By Tharumalee Silva
Investigations into an oil spill which affected the coastline between Wellawatta and Mount Lavinia are continuing as the authorities attempt to identify the actual source of the oil.
The public was urged to stay away from the coastline between Wellawatta and Mount Lavinia due to the oil spill last Sunday (2).
The oil was suspected to have been released from a ship.
Marine Environment Protection Authority General Manager Pradeep Kumara stated that they were only able to detect the spill during the early hours of Sunday morning.
“We suspect the spill occurred late night on Saturday. The oil which washed up extended at a 1 km radius extending from Wellawatta to Mount Lavinia,” he said.
He further explained that these oil spills give birth to “tar balls”, which are withered oils that can be carried hundreds and hundreds of miles by the ocean currents.
The Sri Lanka Coast Guard and the Sri Lanka Navy immediately receive intelligence when incidents such as these occur under normal circumstances.
However, since the oil spill was released late into the night, neither the Coast Guard nor the Navy was able to detect it. “Even though we have a satellite system, we could not differentiate as to which ship was responsible for the oil spill,” Kumara iterated.
He also stated that the Government should invest in more advanced satellite systems to monitor the ongoing operations in the Indian Ocean surrounding Sri Lanka.
However, Kumara stated that it is possible to analyse fingerprints in the oil samples which were collected, but it would be impossible to find out which ship leaked the oil.
Cleaning up the residue
“It wasn’t a huge oil spill and we have managed to clean up 80-90% of the oil. The remaining 10% could not be removed because it was infused into the sand and exist in infinitesimal particles, and we do not have the technology to remove it,” he said.
Kumara also stated that the MEPA remains hopeful that the sand will be naturally cleansed by the sunlight and rainwater.
“The MEPA has collected samples of oil which was residue in the sand to analyse and create a sustainable solution in case an incident such as this occurs in the future,” he said.
According to research done by the University of Delaware, USA, oil spills could be contained with time by letting it break down by natural means. The study indicated that a combination of sun, wind, waves, and current can naturally disperse and evaporate many oils while the time duration will depend on the type of oil which has been spilled.
The research also suggested using booms to contain the oil spill and using skimmer equipment to collect the oil from the surface of the oceans. Further, the use of dispersants – chemicals sprayed on the surface to break up the oil matter and speed up its natural biodegrading – also proves a solution according to the research. The components of oil washed ashore can be broken down by bacteria and other microorganisms into harmless substances such as fatty acids and carbon dioxide by biodegradation.
Fishing industry at risk
The General Manager also stated that the fishermen surrounding these areas have been advised by the MEPA and the Coast Guard to avoid fishing in these areas.
“Once the sludge oil gets attached to the boat, removal can only be done using kerosene oil which is far more expensive,” he said.
He further stated that the oils could be toxic but will gradually dilute and the threat will subside.
Marine life in danger
Kumara also said that no information has been collected so far with regards to the change in marine biodiversity after the oil spill occurred.
He stated that even though it was a small spill, even a drop of toxic oil can cause a lot of harm to the surrounding biodiversity; especially turtle eggs which could die once exposed to toxic oils.
Speaking to The Sunday Morning, Marine Biologist Asha De Vos stated that turtles that lay eggs in the sand will be greatly affected.
“These species will be greatly affected, especially if there are turtles swimming around in the sea – they could accidentally ingest tar balls,” she said.
Further, when hatchlings come back to see, these tar balls could stick on to them which would endanger their lives.
“From Mount Lavinia onwards, we have observed turtle nesting which could have been threatened,” she said.
Further, Department of Fisheries and Aquatic Resources Director General Ginige Prasanna Janaka Kumara stated that they have not received any information as to whether any major scale implications have taken place due to this incident.
“We are working in alliance with the MEPA to analyse the damage,” he said.
The Director General further shed light on how marine life could be threatened in a similar situation.
He stated that the oils can stunt the growth of the coral species and also pose a threat to various species of fish.
“We are currently conducting research surrounding the area the spill occurred. We will be able to come to a conclusion with regard to the situation after a period of one month,” he said.
Nine methods for oil spill clean-up at sea
1. Using booms
This equipment prevents the oil from dispersing further. This method is only effective as long as there is a clear definition of the place of the spill. Further, this method is only efficient when the spill is accessible in a short period of time; the further the oil spreads, it is extremely difficult to contain. It cannot be successfully employed under rough sea waves, high wind velocities, or fluctuating tides.
2. Using skimmers
Once the oil is contained by oil booms, skimmers or oil scoops can be used to skim the oil of the water surface. These instruments vaguely resemble vacuum cleaners by using suction to separate oil and water. The presence of debris and other solid matter in the water can make this task difficult.
