Aquatic environments such as wetlands and estuaries that receive inorganic mercury from either discharges from point sources (like upstream gold mining) or deposition from the atmosphere are places where MeHg pollution is likely. In such systems, anoxic conditions, high concentrations of organic carbon and acidic conditions are likely, hence, they are the perfect place for MeHg to form and its journey to begin until ultimately reaching dangerous concentrations for wildlife and humans [2].

Available data from mercury in higher biota (i.e., methylmercury that has been bioaccumulating) is shown in the map; it seems that the answer of the question entitling this section is everywhere. Also, this is the reason why the consumption of fish from many waterways is not recommended, as fish fed from plankton or smaller fish that had been uptaking the MeHg in the water.