The aim of the report is to contribute to an increased understanding of the impact of oily wastewaters on marine organisms and thereby make it easier for decision-makers to make decisions that ensure a good marine environment. Scrubber water from ships is selected as an example of oily wastewater that is discharged to the sea, and the focus is on PACs as these are identified as the most toxic oil fraction (Adams et al. 2014, Bornstein et al. 2014).
The report presents chemical data on PACs in scrubber water and a review of scientific data on toxicological effects of the detected compounds on organisms in a marine pelagic food web consisting of algae, zooplankton, and fish.
It is also discussed the need to include new scientific findings in risk assessments and not, as is often the case, solely base assessments on existing guidelines and threshold levels. The importance of putting the ecotoxicological data in an ecological context is also addressed. This is an often neglected step in risk assessments, but essential to understand the impacts that scrubber water can be expected to have on marine ecosystems.
Although emphasis of the report is on scrubber water, much of the information can be used for risk assessments of any oil or oil containing water that is discharged to an aquatic environment.