Authorities said on Monday that the oil spill from the bulk carrier mv Rak that sank recently is a minor incident, but environmentalists nonetheless said that its timing was a cause for concern, especially in the context of mangroves' ecology.

At a press conference here on Monday, Inspector General SPS Basra, Commander, Coast Guard Region (west), said that the flow had reduced to 1 tonne an hour on Monday as compared to 1.5 to 2 tonnes an hour on Sunday. But, he said, one could not be certain how long the spill will continue.

Approximately 80-100 tonnes of oil must have spilled from mv Rak into the sea. “But we cannot estimate correctly, as we have not been able to measure it,” Mr. Basra said.

The IG said that the oil traces found on the beaches of Mumbai, Alibaug and Gorai were from mv Rak, because no other ship had sunk in the area. “But please understand, whatever is reaching the coast are mosses which have been generated after the oil was dispersed by spraying OSD [oil spill dispersant],” he said. “We are trying to ensure that the oil doesn't reach the coast.”

While explaining the parameters for categorising oil spill, Mr. Basra said that up to 700 tonnes of oil spill could be described as minor, 700-2000 tonnes as medium and above 2000 tonnes as major.

The timing

But field ecologist Deepak Apte said that the oil spill had to be seen in perspective. “The impact of the oil spill is not measured based on just the volume. The timing is important too. The mangrove ecology is under continuous stress since last year's oil spill after the collision of [msc] Chitra and [mv] Khalijia. This is the seeding season for mangroves. Even a thin film is enough to kill the seeds and can have a major impact on the mangrove ecology.”

Mr. Basra said that one-third of the oil spill generally reached the coastline. “One-third of the oil spill can be controlled through available mechanisms and another one-third is taken care of by natural dispersion. But the remaining one-third does reach the coast.”

As for mitigating further risks, Mr. Basra said that the Directorate General of Shipping would look into whether the oil from mv Rak could be pumped out.

On the methods to mitigate the damage, Mr. Basra said that the choice was restricted. “Various methods like booming and skimming can be used. But due to the rough seas, the only options available with us right now are spraying OSD and churning the oil with propeller option.”

A press release issued by the Directorate General of Shipping said “the continuous trail of the oil leak from the vessel is observed up to 12 nautical miles, very thick oil up to 1 nautical mile, thick layer of oil up to 2 nautical miles and thereafter only oil sheen is visible till 12 nautical miles.”

The ship sank nearly 20 nautical miles off the Mumbai coastline.

“The Coast Guard vessel Sankalp, oil pollution response vessel Samudra Prahari and one more response vessel Amrit Kaur are present to abate the oil pollution using oil spill dispersant. These vessels are continuously monitoring the situation. The Coast Guard also conducted air sorties this morning,” the release said.

Clean up operations

State Environment Secretary Valsa Nair Singh too said the oil spill was minor and that the needle of suspicion pointed to mv Rak.

Tar balls were spotted on the beaches of Alibag in Raigad district and at Gorai in Mumbai on Monday morning, a day after they were spotted at the city's Juhu-Versova beach. The government had given Rs 10 lakh each to the Raigad administration and the Brihanmumbai municipal corporation for clean up operations.

“The Brihanmumbai Municipal Corporation started cleaning operations last night [Sunday],” Maharashtra's Environment Minister Sanjay Devtale told reporters here.

The extent of pollution is not much. “The highest concentration is 135 milligram per litre,” he said.

Authorities have ruled out the possibility that the oil found at the beaches could have been from mv Pavit, which ran aground at the Juhu beach recently.

Samples for testing

Fish samples have been taken for examination. The Maharashtra Pollution Control Board would test the samples. The State government had already reissued the ban on fishing. Fishing is in any case banned till August 15.

Apart from the National Institute of Oceanography, the Bombay Natural History Society (BNHS) too has started collecting water samples from the affected beaches. “We collected samples from five places at Juhu and Versova beach today,” Dr. Apte said.