in large water bodies like seas and oceans. Oil spill occurs due to the release of a liquid petroleum hydrocarbon into the aquatic environment. Marine water is especially affected by this form of pollution. Oil pollution is primarily a man-made pollution and is a result of human irresponsible activities.

Oil pollution is mainly because of crude oil. Ships and tankers carrying crude oil across the oceans may cause deadly oil spills in marine water due to various causes, leakage being the most common one. The quantity of oil spills matter when it comes to the significance of oil and water pollution. During marine accidents, the oil spills quantity is enormous. Spillages in such large quantities occur on a regular basis.

Also, shallow water oil spills can be more dangerous than deep water ones sometimes. Oil combines with mud and other dirty substances and sinks to the bottom of the water bodies. As a result of this, the oil tends to stay at the bottom for ages causing harmful effects on the marine life living on the bed of the sea.

When very large amount of oil pollution occurs, it is extremely tedious to clean up the water afterwards. Measures taken to reverse the pollution affects may prove futile, if action is not taken at the right time. So it is wise to take preventive measures rather than treatment ones. Prevention is an important action step but awareness precedes this step.

Without actually having the knowledge of the disasters that this kind of pollution is capable of causing, prevention is seldom seen necessary. Here, we would discuss the detailed account of oil pollution which should serve as an eye opener for all to take control measures more seriously. The cause and effect scenario of oil pollution need to be studied in-depth and only then will the necessary preventive action would seem like the need of the hour!

Causes:

The various causes of oil pollution are listed below:

1. Breakage of oil tankers (oil ships): Mechanical breakage of oil tankers can lead to oil spillage in extremely large quantities. If a tanker breaks down in shallow land, abrasion leading to a hole in the tanker might take place during mechanical and aggressive attempts to get the tanker out of the shoreline. Also, when bunker oil or lubricating oil (required for engines) is being loaded in to any ship, the loading hose can also undergo mechanical breakage leading to oil spillage incidents.
2. Oil pipe leakage: Oil pipe leakages are common and cause a lot of oil pollution. Huge pipelines are laid all across the world and their slightest leakage can prove to of grave danger to water bodies. Offshore drilling waste should be handled with care and their proper and lawful disposal should be ensured.
3. Drilling activities: Drilling activities lead to severe oil pollution. Industries after oil extractions dump the drilling wastes into water bodies. This is extremely detrimental for natural water sources. Companies act irresponsible towards the environment and carry out improper disposal of drilling waste.
4. Human transport or recreational activities: Oil spills may be a result of water sports as well as motor transport on water. Fuel leaks from jet skies, speed boats, etc. can also lead to oil spills. Some water bodies have regular motor traffic on them. These water bodies tend to have concentrated oil pollution in their water due to constant oil pollution.
5. Unskilled Manpower: Unprofessional, careless and unskilled man-power can also be a risk factor for oil pollution. They might do a clumsy job of loading or unloading the crude oil cargo which may prove to be dangerous. Also, applying shortcuts and not following the lawful protocol for cleaning, loading, supervising and unloading, when handling crude oil tankers is often seen among the crew members.
6. Failing to check failures: It is important to check for any failing equipment or parts of a marine vessel before giving it a green signal for making a sea voyage. Any potential failure incidents should be immediately addressed and not look past. Even minute failures can create havoc late. Failing engines in the middle of the sea can lead to substantial oil pollution.
7. Natural causes beyond human control: Natural calamities like storms and tsunamis have also lead to many oil spillage and ship accidents. This is beyond human control and cause maximum damage to marine water. Climatic conditions are something that cannot be bypassed when talking about marine life.
8. Operational oil spills: In any ship, bilge is a space found under the ship engines, at the very base. It is for gathering oil, greasy dirt and water. When the bilge is pumped out by the ship crew, the oil and water separates. The oily waste is supposed to be stocked into a designated holding tank, which is to be thrown out at the next available port. The water that is left over (having oil traces in negligible quantities) is pumped into the ocean after passing it through an oil water separator. This extensive procedure is done to ensure that only traces amount of oil is being pumped out overboard. Hence, if an oil slick is found around a ship, it shows that the ship has not followed the right lawful procedure and has illegally pumped out more oil into the ocean than it is permitted to.
9. Cleaning of tanks: When oil tanks of ships are cleaned, there is high risk of oil spillage in the ocean water. Before loading the new cargo of crude oil into their ship, the ship crew usually cleans the cargo tanks. After thorough cleaning of the cargo oil tank with chemicals and water, the remnant oil residue float on the water at the very base of the cargo tank. This water is normally channeled to an oil water separator to separate only the cargo oily residue at the cargo tank bottom. The fresh crude oil cargo can ideally be loaded over the left over old cargo oil. However, some crew members tend to pump out the remnant old cargo oil residue overboard into the ocean water. This is strictly illegal and should not be encouraged at any cost. This leads to discharging of tons of dirty oil residue into the marine water to cause oil pollution.
10. Run offs from land pollution: Polluting human activities on land may also contribute to water oil pollution. The vehicular oil leaks on land may also get washed off into seas, oceans and other natural water bodies leading to oil pollution.

