A laboratory study of the effects of waterborne cadmium, calcium, and carbonate concentrations on cadmium concentrations in Hyalella azteca (Crustacea: Amphipoda)

Abstract

Cadmium concentrations were measured in the amphipod Hyalella azteca after 10 days exposure to experimentally manipulated (factorial design) calcium, cadmium, and carbonate concentrations in solution. Two experiments were conducted. The first used 3 calcium (2.5, 4.5, 6.5 mg Ca/l) and 3 carbonate (0.00, 0.05, 0.10 meq/l) concentrations, with 100 ng Cd/l in solution. Cadmium concentrations in H. azteca increased significantly (from 1.63 to 2.19 μg Cd/g dry mass) with decreasing calcium concentrations in solution, but were not affected by carbonate concentrations. The second experiment used 3 concentrations of calcium (2.5, 4.5, 6.5 mg Ca/l), cadmium (10, 50, 250 ng Cd/l) and carbonate (0.00, 0.025, 0.100 meq/l). Cadmium concentrations in H. azteca increased significantly (from 1.45 to 3.04 μg Cd/g dry mass) with increasing cadmium concentrations, and decreasing calcium concentrations (from 1.50 to 2.37 μg Cd/g dry mass), but were not affected by carbonate concentrations in solution. Since pH also varied in the experimental solutions (as a correlate of carbonate concentrations), it was concluded that cadmium concentrations in H. azteca are a function of environmental cadmium and calcium concentrations, but are not affected by environmental pH (range 6.8-5.6) or carbonate concentrations.