Sediment toxicity testing integrates responses to sediment variables a
nd hence does not directly indicate cause and effect. One tool for det
ermining cause and effect is sediment spiking, in which relatively unc
ontaminated sediment is amended with known amounts of contaminants, th
en tested for toxicity. However, sediment spiking methods vary conside
rably, The present study details appropriate methodologies (dry and we
t spiking) for amending sediments with a range of organic contaminant
concentrations. i.e., dichlorodiphenyltrichloroethane (DDT) and polych
lorinated biphenyl (PCB). Target and actual concentrations were simila
r. 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.