Assessment of metal-contaminated sediments from the Southeast Missouri (SEMO) mining district using sediment toxicity tests with amphipods and freshwater mussels

Abstract

Executive Summary (1st paragraph) We conducted an assessment of sediment quality of the Big River, which drains inactive lead mining areas in southeast Missouri (SEMO; St. Francois and Washington counties). This study was conducted to support a natural resource damage assessment and restoration (NRDAR) project for the SEMO lead mining district. Sediments were collected in September 2008 from 16 sites in the Big River (15 sites downstream of the St. Francois County mining area), one site in Mineral Fork (a Big River tributary that drains the Washington County mining area), two sites in the Meramec River (upstream and downstream of the mouth of the Big River) and one site in the Bourbeuse River (unaffected by mining activity). Sediments were processed by wet sieving to produce two size fractions for toxicity testing and chemical analyses: bulk sediments (<2 mm particle diameter) and fine sediments (<0.25 mm).