30 April 2011

East Changi oil spill: biodiversity impact studies results out

Sea stars at oil-slicked Tanah Merah were found to be less healthy than those at Pulau Hantu.
Post oil spill: Living Common sea stars (Archaster typicus)
Common sea star at Tanah Merah taken in Oct 10
Grace Chua's article in the Straits Times today shares the results of some studies on the biodiversity impact of last year's oil spill at Tanah Merah.

Tanah Merah was hit by the Changi East oil spill on 25 May 2010, nearly a year ago. Most of the crude on the shore was NOT removed and remains on the shore to this day.
Oil-slicked Tanah Merah: Crude just beneath the sand
Crude still beneath the sand on Tanah Merah, taken in Apr 2011
Several students have been studying this shore for the impact on marine life there. Thanks to Grace Chua, we learn more about their findings.

Janette Goh Kai Ying studied the Common sea stars (Archaster typicus) at Tanah Merah and compared them with those at Pulau Hantu. Those at Tanah Merah took up to two minutes to right themselves, while those from Pulau Hantu, which was not affected by the spill, took 30 to 50 seconds. There were fewer juvenile sea stars in Tanah Merah than on Pulau Hantu's shores, suggesting the oil spill had somehow affected the creatures' reproduction as it took place in the middle of the April-to-June mating season, or that younger sea stars were somehow more susceptible to the oil.

Wong Hiu Fung's study found fewer young dog whelks, a kind of sea snail, in Tanah Merah than on Pulau Hantu.

Effect of dispersants?

In another study, Jeremy Tan lab-tested mixtures of oil and dispersants on green mussels from a local farm. He found that green mussels, which feed by sweeping food in with their gill filaments, could not feed when exposed to commercial dispersants, and suggested the chemicals somehow damaged the mussels' gills.

Other studies

The article reports: "In another study last year, Prof Chou Loke Ming worked with the National Parks Board (NParks) and National Environment Agency (NEA) to assess the immediate impact of the spill on seashore habitats. They found that the short-term impact of the spill and clean-up on the overall ecosystem was not severe."

Future studies?

The article reports: "Besides the NUS projects, NParks and NEA are also hiring a consultant to monitor the affected sites over the long term. An NParks spokesman said the composition of biodiversity in the areas will be surveyed to study if there are any longer-term effects of the oil spill. The result of this second survey will also provide valuable updated baseline data on the biodiversity of these sites, she said."

Full article: Seashore life still reeling from oil spill Fewer creatures found on affected beaches one year after incident: Study, by Grace Chua Straits Times 30 Apr 11

Singapore oil spill as a case study

Recently, an article quoted the Singapore oil spill as an example of how double-hulled tankers provide false security. Living Oceans Society, which opposes plans for crude oil tankers to ply British Columbia said "Although double-hulled tankers have the potential to reduce spill volume in minor groundings or low energy collisions, they are susceptible to a range of construction, maintenance and operation issues that make them more prone to leaks and failures including accelerated corrosion in their cargo tanks and high operating stress levels."

Double-hulled tankers not the answer: Living Oceans Society
Ken Manning - North Island Gazette BC Local News 28 Apr 11;

Opponents and proponents of crude oil tankers plying B.C.s northern coastline continue to thrust and parry.

The latest set of arguments against a plan by Enbridge Inc. to increase the frequency of visits and increase the size of tankers operating in coastal waters is offered by Katie Terhune on behalf of Living Oceans Society, LOS.

Terhune's report says numerous safety concerns associated with double-hull tankers, including corrosion and stress levels, make the vessels unsuitable to be painted as a panacea for oil spill prevention.

The report, Tanker Technology: Limitations of Double Hulls, concludes that Enbridge’s pledge to use double-hulled tankers to service its controversial Northern Gateway Pipeline project will not ensure the B.C. Coast is protected from catastrophic oil spills.

“Double hulls are one of the key safety measures of Enbridge’s Marine Plan for its pipeline project, but it’s an empty assurance that provides a false sense of security,” said Terhune. “In fact, double-hull tankers may actually increase the risk of oil spills.

"Although double-hulled tankers have the potential to reduce spill volume in minor groundings or low energy collisions, they are susceptible to a range of construction, maintenance and operation issues that make them more prone to leaks and failures including accelerated corrosion in their cargo tanks and high operating stress levels," says Terhune in an Apr. 7 press release. "Most importantly, double-hull tanker designs do not address human error, which is responsible for up to 80 percent of total oil spills worldwide. No safety measure can ever fully eliminate the risk of an oil spill. Tankers are run by people and people make mistakes. No technology can change that fact.”

The increase in size of the crude carriers proposed by Enbridge to service its Northern Gateway project compared to those currently plying the route to Kitimat increases the risk exponentially.

The LOS sponsored report says, "If the Northern Gateway project is allowed to proceed, its twin-pipelines running between Alberta’s Tar Sands and Kitimat, B.C. would be serviced by 220 supertankers per year, each carrying up to two million barrels of crude oil through some of the most dangerous waters in the world. The few coastal tankers currently importing condensate to Kitimat are approximately 200 meters in length whereas the supertankers proposed by Enbridge are 350 meters long and can carry four times more cargo. When loaded they can take three kilometres and 15 minutes to come to a complete stop."

The report says a disabled tanker could drift on the B.C. Coast before help arrives.

Terhune said, "... the tankers will not be accompanied by escort tugs or BC Coast Pilots in the open waters of Hecate Straight, Dixon Entrance or Queen Charlotte Sound where wind speeds can reach 200 km/hr and waves higher than 25 metres can develop in less than eight hours. There will be no dedicated rescue tug on standby in the open waters if a tanker loses power or has a steering failure. Instead, Enbridge will send tugs from its Kitimat Marine Terminal with an estimated response time of 10-18 hours during which time a disabled tanker may drift ashore and ground."

The Enbridge website says super-tugs will accompany the tankers and first response units will be stationed in high risk areas and at sea. Enbridge was asked to comment on the findings in Terhune's report, but a reply was not received in time for this article.

Terhune's report cautions readers not to become complacent.

"Despite improvements in oil tanker regulation and technology, and a general decline in oil spills in recent years, accidents continue to occur. They are an inevitable part of shipping. In 2010 alone there were two major spills from double-hulled tankers: the Eagle Otome, with a coast pilot onboard, at Port Arthur, Texas and the Bunga Kelana 3 in the Strait of Singapore. Combined, the two tankers spilled 4.6 million liters of oil into the ocean.

"Double-hulled or not, accidents happen. It would only take one spill to disrupt coastal communities, cultures and the environment for generations to come," says Terhune in conclusion.

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