by J.A.A.S.Ranasinghe

Former Director and Acting Chairman of Marine Environment Protection Authority

MT New Diamond VLCC, Very Large Crude Carrier, flagged in Panama was reportedly carrying over 300,000 Mt of Crude Oil on its voyage to Pradip Port, India from Al Ahmadi in Kuwait when it caught fire off the eastern coast of Sri Lanka resulting in the death of a crew member and the evacuation of 23, five Greek and 18 Philippine nationals. The fire that broke out as a result of the explosion of a boiler resulted in a massive fire in the engine room and the bridge, which controls the ship. Fortunately, the fire had not spread to the oil tanks which would h ave resulted in a major oil spill. If the three million barrels of oil leaked, it could have spealt devastation to many of the marine mammals that live in vibrant habitats along the eastern coast of Sri Lanka and the vibrant eastern economy where a hive of activities is taking place such as fisheries, tourisms, agriculture and consequently to the livelihood income of the people.

Effects of Petroleum Contamination

Petroleum contamination is a growing environmental concern that harms both terrestrial and aquatic ecosystems equally. However, in view of the major disasters caused to the marine environment, the public and regulatory and scientific communities have given more attention to the contamination of marine habitats. This is because marine oil spills can have a serious economic consequence on coastal activities as well as on those who exploit the resources of the sea. Thus, communities that are at risk of oil disasters must anticipate the consequences and prepare for them. The above mentioned disaster is an eye opener for all the stakeholders to take a serious view.

Marine environmental pollution caused by petroleum is of great concern because of the fact that petroleum hydrocarbons are toxic to all forms of life and harm both aquatic and terrestrial ecosystems. In recent years the pollution of marine habitats has caught the attention of researchers and environmentalists owing to the serious impact of oil spills on marine life, as well as on people whose career relies on the exploitation of the ocean’s resources. Additionally, marine life may be affected by clean-up operations, whatever the precautions taken. It may also be indirectly affected by the physical damage to the habitats in which plants and animals live in.

The writer has had firsthand information while being a former Director of the Marine Environmental Protection Authority (MEPA) and has attended series of scientific and technical sessions delivered by the International Maritime Organization (IOM) and effectively contributed to the deliberations with regard to OPRC (Oil Spill Preparedness and Response) a decade ago and it is with such an authoritativeness, the writer compiled this short essay on the effects of petroleum oil spills on marine life. This exercise would not be a worthwhile attempt, if the economic impact of oil spills on coastal activities with special reference to eastern theatre in which the above major fire brokeout and on the people who exploit the resources of the sea.

GLOBAL OIL SPILL TREND

Over the last 50 years, there has been a marked downward trend in oil spills from tankers. The average number of spills per year in the 1970s was about 79 and has now decreased by over 90 percent to a low of six according to the International Tankers Owners Pollution Federation (ITOPF). The lowest annual number of spills was recorded in 2019 and the highest in 1974. If one were to analyze the quantities of oil spilt, one would note that approximately 5.86 million tons of oil have been lost as a result of tanker incidents globally since 1970. However, there has been a significant reduction in volume of oil spilt through the decades. The total amount spilt per decade has reduced by about 95% since the 1970s.

An interesting pattern of alternating sharp decline and stability can be observed for average volume of oil spilt per decade. Nonetheless, quantity of oil spilt in a particular year or a decade is unpredictable, and the trend can be hugely distorted by a single large spill. In case, the fire caused to MT New Diamond resulted in an oil spill over 270,000 Mts, it would have been the one of the major oil spills recorded in recent times in Sri Lanka. The most frequent causes of oil spills are allisions/collisions, groundings and Fires. However, the proportion of groundings has decreased over the decades, making allisions, collisions and Fires, the current most frequent cause of spills. Today, about 99.99% of oil transported by sea arrives safely at its destination. The positive reports on trends in oil tanker spills endorse the hard work by governments, industry and ITOPF in improving safety and standards of operations.

With a spate of major disasters linked to major shipping routes in the past few years, the time is opportune for the world leaders and the international authorities such as IOM to have the wisdom and courage with a view to taking stock on global shipping reforms. It must be pointed out here that Sri Lanka witness more than 800 vessels passing through Sri Lanka per day posing an imminent threat to the Sri Lankan economy. Hence, it cannot be completely ruledout another disaster of this magnitude, if preventive measures are not taken.

Crude oil and its properties

The ill fate MT New Diamond carried crude oil which is a complex mixture of organic compounds. These mainly consist of hydrocarbons, in addition to heterocyclic compounds and some heavy metals. The different hydrocarbons that make up crude oil come in a wide range of molecular weights and structure compounds. These compounds include methane gas, high molecular weight tars, asphaltenes, resins, waxes and bitumen. They also include straight and branched chains, single or condensed rings and aromatic rings such as the monocyclic (benzene, toluene, ethylbenzene and xylene). They additionally include polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, anthracene and phenanthrene. Obviously, the chemical composition of crude oil is injurious not only to the mankind but also to marine ecosystems.

