EcoService Models Library (ESML)
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Variables Details
: (EM-892)
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EM-892 | |
Document Author
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McKane |
Document Year
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Contaminant ?Comment:Class variable |
Contaminant concentration |
Soil moisture (layer 1,2,3,4) ?Comment:Computed as part of the VELMA hydro model. |
Soil organic carbon (layer 1,2,3,4) ?Comment:In VELMA, users specify initial humus (soil organic matter) values (g C/m2) according to soil survey or other data, for example, NRCS soil survey map data. VELMA then calculates initial foc values and subsequent daily changes in foc in response to environmental and management drivers. VELMA calculates foc per soil layer per grid cell per day. |
Water flow ?Comment:Derived as output from the VELMA hydro model. |
Decay rate (maximum) ?Comment:Constant value determined by the class variable; Contaminant. The maximum daily decay rate constant (fraction per day) of a specified contaminant. The Comptox library (https://comptox.epa.gov/#/) lists the half-life for most organic contaminants, from which the daily maximum decay rate constant can be calculated and specified for this parameter. Users can enter the specified half-life value into an online calculator to calculate the decay constant. For example, see https://www.calculator.net/half-life-calculator.html?type=2&chalflife=4&cmeanlifetime=&cdecayconstant=&x=35&y=16. Note that decomposed contaminant amounts are not tracked by the simulation and not reported in its results. This is because contaminants almost always make up an insignificant fraction of the total amount of organic matter within soils. |
Microbial efficiency of decomposition ?Comment:Constant value determined by the class variable; Contaminant. The unitless microbial efficiency (range [0.0, 1.0]) of decomposition of organic contaminants in soil, that is, the ratio of carbon assimilated/total carbon consumed, whereby the difference is that respired as carbon dioxide. Typical microbial efficiencies range from 0.45 to 0.55. |
Molar mass ?Comment:Constant determined by the class variable: Contaminant. Comptox provides the molecular weight for all contaminants in its library. Users need to enter this so that VELMA can calculate solubility. |
Octanol-water partition coefficient ?Comment:Kow (log10) is the experimentally determined ratio of a contaminant's concentration in the octanol (C8H17OH) phase of a two-phase octanol-water system. Kow is a standard indicator of a contaminant’s affinity for adsorption by organic matter. Higher KOW values indicate strongly sorbed, less mobile (hydrophobic) chemicals. User enters KOW value into VELMA based on EPA Comptox website, https://comptox.epa.gov/dashboard. Note that Comptox expresses KOW as KP, a confusing use of terminology. This variable is a constant determined by the class variable; Contaminant. |
Slope intercept of linear regression correlating log(octanol-water partition coefficient) to carbon normalized sorption coefficient ?Comment:This variable is a constant determined by the class variable; Contaminant. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Contaminant-specific regression parameters for calculating KOC can often be applied to chemically similar contaminants, with the caveat that soil organic matter concentrations and mineralogy are within the range of experimental conditions for which the regression was developed (Piwoni and Banerjee 1989; Ho et al. 2005). |
Slope of linear regression correlating log(octanol-water partition coefficient) to carbon normalized sorption coefficient ?Comment:This variable is a constant determined by the class variable; Contaminant. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Contaminant-specific regression parameters for calculating KOC can often be applied to chemically similar contaminants, with the caveat that soil organic matter concentrations and mineralogy are within the range of experimental conditions for which the regression was developed (Piwoni and Banerjee 1989; Ho et al. 2005). |
Solubility in water ?Comment:Constant determined by the class variable; Contaminant. Contaminant solubility values can be found in EPA’s Comptox library (https://comptox.epa.gov/#/). |
Carbon normalized sorption coefficient ?Comment:With the specified survey-based spatial estimates of soil organic carbon (humus), VELMA internally calculates the carbon normalized sorption coefficient, KOC. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Typically expressed as log KOC. |
