Mercury Chloride (II) genotoxicity in Oreochromis niloticus (Pisces, Cichlidae) fingerlings exposed to different temperatures

Mercury chloride (HgCl₂) is a neurotoxic, nephrotoxic, and genotoxic compound found in aquatic environments due to anthropogenic activities and whose effect can be altered by variations in temperature (for example: global warming). The aim of this work was to determine the mean lethal concentration (LC₅₀) for HgCl₂ and its genotoxic effect, inrelationtotheincreaseintemperaturefor Oreochromis niloticus fingerlings. The LC₅₀ results for HgCl₂ during the exposure times (48, 72, and 96 h) and temperatures (28 and 32 °C) showed that the LC_50-96h increased from 0.39 mg L_-1 for 28 °C to 0.66 mg L^-1 for 32 °C. For sublethal evaluation, HgCl₂ concentrations from LC_50-96h were established for 28 and 32 °C, evaluating genotoxicity for 30 days through the nuclear abnormalities (AN) and micronucleus (MN) assay. A higher frequency of AN and MN was observed at 0.07 mg L^-1 of HgCl₂ for 32 °C. It is concluded that the LC₅₀ and genotoxicity (AN and MN) for HgCl₂ increase with increasing temperature from 28 to 32 °C.