Understanding Oil Pollution: Its Causes And Impacts

Oil pollution is a pressing global issue that primarily affects marine environments. It is caused by the release of liquid petroleum hydrocarbons, commonly from tankers, offshore platforms, pipelines, and drilling operations. These spills can be accidental or deliberate, with human error, natural disasters, technical failures, and illegal discharges contributing to the problem. Oil pollution has severe ecological, economic, and health consequences. It harms marine life, renders seafood unsafe, and contaminates air and water. The cleanup and recovery process is challenging, and even small spills can have lasting impacts on sensitive habitats and vulnerable species. With oil transportation and trade increasing, addressing oil pollution requires international cooperation and strict adherence to regulations.

Oil spill causes

Oil spills, a form of pollution, are often caused by human activity, with 30-50% of spills being directly or indirectly caused by human error. Accidents involving tankers, barges, pipelines, refineries, drilling rigs, and storage facilities are the most common cause of oil spills. Collisions during shipping and tanker accidents are a very common cause, with vessel hulls being damaged and leading to oil leaks or spills. In addition, vessels running aground can rupture their hulls and cause oil to be released into the surrounding environment. Aging or poorly maintained vessels can also experience structural failures, such as hull breaches or pipeline failures, resulting in oil spills. Drilling accidents, such as blowouts or wellhead failures, are another common cause of oil spills.

Oil spills can also occur due to natural disasters, such as severe weather events like storms, hurricanes, and tsunamis, which can cause damage to oil infrastructure. High winds, strong currents, and rough seas can rupture pipelines, damage storage tanks, or cause vessels to run aground. Earthquakes or other geological events can cause fractures in the Earth's crust, allowing oil and gas to escape from underground reservoirs and reach water bodies. Volcanic activity can also contribute to oil spills, with underwater eruptions releasing oil and gas stored beneath the seafloor, and above-ground eruptions generating solidified lumps of oil, known as tar balls or tar mats, which can impact coastal ecosystems.

Oil spills can also be caused by operational discharges from tankers, such as oily tank washings, which can contain hydrocarbon residues. While the importance of this source has decreased over time, it still contributes to marine spills. Additionally, recreational boats can spill oil into the ocean due to operational or human error, unpreparedness, or collisions. While the amounts spilled by recreational boats are typically small, these spills are hard to track due to underreporting.

Land-based sources, such as oil storage facilities, terminals, and refineries, can also contribute to oil spills. Oil can reach the oceans through runoff from roads, oil on roads flushed into oceans during rainstorms, and oil from rivers, which is estimated to contribute to 11% of oil pollution in the oceans. Oil spills on land can occur through pipeline ruptures or well blowouts and can have different impacts compared to maritime spills, as oil on land does not spread as quickly, and the effects remain localised.

Environmental impact

Oil pollution has a significant impact on the environment, affecting marine life, ecosystems, and human health. Oil spills, in particular, have devastating consequences for wildlife and natural habitats. Oil exploration, production, and transportation activities can all contribute to this problem.

Oil spills frequently occur during the transportation of crude oil. When oil is released into the ocean, it creates monumental environmental damage. Each year, 706 million gallons of waste oil enter the oceans, with significant impacts on marine life and ecosystems. Oil spills can occur naturally due to the eroding of sedimentary rocks, but human activities related to offshore oil exploration and transportation are also significant contributors. Roads are primary sources of pollution, with crude oil contamination adversely impacting aquatic ecosystems.

The toxicity of spilled oil depends on factors such as its type, density, and origin. Crude oils, with high concentrations of heavy metals and polycyclic aromatic hydrocarbons (PAHs), pose significant risks to both human health and marine life. Oil spills can cause physical smothering of organisms, especially those with high viscosity, affecting their ability to respire, feed, and regulate body temperature. The lighter chemical components of oil spills can be absorbed into the organs, tissues, and cells of organisms, causing chemical toxicity with potentially lethal effects.

Oil spills can also lead to ecological changes by disrupting the balance of key organisms within an ecological community. They can contaminate bird and turtle nests, impacting breeding and reproduction. Oil-coated feathers and fur can impair buoyancy, causing drowning, and can lead to the ingestion of oil during preening, resulting in gastrointestinal and organ damage. Oil spills have been shown to have generational effects on immune systems, as observed in studies of bottlenose dolphins post-Deepwater Horizon event.

In addition to marine life, oil pollution also affects plant life and soil ecosystems. Oil can contaminate rivers, streams, and lakes, with just one litre of oil capable of contaminating one million litres of water. Oil forms a thin layer on the water surface, preventing oxygen from reaching aquatic plants and animals. It can also impact soil health, reducing water-holding capacity, moisture content, and microbial activity.

Human health impact

Oil spills have been shown to have a range of adverse effects on human health. The health effects depend on factors such as the type of oil spilled, the location of the spill, the level of exposure, and the route of exposure. People involved in cleaning up oil spills and those living in affected areas are particularly at risk.

One of the main ways humans are exposed to oil spills is through contaminated food. Oil compounds can bioaccumulate in living organisms, becoming more concentrated as they move up the food chain. This means that humans can be exposed to high levels of contaminants even if they live far away from the spill site. For example, consuming contaminated fish has been shown to have serious health effects.

