Document Details

UPTAKE OF RADIOISOTOPES AND THEIR TRANSFER THROUGH FOOD CHAINS BY MARINE ORGANISMS ANNUAL REPORT, 1959-1960

EGO, W T; TOWNSLEY, S J; REID, D F

Location - DOE/NNSA NUCLEAR TESTING ARCHIVE Address - P.O. Box 98521 City - Las Vegas State - NV Zip - 89193-8521 Phone - (702)794-5106 Fax - (702)862-4240 Email - NTA@NV.DOE.GOV

REPORT

1961 Sep 30

Never classified

0040

NV0015559

TID6630

U HAWAII

1994 Aug 26

2003 Sep 18

THE RESULTS OF EXPERIMENTS PERFORMED TO ELUCIDATE THE MECHANISM BY WHI CH THE CICHLID TILAPIA MOSSAMBICA MAINTAINS ITS OSMOTIC EQUILIBRIUM AR E REPORTED. USING THE PREVIOUSLY DESIGNED COMPARTMENTALIZED TANK, MEAS UREMENTS HAVE BEEN MADE TO SHOW THE ABILITY OF THESE FISH TO ABSORB ST RONTIUM AND SODIUM IONS DIRECTLY FROM THE ENVIRONMENT. ALL ROUTES OF A BSORPTION AND EXCRETION HAVE BEEN STUDIED UNDER VARIABLE EXPERIMENTAL CONDITIONS. STRONTIUM-85 HAS BEEN USED TO MEASURE CA++ AND SR++ DISCRI MINATION BY FISH. ANALYSIS OF THE DATA SHOWS THAT MORE OF THESE CATION S PASS THROUGH SEA WATER ADAPTED FISH THAN THROUGH FRESH WATER ADAPTED FISH; ALTHOUGH IN THE FORMER CASE A SMALLER QUANTITY OF RADIOACTIVITY IS MEASURED. THE DIFFERENCE BETWEEN THE QUANTITY OF THESE IONS EXCRETE D IN THE URINE COULD NOT ACCOUNT FOR THE APPARENT DISCRIMINATION IN TH E FISH. EXPERIMENTS USING NA-22 TO STUDY SODIUM ACTIVITY SHOW THAT RAP ID EXCHANGE OF SODIUM OCCURS IN BOTH SEA WATER AND FRESH WATER ADAPTED FISH. BECAUSE OF THE RESULTS OBTAINED IN THESE EXPERIMENTS, PRELIMINAR Y TESTS HAVE BEEN PERFORMED TO SHOW WHAT EFFECT STRESS AND ADRENOCORTI CAL HORMONES MAY HAVE ON THE SELECTIVE ABSORPTION AND EXCRETION OF ION S. THE ENTIRE BODY SURFACE OF TILAPIA IS PERMEABLE, AND IT IS PRESUMED THAT THIS PERMEABILITY MAY BE ALTERED UNDER STRESS AND/OR HORMONAL ACT IVITY. NO CLEAR STRESS RELATIONSHIP HAS BEEN OBTAINED AS YET; HOWEVER, IT APPEARS THAT DOCA INCREASES THE PREMEABILITY OF THE ENTIRE SURFACE OF THE FISH TO NA-22, RESULTING IN AN INCREASED ACCUMULATION AND OUTPU T OF APPROXIMATELY TWICE THAT IN THE CONTROL FISH. RESULTS OF TWO ARTI FICIAL FOOD WEB EXPERIMENTS ARE PRESENTED. USING ZINC-65 TO LABEL SEA WATER, RESULTS OF EXPERIMENTS ON THE RADIOZINC ACCUMULATIONBY CHLAMYDO MONAS SP?, ARTEMIA SALINA, AND CHAETODON MILIARIS DIRECTLY FROM SOLUTI ON AND THROUGH FEEDING ARE PRESENTED. IT IS POSTULATED THAT DIRECT ABS ORPTION FROM SEA WATER WILL BE THE MOST IMPORTANT METHOD FOR ACCUMULAT ION OF THIS ELEMENT BY THESE ORGANISMS. BECAUSE PLANKTONIC AND BENTHIC ORGANISMS APPEAR TO CONCENTRATE TRACE IONS IN THE MARINE ECOSYSTEM, IN ITIAL STUDIES HAVE BEEN EMPLOYED TO SHOW WHAT EFFECT CHEMICAL CHANGES IN THE ENVIRONMENT MAY HAVE ON THE ACCUMULATION OF ISOTOPES BY REPRESE NTATIVE ORGANISMS. DATA OBTAINED ON CHLAMYDOMONAS SP?, ARTEMIA SALINA, AND THE BRACHIOPOD LINGULA REEVI, EXPOSED TO SEA WATER CONTAINING NA-2 2 ARE PRESENTED. IT IS FOUND THAT THE SODIUM IN THESE ORGANISMS REACHE S AN EQUILIBRIUM WITH THE ENVIRONMENT VERY RAPIDLY. INDICATIONS POINT TO THE FACT THAT THE QUANTITY OF NA-22 ACCUMULATED IS RELATED TO THE A BILITY OF THE ORGANISMS TO REGULATE AND SELECTIVELY ABSORB IONS. DATA ON THE RELATIONSHIP OF ORGAN SIZE TO FISH SIZE ARE PRESENTED. COMMENTS ON THE HANDLING AND USE OF TILAPIA MOSSAMBICA FOR LABORATORY PROCEDURE S ARE ALSO INCLUDED.