Geology topics
Marvin J. Fishman
Publications and source records attributed to Marvin J. Fishman.
A standard-reference water-suspended sediment sample for total recoverable metals
The U.S. Geological Survey has been preparing and maintaining a library of standard-reference water samples for dissolved inorganic constituents for 19 years. Recently, the reference-sample program was expanded to include a water-suspended sediment mixture for the determination of total recoverable metals. An interlaboratory round-robin study was conducted. Digestion procedures used by the U.S. Geological Survey and the U.S. Environmental Protection Agency were used to solubilize the metals before their measurement. The data indicate the both digestion procedures for total recoverable metals are essentially equivalent. Precision data are comparable to those data obtained in standard-reference water samples for dissolved metals.
Automation of an ion chromatograph for precipitation analysis with computerized data reduction
Interconnection of an ion chromatograph, an autosampler, and a computing integrator to form an analytical system for simultaneous determination of fluoride, chloride, orthophosphate, bromide, nitrate, and sulfate in precipitation samples is described. Computer programs provided with the integrator are modified to implement ionchromatographic data reduction and data storage. The liquid-flow scheme for the ion chromatograph is changed by addition of a second suppressor column for greater analytical capacity. An additional vave enables selection of either suppressor column for analysis, as the other column is regenerated and stabilized with concentrated eluent. Minimum limits of detection and quantitation for each anion are calculated; these limits are a function of suppressor exhaustion. Precision for replicate analyses of six precipitation samples for fluoride, chloride, orthophosphate, nitrate, and sulfate ranged from 0.003 to 0.027 milligrams per liter. To determine accuracy of results, the same samples were spiked with known concentrations of the above mentioned anions. Average recovery was 108 percent.
Selected methods of the U.S. Geological Survey for the analyses of wastewaters
No abstract available.
Determination of selenium in water
The determination of selenium by hydride generation atomic absorption spectrophotometry using zinc is widely used. Very little is mentioned, however, on possible interferences. In an attempt to use this technique for the determination of selenium in natural waters, interferences were found. The most serious interference occurred when arsenic was present. As little as 5 μg of arsenic/l suppressed the formation of selenium hydride. Because arsenic may be present with selenium in natural waters, the above method was abandoned in favor of the following atomic absorption spectrophotometric method for the determination of both inorganic and organically bound selenium. Organic selenium compounds, if present, are first decomposed by digestion with potassium permanganate in hot acid solution. The solution is then made basic and the solution evaporated to dryness in the presence of calcium chloride which prevents the loss of selenate during the evaporation. Hydrochloric acid is added to the residue to reduce the selenate to selenite. Quantitative reduction is obtained without loss of selenium by controlling the temperature, time, and acid concentration. It should be emphasized that the selenium must be in the selenite form prior to its final reduction. The selenium is finally liberated from 6M hydrochloric acid solution with stannous chloride and the selenium hydride vapor subsequently removed from solution by aeration and swept by a flow of nitrogen into a hydrogen flame where it is determined by atomic absorption at 196.0 nm. The method may be used to analyze water samples containing at least 2 μg/l of selenium.
Adsorption of cesium on clay minerals
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