EnvironmentPollutionWater Pollution

How Do Oil Spills Affect the Environment?

How Do Oil Spills Affect the Environment?


Ships are the chief transport medium for oil. This results in oil spill disasters on the water bodies. Not just the oceanic ecosystem, but it affects the entire environment. And the adverse effects of oil spills on the environment can only deepen once started.

Deep water Horizon oil spill was the most disastrous oil spill in US history that has released 130 million gallons of oil into the seawater. As for the adverse effects, the spilled oil has injured thousands of species—found dead and injured, littered shorelines, destroyed fisheries, and impacted the economy.

Thus, it is critical to understand the level of problem such an accident can create and how we can prevent the environment from it.

Transportation of oil from the sources of production to the place where we can use it for various purposes is not new. It has been happening for centuries. And the possible environmental problems also aren’t the latest to observe.

However, globally, the rate of oil trade is increasing and expanding, raising the chances of critical oil spill situations.

We explain this topic with the motto to grasp how oil spills affect the environment. So, let’s dig deeper!

What Is an Oil Spill, And How Does It Happen?

An oil spill is a type of disaster that occurs during the transport of oil from one place to another through a ship.

A review shows that tankers are the transport medium for about 60% of oil from one production location to the trading location.

It mostly happens through accidents with oil tankers that seriously affect the environment. Some of the possible causes of oil spill disasters include;

  • The accidents with tankers, pipelines, drilling rigs, refineries, barges, and other oil stores.
  • Carelessness of people.
  • Hurricanes, storms, high wind, waves.
  • Breaking down of equipment.
  • Illegal dumping.
  • Pirate attacks.

Sometimes the leakage is small, while sometimes, it takes an enormous form. The small oil spills are due to operational failure at loading and unloading. On the other hand, the large spills are due to explosions, shipwrecks, and collisions.

Whatever the case may be, oil spills always affect the marine environment, human health, marine biology, coastlines, economy, and the overall ecosystem.

What Happens After an Oil Spill?

Firstly, the heat from the tropical sun and wave action causes some amount of the spilled oil to evaporate. Through the continuous wind movements, the oil can spread to a long distance on the water.

Some oil (about 1%) reacts with sun rays and produces toxic hydrocarbon compounds. As the amount is relatively small, it doesn’t affect the ecosystem significantly.

While some quantities of oil, after being broken down into small particles, settle down to ocean ground through sedimentation.

A few quantities of hydrocarbons dissolve with the water—dispersion—and most amounts get removed from the water bodies. Deep down the ocean, a few organisms take the role of degrading some concentrations of oil matter.

Some oil on the water gets emulsified, which means broken down into tiny droplets and, after mixing with seawater, can create a viscous substance called Mousse.

Effects of Oil Spills on the Environment

As we grasp the basics, let’s know how oil spills affect the environment.

Oil Spills Prevent Sunlight from The Oceanic Ecosystem

First, oil spills create a thin layer of oil spreading over the water. This layer is termed slick. This thin layer might undergo several phases. As the polarity of oil and water is quite different, they cannot mix. And the density of oil allows it to float on the ocean surface.

If the quantity of oil spills is high, it might extend to certain miles over ocean bodies. The extended oil layer is now called sheen. The thickness of the sheen is seen to be 0.01 mm thick.

Moreover, the spread oil layer blocks the sunlight from entering the ocean water. This blockage is life-threatening for producers like phytoplankton. And as phytoplanktons and producers serve food to the upper level, the entire ecosystem gets affected.

Oil Spills Can Affect the Environment for Years

If not cleared entirely, contaminated oil can store in salt marshes and mangrove swamps for decades.

Some examples of oil spills that happened for months are Prestige and Betelgeuse. This also has impacted the economy enormously.

A review shows the long-term effects of Oil spills on the organisms of that environment. Some claims show that a seabird species Morre might not recover for 20 to 70 years.

This might be because of the impact the contaminant causes on their reproductive system.

Also, another research published by Lance et al, explains that the population of affected birds during the Exxon Valdez Spill has not recovered for nine years and more.

Furthermore, some studies show that a few species repopulate to their prespill mass takes quite a long time (for years). Thus, pollution causes immense damage in the long term.

Oil Spills Contaminate the Ocean Water


After an oil spill, about 30-40% of the oil evaporates naturally. Yet, the percentage highly depends on the density of oil. Lighter oils evaporate quickly and more efficiently than heavy oils.

