Table 1.—Uptake of cadmium by livers and gills of cunners, Tautogolabrus adspersus, exposed for 96 hr at various 
concentrations of cadmium, as CdCl,*H,0, in artificial seawater. 
Concentrations of cadmium in tissues 
Concentration 
of cadmium 
in artificial 
Individual experiments 
Individual experiments 
seawater 
(ppm) Ay. 1 2 3 Av. 1 2 3 
o--------- ppm wet weight basis’--------- ----------ppm dry weight basis'---------- 
LIVER TISSUE 
0 1.2 0.95 1.65 0.85 5.5 3.6 6.7 ao 
3 16.0 13.5 21.5 13.0 54.5 41.0 75.0 47.5 
6 34.5 39.0 36.5 27.5 119.5 125.0 131.0 102.0 
12 55.0 54.5 65.0 45.0 198.7 182.5 236.0 177.5 
24 110.7 143.0 109.0 80.0 390.0 454.0 386.5 329.5 
48 195.0 267.0 160.5 157.0 761.3 928.0 744.0 611.5 
GILL TISSUE 
0 ile Heil 0.9 3 5.4 5.4 5.0 eS, 
3 3.0 4.3 2.3 2.5 16.5 21.5 11.5 16.5 
6 3.4 5.1 2.4 Pil 17.5 28.0 12.5 13.0 
12 6.3 7.5 5.8 5.6 31.8 38.5 28.0 29.0 
24 11.9 16.0 12.0 7.8 66.5 88.5 60.5 44.0 
48 33.5 43.0 27.5 30.0 171.3 226.5 135.0 152.5 
‘ Liver and gill tissues from four to five fish per exposure level were composited and analyzed in duplicate for each experi- 
ment. The values shown for individual experiments are averages of the duplicate analyses. 
D Experiment 1 
Experiment 2 
O Experiment 3 
@ Average of 1-3 
Cadmium Concentration In Gills(ppm,wet wt.) 
036 12 24 48 
Cadmium Concentration In Seawater (ppm) 
Figure 2.—Uptake of cadmium by the gills of cunner held 96 hr 
in various concentrations of cadmium (as cadmium chloride) in 
artificial seawater. 
cadmium exposure levels were virtually the same, and 
moderate increases occurred at 12 and 24 ppm levels. 
There was a very sharp increase, however, at the 48 
ppm level, which may be related to physiological gill 
damage. Thurberg and Dawson (this report, Part III) 
found a marked depression in oxygen consumption 
rates of gill tissues, as well as a breakdown of os- 
moregulation in cunners exposed to 48 ppm cadmium. 
Clearance Study 
Substantial reductions in cadmium residues were 
found in the gills, red blood cells, and serum of 
cadmium-exposed fish held in clean running seawater 
for 1 mo after exposure. In contrast, muscle and car- 
cass samples of these fish showed very little reduction 
in cadmium residues, as compared to fish examined 
immediately after exposure to cadmium (Table 2). 
Liver samples produced variable results (Table 2). 
Cadmium concentrations in livers of fish examined 
immediately after exposure varied from 30 to 117 ppm 
(x = 64.2), a nearly 4-fold difference. Cadmium con- 
centrations in livers of fish held 1 mo in clean running 
seawater after exposure, varied only 5-11 ppm (x = 
10) in three of the fish, but varied from 62 to 155 ppm 
(x = 92) in the other four fish. 
In spite of the pooling of blood samples (which 
reduced the number of possible observations), cad- 
mium concentrations in both serum and red blood 
cells were as variable as those observed in the in- 
dividual liver samples (Table 2). All blood pools from 
“cleared”? fish, however, had substantially lower 
levels of cadmium than those from fish sacrificed im- 
mediately after exposure to cadmium. 
Gill tissues showed a greater clearance of cadmium 
than did the other tissues examined. Gills of fish 
sacrificed immediately after exposure contained 6.2- 
10.6 ppm cadmium (x = 8.1), and gills of fish held in 
