Abstract
The Norwegian Coastal Administration (NCA) and SINTEF have since 2016 studied several of the new generation low sulphur fuel oils (LSFO). This paper presents findings from an Arctic Council project jointly led by the two working groups Protection of the Arctic marine Environment (PAME) and Emergency Prevention Preparedness and Response (EPPR). The project is named “Low Sulphur fuels, fate and behaviour in cold water conditions” where 7 LSFOs from refineries in Europe and Canada were studied. The focus was on the oils’ physical-chemical characteristics and acute toxicity. Low-energy Water Accommodated Fractions (WAFs) of the LSFOs were prepared at 2 °C, and the WAFs chemical characteristics and acute toxicity studied using the marine copepods Calanus finmarchicus and Acartia tonsa as test organisms. In addition, toxic units were calculated.
From the SINTEF and NCA studies, as well as other studies performed by other research institutes and the industry, it has become evident that Very Low Sulphur Fuel Oil (VLSFO) and Ultra Low Sulphur fuel Oil (ULSFO) particularly have lower viscosity and higher pour point than their “traditional” Heavy Fuel Oil (HFO) equivalents. Other properties vary significantly as well. This was also observed here, as there was a wide variability in physical-chemical properties and the chemical composition of these LSFOs, for example their pour points varied from −36 to +39 °C, which will result in very different behaviour if these oils are spilled on sea, especially under cold water conditions.
The results showed that the chemical composition of the WAFs and their corresponding acute toxicity varied, as for some oils, no mortality was observed in the test organisms, while for other oils it was observed up to 100% mortality when the test organisms were exposed for the highest WAF concentration. The studies have identified a span in properties, chemistry, and relative toxicity of the oils and their WAFs, and their characteristics relevant for impact on the marine environment when spilled in cold or Arctic seawater. The importance of generating data about the fuel oil properties combined with experience has become key factors when deciding the best strategy for an oil combat response operation to these fuels today.