Chapter 10 Radiatioti of Aquatic Organisms 99 



TABLE 4 Counts of the Primordial Germ Cells rainbow trout chronically fed P^- died in ap- 

 iN THE Gonads of Chinook Salmon Compared proximately 6 weeks when the concentration of 

 By Days After Exposure and By Dosage i ^^^ -^^^^p^ j^ ^^^^^ ^^^ ^i^^^^ ^^ maximum up- 

 Exposed fish take, reached a level of 18 to 65 iic/g (giving 

 kradiation Tr" %'50 r 500 r 1000 r a dose of about 1200 rads per day). Other 



9 33 42 25 27 trout remained alive during the 12 weeks' ex- 



16 46 31 64 27 periment with concentrations of P^- in the bone 



23 32 35 108 39 ^s high as 10 fic/g. Although these fish showed 



, , 28 42 ^"^ external evidence of radiation damage other 



44 ^ 32 124 79 71 than a slight reduction in growth rate, subse- 



51 453 83 65 53 quent dissection revealed that some damage 



58 2,085 287 55 25 h^d occurred. The syndrome was similar to that 



^5 1'058 683 286 47 described for trout damaged by X-irradiation, 



79 6,569 380 131 67 • i, .u u i j c ^u i 



03 7 206 247 94 69 especially the breakdown or the vascular system 



— as evidenced by hemorrhage of the liver and 



Average 1,595.4 182.6 89.2 43.1 musculature. 



1 Counts of over 1,000 r were arrived at by first In experiments that have taken place at Eni- 



making total counts on all five-micron sections and j^ ^^j g-j^j^j ^^^jj^ ^^^ resulting radio- 



calculating the actual number or germ cells present us- 1 1 n 



ing the average size of the ceil nucleus (9.2 microns) active materials that entered the water usually 



and actual cell counts of the other fish as a basis. In provided three types of exposure to the aquatic 



cases where every fifth section only was used (as in ^ . ,, v _ r j-u^ _ j.-^i-:^^ ^o^^ 



the 65th, 79th and 93rd day series) actual counts were organisms: (1) some of the radiation came 



obtained by multiplying original counts by five and from contamination of the environment, (2) 



then correcting for size of the cell nucleus. Data from particulate matter, such as Specks of radioactive 



Welander et al. (1948). \ ^ ■ r. ..i j • ju J <-^ 



debris often settled on organisms or adhered to 



J. ^. .,• ., .. „ „, 1 ^ _^ mucus coverings, etc., or (3) the radioactive 



are more radiation sensitive than the older, ma- ., °,' ' .^ ' . ,,, rj 



r materials entered the organism through the tood 



Tit i.iuj rci-fj- chain where it was absorbed and incorporated 



In all respects, the damage effects of radia- '-"'^i" vvi .. .. ,•■,,,,, *^ i 



. r . • -1 -J .-• 1 ^ *.u^ f into the organism or eliminated by the usual 



tion in fish are similar or identical to the et- ' & ^ 



facts seen in other vertebrate animals. In gen- biological processes. , ,. . 



eral, the syndromes have a similar pattern Although vast amounts of radiation may be 



throughout the animal kingdom depending on P^-^sent immediately following a weapons test, 



the dose amounts that surely would produce measurable 



2. Relative susceptibility of organs to ra- changes in the exposed aquatic forms no spe- 



dioactive material ^^^'^ instances were found in which direct so- 



For most experiments with aquatic organ- matic damage could be charged to radiation 



isms conducted to date radiation from external effects. 



sources has been used. In the work of Chipman It must be realized that in as complex an en- 



(1955) and Hiatt, Boroughs, Townsley, and vironment as a coral atoll following the fate of 



Kau (1955) radiation from isotopic sources in individual populations is very difficult. The 



the body was used, but at such low levels so- most sensitive forms, the fishes, undoubtedly are 



matic damage was not evident. weakened from somatic and functional damage 



The uptake of lethal levels of P^^ is being by radiation. Such weakened forms are usually 



studied by Watson (unpublished data) . Adult eaten soon by the large carnivorous fishes that 



TABLE 5 Counts of the Glomeruli in the Kidney of Chinook Salmon Larvae After Irradiation 



in Eyed Egg Stages ^ 



Days 



Dose , 



inr 23 30 37 



12 36 42 



250 2 38 16 



500 8 16 38 



1000 26 28 



1 After Welander et al. (1948), counts on 36 fish. 



