Development of a toxicity identification evaluation procedure for characterizing metal toxicity in marine sediments

A multiagency effort is underway to develop whole sediment toxicity identif ication evaluation (TIE) methods. Whole sediment TIE methods will be critic al tools for characterizing toxicity at hazardous waste sites (e.g., Superf und sites) and in the conduct of environmental risk assessments. The resear ch approach is based on the predominance of three classes of toxicants in s ediments: ammonia, nonpolar organic chemicals, and metals. Here we describe a procedure for characterizing acute toxicity caused by metals in whole ma rine sediments. The procedure involves adding a chelating resin to sediment s, resulting in the sequestration of bioavailable metal while not stressing testing organisms. Within the testing chambers, the presence of resin resu lted in statistically significant reductions in the overlying and interstit ial water concentrations of five metals (cadmium, copper, nickel, lead, and zinc) generally by factors of 40 and 200. Toxicity to both the amphipod Am pelisca abdita and mysid Americamysis bahia (formerly Mysidopsis bahia) of sediments spilled with the five metals was decreased by approximately a fac tor of four when resin was present. While very effective at reducing the co ncentrations and toxicity of metals, the resin has only minor ameliorative effects on the toxicity of ammonia and a representative nonpolar toxicant ( Endosulfan). Resin and accumulated metal were easily isolated from the test ing system following exposures allowing for the initiation of phase II TIE (identification) procedures. This procedure using the addition of a chelati ng resin provides an approach for determining the importance of metals to t he toxicity of marine sediments. Work is continuing to validate the method with environmentally contaminated sediments.