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Oil spills from ship traffic or oil production represent a huge threat to the environment. A controlled and thick oil slick is crucial in relation to combatting oil spills, not least for Arctic waters, before introducing the oil spill response method in situ burning. Recently, herding agents have been introduced, with success, as a measure to contain and thicken oil spills, when sprayed to the perimeter of the slick. In this study, we evaluated potential environmental impacts of using herding agents. Toxicity, bioaccumulation and biodegradability of the two herders ThickSlick 6535 (TS6535) and Siltech OP‐40 (OP‐40) were studied in laboratory set-ups with Arctic water and the high Arctic copepod, Calanus hyperboreus. TS6535 was found to biodegrade rapidly within 7 days, and did not seem to bioaccumulate in the copepods or affect their grazing activity. Tests with OP-40 showed bioaccumulation in the copepods, sublethal effects (as reduced grazing activity) and limited biodegradation. The results thus indicate that OP-40 may possibly pose a risk to the Arctic marine environment. The data and knowledge from the tests poses valuable input to assess the potential environmental impacts from using herders in Arctic waters in connection with oil spill response. However, more knowledge is still needed to fully understand the fate and effect of herders in the environment; this also includes possible combined and/or cumulative effects from herders and oil.

Sculpins are widely used as key species for monitoring heavy metal pollution near arctic mine sites. Typically, metal concentrations in liver and muscle tissue have been used as a proxy for metal exposure but such analyses lack temporal information of uptake and accumulation. Otoliths (ear bones) are considered metabolically stable and can potentially contain a complete record of the fish’s metal exposure history. To investigate the otolith chemistry of sculpins and the potential of these as records of metal exposure, common sculpins (Myoxocephalus scorpius) were collected at five sites near a former Pb–Zn mine in West Greenland. Otoliths were analyzed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for 12 elements of which Mg, Mn, Sr, Ba, and Pb were detected. The highest Pb concentrations were found within the otoliths from the most Pb-polluted sites near the mine (up to 0.6 ppm), and decreasing concentrations were observed in a gradient away from the mine. Notably, Pb and Sr variations were closely correlated and showed an annual oscillatory pattern with peaks consistently found in the winter zones. It is not clear to what the extent high winter-time accumulation of Pb in the otoliths is due to high winter-time exposure of Pb through diet or water and/or to physiological processes such as growth in the sculpins. The study indicates that LA-ICP-MS analyses of sculpin otoliths have the potential to become a valuable method for assessing time-resolved metal loading near mine sites but also that more studies are required to investigate the links between metal sources, pathways, and processes affecting otolith metal deposition.

In situ burning is a method by which oil is burned at a spill site under controlled conditions, and this method is subject to increased interest due to its applicability in the Arctic. This paper reviews the literature regarding the characterization and environmental effects of burn residues in Arctic waters. The results of a systematic literature search indicate that only a very limited number of studies have arctic pertinence. From the review, it is also indicated that the properties and composition of the residues depend on the efficiency of the burning and the oil type. Furthermore, the studies within the frame of the literature search reach consensus that in situ burning may increase the concentrations of large poly-aromatic hydrocarbons (PAHs; high ring number) while reducing small PAHs (low ring number). There are very few toxicity studies of burn residues on aquatic and arctic organisms, and to enhance the knowledge base, more organisms as well as oil types must be studied. Furthermore, there is a lack of studies investigating the potential effect of sinking burn residues on benthic organism and the smothering effects of the more viscous burn residues on birds and other organisms related to the sea surface. More knowledge regarding environmental fate and effect of residues is crucial to complete a robust net environmental benefit analysis prior to an oil spill response operation in arctic waters.