Effects of cadmium-spiked sediment on cadmium accumulation and bioturbation by nymphs of the burrowing mayfly Hexagenia bilineata
We assessed accumulation of cadmium (Cd) and bioturbation by nymphs of the burrowing mayfly Hexagenia bilineata as indicators of exposure to Cd-spiked sediment in a 21-d test. Surficial sediments (top 5 cm) from Pool 7 of the Upper Mississippi River were spiked with Cd to concentrations of 3, 7, and 15 μg Cd g-1 dry weight. The experimental design was completely randomized, with three Cd-spiked sediment treatments plus an unspiked sediment control (1 μg Cd g-1 dry weight), and 10 nymphs in each of six replicates per treatment. Nymphs accumulated Cd during the 21-d exposure; mean concentrations varied from 0.22 to 6.24 μg g-1 dry weight, and tissue concentrations were correlated with Cd concentration in unfiltered test water (r = 0.93, P <0.01) and test sediment (r = 0.93, P <0.01). The effect of Cd on bioturbation by nymphs, as indicated by turbidity, differed significantly among treatments (P = 0.045) and over time within treatments (P = 0.01). Turbidity progressively decreased as Cd concentration in the sediment increased, up to 7 μg g-1; however, turbidity in the 15 μg g-1 treatment (our greatest exposure concentration) did not differ significantly from the control. Concentrations of Cd in unfiltered, overlying test water increased significantly within treatments during the test, indicating that nymphs mobilized sediment-associated Cd into the overlying water, presumably through burrowing and respiratory activities.
Citation Information
Publication Year | 1999 |
---|---|
Title | Effects of cadmium-spiked sediment on cadmium accumulation and bioturbation by nymphs of the burrowing mayfly Hexagenia bilineata |
DOI | 10.1023/A:1005089601201 |
Authors | Michelle Bartsch, W. Gregory Cope, Ronald G. Rada |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Water, Air, & Soil Pollution |
Index ID | 70006706 |
Record Source | USGS Publications Warehouse |
USGS Organization | Upper Midwest Environmental Sciences Center |