No abstract available

[en] A technique for measuring the direction of movement of sandy sediments by means of a radiotracer is described. An artificial sediment fabricated from glass containing a small percentage of arsenic is irradiated in a nuclear reactor to produce ⁷⁶As (T1/2 = 26.4 hr). This material is then inserted into the particular sediment to be studied and its movement followed by monitoring the 560-keV γ-ray emission with a submersible NaI detector. A test of the method at Point Pelee on the north shore of Lake Erie with 140 g of artificial sediment containing 180 mCi of ⁷⁶As demonstrated that the redistribution of the radioactive material by the bottom current could be readily followed for at least three days after insertion. (author)

[en] Equilibrium experiments using Dowex 50 ion-exchange resin and nitric acid solutions of Pu³⁺, UO₂²⁺, Fe²⁺ cations have yielded values for the absorption affinities for these ions. Trivalent plutonium was found to be far more strongly absorbed than UO₂²⁺ and Fe²⁺. Column studies have shown that uranium can be completely separated from plutonium even when the initial concentration of uranium is very much greater than that of the plutonium. A plutonium concentration increase of about fifty-fold can be obtained from solutions about 10^-3 M in plutonium and 1.0M in nitric acid. The equation K_Pu³⁺ = X_R (1-X_S)³ C_S²/X_S (1-X_R)³ C_R² for estimating the maximum amount of plutonium taken up by a column of resin of unit volume from a solution of total equivalent concentration, C_S , has been shown to hold for values of C_S up to 3 equivalents per litre. X_R, the equivalent fraction of plutonium on the resin, is the number of equivalents of plutonium absorbed by the resin divided by the total capacity of the column. X_S, the equivalent fraction of plutonium in solution, is the equivalent concentration of plutonium divided by the total equivalent concentration of cations in solution. C_R is the total capacity of the resin in milli-equivalents per gram of dry resin. Recommendations have been made for the application and operation of ion-exchange columns in the Plutonium-Extraction Plant. (author)

No abstract available

[en] Equilibrium experiments have shown Pu⁺⁴ to be absorbed from nitric acid onto an anion resin as a complex anion Pu(NO₃)₆^-2. The amount of absorption is dependent on the plutonium and nitric acid concentrations in the equilibrium solution with a maximum at 7N to 8N HNO₃. A low cross-linked resin has a higher capacity and reaches equilibrium more rapidly than the normally supplied resin. Saturation capacity of one per cent cross-linked Nalcite SBR (Dowex 1), 50 -- 100 mesh, is 385 mg Pu/gram dry resin. (author)

[en] A method is described for bringing a sediment sample into solution and subsequently carrying out analysis for ²¹⁰Pb, ²²⁶Ra and ¹³⁷Cs. Silica is removed from the sample by cyclic HNO₃-HF treatments. ¹³⁷Cs is separated from ²¹⁰Pb and ²²⁶Ra in a carbonate fusion, extracted by absorption on ammonium molybdophosphate, precipitated directly with BiI₃ in presence of citric acid, and β-counted. ²¹⁰Pb and ²²⁶Ra are separated out by 70-75% HNO₃ precipitation. Further purification and mutual separation of the two radionuclides is achieved by solvent extraction and anion-exchange techniques. ²¹⁰Pb and ²²⁶Ra are determined by β- and α-counting of their chromate precipitates, respectively, after allowing suitable ingrowth periods for their daughters. The procedural steps effectively eliminate possible interference from other natural or fall-out radioactivities

[en] Pb-210, Ra-226 and Cs-137 profiles have been measured for sediment cores from three locations in western Nipigon Bay, Lake Superior, Canada. Compaction of the sediment with depth of burial was taken into account in calculating recent sedimentation rates and age profiles at these locations from the excess Pb-210 profiles. The rates at two of the locations were 0.85+-0.03 mm y^-1 (16.7 mg cm^-2 y^-1) and 1.39+-0.12 mm y^-1 (29.5 mg cm^-2 y^-1). The third core had an anomaly in the Pb-210 profile below a depth of 3.5 cm corresponding to the time that the outfall of a nearby pulp mill was relocated. The Cs-137 profiles of the two undisturbed cores were in accord with the corresponding age/depth curves derived from the Pb-210 measurements. (orig.)

[en] ²¹⁰Pb and ¹³⁷Cs activities were determined in sediment cores from Lakes Matagami and Quevillon, northwest Quebec, Canada. Following correction for the compressive effect of sedimenting materials, present-day sedimentation rates have been calculated from the excess ²¹⁰Pb profiles. The rates are found to be 0.81 mm.year^-1 (59 mg.cm^-2.year^-1) and 0.52 mm.year^-1 (35 cm^-2.year^-1) in Lake Matagami and Lake Quevillon, respectively. ¹³⁷Cs measurements are in accord with these values. (author)

[en] Radionuclide concentrations in digester sludge and effluent samples from Hamilton and Dundas sewage treatment plants, located at the western tip of Lake Ontario, have been determined by high-resolution γ-ray spectrometry. The radionuclides ⁵¹Cr, ⁷⁵Se and ¹³¹I, which are used in nuclear medicine procedures, were found in sludge samples. Very low concentrations of ⁵¹Cr, entering Lake Ontario through the Hamilton plant effluent discharge, have little effect on lake water quality. (author)

[en] The purpose of this investigation was to compare the results of indirect measurements of radionuclide concentrations in water with those measured directly. The levels of ¹³⁷Cs and ²²⁶Ra in western Lake Ontario nearshore waters were derived from high-resolution γ-spectrometric measurements on aluminum hydroxide sludge samples obtained from four water treatment plants. The concentrations of ¹³⁷Cs evaluated by this indirect technique averaged 0.036 compared with 0.023pCi 1^-1 measured directly, while those of ²²⁶Ra averaged 0.047 compared with the direct measurement of 0.03 pCi 1^-1. The concentrations of a number of other radionuclides at these locations were also calculated from the sludge γ-ray measurements. (author)