Salinity fluctuation influences the toxicity of 1-octyl-3-methylimidazolium chloride ([Cmim]Cl) to a marine diatom Phaeodactylum tricornutum.

In this work, a marine diatom (Phaeodactylum tricornutum) was exposed to 1-octyl-3-methylimidazolium chloride ([Cmim]Cl) for 96 h at three different salinities (25, 35, and 45 ‰) for investigating their interactive effects. Results showed that values of EC and EC at 96 h of exposure were 0.29, 1.06, 2.01 μg L and 7.21, 7.71, 7.25 mg L when the salinities were 25, 35, and 45 ‰, respectively, meaning that salinity fluctuation affected the toxicity of [Cmim]Cl to this diatom. Changes in chlorophyll a contents and chlorophyll fluorescence parameters suggested that [Cmim]Cl and salinity fluctuation had a significant interactive effect on the algal photosynthesis. In addition, soluble protein content and activities of antioxidant enzymes in algal cells changed significantly. Increased malondialdehyde contents indicated that the combined stresses could induce excessive production of reactive oxygen species leading to oxidative damage to the algal cells.