Oil spills are among the most emotive forms of environmental pollution because of the visibility of impacts, but their overall threats to human health are generally low.
Oil spills can happen on land or at sea, and can include leaks from ships, wells, pipelines and other sources. The scale of the problem will depend on the amount and type of oil that leaks, where the leak takes place, and what the local climatic conditions are — but in all cases most of the harm will occur in the immediate aftermath of the spill.
Oils spills at sea or in coastal areas are of particular concern because of the risk to fragile ecosystems and associated livelihoods. Oil can harm birds and marine mammals as it can coat their fur or feathers and limit their ability to swim, float or fly.
Many animals die as a result of this or because of the effects of ingesting the toxic oil. The oil can have further impacts on the marine food chain by poisoning fish and smaller creatures and by blocking the light that algae need to grow.
People who live in the immediate area of an oil spill face exposure to toxic compounds such as benzene that can become airborne. There is also a risk that people could ingest small quantities of oil if they eat shellfish or other sea creatures that have been contaminated. However, by far the greatest health threats that an oil spill poses will be to the people who work to clean up the oil.
Beyond these direct environmental and health threats, there can also be significant direct economic impacts, even before the cost of cleaning up a spill. The economies of coastal communities that depend on fishing or tourism are particularly vulnerable to marine oil spills, for instance.
Despite all of the potential impacts of oil spills, the natural environment is remarkably resilient to them over the long term, as natural chemical and biological processes can break down many of the components of oil. However, some of the toxic components of oil are thought to be able to accumulate in the food chain. If so, they could be causing problems many years after the event.
Oil spills can take months or years to clean up. Various methods can be used to contain oils spills or try to minimize their effects, but in situations where remediation could create additional problems for sensitive environments it may be appropriate to let nature take its course.
Options include using living organisms such as fungi or microbes to break the oil down into safer chemicals (known as bioremediation), or using chemicals to disperse, solidify or absorb the oil. Scientists warn, however, that some chemicals can also harm marine life.
More mechanical approaches include skimming (collecting oil that gathers on the surface of land or water), and dredging (for dense oil that has sunk to the bottom of the sea), and deploying boom
An expensive but effective tactic that can be used at sea is to suck up water and oil with a vacuum pump and then use a centrifuge to separate the two components. The water can be returned to the sea, while the oil can be stored on a tanker.
Controlled burning can be used to stop oil leaking from oil rigs or wells, whether at land or sea, but this can cause serious air pollution. This is a trade-off because by burning the oil — and destroying its most toxic element — the overall impact on the environment may be less than if the oil was allowed to continue to leak.
Oil spills, particularly those that affect delicate coastal environments, may look worse than they really are so journalists need to take care to report the true scale of the threat. It is important to bear in mind that natural oil seeps have occurred on Earth for millions of years and that oil itself is a natural substance than can degrade over time.
Oil spills in deep ocean water are less damaging than those in which oil reaches shorelines. But while images of sea-birds smothered in oil are what many people associate with oil spills, much of the oil that leaks because of human activities does so on land.
Journalists who are focusing on environmental impacts of an oil spill should pay close attention to the methods that are used in any clean-up operations. Some detergents that can be used are themselves harmful chemicals that are strictly controlled. In some cases they may cause unnecessary additional damage to the environment.
It is also important to know what kind of oil has leaked. Some are more toxic than others. Some evaporate more quickly than others.
Companies that are responsible for oil spills, and governments that want to manage public opinion, may try to stop journalists from reporting on the situation. Reporters claimed that this happened in 2010 following the Deepwater Horizon oil spill in the Gulf of Mexico (see this article in the Columbia Journalism Review).
CASE STUDY – Nigeria’s oil-stained delta
The 2010 Deepwater Horizon oil spill was massive in scale and received considerable media coverage as a result. But in recent decades, vast quantities of oil have leaked every year into the land and wetlands where poor communities live in Nigeria’s Niger Delta. Media coverage of this story outside of Nigeria has been minimal.
The delta is the source of some of the finest quality oil in the world, and big multinational companies have been extracting it since the 1950s. Hundreds of pipelines carry all through the region, but the pipes are often leaky and the oil spills out to contaminate farmland, wells for drinking water, forests and waterways from which people seek fish and crabs to eat.
The situation has led to social conflict and numerous allegations of human rights abuses. Local people accuse the oil companies of negligence and their government of corruption and collusion. The oil companies say, however, that most of the oil spills are caused by vandalism, theft or sabotage by militants.
With hundreds of spills happening every year, this is a story that shows no signs of going away any time soon. For more details, see these articles in The Guardian, the New York Times and this video report by Aljazeera.
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