Methylmercury (MeHg) is an important toxic substance in aquatic system and is of great concern due to its bioaccumulation and biomagnification effect on food chain. Inorganic mercury can be methylated into methylmercury during biotic or abiotic processes. Methylmercury (MeHg) is an important toxic substance in aquatic system and is of great concern due to its bioaccumulation and biomagnification effect on food chain. Inorganic mercury can be methylated into methylmercury during biotic or abiotic processes.