Spiking sediment with organochlorines for toxicity testing

Sediment toxicity testing integrates responses to sediment variables and hence does not directly indicate cause and effect. One tool for determining cause and effect is sediment spiking, in which relatively uncontaminated sediment is amended with known amounts of contaminants, then tested for toxicity. However, sediment spiking methods vary considerably. The present study details appropriate methodologies (dry and wet spiking) for amending sediments with a range of organic contaminant concentrations, i.e., dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyl (PCB). Target and actual concentrations were similar. A dose response was determined for DDT, but PCB was not toxic in an acute sediment toxicity test. Chronic testing of these same sediments is reported in a companion article in this issue.