Marine experts: Will take months to assess Chennai oil spill damage

Feb 03, 2017, 09:37 IST | Vinod Kumar Menon

The Chennai oil spill could spell black doom for the marine ecology, fear scientific experts who have warned of catastrophic consequences unless the slick is cleared up quickly.

The oil spill took place after two ships -- MT Dawn Kanchipuram and MT BW Maple -- collided off the Ennore coast, about 2 km near the Kamarajar Port. One ship was entering the port laden with LPG, while the other was leaving the port with petroleum and diesel.

Experts estimate that at least 20 tonnes of oil has leaked into the ocean and this will continue to get trapped in the maze of garbage littered across the shoreline and harm aquatic life.

Ongoing efforts
The Coast Guard, with the help of the local administration and NGOs, is persisting in its efforts to clear the oil slick at the worst hit area near Ramakrishna Nagar Kuppam village, and has already collected approximately 40 tonnes of oil and sludge. However, this may not be enough to prevent catastrophic repercussions on the marine eco-system, said scientific experts.

The oil spill took place after MT Dawn Kanchipuram and MT BW Maple collided off the Ennore coast on Saturday. Pics/Indian Coast Guard
The oil spill took place after MT Dawn Kanchipuram and MT BW Maple collided off the Ennore coast on Saturday. Pics/Indian Coast Guard

Dr MV Ramana Murthy, scientific head and director of the Integrated Costal and Marine Area Management, Project Directorate (ICMAM), Chennai, said, "We have already collected samples from the affected areas and are likely to have our reports ready by February 7. Prima facie, we suspect, that other than furnace oil, even crude oil has leaked. Our estimate is more than 20 tonnes oil has sneaked into the ocean. The first two days witnessed high currents towards the southern side of the coast, impacting the smaller fish and has caused serious consequences for the marine and costal habitats. The spill has already crossed 20 km and might head another few km south of the coast before it gets diluted."

Could have been worse
"Luckily, most of the migratory birds were on the northern side of the coast and were not affected. The mangroves are also located far inside the creeks, and so far there has been no impact on them," said Dr Murthy.

The coast guard and local administration have already cleared approximately 40 tonnes of oil and sludge
The coast guard and local administration have already cleared approximately 40 tonnes of oil and sludge

A senior coast guard official added, "Preliminary inquiries have revealed that the furnace oil that was stored at the bottom of the vessel started leaking. Luckily, the diesel and petroleum that was on upper berth remained unaffected due to the impact. Moreover, the incident happened close to the shore. Had it been mid-sea, the damage would have been more severe."

Too soon to say?
However, it could be weeks or months before the true extent of damage becomes clear, according to Dr Jiyalal Jaiswar, former chief scientist, Council of Scientific and Industrial Research (CSIR- National Institute of Oceanography).

"The oily film blocks sunlight from penetrating the water and hampers the process of photosynthesis, a process through which aquatic plants build essential nutrients. This results in the death of the entire food chain, starting from the plant life to the phytoplankton, zooplankton, fish," said Jaiswar.

"It's possible that petroleum hydrocarbon can deposit at the bottom of the sea and harm bottom-dwelling organisms (benthos), which will have long term damages. Also, the water quality and concentration of dissolved oxygen is also altered due to absorption of the petroleum hydrocarbon, hampering the whole eco-system in the spill region. It usually takes a fortnight to a few months for these effects to appear," he added.

20km
Extent of oil spill

40tonnes
Oil and sludge cleaned up so far

Mumbai was worse
In August 2010, two Panamanian cargo ships - MSC Chitra and MV Khalijia III — collided 10 km from the Mumbai harbour. Approximately 400 tonnes of oil spilled into the sea, spreading as far as Mandva and Alibagh due to the high tide. A criminal case was registered at the Yellow Gate police station and the matter is under trial.

Ecological impact
> Aquatic flora and fauna could be covered in oil
> Oil will contaminate the food chain and could harm humans
> If unchecked, oxygen in sea will reduce
> New generation of aquatic life at risk
> Mangroves could die
> It will take 6 months to a year for oil to naturally clear out
> Removing oil from rocks and sand on sea bed is even harder
> Substrate life such as crabs, lobsters, etc. could die out meanwhile

Operation Clean-up
Apart for the coast guard and the Tamil Nadu Pollution Control Board and state fire service, 200 volunteers are participating from various organisations such as Tree Foundation, Hindustan Institute of Maritime Training and GKM Marine. Coast guard helicopters are carrying out regular sorties for continuous monitoring of the drift pattern of oil slick. The sea vessel, ICGS Varad, has been deployed with spill spray arms and oil spill dispersant to combat the slick. In addition, inaccessible areas are being cleared manually.

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