Gram solubility coefficient ?Comment:VELMA calculates a gramSolubilityCoefficent value “behind the scenes” as: gramSolubilityCoefficient = molarMass * molSolubilityCoefficient, with units, g/L = g/mol * mol/L |
Soil-water partition coefficient | Chemical transfer amount | |
Variable ID
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22019 | 22100 | 22092 | 22023 | 22098 | 22101 | 22102 | 22096 | 22020 | 22021 | 22022 | 22095 | 22093 | 22097 | 22094 | 22099 |
Not reported | Not reported | Not reported | foc | Not reported | Not reported | Not reported | Not reported | Koc | Not reported | Not reported | Not reported | Koc | Not reported | Kp | Not reported | |
Qualitative-Quantitative
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Qualitative (Class, Rating or Ranking) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) | Quantitative (Cardinal Only) |
Cardinal-Ordinal
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Non-Ordinal | Cardinal | Cardinal | Cardinal | Cardinal | Cardinal | Cardinal | Cardinal | Cardinal | Cardinal | Cardinal | Cardinal | Cardinal | Cardinal | Cardinal | Cardinal |
Not applicable | Not reported | mm |
unitless (0-1) ?Comment:Fraction (0-1) = [(g soil humus carbon) / (g bulk soil) |
mm day^-1 | % day^-1 | % | g mol^-1 |
unitless ?Comment:unitless ratio, Log10 |
unitless | unitless | mol L^-1 | unitless | g L^-1 | (mg/kg bulk soil) / (mg/liter water) | g m^-2 |
Contaminant ?Comment:Class variable |
Contaminant concentration |
Soil moisture (layer 1,2,3,4) ?Comment:Computed as part of the VELMA hydro model. |
Soil organic carbon (layer 1,2,3,4) ?Comment:In VELMA, users specify initial humus (soil organic matter) values (g C/m2) according to soil survey or other data, for example, NRCS soil survey map data. VELMA then calculates initial foc values and subsequent daily changes in foc in response to environmental and management drivers. VELMA calculates foc per soil layer per grid cell per day. |
Water flow ?Comment:Derived as output from the VELMA hydro model. |
Decay rate (maximum) ?Comment:Constant value determined by the class variable; Contaminant. The maximum daily decay rate constant (fraction per day) of a specified contaminant. The Comptox library (https://comptox.epa.gov/#/) lists the half-life for most organic contaminants, from which the daily maximum decay rate constant can be calculated and specified for this parameter. Users can enter the specified half-life value into an online calculator to calculate the decay constant. For example, see https://www.calculator.net/half-life-calculator.html?type=2&chalflife=4&cmeanlifetime=&cdecayconstant=&x=35&y=16. Note that decomposed contaminant amounts are not tracked by the simulation and not reported in its results. This is because contaminants almost always make up an insignificant fraction of the total amount of organic matter within soils. |
Microbial efficiency of decomposition ?Comment:Constant value determined by the class variable; Contaminant. The unitless microbial efficiency (range [0.0, 1.0]) of decomposition of organic contaminants in soil, that is, the ratio of carbon assimilated/total carbon consumed, whereby the difference is that respired as carbon dioxide. Typical microbial efficiencies range from 0.45 to 0.55. |
Molar mass ?Comment:Constant determined by the class variable: Contaminant. Comptox provides the molecular weight for all contaminants in its library. Users need to enter this so that VELMA can calculate solubility. |
Octanol-water partition coefficient ?Comment:Kow (log10) is the experimentally determined ratio of a contaminant's concentration in the octanol (C8H17OH) phase of a two-phase octanol-water system. Kow is a standard indicator of a contaminant’s affinity for adsorption by organic matter. Higher KOW values indicate strongly sorbed, less mobile (hydrophobic) chemicals. User enters KOW value into VELMA based on EPA Comptox website, https://comptox.epa.gov/dashboard. Note that Comptox expresses KOW as KP, a confusing use of terminology. This variable is a constant determined by the class variable; Contaminant. |
Slope intercept of linear regression correlating log(octanol-water partition coefficient) to carbon normalized sorption coefficient ?Comment:This variable is a constant determined by the class variable; Contaminant. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Contaminant-specific regression parameters for calculating KOC can often be applied to chemically similar contaminants, with the caveat that soil organic matter concentrations and mineralogy are within the range of experimental conditions for which the regression was developed (Piwoni and Banerjee 1989; Ho et al. 2005). |
