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Abstract The aim of the present study is to investigate the 65 60 uptake and retention of in and Co by the Nile cat fish Clarias Lazera. -C-E-A- P-p-L-=- -- -2 The living organisms ha~e been exposed to ?%Lfternal and/ or illternal q&.ations of varrious origins, and to the rodioactive materials that are released to the environment. and Ln turn reach the living wganisms , The uptake of radionuclides by the aquatic organi- SIBS occur by absorption through the surface of the skin) by 3i.ffusion of ions from the water through the outer semipremeable membranes and/or by ion exchange Several ’fsctors influence the uptake of radionuclides . by the aquatic organism such as : water salinity, pH , temperature , physical and chemical formsof the radioactive element$, the presence of small amount of dissolved radionucli@es, size of the fish, the time of exposure to the radioactive solution and the concentration level of the radionuelides. The stud.y, of the behavio:uz of radionuclides in Ismailia Canal may help to develope the safe limits of disposal of low level radioactive materials that may reach this canal. In the present study the uptake and 65 60 body and in mudcles and bone of the cheap fresh’water , fish, namely; the Nile catfish ; Clarias Lazera The parameters studied in this investigation are : 1. Effect of contact time. 2. Effect of Carrier Ooncentration. 3. Effect of pH. 4. Effect ’of competing ions concentrations. 5. Effect of isotope &oncentration. 6. The retention of radionuclides by the fish. -C--H---A--P--T-E--R-- ----- --I--1- This chapterisaabrief survey of the literature given by different uthors as cited in the international periodicals and reports. As far as possible this review gave a picture about the behaviour of different aquatic biota in some different aquatic environs towards either 65 60 Zn or Co . The different parameters affecting the uptake and retention of the radionuclides by the aquatic biota were also reviewed. In t h i s chapter d e t a i l e d experimental techniques are given. The Clarias Lazera f i s h were collected’frorn Ismailia Canal and rnaintaiq&in large g l a s s aquaria containing canal water f o r acclimation to laboratory conditions f o r two weeks before s t a r t i n g experimental work. The f i s h were fed daily to a d i e t t h a t cons.med immediately. The f i s h were starved f o r a period of 48 hrs before the start of each experiment and they were not fed throughout the experimental period. |