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The biennial review of atomic-weight determinations and other cognate data has resulted in changes for the standard atomic weights of 11 elements. Many atomic weights are not constants of nature, but depend upon the physical, chemical, and nuclear history of the material. The standard atomic weights of 10 elements having two or more stable isotopes have been changed to reflect this variability of atomic-weight values in natural terrestrial materials. To emphasize the fact that these standard atomic weights are not constants of nature, each atomic-weight value is expressed as an interval. The interval is used together with the symbol [a; b] to denote the set of atomic-weight values, Ar(E), of element E in normal...
The geochemical model PHREEQC is capable of simulating a wide range of equilibrium reactions between water and minerals, ion exchangers, surface complexes, solid solutions, and gases. It also has a general kinetic formulation that allows modeling of nonequilibrium mineral dissolution and precipitation, microbial reactions, decomposition of organic compounds, and other kinetic reactions. To facilitate use of these reaction capabilities in scripting languages and other models, PHREEQC has been implemented in modules that easily interface with other software. A Microsoft COM (component object model) has been implemented, which allows PHREEQC to be used by any software that can interface with a COM server—for example,...
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The shortgrass steppe is a semi-arid grassland, where elevated CO2 reduces stomatal conductance and promotes soil moisture storage. Enhanced biomass growth from elevated CO2 has been attributed in part to soil moisture effects. However, the influence of this soil moisture feedback on C cycling has received little attention. We used open-top chambers to increase atmospheric CO2 concentrations to twice-ambient for four growing seasons. Soil respiration rates and stable C isotopes of soil CO2 were measured during the third and fourth seasons. Elevated CO2 increased soil respiration rates by ?25% in a moist growing season and by ?85% in a dry season. Stable C isotope partitioning of soil respiration into its components...
Fate of radium (Ra) in liquid regeneration brine wastes from water softeners disposed to septic tanks in the New Jersey Coastal Plain was studied. Before treatment, combined Ra (226Ra plus 228Ra) concentrations (maximum, 1.54 Bq L−1) exceeded the 0.185 Bq L−1 Maximum Contaminant Level in 4 of 10 studied domestic-well waters (median pH, 4.90). At the water table downgradient from leachfields, combined Ra concentrations were low (commonly ≤0.019 Bq L−1) when pH was >5.3, indicating sequestration; when pH was ≤5.3 (acidic), concentrations were elevated (maximum, 0.985 Bq L−1 – greater than concentrations in corresponding discharged septic-tank effluents (maximum, 0.243 Bq L−1)), indicating Ra mobilization from leachfield...
    map background search result map search result map Elevated atmospheric CO 2 effects and soil water feedbacks on soil respiration components in a Colorado grassland Chloride Project, I.P. Location and Interpretation Plan Geologic Map (Chloride?) Chloride Project Geochemical Location Plan - Copper Chloride Project Geochemical Location Plan - Molybdenum Chloride Project Geochemical Location Plan - Zinc Chloride Project I.P. Traverse Sectional Data Sheet Line No. 4 Chloride Project Vertical Intensity Magnetic Survey North American Mines, I.P. Traverse Sectional Data Sheet Line No. 2 North American Mines, I.P. Traverse Sectional Data Sheet Line No. 3 Chloride Project I.P. Traverse Sectional Data Sheet Line No. 5 Chloride Project, Ricuerdo, I.P. Traverse Line No. 1 Sheet 1 Elevated atmospheric CO 2 effects and soil water feedbacks on soil respiration components in a Colorado grassland