SUMMARY ABSTRACT 
The cunner, Tautogolabrus adspersus, was exposed to six concentrations of cadmium, as 
cadmium chloride (CdCl, -2'2 H, O), for 96 hr. At the end of this exposure period, tests of blood serum 
osmolality and gill tissue oxygen consumption were performed. High levels (48 ppm) of this metal 
resulted in abnormally high serum osmolality, and an exposure as low as 3 ppm reduced the normal 
rate of oxygen consumption. Both of these parameters may be related to observed tissue damage. 
The histopathological effects of acute exposure of the cunner to cadmium were manifested in the 
kidney, intestine, hemopoietic tissue, epidermis, and gill. Few significant changes were noted in fish 
exposed to concentrations less than 48 ppm. The results implicate renal failure as the probable cause 
of death subsequent to acute exposure to cadmium. 
Clearance of intracardially injected bacteria from the blood of cunners exposed to 12 ppm cad- 
mium was examined. The rate of bacterial uptake in the cells of the liver and spleen was increased, 
but the bacterial death rate within these cells was decreased. Exposure of fish at 3 to 24 ppm failed to 
influence antibody production against sheep red blood cells. 
The activity of two liver enzymes changed significantly with exposure to cadmium. Aspartate 
aminotransferase was lower in the exposed fish, and a magnesium-linked oxidoreductase in exposed 
fish required 10 times as much added magnesium to reach the same level of activity as in the control 
fish. 
Chemical analyses were made for uptake and clearance of cadmium from exposed cunners. In the 
uptake study, cadmium residues averaged 8.5 times higher in liver than in gills. In the clearance 
study, substantial reductions in cadmium residues were found in the gills and blood of fish held in 
clean seawater for 6 wk after exposure to cadmium, as compared to fish sacrificed immediately after 
exposure. Muscle and carcass samples from the “‘cleared’’ fish showed little reductions in cadmium 
levels. 
ACKNOWLEDGMENT 
The authors of each section of this study thank Rita S. Riccio for her critical reading and typing of 
this manuscript. 
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