Effects

The effect of oil pollution is disastrous, especially on the aquatic flora and fauna. Given below are various possible adverse effects of oil pollution.

1. Damage to ecosystem: Oil pollution is a major threat to our ecosystem, especially the aquatic ecosystem. Ecological impact of oil spills on the aquatic animals depends on the location of the oil spills and also on the sensitivity of the local organisms to oil pollution. Oil spills greatly decrease animal breeding population and also harm their nesting habitats. This leads to the consequent shrinkage of the local prey population thus unbalancing the aquatic food chain and ecosystem. Plants in the water also cannot survive in poisonous oily environment and die a pre mature death, ahead of their life cycles.
2. Damaging effect marine biodiversity: Marine biodiversity will get great affected by oil pollution. Oil spills can cause potential harm to the marine birds. Their feathers get coated with the oily water which hampers with the water repelling property of their plumage. This might increase their chances of drowning in water as their buoyancy might considerably decrease. Also, aquatic animals and birds and mammals may tend to ingest the oily contaminated water which could mean harm to their health by poisoning them. Oil spills are also dangerous for fish and shellfish. Oil ruins the insulating capability of furry mammals like sea otters. This may adversely affect their body temperature maintenance. Oil spill happens all over the sea and the location decides the injury or death rate of the birds and animals. It is a pity how human activities are constantly upsetting the marine biodiversity.
3. Economic loss: Oil spillage if happens in high concentrations is very difficult to clean, no matter how much effort is invested into it. Also, the cleanliness regime is anything but cheap. Huge amount of money need to be spent to tidy up the oil spillage mess and then also the result may not be 100% satisfactory. Oil pollution is proportional to considerable economic loss. Also, spillage of crude oil is of great loss as crude oil is precious and very expensive.
4. Altering the water temperature: The oil layer present at the surface of water will tend to absorb more heat from sun rays and may significantly increase the surface water temperature. Also, it might block the sunlight from reaching into the depths of water with uneven heat distribution across the depths of the water body. This can alter the natural hydrodynamics of the water bodies which may lead to lesser oxygen supply at certain depths of water.
5. Effect on coastal areas: The shore lines and sandy beaches in coastal areas may also be an indirect victim of oil water pollution. The oil contaminated water is usually swept across the shoreline by the waves in high tides. This makes the beaches dirty and unsafe for the human population as well. Thus, coastal areas are continuously contaminated due to oil pollution.
6. Degrades water quality: Oil pollution seriously degrades the water quality on a long-term basis. Being insoluble in water, oily water always exists as bi-layer. Also, at the shore lines, the current of waves might even turn the oily water into a turbid oil water emulsion (wherein the oil and water exist as a single turbid phase due to constant mechanical mixing forces). This degrades the quality of water further.
7. Tourism industry affected: Tourism industry is greatly affected by oil spills and oil pollution. Due to increasing oil pollution on beaches and shorelines, recreational activities of tourists like boating, swimming, diving, adventure sports are taking a back seat. Unclean and unhealthy water will repel tourists from undertaking these activities completely.
8. Industry problems: Many industries use clean water from natural water bodies for cooling purposes. Industries like power plants, nuclear plants and desalination plants need constant water supply from surface waters. These industries may also pose a risk of getting oily and contaminated water due to oil pollution. This may lead to contamination in their pipes and might not yield effective cleaning too.

