A study carried out by the International Council on Clean Transportation (ICCT) has found that cargo ships are discharging potentially harmful waste into the oceans. Waste from the exhaust cleaning systems, also known as scrubbers, is dumped close to shores. The study has established that about 80% of the waste water ends up near shorelines, including popular cruise destinations such as Italy and the Bahamas, and in ecologically sensitive areas, like the Great Barrier Reef.
The scrubber system is a shortcut that has been introduced by ship companies that do not want to move away from toxic, sulfur-rich fuels but must abide by international air quality laws. Due to increasing pressure for the ships to burn low-sulfur fuels, many ship owners have turned to the scrubber system, which purifies the exhaust gases and dumps the resulting waste in oceans to be diluted.
Today, thousands of ships use the scrubber system, compared to just a few hundred in the recent past. The system is being adopted by more large ships, but it poses the risk of contaminating the oceans with toxic waste.
Liudmila Osipova, ICCT researcher in Berlin and the lead author of the study, said that the sludgy discharge will continue growing in oceans as more ships turn to this option.
“It means that every year, quite high concentrations will accumulate in these areas and will be growing and growing,” Osipova said.
Although ship owners have an option of making the system more efficient, this comes at a higher cost that many aren’t willing to pay. The research points out that many ships use an open-loop scrubber system, which mixes exhaust gases with seawater to filter it and releases the resulting sludge back to the oceans. On the contrary, ships could use a closed-loop scrubber system, which at least treats the liquid waste before discharging but costs more money.
Although the full extent of the effect of scrubber waste water is not known, a previous study has shown that the water can be acidic. The system has not been investigated in detail to ascertain the impact of the water on marine life and coastal communities.
“We’re facing a truly global crisis, and it’s the kind of thing that requires bold solutions,” Dan Hubbell, manager of the Ocean Conservancy’s shipping emissions campaign in Washington, D.C., said. “A piece we’ve struggled with is the industry’s preference for short-term fixes.”
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