Direct exposure to oil spills can occur through breathing contaminated air, skin and eye contact, and ingestion of contaminated water. Health problems associated with direct exposure include skin and eye irritation, neurological problems, respiratory issues, and stress.

Long-term exposure to oil spills has been linked to more severe health issues. Studies have found that hydrocarbons, the principal component of oil, are carcinogenic. However, the full extent of the long-term health effects of oil spills is not yet well understood due to a lack of long-term studies.

The use of dispersants in oil cleanup operations has also been associated with human health concerns, including obesogenicity, toxicity, and illnesses from aerosolization. Additionally, oil spills can have indirect effects on human health by disrupting ecosystems and economies, particularly in communities that are heavily reliant on natural resources.

Overall, oil spills pose a significant threat to human health, and more long-term research is needed to fully understand the range and severity of potential health impacts.

Oil spill prevention

Oil pollution is a global issue that arises from both highly publicised spills and long-term, low-level illegal discharges. Oil spills can have severe environmental and economic consequences. They can result from the release of crude oil from tankers, offshore platforms, drilling rigs, wells, and pipelines, as well as spills of refined petroleum products such as gasoline and diesel fuel, as well as their by-products.

To prevent oil spills, several measures can be implemented:

International Regulations and Conventions:

International organisations such as the UN International Maritime Organization (IMO) and the International Tanker Owners Pollution Federation (ITOPF) have implemented regulations to control operational discharges and reduce the risk of accidents. For instance, MARPOL amendments in 1992 mandated double hulls for large tankers, significantly reducing the number and impact of spills. Other conventions like the London Convention and international oil pollution compensation funds also address marine pollution.

National and Regional Initiatives:

National and regional authorities play a crucial role in preventing oil spills. For example, the US Environmental Protection Agency (EPA) has regulatory programs, including the Spill Prevention, Control, and Countermeasure (SPCC) rule and the Facility Response Plan (FRP) rule, to help facilities prevent and prepare for oil discharges. The SPCC rule applies to facilities with significant oil storage capacities and those located near navigable waters, aiming to prevent oil from entering waterways.

Many organisations and institutions have developed oil spill prevention plans, providing detailed procedures to prevent and manage spills. These plans include the use of booms, spill berms, and sorbent pads to contain and clean up spills, as well as the proper disposal of contaminated materials. St. Mary's University, for instance, has a comprehensive Spill Prevention, Control, and Countermeasure (SPCC) Plan that outlines procedures for different scenarios, including indoor and outdoor spills.

Safe Refuelling Practices:

Recreational boaters and small-vessel owners should adopt safe refuelling practices to prevent oil spills. This includes knowing the tank's capacity, leaving room for fuel expansion, using absorbent pads or fuel collars to catch drips, and properly managing any spills that occur.

Bilge Water Management:

Bilge water, or the water collected in the lowest part of a ship, can contain oil residues. By implementing proper bilge water management practices, such as using bilge socks made from oil absorbent pads, discharges of oily water can be prevented. Additionally, ensuring proper tank-cleaning procedures, such as the load-on-top (LOT) process, can significantly reduce operational sources of oil pollution.

By implementing these measures and continuing to develop innovative solutions, we can effectively prevent oil spills and minimise their impact on the environment and human health.

Oil spill clean-up

Oil spills are a major ecological threat, with around 90% of the world's oil transportation occurring through oil tankers. Oil spills can be caused by human error, natural disasters, technical failures, or deliberate releases. The largest and most damaging spills usually involve the release of petroleum or heavy bunker fuel from tankers, drill platforms, barges, or ships.

Containment and Recovery

Containment booms (floating barricades) are often used as a first response to prevent the oil slick from spreading and reaching sensitive habitats and shorelines. Once the oil is contained, response vessels may use sorbent pads, skimmers, and vacuum systems to remove the oil from the water. Sorbents are materials that absorb or adsorb oil, such as hay, peat moss, straw, or vermiculite. After absorption, sorbent materials must be retrieved carefully to avoid sinking and posing risks to aquatic life.

Dispersants

Dispersants are chemicals that can be sprayed onto large oil slicks to break down the oil and limit its impact on the environment. They are typically used in situations where mechanical removal methods are inaccessible or ineffective. However, dispersants may generate air pollutants and should be used with caution near populated areas.

In-Situ Burning

In-situ burning involves containing the oil slick with fire-resistant booms and then igniting it to burn off the oil from the water's surface. This method is only suitable in calm conditions, far from shorelines and populated areas, as it produces toxic fumes and residues.

Alternative Shoreline Clean-up Methods

Solidifiers, bioremediation, and in-situ burning are alternative methods for shoreline clean-up. Solidifiers modify the consistency of oil, turning it into a solid to prevent adhesion to the ground. Bioremediation involves applying fertilizers to the spill area to accelerate bacterial oil degradation. These methods are currently under study and are not yet permitted in some places, such as Canada.

Natural Decomposition

In remote or inaccessible locations, allowing the oil to naturally decompose through the action of the sun, wind, weather, tides, or naturally occurring microbes may be considered. While cost-effective, this approach is time-consuming and requires constant monitoring.

Remote Sensing

Remote sensing is a technology that employs electromagnetic radiation to detect, monitor, and assess oil spills without direct contact. It can be particularly useful in marine environments, helping to identify spills and track their movement.

Frequently asked questions