Mercury is an extremely toxic metal with high industrial use (as chemical reaction catalyst) and in agriculture (as pesticide). Because of this use mercury is an important environmental contaminant of water and food (fish and seafood). Mercury has the peculiarity of its biogeochemical cycle where the inorganic forms of this metal (Hg⁰ and Hg⁺²) are converted into organic species (methylated) by bacteria that normally inhabit the sludge of lakes, rivers and oceans. The methylated species bioaccumulate through the food chain of aquatic organisms, reaching high concentrations in the predatory species. Its toxic effects include losses in motor coordination, vision, and hearing when adults individuals are intoxicated. Pregnant women exposed to this metal can generate children with a high degree of neurological damage, including cerebral palsy, microcephaly, blindness and deafness.