- Satellite images show a silvery trail originating from a cargo ship that sank off western Sri Lanka in early June, raising fears of an oil spill.
- Authorities say the nearly 350 metric tons of fuel carried by the X-Press Pearl hasn’t leaked, but have activated contingency plans in the event of a spill.
- Experts say the consistency of the slick appears to rule out fuel oil, but say tests need to be carried out to confirm the source.
- A likely algal bloom has also sprung up around the wreck, attributed to the leak of the ship’s cargo of nitric acid, and operations are ongoing to clean up the tons of plastic beads that spilled from the ship and have washed up on shore.
COLOMBO — Satellite images have captured a silvery slick spreading on the surface of the sea from the burnt-out wreck of a cargo ship that sank off Colombo earlier this month, but authorities deny there’s been a much-feared fuel oil spill.
The images first appeared on June 4, two days after the Singapore-flagged X-Press Pearl sank following an onboard fire. They showed a long, silvery trail originating from the ship and spreading several kilometers. Analyzing a series of such images taken over subsequent days, the Marine Pollution Surveillance Program at the U.S. National Oceanic and Atmospheric Administration (NOAA) indicated it was possibly an oil slick generating from the sunken ship.
The slick was 2.74 nautical miles (5.07 kilometers) north of the ship, and images from June 12 indicated the slick was getting thicker, covering an area of 0.67 square kilometers (0.25 square miles).
The X-Press Pearl was carrying 297 metric tons of heavy fuel oil and 51 metric tons of marine fuel oil. Environmental activists and experts have warned that a spill of this oil from the stricken ship would spark an unprecedented marine disaster for Sri Lanka. But authorities say the slick in the images isn’t the ship’s fuel.
No oil spill
“We sent our vessels to the area and no large scale spill of bunker oil [has] been reported from the X-Press Pearl,” said navy spokesman Indika de Silva. He said the slick was the result of light-colored oily substances getting released in the aftermath of the ship’s burning and sinking.
De Silva said the navy was working with officials from the National Aquatic Resources Research and Development Agency (NARA) to collect samples for further analysis. NARA officials say they need about two weeks to analyze the water samples to offer a conclusive statement.
Initial inspections confirmed the oil tanks were not damaged by the fire. Experts also note that heavy ship fuel oil is a thick, blackish, tar-like substance, whereas what was captured in the satellite images was grayish or silvery.
“While satellites imagery are useful tools in detecting spills, monitoring and assessing ongoing events, and planning countermeasures, it can sometimes bring false positives of spills such as those caused by algal blooms, so it is important to have closer inspection and water sample analysis,” Christopher Reddy, a senior scientist at the Woods Hole Oceanographic Institute, told Mongabay.
Reddy has studied extensively images of oil spills in different parts of the world. He says close analysis and inspection is necessary to conclude “whether there actually is oil, type of oil, or the amount being released and whether a leak was in the ship’s cargo hold or fuel tanks, indicating potential for a much larger release.”
Despite its tarry appearance, heavy fuel oil in the ocean is often easier to clean than spills of other hydrocarbons. Marine fuel oil, or marine diesel, which can spread rapidly, forming a characteristic rainbow-hued slick, would be less viscous, but harder to contain and recover than a heavy fuel oil spill, Reddy added.
“Every spill is different, and the amount of oil that enters the water is only the first of many variables that can cause a long-term environmental disaster from a near-miss,” Reddy said.
Even though they can’t yet confirm a spill, Sri Lankan authorities are still preparing for the worst. The Marine Environmental Protection Authority (MEPA) has activated the National Oil Spill Contingency Plan (NOSCOP) to ensure…