Which pollutant is known to bioaccumulate in aquatic food chains and is commonly linked to coal burning?

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

Answer: (D)

Mercury is the pollutant that fits this pattern. When coal is burned, mercury is released into the environment and can end up in water bodies. In aquatic systems, certain microbes convert inorganic mercury into methylmercury, a form that is readily absorbed by organisms and binds tightly to body tissues. This methylmercury persists and becomes more concentrated as small organisms are eaten by larger ones, a process called biomagnification. As a result, top predators like larger fish accumulate the highest levels, which is why mercury is so closely linked to coal burning and why fish advisories emphasize avoiding high-mercury species. Lead, arsenic, and cadmium are toxic too, but their pattern of accumulation and their strongest associations differ from mercury’s clear link to coal-fired emissions and aquatic food-chain bioaccumulation.