Slope of linear regression correlating log(octanol-water partition coefficient) to carbon normalized sorption coefficient ?Comment:This variable is a constant determined by the class variable; Contaminant. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Contaminant-specific regression parameters for calculating KOC can often be applied to chemically similar contaminants, with the caveat that soil organic matter concentrations and mineralogy are within the range of experimental conditions for which the regression was developed (Piwoni and Banerjee 1989; Ho et al. 2005). |
Solubility in water ?Comment:Constant determined by the class variable; Contaminant. Contaminant solubility values can be found in EPA’s Comptox library (https://comptox.epa.gov/#/). |
Carbon normalized sorption coefficient ?Comment:With the specified survey-based spatial estimates of soil organic carbon (humus), VELMA internally calculates the carbon normalized sorption coefficient, KOC. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Typically expressed as log KOC. |
Gram solubility coefficient ?Comment:VELMA calculates a gramSolubilityCoefficent value “behind the scenes” as: gramSolubilityCoefficient = molarMass * molSolubilityCoefficient, with units, g/L = g/mol * mol/L |
Soil-water partition coefficient | Chemical transfer amount | |
Predictor-Intermediate-Response
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Predictor |
Predictor |
Predictor |
Predictor |
Predictor |
Predictor |
Predictor |
Predictor |
Predictor |
Predictor |
Predictor |
Predictor |
Intermediate (Computed) Variable |
Intermediate (Computed) Variable |
Intermediate (Computed) Variable |
Response |
Predictor Variable Type
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Time- or Space-varying Variable |
Time- or Space-varying Variable |
Time- or Space-varying Variable |
Time- or Space-varying Variable |
Time- or Space-varying Variable |
Constant or Parameter | Constant or Parameter | Constant or Parameter | Constant or Parameter | Constant or Parameter | Constant or Parameter | Constant or Parameter | Not applicable | Not applicable | Not applicable | Not applicable |
Response Variable Type
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Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable |
Computed Variable |
Data Source/Type
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Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable |
Variable Classification Hierarchy
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4. Human-Produced Stressor or Enhancer of Ecosystem Goods and Services Production |
4. Human-Produced Stressor or Enhancer of Ecosystem Goods and Services Production |
5. Ecosystem Attributes and Potential Supply of Ecosystem Goods and Services |
5. Ecosystem Attributes and Potential Supply of Ecosystem Goods and Services |
5. Ecosystem Attributes and Potential Supply of Ecosystem Goods and Services |
4. Human-Produced Stressor or Enhancer of Ecosystem Goods and Services Production |
5. Ecosystem Attributes and Potential Supply of Ecosystem Goods and Services |
4. Human-Produced Stressor or Enhancer of Ecosystem Goods and Services Production |
4. Human-Produced Stressor or Enhancer of Ecosystem Goods and Services Production |
4. Human-Produced Stressor or Enhancer of Ecosystem Goods and Services Production |
4. Human-Produced Stressor or Enhancer of Ecosystem Goods and Services Production |
4. Human-Produced Stressor or Enhancer of Ecosystem Goods and Services Production |
5. Ecosystem Attributes and Potential Supply of Ecosystem Goods and Services |
4. Human-Produced Stressor or Enhancer of Ecosystem Goods and Services Production |
5. Ecosystem Attributes and Potential Supply of Ecosystem Goods and Services |
4. Human-Produced Stressor or Enhancer of Ecosystem Goods and Services Production |
--Human-caused release, presence or characteristics of polluting substances |
--Human-caused release, presence or characteristics of polluting substances |
--Physical/chemical characteristics of nonliving ecosystem components |
--Chemical (C, N, P, sediment/particulate) characteristics of ecosystem components |
--Physical/chemical characteristics of nonliving ecosystem components |
--Human-caused release, presence or characteristics of polluting substances |
--Biological characteristics, processes or requirements of living ecosystem components |
--Human-caused release, presence or characteristics of polluting substances |