3. Using sorbents
Sorbents soak up liquids by absorption or adsorption (forming a thick layer over the liquid). Materials such as hay, vermiculite, and straw can be used for this after the absorption. The sorbent materials must be retrieved efficiently which may prove to be worse if ignored. Sorbents after absorption become heavier, making them difficult to retrieve and also pose a risk to aquatic life at the bottom of the sea. They are most effective in small spills or to manage the leftover traces of a larger spill.
4. In-situ burning
This method is referred to when the oil is ignited to burn the oil off the water. This method effectively removes up to 98% of the oil spill and proves to be more effective than any other method. However, the fumes that are released by burning the toxic oils pose a threat to aquatic resources and the air. Further, this method can only be adopted if the oil spill is small and contained.
5. Using dispersants
This method is adopted by spraying chemicals on the surface of the oil spill to increase the integration of oil. Chemicals such as Corexit 9500 allow the oil to naturally bond with the water by increasing the surface area of each molecule. However, this method creates tar balls as the oil combines with water; it gets mixed with sand and debris present in the water which results in the formation of tar which finds their way to the shores.
6. Hot water and high-pressure washing
This method is used to dislodge the trapped and weathered oil from locations that are generally inaccessible to machinery. Water is then heated up and sprayed by hand using high-pressure wands and nozzles. Then, the oil which is flushed to the surface is collected using skimmers.
7. Manual labour
This method uses manual methods such as hands, rakes, shovels, etc. to clean the surface oil and oily debris and place them in special containers to be removed from the shoreline. This method is only applicable when cleaning up slicks on shorelines. This economically viable solution also provides relief to unemployment.
8. Bioremediation
Bioremediation refers to the use of specific microorganisms to remove any toxic or harmful substances. There are various classes of bacteria, fungi, Achaea, and algae that degrade petroleum products by metabolising and breaking them into simpler and non-toxic molecules (mostly fatty acids and carbon dioxide).
9. Chemical stabilisation of oil by elastomers
Compounds such as “elastol”, which is poly iso-butylene (PIB) in a white-powdered form, can also be used to confine oil spills. The compound gelatinises or solidifies the oil on the water surface and thus, keeps it from spreading or escaping. The gelatine is easy to retrieve, and this makes the process highly efficient.
Investigations into an oil spill which affected the coastline between Wellawatta and Mount Lavinia are continuing as the authorities attempt to identify the actual source of the oil.
The public was urged to stay away from the coastline between Wellawatta and Mount Lavinia due to the oil spill last Sunday (2).
The oil was suspected to have been released from a ship.
Marine Environment Protection Authority General Manager Pradeep Kumara stated that they were only able to detect the spill during the early hours of Sunday morning.
“We suspect the spill occurred late night on Saturday. The oil which washed up extended at a 1 km radius extending from Wellawatta to Mount Lavinia,” he said.
He further explained that these oil spills give birth to “tar balls”, which are withered oils that can be carried hundreds and hundreds of miles by the ocean currents.
The Sri Lanka Coast Guard and the Sri Lanka Navy immediately receive intelligence when incidents such as these occur under normal circumstances.
However, since the oil spill was released late into the night, neither the Coast Guard nor the Navy was able to detect it. “Even though we have a satellite system, we could not differentiate as to which ship was responsible for the oil spill,” Kumara iterated.
He also stated that the Government should invest in more advanced satellite systems to monitor the ongoing operations in the Indian Ocean surrounding Sri Lanka.
However, Kumara stated that it is possible to analyse fingerprints in the oil samples which were collected, but it would be impossible to find out which ship leaked the oil.
Cleaning up the residue
“It wasn’t a huge oil spill and we have managed to clean up 80-90% of the oil. The remaining 10% could not be removed because it was infused into the sand and exist in infinitesimal particles, and we do not have the technology to remove it,” he said.
Kumara also stated that the MEPA remains hopeful that the sand will be naturally cleansed by the sunlight and rainwater.
“The MEPA has collected samples of oil which was residue in the sand to analyse and create a sustainable solution in case an incident such as this occurs in the future,” he said.
According to research done by the University of Delaware, USA, oil spills could be contained with time by letting it break down by natural means. The study indicated that a combination of sun, wind, waves, and current can naturally disperse and evaporate many oils while the time duration will depend on the type of oil which has been spilled.
The research also suggested using booms to contain the oil spill and using skimmer equipment to collect the oil from the surface of the oceans. Further, the use of dispersants – chemicals sprayed on the surface to break up the oil matter and speed up its natural biodegrading – also proves a solution according to the research. The components of oil washed ashore can be broken down by bacteria and other microorganisms into harmless substances such as fatty acids and carbon dioxide by biodegradation.
