TEXTE Environmental Impacts of Exhaust Gas Cleaning Systems for Reduction of SOx on Ships — Analysis of status quo 
Report compiled within the framework of the project ImpEx 
concentrations at the higher exposure concentrations was observed: in the crustacean test some 
organisms stayed at the water surface, while in the fish test abnormal swimming (surface 
swimming) and nose raising was observed immediately after transferring the organisms to the 
test solution. 
Based on the results of the tests with these three marine organisms, the study concluded that by 
diluting the EGCS discharge water to about 1/8 no obvious acute effect on the indicator 
organisms was observed. The authors also identified low pH and low dissolved oxygen 
concentration as predominant factors of the observed toxicity effects. It should be noted that 
both dissolved oxygen and pH were not adjusted to the recommended values in the standard 
methods during the preparation of the samples for the tests. 
Koski et al. (2017) investigated the lethal and sub-lethal effects of OL-EGCS discharge water 
exposure on a common neritic copepod, focusing on threshold (metal) concentrations, exposure 
pathways and potential synergistic effects of the discharge water constituents. Additionally, 
collected organisms from a harbour were analysed for toxic effects due bioaccumulation of 
heavy metals caused by EGCS discharge water. 
The direct exposure to discharge water increased adult copepod mortality and reduced feeding 
at metal concentrations which were orders of magnitude lower than the single lethal 
concentrations reported in the literature, suggesting synergistic effects on plankton productivity 
and bioaccumulation of metals. In contrast, reproduction was not influenced by dietary uptake 
of contaminants. The authors suggested the uptake route of metals as possible explanation to 
the higher sensitivity of feeding and survival, since vanadium, nickel and lead were mainly taken 
up directly from the water and therefore had a minor effect on reproduction. 
The results of the analysis on the collected plankton indicated that some of the substances 
present in EGCS discharge water might bioaccumulate in the food chain. The high concentrations 
of vanadium on plankton remained unexplained. The authors prioritize further investigations to 
determine the sources and effects of vanadium and other metals, considering the current needs 
for management of different industrial and maritime activities in coastal waters. 
No detrimental effects were observed at 1% EGCS discharge water exposure, suggesting that by 
ensuring a rapid dilution of discharges, the impact of EGCS discharge water can be kept minimal 
and comparable to that from atmospheric deposition, before EGCS technology was implemented. 
The algal growth as a response to EGCS discharge water was measured as well. The authors 
observed at 100% discharge water exposure complete inhibition of algal growth, although half 
of the cells remained through the experiment; at 10% discharge water exposure, however, an 
increase in cell growth was reported. 
7.3 Environmental risk assessment (PEC/PNEC approach) 
The quotient between Predicted Environmental Concentration and Predicted No-Effect 
Concentration (PEC/PNEC) is employed typically in the environmental risk assessment of 
substances or mixtures. Ifthe PEC/PNEC quotient is greater than 1, the substance is of 
environmental concern, while when the quotient is below 1, there is no significant risk expected 
based on the current knowledge. This approach has been found to be used in some research 
works for the assessment of EGCS discharge water. Table 5 summarizes the methodology and 
conclusions of the studies of Faber et al. (2019), Magnusson et al. (2018), Behrends (in 
preparation), Kasseris et al. (2020) and MLIT (2018). All studies covered EGCS discharge water 
from OL systems, only the IVL study (Magnusson et al., 2018) assessed also CL systems. 
Similarly, most of the studies used a whole effluent approach, while the CE Delft study (Faber et 
al., 2019) employed only a single-substance approach. However, for a complete risk assessment,