--Human-caused release, presence or characteristics of polluting substances |
--Human-caused release, presence or characteristics of polluting substances |
--Human-caused release, presence or characteristics of polluting substances |
--Human-caused release, presence or characteristics of polluting substances |
--Physical/chemical characteristics of nonliving ecosystem components |
--Human-caused release, presence or characteristics of polluting substances |
--Physical/chemical characteristics of nonliving ecosystem components |
--Human-caused release, presence or characteristics of polluting substances |
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----Other, multiple, unspecified or unclear |
----Other, multiple, unspecified or unclear |
----Physical/chemical characteristics of soils, substrates, rocks |
----Carbon-related characteristics of ecosystem components |
----Physical/chemical characteristics of water |
----Other, multiple, unspecified or unclear |
----Biological characteristics, processes or requirements of ecological communities |
----Other, multiple, unspecified or unclear |
----Other, multiple, unspecified or unclear |
----Other, multiple, unspecified or unclear |
----Other, multiple, unspecified or unclear |
----Other, multiple, unspecified or unclear |
----Physical/chemical characteristics of soils, substrates, rocks |
----Other, multiple, unspecified or unclear |
----Physical/chemical characteristics of soils, substrates, rocks |
----Other, multiple, unspecified or unclear |
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------Soil hydrologic characteristics |
------Carbon presence (in terrestrial or aquatic ecosystem components) |
------Other, multiple, unspecified or unclear |
------Soil communities |
------Other, multiple, unspecified or unclear |
------Soil contaminants |
Contaminant ?Comment:Class variable |
Contaminant concentration |
Soil moisture (layer 1,2,3,4) ?Comment:Computed as part of the VELMA hydro model. |
Soil organic carbon (layer 1,2,3,4) ?Comment:In VELMA, users specify initial humus (soil organic matter) values (g C/m2) according to soil survey or other data, for example, NRCS soil survey map data. VELMA then calculates initial foc values and subsequent daily changes in foc in response to environmental and management drivers. VELMA calculates foc per soil layer per grid cell per day. |
Water flow ?Comment:Derived as output from the VELMA hydro model. |
Decay rate (maximum) ?Comment:Constant value determined by the class variable; Contaminant. The maximum daily decay rate constant (fraction per day) of a specified contaminant. The Comptox library (https://comptox.epa.gov/#/) lists the half-life for most organic contaminants, from which the daily maximum decay rate constant can be calculated and specified for this parameter. Users can enter the specified half-life value into an online calculator to calculate the decay constant. For example, see https://www.calculator.net/half-life-calculator.html?type=2&chalflife=4&cmeanlifetime=&cdecayconstant=&x=35&y=16. Note that decomposed contaminant amounts are not tracked by the simulation and not reported in its results. This is because contaminants almost always make up an insignificant fraction of the total amount of organic matter within soils. |
Microbial efficiency of decomposition ?Comment:Constant value determined by the class variable; Contaminant. The unitless microbial efficiency (range [0.0, 1.0]) of decomposition of organic contaminants in soil, that is, the ratio of carbon assimilated/total carbon consumed, whereby the difference is that respired as carbon dioxide. Typical microbial efficiencies range from 0.45 to 0.55. |
Molar mass ?Comment:Constant determined by the class variable: Contaminant. Comptox provides the molecular weight for all contaminants in its library. Users need to enter this so that VELMA can calculate solubility. |
Octanol-water partition coefficient ?Comment:Kow (log10) is the experimentally determined ratio of a contaminant's concentration in the octanol (C8H17OH) phase of a two-phase octanol-water system. Kow is a standard indicator of a contaminant’s affinity for adsorption by organic matter. Higher KOW values indicate strongly sorbed, less mobile (hydrophobic) chemicals. User enters KOW value into VELMA based on EPA Comptox website, https://comptox.epa.gov/dashboard. Note that Comptox expresses KOW as KP, a confusing use of terminology. This variable is a constant determined by the class variable; Contaminant. |