Fishing industry at risk
The General Manager also stated that the fishermen surrounding these areas have been advised by the MEPA and the Coast Guard to avoid fishing in these areas.
“Once the sludge oil gets attached to the boat, removal can only be done using kerosene oil which is far more expensive,” he said.
He further stated that the oils could be toxic but will gradually dilute and the threat will subside.
Marine life in danger
Kumara also said that no information has been collected so far with regards to the change in marine biodiversity after the oil spill occurred.
He stated that even though it was a small spill, even a drop of toxic oil can cause a lot of harm to the surrounding biodiversity; especially turtle eggs which could die once exposed to toxic oils.
Speaking to The Sunday Morning, Marine Biologist Asha De Vos stated that turtles that lay eggs in the sand will be greatly affected.
“These species will be greatly affected, especially if there are turtles swimming around in the sea – they could accidentally ingest tar balls,” she said.
Further, when hatchlings come back to see, these tar balls could stick on to them which would endanger their lives.
“From Mount Lavinia onwards, we have observed turtle nesting which could have been threatened,” she said.
Further, Department of Fisheries and Aquatic Resources Director General Ginige Prasanna Janaka Kumara stated that they have not received any information as to whether any major scale implications have taken place due to this incident.
“We are working in alliance with the MEPA to analyse the damage,” he said.
The Director General further shed light on how marine life could be threatened in a similar situation.
He stated that the oils can stunt the growth of the coral species and also pose a threat to various species of fish.
“We are currently conducting research surrounding the area the spill occurred. We will be able to come to a conclusion with regard to the situation after a period of one month,” he said.
Nine methods for oil spill clean-up at sea
1. Using booms
This equipment prevents the oil from dispersing further. This method is only effective as long as there is a clear definition of the place of the spill. Further, this method is only efficient when the spill is accessible in a short period of time; the further the oil spreads, it is extremely difficult to contain. It cannot be successfully employed under rough sea waves, high wind velocities, or fluctuating tides.
2. Using skimmers
Once the oil is contained by oil booms, skimmers or oil scoops can be used to skim the oil of the water surface. These instruments vaguely resemble vacuum cleaners by using suction to separate oil and water. The presence of debris and other solid matter in the water can make this task difficult.
3. Using sorbents
Sorbents soak up liquids by absorption or adsorption (forming a thick layer over the liquid). Materials such as hay, vermiculite, and straw can be used for this after the absorption. The sorbent materials must be retrieved efficiently which may prove to be worse if ignored. Sorbents after absorption become heavier, making them difficult to retrieve and also pose a risk to aquatic life at the bottom of the sea. They are most effective in small spills or to manage the leftover traces of a larger spill.
4. In-situ burning
This method is referred to when the oil is ignited to burn the oil off the water. This method effectively removes up to 98% of the oil spill and proves to be more effective than any other method. However, the fumes that are released by burning the toxic oils pose a threat to aquatic resources and the air. Further, this method can only be adopted if the oil spill is small and contained.
5. Using dispersants
This method is adopted by spraying chemicals on the surface of the oil spill to increase the integration of oil. Chemicals such as Corexit 9500 allow the oil to naturally bond with the water by increasing the surface area of each molecule. However, this method creates tar balls as the oil combines with water; it gets mixed with sand and debris present in the water which results in the formation of tar which finds their way to the shores.
6. Hot water and high-pressure washing
This method is used to dislodge the trapped and weathered oil from locations that are generally inaccessible to machinery. Water is then heated up and sprayed by hand using high-pressure wands and nozzles. Then, the oil which is flushed to the surface is collected using skimmers.
7. Manual labour
This method uses manual methods such as hands, rakes, shovels, etc. to clean the surface oil and oily debris and place them in special containers to be removed from the shoreline. This method is only applicable when cleaning up slicks on shorelines. This economically viable solution also provides relief to unemployment.
8. Bioremediation
Bioremediation refers to the use of specific microorganisms to remove any toxic or harmful substances. There are various classes of bacteria, fungi, Achaea, and algae that degrade petroleum products by metabolising and breaking them into simpler and non-toxic molecules (mostly fatty acids and carbon dioxide).
9. Chemical stabilisation of oil by elastomers
Compounds such as “elastol”, which is poly iso-butylene (PIB) in a white-powdered form, can also be used to confine oil spills. The compound gelatinises or solidifies the oil on the water surface and thus, keeps it from spreading or escaping. The gelatine is easy to retrieve, and this makes the process highly efficient.