Abstract |
Methods are described for controlling pollution from mercury-laden sediment deposits on the bottom of streams and lakes. Five sediment samples containing from 6 ppm to 500 ppm mercury were investigated. A variety of methods for recovering the mercury values from dredged sediments were explored. Density fractionation, particle size fractionation, flotation, roasting and leaching were the methods studied. Roasting and chemical leaching afford the greatest promise for inexpensive removal and recovery of the mercury. The use of an iron overlay in the form of crushed automobile bodies topped with sand could be an inexpensive and effective method of isolating mercury-containing sediments from a water overlayer. An important attraction of using iron as an overlay is its ability to reduce methylmercury ions as well as mercuric ions to elemental mercury. (Author) |