Assessment of the bioaccumulation of nicotine and cotinine by the crustacean Daphnia magna

Objectives. This study aimed to investigate the toxicity of nicotine and its metabolite cotinine on crustacean D. magna, and evaluate the quantity of compounds accumulated by D. magna. Materials and Methods. The bioassays involved the exposure of D. magna to varying doses of nicotine and cotinine, for 24 h and 48 h. The amount of bioaccumulated nicotine and cotinine was determined by an HPLC-DAD method. Results. The study has revealed that nicotine is more toxic than cotinine on D. magna, as the medium lethal concentration (LC50) values were higher for nicotine compared to cotinine. After 24 hours of exposure, D. magna accumulated comparable amounts of nicotine and cotinine. However, after 48 hours of exposure, the crustacean accumulated significantly lower levels of nicotine, which is consistent with the higher toxicity of nicotine compared to cotinine. Conclusions. These findings demonstrated that nicotine triggers various alterations in aquatic organism, hence jeopardizing the equilibrium of the aquatic ecosystem within a little timeframe.