Results indicated that the acute V. fischeri test is suitable tool as a part of screening level risk assessment of boreal ASS impacted estuaries and it should be used together with other risk assessment tools. In contrary to the acute V. fischeri test, the sediments were not toxic to the chironomid midge C. riparius. Chironomids are able to survive in challenging conditions and C. riparius is considered as an opportunistic species, since its response to various toxicants can be dependent on the quantity and quality of food available (de Haas et al., 2002). It is also recognized that species sensitivity to toxicants varies and toxicity tests should be conducted with multiple species in risk assessment (Tuikka et al., 2011).