To reduce toxic sulfur emissions, shipping companies are installing equipment to clean the flue gases from the ships. But research shows that the so-called scrubber systems threaten marine ecosystems.
The International Maritime Authority has decided that ships must reduce their sulfur emissions into the air, as they are harmful to human health.
The basic idea is to phase out the environmentally toxic fuel bunker oil. At the same time, the regulations allow shipping companies to instead equip their vessels with systems (so-called scrubbers) that wash the exhaust gases in water and then release them into the sea.
– You turn the chimney from the sky down into the water and thus add a source of emissions into the sea, says Kerstin Magnusson, biologist at IVL Swedish Environmental Institute and expert on environmental toxins in the sea.
The decision was made without any impact assessment, she believes.
As it pays for shipowners to install scrubbers, compared to switching to clean fuel, there has been a dramatic increase in such treatment systems since then.
Now Kerstin Magnusson, together with other researchers at IVL Swedish Environmental Institute and the Norwegian Polar Institute, has studied the effect that emissions of scrubber water have on the plankton organism lobster.
Tests show that the discharge water contains toxins that seriously damage the plankton animals. On the one hand, there is a significant reduction in the number of animals reaching reproductive age, and on the other hand, mortality increases sharply. The effect is noticeable even at low levels of scrubber water in the organism’s exposure water.
It is estimated that 4,500 vessels are equipped with scrubbers, which discharge up to 400 cubic meters of poisonous water per hour. This means that the concentration of scrubber water around the waterways is approaching the levels that give rise to harmful effects, according to the researchers.
Furthermore, Magnusson points out that the field is under-studied, the number of scientific articles on the subject can be counted on one hand.
– This makes it difficult to say what the effects will be in the long run. We have looked at a species and there we saw effects.
At the same time, the crayfish is not just any organism, she emphasizes. It makes up 80 percent of the world’s zooplankton stock and plays a key role for the food chain as a staple food for virtually all existing fish.