Geology topics
L. L. Thatcher
Publications and source records attributed to L. L. Thatcher.
Modified determination of radium in water
The proposed method embodies a barium sulfate carrier precipitation, filtration through molecular filter membranes, and collection of activity after prescribed aging period. The method is sufficiently accurate and precise to indicate the potability of water and for use in general studies of radium in chemical hydrology. Amounts of radium as low as 0.1 μ μ c. can be detected by using 1 -hour counting times. Radium-226 is used as the standard and the results indicate about 100 to 110 % of the activity of the alpha-emitting radium isotopes as radium-223, radium-224, and radium-226.
Determination of uranium in natural waters
The fluorophotometric determination of uranium was studied to develop a procedure applicable to the routine analysis of waters. Three grams of the high carbonate flux are used in a dilution procedure with spiking. Because of the comparatively high reflectivity of this large disk and the low uranium concentration, a correction for nonquenched light is required. A formula is developed to compensate for the effect, an electrical fusion device is described, and the problem of fixing uranium in waters is discussed.
Modified zirconium-Eriochrome Cyanine R determination of fluoride
The Eriochrome Cyanine R method for determining fluoride in natural water has been modified to provide a single, stable reagent solution, eliminate interference from oxidizing agents, extend the concentration range to 3 p.p.m., and extend the phosphate tolerance. Temperature effect was minimized; sulfate error was eliminated by precipitation. The procedure is sufficiently tolerant to interferences found in natural and polluted waters to permit the elimination of prior distillation for most samples. The method has been applied to 500 samples.
The distribution of tritium fallout in precipitation over North America
In 1958 the U.S. Geological Survey and the U.S. Weather Bureau jointly conducted a study of tritium fallout distribution over the continental United States, Alaska, and Puerto Rico. The observation period extended from early April to late July in most areas. While this was insufficient to cover the decay side of the curve, it was sufficiently long to establish general trends of tritium activity contours. Tritium activities were found to be maximum in the north central part of the country and minimum in coastal areas. The tritium activities show an inverse correlation with chloride concentrations in precipitation . Tritium activities in precipitation appear to be influenced by several “low altitude effects” particularly in storms of brief duration. Ground level tritium activity measurements are not directly representative of tritium in cloud moisture because of these effects.