Experts, volunteers assessing oil spill damage

Workers carting away oil-tainted sand on St John's Island. Some volunteers spent the Chinese New Year weekend visiting the oil-slicked shores.

SINGAPORE - Marine experts and nature enthusiasts have been documenting the damage to the Southern Islands after two sets of vessel collisions last week left some of their shores oil-slicked.

Since Jan 30, officers from the National Parks Board have conducted multiple visual habitat and biodiversity assessments of the oil spill, including one with volunteers from the WildSingapore group, in the affected sites, NParks' National Biodiversity Centre director Lena Chan told The Straits Times.

She said: "As of our most recent visual assessment from a boat on Feb 5, we did not observe oil on the surface of the waters along the route of the boat journey around several of the Southern Islands.

"However, some oil residue was observed on the north-eastern coastline of Pulau Semakau and the sea walls of offshore islands like Sisters' Island and St John's Island," she added.

The impact on biodiversity is "most likely minimal", said Dr Chan, compared to a 2010 oil spill off Tanah Merah, when some 2,500 tonnes of oil was spilt in a collision between a bulk carrier and a tanker.

Then, areas like Chek Jawa and Changi Beach were affected.

A Maritime and Port Authority of Singapore spokesman said the container ship Feihe spilt about 280 tonnes of fuel oil in its collision on Jan 29, while the NYK Themis spilt about 400 tonnes of fuel oil on Jan 30.

Said Dr Chan: "We will continue to monitor the situation and will work closely with NGOs, volunteer groups and academics to evaluate the impact of the oil spill on the biodiversity in the affected areas."

Some volunteers spent the Chinese New Year holiday weekend visiting the oil-slicked shores, taking photos and blogging.

Ms Heng Pei Yan, 27, a guide with volunteer group Naked Hermit Crabs, was at Kusu Island last Friday, the first day of Chinese New Year, and Pulau Semakau the following day.

At Kusu Island, she saw oil marks on the inner sea wall of the lagoon and on the sand flats. Corals in the lagoon had trapped some oil and there was a sheen on the water.

"I was a bit shocked and worried for the animals," she said. "We found sea hares (a type of sea slug) covered in oil and they were so stressed. The best we could do was to try and relocate as many as we could to a 'cleaner' location."

Coral reef expert Chou Loke Ming, from the National University of Singapore, said oil slicks can coat plants and fish gills, preventing them from getting enough oxygen, and cut corals off from sunlight.

Volatile organic compounds in oil can also dissolve in water and be toxic to marine life.

Over time, oily sludge will break down, and it does so faster in a hot, sunny tropical climate than a cold one, said Professor Chou. "The removal of most of the oil slick - that was a good response," he said.

The oil was skimmed off or dispersed as it floated, and bags of oil-slicked sand were shovelled up and removed from beaches by the authorities.

Life can return to a damaged shore or tide zone from elsewhere within a few months if conditions improve but full recovery can take years, he added.

caiwj@sph.com.sg


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