Thermodynamics of Inorganic Nitrogen Transformations1

Lindsay, W. L.; Sadiq, Muhammad; Porter, L. K.

doi:10.2136/sssaj1981.03615995004500010014x

Cited by 10 publications

(12 citation statements)

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“…Denitrification occupies a position of pivotal importance in the N cycle of the biosphere. In its absence, all biologically available N that has been released from igneous rocks of the Earth's original crust and mantle would have been converted long ago to its more thermodynamically stable form of NO3-in the oceans [Lindsay et al, 1981]. Therefore this process, which is often viewed by biologists as a mechanism for loss of plantavailable N, also represents the first step in the recovery of excess oxidized N by replenishing the supply of atmospheric N2 available to symbiotic and nonsymbiotic N-fixing microorganisms.…”

Section: Denitrificationmentioning

confidence: 99%

NO_x And N₂O Emissions From Soil

Williams¹,

Hutchinson²,

Fehsenfeld³

1992

Global Biogeochemical Cycles

457

198

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Emission Of NOx (principally NO) and N2O from soils is reviewed with particular emphasis placed on the atmospheric and ecological implications of this source. The photochemistry of these species in the atmosphere is summarized as well as the methods available for the determination of fluxes. Processes which produce and consume both NO and N2O in soils are principally microbiological in nature and are linked directly and indirectly with the chemical and physical factors that control gaseous transport through the soil medium. Linkages among these processes occur over many different temporal and spatial scales which makes interpretation of the available data difficult. A summary of results from laboratory and field studies shows that considerable spatial and temporal variability exists in the emissions. This variability can be related to factors such as temperature, water content, soil composition, nutrient availability, vegetation, disturbances (e.g., burning, agricultural practices), and others. Because NOx and N2O play central roles in many important environmental problems, there is a need for accurate estimates of the magnitude of the soil source, but the large degree of variability in the existing data makes extrapolation highly uncertain. To overcome this uncertainty, models are required which can simulate the processes responsible for production, consumption, and transport of these species at all relevant temporal and spatial scales. Integrated field studies will also be required to validate the model results.

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Section: Denitrificationmentioning

confidence: 99%

NO_x And N₂O Emissions From Soil

Williams¹,

Hutchinson²,

Fehsenfeld³

1992

Global Biogeochemical Cycles

457

198

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“…Nitrogen can occur in other forms, such as cyanide (CN -) and in aqueous systems affected by industrial waste disposal. The rate at which equilibrium is reached among the different redox states of nitrogen is very slow in abiotic systems because of the high-activation energies associated with nitrogen redox reactions (Lindsay et al 1981). …”

Section: Nitratementioning

confidence: 99%

“…The behavior of nitrogen species, such as nitrate, in aqueous, sediment, and geochemical systems has been discussed by Lindsay (1979), Lindsay et al (1981), , Hem (1986), and others. A large number of studies have been completed related to the chemical and biological processes that transfer nitrogen between the atmosphere, lithosphere, hydrosphere, and biosphere.…”

Section: A8 Nitratementioning

confidence: 99%

“…Nitrogen can occur in other forms, such as cyanide (CN -), in aqueous systems affected by industrial waste disposal. The rate at which equilibrium is reached among the different redox states of nitrogen is very slow in abiotic systems because of the high activation energies associated with nitrogen redox reactions (Lindsay et al 1981). Relative to the geochemical conditions in the vadose zone, nitrogen will be present typically as the highly mobile NO 3 -(nitrate) species based on thermodynamic considerations and characterization data for Hanford vadose zone sediments (e.g., see Hanford vadose zone characterization reports by Serne and Brown cited in the main text of this data package).…”

Section: A8 Nitratementioning

confidence: 99%

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Geochemical Processes Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford Site

