A large quantity of oil, spilt from a sunken tanker in a river near the Sunderbans, may pose a serious threat to the ecological balance of the largest mangrove forest in the world.
The tanker, carrying 350,000 litres of furnace oil, sank in the Shela river near the forest in Mongla upazila of Bagerhat district at around 5:00am yesterday (Tuesday), after being hit by a cargo vessel.
M Giasuddin, managing director of Harun & Company, owner of the tanker, said an empty cargo trawler rammed into their vessel, OT Southern Star 7, from behind when it was anchored at Joymongol in the Shela river. Cracks developed at the bottom of the vessel. Poor visibility due to dense fog may have caused the accident, he added.
Seven crew members who were on board the tanker managed to swim ashore, but its master, Mokhlesur Rahman, 45, is missing, said Giasuddin. A team of the Coast Guard was conducting a search operation for Rahman.
The spilt oil has spread over an area of around 20 square kilometres in the Sunderbans, including Joymoni, Nandobala, Andharmanik and Mrigomari. Experts fear more areas will be affected by the oil spill.
Marine resources will be the worst hit as the oil spill is feared to spread in and around the Sunderbans and may reach the Bay, experts feared.
Professor Dilip Kumer Dutta of the environmental science department at Khulna University said the oil spill will create a dire and prolonged impact on the coastal ecology of the Sunderbans. “The Sunderbans is a mangrove forest and most of the trees use their unique roots for respiration. The trees grow pencil-like roots called pneumatophores which take in oxygen from the air. During high tides, roots of the mangrove trees will be covered with oil and the respiration process will be obstructed,” Prof Dutta said.
“If this situation continues for a prolonged period, most of the trees living along the coastal belt of the forest will die. Besides, fisheries, as well as aquatic resources, will suffer from the lack of oxygen,” he said.
Because of a lack of water flow in downstream areas, the tidal surge in the Bay will not be able to sweep the oil spill off quickly, which in the long term, will affect the ecological balance of the Sunderbans, Prof Dutta added.
The situation is going from bad to worse since government departments, including the Mongla Port Authority and the Forest Department, do not have any system to remove the floating oil or control it from spreading, divisional forest officer (DF0), East Sunderbans, Amir Hussain Choudhury said.
However, chairman of Mongla Port Authority (MPA), Commodore Habibur Rahman Khan, has suggested that BNS Shahid Ruhul Amin should be deployed. The Navy ship has equipment to consolidate the oil slick by discharging chemical. By this, the damage can be controlled to some extent, he added.
The vessels are plying through the Shela river after the closure of the Ghasiakhali channel three years ago.
Since then the BIWTA has been using the Shela as an alternate route. Environmentalists have been demanding closure of this route as an alternate channel since it was posing threat to the Sunderbans.
Anir Hosain Choudhury, DFO of East Sunderbans, said due to oil pollution the dolphin sanctuary on the Mrigomari-Nandabal-Andharmanik has been threatened. This may force the dolphins to migrate from there.
Assistant conservator of forests of the Chandpai range, Abul Kalam Azad, said that the front of the tanker has sunk, leaving its back floating above the water. He estimates that almost all the oil the tanker was carrying has leaked out. During his visit to the area during ebb tide in the afternoon, he saw that the oil slick has spread in rivers and canals over an area of 20 square kilometres inside the Sunderbans. The slick is close to the dolphin sanctuary. Before the high tide at night, the oil slick may enter the sanctuary on the Shela river, the forest official apprehended.
Not only dolphins, but other aquatic lives, flora and fauna and the entire eco-system of the Sunderbans, a World Heritage site, will be affected, he added.
Replying to a query, the green activist said the forest department and other organisations do not have the capability to stop it.
“The government should formulate a standard guideline or policy on the plying of vessels inside the Sunderbans for the sake of aquatic lives, flora and fauna, including the dolphins. If it is not done immediately, the entire eco-system of the Sunderbans will be destroyed in 50 years due to such incidents and the Rampal power plant,” Motin warned.