Management of oil pollution Revision Notes

Oil spills pose a significant threat to marine and coastal environments, often resulting from accidents involving oil tankers and ships. To reduce the risk of such pollution, international agreements have been established. The MARPOL (Marine Pollution) convention is a key treaty that sets out regulations to prevent pollution from ships, including oil discharge.

MARPOL requires ships to follow strict operational procedures, such as proper handling and disposal of oily waste, and mandates equipment standards to minimise accidental spills. Compliance is monitored by member countries, and violations can lead to penalties. This international cooperation is crucial because oil pollution can affect multiple countries' coastlines due to ocean currents.

• MARPOL convention regulates ship operations to reduce oil pollution.
• It includes rules on oil discharge, waste management, and ship equipment.
• International cooperation is essential due to transboundary nature of marine pollution.

One effective method to prevent oil spills from tanker accidents is the use of double-hulled oil tankers. Unlike single-hulled tankers, double-hulled vessels have two layers of watertight hulls separated by a space. This design provides an additional barrier against leaks if the outer hull is damaged in a collision or grounding.

For example, if a ship runs aground and breaches the outer hull, the inner hull remains intact, preventing oil from escaping into the sea. This design has become a standard requirement in many countries following major oil spill disasters, significantly reducing the frequency and volume of spills from tanker accidents.

• Double-hulled tankers have two layers of hull to prevent leaks.
• They reduce the risk of oil escaping after hull damage.
• This design is now widely adopted to improve marine safety.

Despite prevention efforts, oil spills still occur and require prompt management to reduce environmental damage. Several techniques are used to contain and remove oil from marine and coastal ecosystems.

Booms are floating barriers deployed around the spill to contain the oil and prevent it from spreading further. They are especially useful near sensitive coastal areas. Detergent sprays, or dispersants, chemically break down the oil into smaller droplets, promoting natural biodegradation and reducing the oil’s impact on wildlife and shorelines. However, dispersants must be used carefully due to potential toxicity.

Skimmers are mechanical devices that remove oil from the water surface by skimming or suction. They are effective in calm waters but less so in rough seas. Combining these methods allows responders to adapt to different spill conditions and ecosystems.

• Booms contain oil to limit spread, protecting sensitive areas.
• Detergents break down oil to speed natural degradation.
• Skimmers physically remove oil from the water surface.
• Techniques are chosen based on spill size, location, and environmental sensitivity.

The Exxon Valdez oil spill in 1989 is a well-known example of a major marine oil pollution incident. The tanker ran aground in Prince William Sound, Alaska, releasing approximately 42 million litres of crude oil. The spill caused extensive damage to marine life and coastal habitats.

Response efforts included deploying booms to contain the oil, using skimmers to remove it, and applying detergents to break down the oil. Despite these efforts, the spill’s scale and the remote location made cleanup difficult. The incident led to stricter regulations, including requirements for double-hulled tankers in the United States and improvements in spill response planning.

Studying this case helps understand the challenges of managing large spills and the importance of prevention and preparedness.

• Exxon Valdez spill released 42 million litres of oil in 1989.
• Response used booms, skimmers, and detergents but faced challenges.
• Led to stricter tanker design and improved spill management policies.
• Highlights the need for effective prevention and rapid response.