Cantrell¹,

Zachara²,

Dresel³

et al. 2007

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Companion reports that review other subject matter areas relevant to contaminant transport within the vadose zone beneath the SST WMAs, the IDF, and groundwater have been recently published. The specific subject areas include the geology of the SST WMAs iv contaminants released to the vadose zone exhibit a wide range of mobility behaviors. Many tank waste contaminants have been strongly retarded by adsorption and precipitation reactions (e.g., cesium, plutonium, americium, and europium), while others have remained mobile (e.g., technetium, nitrate, and selenium). Still others show variable, waste-specific behaviors (e.g., cesium [where sodium concentrations are very high], strontium, chromium, and uranium) that are closely tied to evolving composition of pore water in the sediments, and for chromium, a change in oxidation state. The temperature of in-ground tank waste has moderated by heat exchange with the subsurface sediment, and high concentrations of base (OH -) have been neutralized through reactions with sediment minerals and secondary mineral precipitation. Major geochemical features that may potentially affect the mobility of key contaminants of interest in the vadose zone include oxidation state, aqueous speciation, solubility, and adsorption reactions.Processes suspected of facilitating the far-field migration of immobile radionuclides, such as formation of stable aqueous complex formation and mobile colloids, were found to be potentially operative, but unlikely to occur in the field. An exception is the enhanced migration of cobalt-60 facilitated by the formation of highly stable aqueous-cyanide complexes. Certain fission-product oxyanions (e. • Adsorption is suppressed by large concentrations of tank waste anions (e.g., NO 3 -, OH -, and CO 3 2-)• Surface charge of clay-size minerals is negative and will therefore tend to repel anions• Unlike chromium, their less-soluble, less-mobile reduced forms are unstable in oxidizing environments.Laboratory studies conducted through PNNL's Vadose Zone Characterization Project and basic-science geochemical studies are expected to continue in partnership to provide information to further refine the conceptual model used for risk assessment modeling. Results of these studies can be used to help ascertain uncertainties associated with the refinement of the conceptual models for contaminant migration in the vadose zone beneath the single-shell tanks. Results can also provide improved parameterization, such as distribution coefficients (K d ), and mathematical constructs used by modelers to predict contaminant mobility under these conditions, and to decrease the degree of conservatism incorporated in these models.For various reasons, risk assessment models typically use various approximations to represent the conceptual model developed for the site. Adsorption is frequently approximated using empirical distribution coefficients (K d s). Although the use of empirical distribution coefficients can potentially lead to erroneous results under certain conditions where the...

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“…Even though no explanation can be offered at present with full certainty, the assumptive reason for such an anomalous observation during the period appears to be closely related to the prevalent oxidation states of transient-like metals oscillating between Fe2+eFe3+ in Column I11 and Mn2+*hln3+ in Column IV, and which in turn might very well cause temporal variation in the nitrate reduction activity in these two columns. In this connection it is worth pointing out that considerable work has been reported which characterizes the thermodynamic data on iron (Chao & Kroontje, 1966) and manganese (Bricker, 1965;Zordon & Hepler, 1968) as well as studies the reactions of iron (Ponnamperuma et al, 1967;Lindsay et al, 1981) and manganese (Patrick & Turner, 1968;Ponnamperuma et al, 1969;Gotoh & Patrick, 1972) in flooded soils. However, the effluent concentration of NOT-N in all three columns remained zero during the rest of the monitoring period and indicated a long-term stability in the nitrate reduction activity that prevailed in these columns.…”

Section: Not-n Liter-') and Systematic Leaching During 610 Days Seementioning

confidence: 99%

Studies on Nitrate and Nitrite Reduction in Soil under Modelled Conditions of Anaerobiosis, Reduction Potentiality and Systematic Leaching

Ghoshal

1983

Acta Agriculturae Scandinavica

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Thermodynamics of Inorganic Nitrogen Transformations1

Cited by 10 publications

References 0 publications

NO_x And N₂O Emissions From Soil

NO_x And N₂O Emissions From Soil

Geochemical Processes Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford Site

Studies on Nitrate and Nitrite Reduction in Soil under Modelled Conditions of Anaerobiosis, Reduction Potentiality and Systematic Leaching

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Thermodynamics of Inorganic Nitrogen Transformations1

Cited by 10 publications

References 0 publications

NOx And N2O Emissions From Soil

NOx And N2O Emissions From Soil

Geochemical Processes Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford Site

Studies on Nitrate and Nitrite Reduction in Soil under Modelled Conditions of Anaerobiosis, Reduction Potentiality and Systematic Leaching

Contact Info

Product

Resources

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NO_x And N₂O Emissions From Soil

NO_x And N₂O Emissions From Soil