The toxic and accumulative effects of short-term exposure to cadmium in rainbow trout (Oncorhynchus mykiss).

Groups of 20 trout (Oncorynchus mykiss) were exposed for 3-w periods to different subacute oral doses of Cl2Cd (0.01, 0.025 or 0.05 microgram Cd/mL). Cadmium toxicity and accumulation were studied in kidney, liver, gills, muscle and brain weekly. Cadmium determination was carried out using atomic absorption spectrocopy (AAS) with graphite furnace. After 21 d exposure, cadmium concentrations increased significantly. In all tissues studied except muscle and brain. Cadmium storage presented the following sequence: kidney > liver > gills. At the beginning, cadmium accumulation was linearly dose dependent (r = 0.999). Then, at the highest dose (0.05 microgram Cd/mL) accumulation increased rapidly during the second week of exposure until equilibrium was reached. In contrast, liver did not accumulate cadmium selectively, suggesting that liver is able to eliminate cadmium, perhaps through metallothionein formation. Cadmium levels in gills were higher than controls (P < 0.05) and showed signs of equilibrium after the first week. According to organ weight/body weight ratios, there was similar accumulation behavior. Liver and kidney ratios increased dose dependently, but gills and brain did not have significant differences.