Toxicity of copper‐spiked sediments to freshwater invertebrates

Abstract

AbstractNatural freshwater sediments from two Oregon sites were spiked with copper in the laboratory and two static toxicity tests were conducted with series of copper concentrations ranging from 59 to 10,600 mg/kg of dry sediment. Water (800 ml) was added to 1‐liter test beakers over the sediment (200 ml) and repeatedly removed and replaced to lower the aqueous copper concentrations. When copper concentrations stabilized, i.e., attained equilibrium between water and sediment, the midge Chironomus tentans, the cladoceran Daphnia magna and the amphipods Hyalella azteca and Gammarus lacustris were introduced as test animals in solid‐phase sediment toxicity bioassays. Based on dry‐weight sediment copper concentrations, LC50 values (48‐h for Daphnia, 10‐d for other organisms) ranged from 681 to 2,296 mg/kg.