Sri Lanka braces for fallout of sunken cargo ship’s toxic payload

COLOMBO: Along the shoreline north of Colombo, Sri Lanka’s commercial capital, the beaches are littered with millions of tiny white pellets, each about the size of a peppercorn.

“The polyethylene pellets can be seen everywhere along the beaches,” says Mala Damayanthi Amarasinghe, a senior professor at the University of Kelaniya.

They’re also in the water, and anecdotal accounts paint a worrying picture about their extent there. Local fishers laid nets in their traditional fishing grounds and returned a few days later, Amarasinghe tells Mongabay. “They found that there were no fish, and that the nets were covered with synthetic fibers that made them completely unusable,” she says. “This indicates that the bottom of the fishing ground contains materials from the burning ship.”

The “burning ship” is, or was, the MV X-Press Pearl, a newly built Singapore-flagged freighter that caught fire in late May and partially sank off Colombo in early June. The ship’s cargo, much of which fell overboard during the fire and subsequent sinking, included several containers of plastic beads, or nurdles — the raw material for making plastic items — as well as 25 metric tons of nitric acid. It was also carrying 378 metric tons of bunker fuel.

Plastic pollution

So far, the most visible impact of this marine disaster has been the millions of nurdles that have washed up on the shore, snagged in mangroves, or remain in the sea.

“Debris and microplastics can cause entanglement, infections, injuries, and higher mortality rates in marine life,” says Dilanthi Koralagama, a senior lecturer at the University of Ruhuna. “Seabirds might ingest the plastic pellets or debris, which will negatively affect their health or even kill them.”

But there are also growing concerns about potential leaks of nitric acid and bunker fuel, which would compound what’s already being described as one of Sri Lanka’s worst environmental disasters. It was a leak of nitric acid that fueled the fire on board the ship in the first place.

Amarasinghe says that in some places, patches of waterfront vegetation seem to have suffered burns and died, possibly due to the chemicals sweeping onshore with the waves. Apart from that, there is no prominently visible damage to the coastal environment and surface waters, and both mangrove ecosystems and lagoons seem unaffected so far.

Bracing for the worst

Water samples have been taken for analysis and the situation is being closely monitored, but at this stage, there are only scenarios, possibilities, and contingency plans, experts and officials say. Much will depend on the exact chemical composition of any leaked chemicals, their dilution in the ocean, and the currents and weather patterns.

“These chemicals can be diluted in the water, but we do not know how far they can travel,” says Sudarsha De Silva, co-founder of Earthlanka Youth Network. “If the dilution continues and the contamination reaches a huge area, it could affect coral reefs and other marine ecosystems. However, due to its high buffering capacity, it is very difficult to get changes in pH value in seawater.”

Changes to the seawater’s chemistry could affect mangroves and seagrass habitats, says D.D.G.L. Dahanayaka, a senior lecturer at the Open University of Sri Lanka. “Coral reefs are particularly sensitive to prolonged increases in seawater temperature and changes of pH value. In the present scenario, leakage of nitric acid can cause temperature increases and pH changes of the area, increasing the risks of coral bleaching and death.”

Hemantha Withanage, executive director of Colombo-based NGO the Centre for Environmental Justice, says the X-Press Pearl was carrying other potentially hazardous cargo. “Besides the chemicals, there are copper slag, lead ingots, and other environmentally harmful substances. Until they are completely taken out of the ocean, they will continue to cause damage. We don’t know how many months it will take to remove them, as this is a difficult task and has to be done by specialized divers.”

Long-term damage

The area around where the X-Press Pearl now sits half-submerged, about 16 kilometers (10 miles) offshore, comprises fertile fishing grounds and is habitat to a rich biodiversity including many species of fish, crabs and prawns. “Generally, the continental shelf area has the highest biodiversity of the entire marine environment,” Koralagama says. “The accumulation of contaminants and noxious substances could be lethal to this biodiversity.”

The coastal and marine environment is complex and highly interconnected, she adds. Beyond the direct impacts, there’s a strong possibility that the contamination could cascade through the food webs and affect plants, animals and, ultimately, humans.

Koralagama notes, for instance, that microplastic deposits on algae and zoo plankton reduces oxygen release through photosynthesis and causes higher mortality and contamination among the small pelagic species that feed on them. If seagrass beds and coral reefs are affected, fish and shrimp will lose breeding places and habitats. Changes in water quality or temperature can also affect fingerlings or destroy fish eggs, larvae and plankton.

“The long-term accumulation of debris, hydrocarbons, microplastics and other noxious substances in coastal, lagoon and estuary waters could lead to gradual changes, spreading to other peripheral areas toward Kalpitiya and Mannar,” Koralagama says. “A loss of primary producers and fingerlings could make the entire ecosystem unhealthy and unsustainable.”

Sometimes, impacts are only visible after a long time. Amarasinghe cites the case of mangrove trees in Koggala lagoon that started producing strange, discolored propagules — seed pods — which might impair their reproductive cycle. She says the cause of that could be a major oil spill that occurred 15 years earlier, in 2006.

Mitigation efforts

The potential short- and long-term environmental impacts are severe, but there are options and plans to mitigate them. Already, oil booms have been installed across lagoons, fishing activity has been restricted, and cleanup efforts are underway with the involvement of the Marine Environment Protection Authority (MEPA), Coast Guard, Navy, Air Force, and other government agencies.

“MEPA has established an operations room to manage the situation and coordinate efforts,” says Terney Pradeep Kumara, the MEPA general manager. “We are waiting for the waste to come to the coast and are using all processes to collect it. As a next step, the waste will be segregated and upcycled or disposed. However, there is 60-70% sand collected with the nurdles that has to be extracted and transported back to the shore.”

Koralagama says the technology exists to remove oil and other noxious substances safely from the sunken ship. She adds that frequent testing of water quality, long-term monitoring, and the application of buffering methods to absorb contaminants are needed to better understand and mitigate the impacts.

Despite concerted efforts, it might not be possible to mitigate all impacts, says Withanage: “The plastic pellets cannot be completely removed from the environment, they will stay there for hundreds of years.” Whatever has leaked from the destroyed ship might stay in the environment and impact food webs through bioaccumulation, he says. “Even five to 10 years later, we will find contaminated fish. The chemical contamination might be there for the next two decades, and fish feeding in the area will continue to get contaminated.”

For now, the true scale of the fallout on Sri Lanka’s marine and coastal environment is uncertain. Even with mitigation and protection measures in place, the X-Press Pearl incident has the potential to seriously affect biodiversity and ecosystem services, threatening natural systems as well as human livelihoods, well-being, and the coastal economy.