Ecotoxicological effects of seawater scrubbing and its relation to ocean acidification

Research Project, 2013 – 2016

The emissions to air of particulate matter and SO2 from shipping constitute an increasing part of the total emissions to air. The societal cost of the emissions in terms of people´s health as well as impact on nature is large. To reduce the impact from shipping, the International Maritime Organization (IMO) adopted a convention which strengthened the requirements on the permitted sulphur levels in ships´ fuels. However, several studies indicate that the change towards expensive low-sulphur fuel may shift the transportation from shipping towards land-based modes and such outcome may instead affect the air quality negatively. An alternate, and by IMO approved, method to reduce emissions to air while still using the cheaper heavy fuel oil is seawater scrubbing (SWS). In SWS, the emissions are cleaned through seawater but the acidic and potential toxic discharge water is released directly to the marine environment. Hence, a major question is if SWS is a feasible large-scale solution to meet the stringent rules on sulphur emissions from marine fuels. In the proposed project an environmental risk assessment (ERA) of SWS will be performed. The ERA will be based on biological test methods for generating site-specific predicted no-effect concentration (PNEC) of the discharge water in sea areas around the Swedish coast. In addition, an exposure assessment will be conducted for estimating the predicted environmental concentration (PEC) of the discharge water in the marine environment.