Polycyclic aromatic compounds (PACs) in oily wastewater from shipping with a focus on scrubber water

To reduce emissions of hazardous combustion gases to air, ship owners can switch to cleaner fuels or install so called “scrubbers”, onboard the ship. In a scrubber, combustions gases are sprayed with water and the dirty wash water, the scrubber water, is discharged to the sea. The number of ships with scrubbers and the volumes of discharged scrubber water have increased dramatically the past decade. When allowing the use of scrubbers, the focus was on improving the air quality, while the impact on the marine environment was not considered. We have here analysed polycyclic aromatic compounds (PACs), the most toxic fraction of oil, in scrubber water from ships, and reviewed recent ecotoxicological scientific literature on PAC toxicity to marine organisms. Our conclusion is that in areas with intense shipping there is a serious risk for negative effects on marine organisms.