By Ben Harder
Fall leaves that drop into stagnant waterways could release significant doses of a highly toxic form of mercury, new research suggests.
Mercury-tainted fish pose a considerable health risk to people (SN: 3/9/91, p. 152). Before the metal can enter the aquatic food chain, however, it must be converted from its common, inorganic form into the organic compound methylmercury. That process, promoted by bacteria, occurs readily in wetlands, which are rich in organic matter but oxygen-deprived, and landfills (SN: 7/7/01, p. 4: Landfills Make Mercury More Toxic).