Characteristics of sediments from a stormwater management pond

Physical and chemical characteristics of bottom sediment from an on-stream stormwater pond were described by the depth of sediment accumulations, particle size distribution, water content, concentrations of total metals, and distribution of metal fractions determined by a sequential analysis. Except for a sand/gravel spit by the creek inflow, bottom sediments comprised silt and clay, with high water content (up to 80%, by volume), and accumulated at a rate of 0.02 m·yr⁻¹ (bulk sediment depth). Sediments contained elevated levels of heavy metals, among which the levels of Cr, Cu and Pb caused the greatest environmental concerns. Furthermore, sequential analysis indicated that up to 70 - 90% of total metals in these sediment was in potentially mobile forms. Without further treatment, these sediments could not be reused in urban areas, nor readily disposed at municipal landfills.