Which heavy metal commonly enters water via coal burning?

• A. Lead
• B. Arsenic
• C. Mercury
• D. Cadmium

Answer: (C)

Mercury is the heavy metal most commonly entering water from coal burning. Coal contains trace amounts of mercury, and when it’s burned the mercury is released as vapor and can be carried by the atmosphere over long distances. Eventually it deposits onto land and into water bodies. In these waters, bacteria can convert inorganic mercury into methylmercury, a highly toxic form that readily bioaccumulates up the aquatic food chain, ending up in fish and affecting human health. This atmospheric transport and the subsequent transformation in water make mercury the standout pollutant linked to coal combustion.