Physical contact is the major route of exposure and usually affects birds and furred mammals. These animals rely on their outer coats for buoyancy and warmth. Consequently, they often succumb to hypothermia, drowning and smothering when oil flattens and adheres to the outer layer. A second general exposure route is through the ingestion or inhalation of the hydrocarbon by organisms that reside on the surface. Exposure by these routes leads to absorption into the bloodstream via the gastrointestinal or respiratory tracts.

Toxicity of oil dispersants

Oil dispersants (57 chemical ingredients approved for use by the US EPA) are a common tool used after oil spills in marine environments. They break up oil slicks on the water surface and increase the oil’s rate of biodegradation. Oil dispersants are quickly used when other means, such as oil containment and removal, are insufficient. However, consequences of the toxicity of oil spill dispersants alone or in the presence of oil must be evaluated. Generally, undispersed oil poses the greatest threat to shorelines and surface-dwelling organisms. However, most dispersed oil remains in the water column where it mainly threatens pelagic and benthic organisms.

Fate of oil spills in the marine habitats

After oil is spilled at sea and with the effect of wind and water current, the oil spreads out and moves on the water surface as a slick a few millimetres thick. At the same time, it undergoes a series of chemical and physical changes. These processes are collectively termed ‘weathering’. Weathering causes the spilled oil to break down and become heavier than water. Some of these processes, like the natural dispersion of oil into water, lead to the removal of the oil from the sea surface and facilitate its natural breakdown in the marine environment. Others, particularly the formation of water-in-oil emulsions, cause the oil to become more persistent and remain at sea or on the shoreline for prolonged periods of time. The speed and relative importance of these processes depend on a number of factors. These include the quantity spilled, the oil’s initial physical and chemical characteristics, weather and sea conditions and whether the oil remains at sea or is washed ashore. Ultimately, the marine environment usually eliminates spilled oil through the long-term process of biodegradation.

Oil spills on marine organisms

Ultimately, the impact of oil on marine organisms depends on the fate of the oil. As previously described, when oil is present in the environment, it is either dispersed in the top layer of the water (littoral zone) or remains on the surface and, consequently, on the coastal areas. If the oil is not dispersed, it remains on the surface. In this case, currents bring the oil towards coastal areas which harms coastal organisms like invertebrates, mammals and birds. However, if the oil is dispersed, organisms, such as fish, plankton and larvae, are immediately subjected to oil toxicity.

Oil spills on planktonic organisms

Zooplankton is a particularly important food resource, especially for baleen whales. It can influence or control the primary productivity by top-down effects in return. Its population dynamic change can influence the biomass of other marine animals like fish by bottom-up effects. Some zooplankton, such as copepods, euphausiids and mysids, assimilate hydrocarbons directly from seawater and by ingesting oil droplets and oil contaminated food. The ingestion of oil by these organisms often causes mortality, while surviving organisms often show developmental and reproductive abnormalities.

Oil spills on coral reefs

In addition, recreational attractions for divers, coral reefs are considered to be important constituents of marine ecosystems. This is because they are important nurseries for shrimp, fish and other animals. The aquatic organisms that live within and around the coral reefs are at risk of exposure to the toxic substances within oil, as well as smothering. They are rapidly deteriorating because of a variety of environmental and anthropogenic pressures. Thus, they are suffering significant changes in diversity, species abundance and habitat structure worldwide. Oil dispersants are potentially harmful to marine life including coral reefs. In a study using coral nubbins in coral reef ecotoxicology testing, found that dispersed oil and oil dispersants are harmful to soft and hard coral species at early life stages.

Oil spills on fish

Due to the well-developed hepatic mixed function oxygenase (MFO) system, in addition to the reactivity of the metabolites that would not be released in a toxic form during digestion and absorption, most fish, even in heavily oil-contaminated environments, do not accumulate and retain high concentrations of petroleum hydrocarbons. Thus, they are not likely to transfer them to predators. Thus, no serious threat is predicted.

Oil spills on seabirds

As one of the major routes of exposure, physical contact usually affects birds. For example, thousands of African penguins (Spheniscus demerus) were oiled following the 2000 Treasure oil spill in South Africa.An evaluation of the impact of oil spills on seabirds has not been fully appreciated during incidents, despite pressure from the public concern, media and other interested parties for precise and up-to-date information on the damage. Consequently, the approximate numbers of seabird casualties involved in many major spills have only been estimated, while impacts at the population level have been difficult to determine. Natural variation and the huge range of factors that influence bird population statistics make it difficult to assess the impact of oil spill on sea birds.