A few amounts of oil react with sunlight, specifically with the UV-radiation, and perform a process called photolysis. In this process, the radiation oxidizes the oil into some toxic acidic and phenolic elements, contaminating the ocean water immensely. Nevertheless, this toxic product passes through the entire ecosystem and is enough to destroy it.

Oil Spills Affect the Coastline Badly

In some cases, the oil gets influenced by heatwaves and currents. This eliminates the oil from the coastal region through evaporation and leaves some patches. It takes a little longer for the oil to reach the shore.

The toxic chemicals with oil or several elements on the ocean surface affect flora and fauna.

Further, millions of people in the coastal areas rely on seafood to live. Thus, an oil spill near the coastline affects the coastal communities hugely.

The largest coastline-affected oil spill was the deepwater horizon oil spill in the Gulf of Mexico. This spill has oiled about 2113 Km of shoreline.

Some affected biota during this accident includes marsh invertebrates, marsh vegetations, nearshore decapods and fishes, marine turtles and mammals, coastal and terrestrial bird populations, and microbial communities.

Oil Spills Can Affect the Seabirds Immensely

Seabirds get impacted by the oil spills considerably.

According to a review published in Elsevier Science, seabirds are highly vulnerable to oil spills. This paper shows an estimation of 35,000 seabirds that were affected during the Exxon Valdez Oil Spill.

However, none of the studies can predict how much damage an oil spill can cause to the birds. This is because there’s no relationship between the extent of the oil spill and the birds affected.

It has been believed that the Amoco Cadiz Oil Spill was one of the most disastrous oil spills in history. That is because of its high impact on the environment.

As a result of this oil spill case, about 200 miles of shoreline has been contaminated. It has destroyed more than 20,000 birds, millions of molluscs, crustaceans, and other invertebrates.

Oil Spills Directly Affect the Health of Sea Organisms

After consuming the oil with water, some organisms like fishes, turtles, and dolphins look striped and patched with black and brown color. These are the immediate effects on organisms after an oil spill.

Some long-term effects of oil spills on sea organisms include strandings, lung diseases, stress, reduced immunity, and infertility.

As per a report from ocean.si.edu, the Gulf of Mexico oil spill in 2010 has killed many dolphins, and only 20% of dolphins still can carry healthy babies.

Further, during this spill, about 1,67,600 turtles were washed off. Deepwater and coastal coral colonies also get affected largely during this spill.

It Can Be Life-Threatening for The Workers of The Ships

In almost all the most significant oil spills, the slick caught fire, which took the lives away from the ship workers.

For example, the result of the Atlantic Empress Oil spill had thrilled people where the spills were burnt for two weeks, and 27 sailors lost their lives during this accident. The oil was dispersed and removed naturally, causing little to light effect on the environment.

Cases of Oil Spills

If you have ever heard of the most dangerous oil spill cases in history, you might have goosebumps by attending to the environmental effects.

Some of those includes,

  • The Amoco Cadiz oil spill in 1978
  • The Atlantic Empress Oil Spill in 1979
  • The Castillo de Bellver Oil Spill in 1983
  • The Kolva River Spill in 1994
  • BP’s Deepwater Horizon oil spill in 2010

There are more to this list. However, our purpose is to share the effects of these accidental oil spills on the environment. Some of the recent oil spill cases in the past decade include,

  • Callao oil spill in 2022
  • New Orleans oil spill in 2021
  • Orange country oil spill in 2021
  • Mediterranean oil spill in 2021
  • Colonial pipeline Gasoline spill in 2020

These, with some other instances, also provide evidence for the environmental effects of oil spills.


These are some effects of oil spills on our environment which can vary according to the number of oil spills, density of oil, and spill location. Besides affecting the ocean and other aqueous ecosystems, oil spills also impact humans.

As per a review on the consequences of oil spills, the location of the spill determines how costly it is going to affect humans.

This study further explains that nearshore oil spills demand 4 to 5 times more cost and effort than spills away from the shore.

For example, the authors of another study, White and Molly, shared the instance of the Atlantic Express Spill in 1979. This spill has no considerable effect on human mass because of its distance from offshore.

Innovative disaster management is crucial for controlling a severe oil spill condition. Some management steps include rapid action through several advanced technologies. And further, there is a considerable difference that has been shown by the involvement of volunteers and military staff. An instance of such cases were Habei-spirit and Amoco Cadiz tanker spills.

Prespill planning is another excellent way to determine the extent of oil spill effects on the environment and control the scenario. Please comment below for any queries.

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