Preventive & Control Measures:

In order to deal with oil pollution, it is essential to take sufficient preventive and control measures around the globe. Water is the most important natural resource and it`s quality is of utmost importance. Thus, preserving the natural purity of water should be of top priority. Since oil pollution is a major water pollutant, let us see some important measures as to how to control and prevent the same.

1. Use of Trained people: Drilling should only be done by highly skilled and trained people. This will prevent the otherwise unwanted oil pollution.
2. Proper quality checks: Quality cannot be compromised when it comes to ships and oil tankers in marine waters. Their mechanical parts and equipment need to pass strict quality checks to be proven safe against any oil spill hazards. Extra attention is required while installing the pipes in tankers. Any probable leakage issue should be eliminated before it sets out on the sea.
3. Efficient Disaster Management Plan: Government of all countries worldwide should treat oil pollution seriously and come up with a suitable disaster management plan to deal with this problem. Local environmental agencies should also step up their action plans towards the recovery of polluted water bodies. A plan should be developed to direct the restoration process and incorporate things like coral and plantation reconstruction, shoreline improvements and transport restrictions across water bodies. Public access to severely affected coastlines should be restricted to avoid human health hazards.
4. Bioremediation: When bacteria are used to clean up oil spills in the marine environment, it is termed as bioremediation. Bioremediation is a process that uses natural decomposers and plant enzymes to treat the contaminated water. Certain specific bacteria come of use when thinking of bioremediation of hydrocarbons present in oil and gasoline.
5. Regular inspection of oil sites: Regular skimmers need to be employed in marine water to monitor and control oil spills. Skimmers are boats that help scoop the spilled oil from the surface of the polluted water. This way immediate action can be taken in case of accidents to avoid long-term damage in serious proportions. Even if certain operational carelessness can be avoided with stricter rules, the accidents cannot be predicted nor dodged. Hence, employing an emergency team is the way to go.
6. 24/7 emergency team: The government should have a 24/7 emergency team ready for any marine accidents and oil spill incidents. An effective team will facilitate immediate clean up of the mess that any such incidents might cause.
7. Laws and Regulations: Several laws and regulations have been operational since long in most of the countries, but still oil pollution has been on the rise. The laws should be implemented on ground level and facilities should be checked regularly for proper maintenance and documentation of their procedures for discharge as well as loading. Also, mock drills should be mandatory for all vessels, so as to be prepared to clean up oil spills in emergency situations.
8. Chemical treatment: The oil spills in the water bodies can be cleaned up the chemical way. Using sorbents (big sponges which absorb oil) oil spills can be cleaned. Also, chemical dispersants effectively break down oil into its corresponding chemical constituents.
9. Physical methods: Physical methods can also be employed for cleaning oil spills. Vacuum trucks can suck up spilled oil from the beaches and the surface of water. Oil spills in beaches may also contaminate ocean water. So, shovels and road machinery can be used to clean up oil on the beach. Oil contaminated sand and gravel can be picked up and moved away, so that the waves hitting the shores do not pick up the oily residues to cause oil water pollution. Floating barriers called ‘booms’ can also be used to prevent oil pollution. This is usually done by planting a large boom around a leaking oil tanker to collect it before it causes massive water contamination.
10. Leaving it undisturbed: If the amount of oil spill is not of mammoth proportions and the area of oil spill has no potential risk of polluting coastal areas, marine industries, etc., it is best to be left alone. Oil is naturally degraded by a combination of sun, wave action, water temperature and natural microbes, over time. This phenomenon is called ‘Weathering’. Thin surface films of oil can easily be cleansed by natural weathering.

Conclusion: Oil pollution is a serious threat to our environment and ecosystem and needs to be controlled with urgency. Strict regulations and guidelines should be implemented and supervised at regular intervals of time to ensure proper compliance.

- Purbita.