Physical and chemical data on sediments deposited in the Missouri and the Mississippi River flood plains during the July through August 1993 flood

Because sediments deposited by the 1993 floods on the Missouri and Mississippi rivers were thought to contain elevated concentrations of nutrients and trace elements, sediment deposits were sampled at 25 floodplain locations. The samples were analyzed for particle size, water content, volatile solids, nutrients, carbon, selected trace elements, pesticides, and semivolatile organic compounds. Preflood soil samples were analyzed for particle size only. Procedures for selecting sites, techniques developed for sampling, laboratory and analytical methods, and quality assurance methods also are described.