Oil spills on marine mammals

Marine mammals include bottlenose dolphins, fins, humpbacks, rights, sei whales, sperm whales, manatees, cetaceans, seals, sea otters and pinnipeds. As previously indicated, the physical contact of oil with furred mammals usually affects these animals because they rely on their outer coats for buoyancy and warmth. Consequently, these animals often succumb to hypothermia, drowning and smothering when oil flattens and adheres to the outer layer.

As part of their activities, all marine mammals spend a considerable amount of time at the surface. Here, they swim, breathe, feed or rest. Thus, the possibility of their contact with a surface slick, water-in-oil emulsion, or tar balls, is high. In heavy pelage marine mammals, such as fur seals, sea otters and polar bears, this contact may lead to fouling. Polar bears and otters groom themselves regularly as a means of maintaining the insulating properties of the fur and may, thereby, ingest oil. Animals with smooth surfaces or relatively little to no pelage, such as whales, dolphins, manatees and most seals, have an advantage as oil would have fewer tendencies to adhere to their surface.

Oil that contaminates a shore is likely to severely affect pinnipeds. Pinnipeds require such areas for nursery and, to a lesser extent, otters and bears. Some of the oil is eventually returned in subtidal sediments, where it may transfer to gray whales, walrus and some seals. Such species feed heavily on benthic animals.

When marine mammals encounter fresh oil, they are likely to inhale volatile hydrocarbons evaporating from the surface slick. These volatile fractions contain toxic monoaromatic hydrocarbons (benzene, toluene and xylenes) and low molecular weight aliphatics with anaesthetic properties. The inhalation of these volatile hydrocarbon compounds is potentially harmful. The inhalation of concentrated petroleum vapours can cause the inflammation of and damage to the mucus membranes of airways, lung congestion or even pneumonia. Volatile benzene and toluene, which can be inhaled, can be transferred rapidly from the bloodstream into the lungs. Furthermore, they can accumulate from the blood into the brain and liver, causing neurological disorders and liver damage.

Oil spills on marine plants

In several aspects, aquatic plants are important to the functioning of ecosystems. These include the fact that they are oxygen producers, their ability to sequester carbon and for their base position in aquatic food chains. In addition, they serve as nursery, feeding and breeding habitats for a variety of animal and plant species, including recreationally and commercially important fish. Plants and animals are affected by the oil in which they come into contact with as a result of an oil spill. In their review of toxicities of oils, dispersants and dispersed oils to algae and aquatic plants.

Communities at risk of marine oil spills/anticipation and preparation

The threatening of marine environments with the petroleum oil spills has caught the attention of many communities, encouraging them to develop their own plans and policy issues. These have ranged from permitting or prohibiting increased oil transport volumes, to developing the capacity to respond to and recover from potential spill disasters.

Local communities that depend on the fishing industry, aquaculture and tourism should realize that the impact of an oil spill is governed by complex factors. These include the oil spill’s volume and location relative to fishing/cultivation areas, currents, tides and wave action. Other factors include whether species harvested in the region are sedentary or mobile, as well as government decisions relating to fishing bans and compensation schemes.

Economic impact of oil spills in the Eastern Region

Though Eastern Province (EP) has primarily an agriculture-based economy, it has an appreciable contribution to the national economy by way of Fish production and tourisms. Approximately, 25% of the nations fish production is generated by the EP and livelihood income of the fishing community employed in the coastal belt has a tremendous impact of the socio-economic status of the people. The EP has also received an unprecedented development in the tourism sector in the last few decades in that Pottuvil Arugam Bay, Lahugala Panama Beach, Pigeon Island, Nilaveli Beach have become attractive tourist destinations. Hence, any possible oil spill of a huge magnitude could have a devastating impact on all these vibrant economic sectors. Marine oil spills can have a serious impact not only on marine life, but on the gamut of all economic coastal activities and the communities that exploit the resources of the sea as seen above.

Involvement of multiplicity of Players

All in all, the joint efforts put in by Sri Lanka Navy, Air Force, Ports Authority and our Indian counterparts in dousing this fire have to be commended. His Excellency’s timely appreciation to all the players in averting this major calamity is most praiseworthy. It would be grossly unfair, if the names of the Chairperson and the General Manager of the Marine Environment Protection Authority namely Mrs. Dharshani Lahandapura and Dr. Terny Pradeep Kumara gone unnoticed for the magnificent roles they played behind the scene in educating the public and the media as to the possible marine consequences that could have arisen of this catastrophe as well as the mitigatory measures silently adopted to meet the possible oil spill.

Ironically, the above incident has raised many unanswered questions as a whole. As organizations, how much of advanced preparedness the authorities have set in motion to avert maritime catastrophes of this magnitude. Sri Lanka is woefully lacking the sources and resources to meet any eventuality of this magnitude, though it is claimed as a major maritime hub. As committed institutions, what proactive measures have we taken as a nation to deal with the sensitive marine ecosystems referred to above. It is intended to deal with these aspects in a separate column in due course.