Study reveals hazards of ship emissions to the marine environment

A recent study from Chalmers University of Technology in Sweden highlights environmental risks due to the combined emissions of metals and other contaminants into the marine environment. The scientists behind the study showed that water discharged from scrubbers of ships accounts for 90 per cent of the contaminants in the four ports that were included in the study. Scrubbers are used by ships to “wash” pollutants out of the exhaust gases. Cited in a press release by Chalmers, Anna Lunde Hermansson, who is a doctoral student at the Department of Mechanics and Maritime Sciences at Chalmers, said: “The results speak for themselves. Stricter regulation of discharge water from scrubbers is crucial to reduce the deterioration of the marine environment.” Looking at the specific contaminants and their sources, the study found that more than 90 per cent of toxic metals and PAHs (polycyclic aromatic hydrocarbons) originated from scrubber discharge water, while antifouling paints accounted for the largest share of copper and zinc. Addressing the challenges associated with scrubbers, it is reported that the number of ships with scrubbers installed has increased since the mid-2010s. The press release refers to a study that was conducted in 2018, which showed that there were 178 ships with scrubbers operating in the Baltic Sea. The researchers estimate this number has tripled by now, and that there are about 5,000 such ships globally. This would translate into around five per cent of the total fleet. Lunde Hermansson says, however that their share of the fuel consumption is much larger: “…it’s the large ships with high fuel consumption that install scrubbers, because it is more economical for them to do so. So we anticipate that they would account for somewhere around 30 per cent of total fuel consumption in shipping,” she said in the press release. It is also reported that the Swedish Agency for Marine and Water Management and the Swedish Transport Agency have proposed that the Swedish Government should prohibit the discharge of scrubber water within the Swedish archipelago. Erik Ytreberg, who is an associate professor at the Department of Mechanics and Maritime Sciences at Chalmers explained in the press release: “It’s a step in the right direction, but we would have liked to see a stronger ban that extends across larger marine areas, while we also understand the challenge for individual countries to regulate international shipping.”

Source: Press-release “Marine environment at risk due to ship emissions”, https://news.cision.com/chalmers/r/marine-environment-at-risk-due-to-shi...