Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Amphipod sediment bioassays: effects on response of methodology, grain size, organic content, and cadmium

Book ·
OSTI ID:6693835

Ten day sediment bioassays and behavioral tests were conducted with the phoxocephalid amphipod Rhepoxynius abronius to determine individual and interactive effects on response of grain size, cadmium (Cd), and organic content in static and flow-through systems. Effects of freezing sediment and variations in animal sensitivity (due to age and season) were also examined. In addition, bioassays were conducted biannually over a 2-yr period using sediments from 27 stations in central Puget Sound, Washington. Sterile sediments with a mean grain size <29-54 um were acutely toxic to amphipods. The 96-h LC50 for water-borne Cd was 1.7 ppm; the 10-day LC50 for Cd in native sand was 8.8 ppm. Toxicity from Cd and tissue Cd uptake were a direct function of the seawater Cd concentration which decreased with decreasing grain size and increasing organic content. Therefore, Cd bioavailability was not correlated with total Cd in sediment. Survival was similar or lower in a static versus a flow-through system with the magnitude of the difference in response between systems being greatest in contaminated fine-grain sediments. Amphipods were more sensitive during Jan-March then Oct-Nov. Shifts in sensitivity may be related to the recruitment/growth pattern and the overwintering habits of this animal. In bioassays conducted with field sediments, geographic patterns of sediment toxicity were apparent. Survival was negatively correlated with mean grain size and priority pollutant load of 15 heavy metals and 50 organic compounds, although response could not be attributed to any single parameter.

OSTI ID:
6693835
Country of Publication:
United States
Language:
English