The world demonstrates high awareness of environment-related issues, be it climate change, air, or water pollution. Social and economic impacts of man-made and natural disasters are debated more frequently nowadays, be it a tsunami, forest fires, or oil spills. With the increased awareness about the environment, the socio-economic challenges of all kinds of oil spills should be discussed and deliberated more frequently.
The accelerated industrialization and urbanization in the 21st century have led to the world’s rapid economic growth. This growth has fuelled the consumption of oil and other petroleum products in various sectors. The added load on transportation, logistics, and storage has created accidental unpleasant events where an oil spill happens.
According to estimates by International Tanker Owners Pollution Federation (ITOPF), between 1970 and 2016, around 5.73 million tonnes of oil had been spilled to various water bodies (seas and oceans mostly) only due to oil tankers’ leakage.
Global statistics reveal that the number of marine oil spill incidents per year has decreased substantially in the last two decades. It is also true that such incidents continue to happen at irregular intervals, owing to a variety of reasons such as rupture or leakage in the storage tank, vessels, accidents or improper handling during movement of goods, equipment breakdowns, erroneous human activity, offshore drilling, and even natural disasters like storm, hurricane, and so on.
Contamination due to oil spills often persists in the ecosystem for several years and adversely affects the environment, flora, and fauna. Well-organized containment measures undertaken alongside proper equipment handled by trained personnel are considered the gold standard concerning spill response and management in the world. The oil spill response depends on many factors like the physical and ecological characteristics of the area, spill scenario, sea and weather conditions, national and local regulations on oil spill response, and availability of response resources.
The response to an oil spill at sea includes containment and recovery or in-situ burning or dispersant application. Keeping the long-term perils in mind, the foremost objective is to contain the oil spill as soon as possible. Containment of oil spills at sea involves confining the spill to prevent it from spreading or diverting it to a location where it can be recovered or treated. The ideal solution to cleaning an oil spill is to contain the oil within booms for recovery by specialized skimmers; this removes the oil physically from the marine environment. Following this, sorbents play an important role in oil spill clean-ups and clean the final traces of oil spills on water. These are also used as a primary recovery tool for smaller spills and as a passive means during clean-up.
The second option of in-situ burning is the process of burning the floating oil at sea. The decision to burn oil or not is a complex one as the resultant fire and toxic smoke can adversely impact human health. Also, weather, sea, and oil conditions have to be considered before igniting the oil.
The third option of the application of dispersant can be an effective oil spill response strategy if used appropriately. These dispersants are capable of removing significant quantities of oil from the sea surface in a short time. The dispersants transfer the oil into the water columns, where it is broken down by natural processes. The use of dispersant is guided by the characteristics of the oil, weather and sea conditions, location, and environmental issues. The properties of the oil spilled and the location at which the oil spills will largely determine the appropriate clean-up option.
The majority of ship-source oil spills occur close to the coast, and the primary objective is to prevent the oil from reaching the shorelines. This may be limited by time, weather and sea conditions, and the resources available. When the oil reaches the shoreline, a considerable effort is required to clean the entire oil affected area. Clean-up operation onshore is performed in three stages: Emergency Phase, Project Phase, and Polishing Phase.
In the Emergency Phase, the objective is to respond to the spill as rapidly as possible to collect floating oil close to the shoreline with the help of skimmers, pumps, and vacuum trucks. For Project Phase, excavator machines and manpower can be deployed rapidly and effectively to collect oil from the heavily contaminated shoreline and remove oil trapped within sediments. Various sorbents like booms and pads are used in inaccessible areas and are placed along the shoreline to absorb the oil. Final clean-up of oil contamination and removal of oil stains is done in stage three, the Polishing Stage.
An oil spill can be a catastrophic event for a region, endangering wildlife, destroying local vegetation, and creating a range of health issues for humans. When a spill occurs, having a proper spill control program enables quick and effective response. A successful oil spill clean-up depends on the timely availability of personnel, equipment, and materials and upon the organization’s quality to make decisions and manage the clean-up process.