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 
residual fuel oil compositions, which might indicate the predominance of petrogenic 
PAHs. 
Average normalized concentration of benzo[a]pyrene (0.06 ug/L) was below the 
WHO Guidelines limit for drinking-water quality. 
BTEX were found mostly below the detection limit and the maximum measured 
concentrations were 2 ug/L for benzene and toluene, below the WHO Guidelines 
limits for drinking-water quality. 
Vanadium was the most prevalent metal in samples. 
Contribution of copper and zinc probably from corrosion protection anodes and 
marine growth prevention systems, independently from EGCS systems. 
Nitrate normalized concentrations were compliant to the IMO requirement (<60 
mg/L). Baseline nitrate levels in inlet seawater contributed significantly to 
concentrations found in OL discharge water. When subtracting that contribution, the 
average nitrate accumulation resulted in 7 mg/L. Nitrite levels are negligible. The 
authors suggested: 
When reporting for compliance of nitrate levels, inlet concentration should be 
subtracted. 
— Remove the requirement for nitrate measurement from the EGCS Guidelines. 
The study states the essential challenges to keep cleanliness during sampling and to find suitable 
sampling points. 
Koski et al. (2017) (in Table A-4 presented as DTU) from the Technical University of Denmark 
carried out a study funded by the Danish Maritime Fond. This project was actually focused on 
the ecotoxicological effects of EGCS discharge water on coastal plankton (see chapter 7.2) but 
included a special assessment of the influence of some relevant metals contained in discharge 
water. Thus, metals were analysed on samples taken from an OL system on board a RoRo vessel 
(Magnolia Seaways) during a voyage in the open North Sea. The results were compared to metal 
levels in the Copenhagen harbour (sampled and analysed within the project) and in open sea. 
Some of the main findings and discussions highlighted in the report regarding the metal 
concentrations are: 
Vanadium, nickel and lead showed a strong and similar increase due to the scrubbing 
process. All three elements were strongly correlated with concentrations ranking 
EGCS discharge water > inlet water > Copenhagen harbour. 
High concentrations of copper in discharge water were observed, but the highest 
values were measured in the inlet samples. Those values were far above the copper 
‚evels in the open sea and Copenhagen harbour. This could be explained by the use of 
copper as antifouling agent in ship paints and pipe construction. 
a 
Higher concentrations of chromium were detected in inlet water and EGCS discharge 
water. 
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