Slope intercept of linear regression correlating log(octanol-water partition coefficient) to carbon normalized sorption coefficient ?Comment:This variable is a constant determined by the class variable; Contaminant. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Contaminant-specific regression parameters for calculating KOC can often be applied to chemically similar contaminants, with the caveat that soil organic matter concentrations and mineralogy are within the range of experimental conditions for which the regression was developed (Piwoni and Banerjee 1989; Ho et al. 2005). |
Slope of linear regression correlating log(octanol-water partition coefficient) to carbon normalized sorption coefficient ?Comment:This variable is a constant determined by the class variable; Contaminant. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Contaminant-specific regression parameters for calculating KOC can often be applied to chemically similar contaminants, with the caveat that soil organic matter concentrations and mineralogy are within the range of experimental conditions for which the regression was developed (Piwoni and Banerjee 1989; Ho et al. 2005). |
Solubility in water ?Comment:Constant determined by the class variable; Contaminant. Contaminant solubility values can be found in EPA’s Comptox library (https://comptox.epa.gov/#/). |
Carbon normalized sorption coefficient ?Comment:With the specified survey-based spatial estimates of soil organic carbon (humus), VELMA internally calculates the carbon normalized sorption coefficient, KOC. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Typically expressed as log KOC. |
Gram solubility coefficient ?Comment:VELMA calculates a gramSolubilityCoefficent value “behind the scenes” as: gramSolubilityCoefficient = molarMass * molSolubilityCoefficient, with units, g/L = g/mol * mol/L |
Soil-water partition coefficient | Chemical transfer amount | |
Spatial Extent Area
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Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not applicable | Not applicable | Not applicable | Not applicable |
Spatially Distributed?
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Yes | Yes | Yes | Yes | Yes | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Yes | Yes | Yes | Yes |
Observations Spatially Patterned?
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Yes | Yes | Yes | Yes | Yes | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Yes | Yes | Yes | Yes |
Spatial Grain Type
variable.detail.spGrainTypeHelp
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area, for pixel or radial feature | volume, for 3-D feature | area, for pixel or radial feature | area, for pixel or radial feature | area, for pixel or radial feature | Not recorded for Constant or Paarameter Variables | Not recorded for Constant or Paarameter Variables | Not recorded for Constant or Paarameter Variables | Not recorded for Constant or Paarameter Variables | Not recorded for Constant or Paarameter Variables | Not recorded for Constant or Paarameter Variables | Not recorded for Constant or Paarameter Variables | area, for pixel or radial feature | area, for pixel or radial feature | area, for pixel or radial feature | area, for pixel or radial feature |
Spatial Grain Size
variable.detail.spGrainSizeHelp
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user defined | user defined | user defined | user defined | user defined | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | user defined | user defined | user defined | user defined |
Spatial Density
variable.detail.spDensityHelp
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Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not applicable | Not applicable | Not applicable | Not applicable |
EnviroAtlas URL
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Contaminant ?Comment:Class variable |
Contaminant concentration |
Soil moisture (layer 1,2,3,4) ?Comment:Computed as part of the VELMA hydro model. |
Soil organic carbon (layer 1,2,3,4) ?Comment:In VELMA, users specify initial humus (soil organic matter) values (g C/m2) according to soil survey or other data, for example, NRCS soil survey map data. VELMA then calculates initial foc values and subsequent daily changes in foc in response to environmental and management drivers. VELMA calculates foc per soil layer per grid cell per day. |
Water flow ?Comment:Derived as output from the VELMA hydro model. |
Decay rate (maximum) ?Comment:Constant value determined by the class variable; Contaminant. The maximum daily decay rate constant (fraction per day) of a specified contaminant. The Comptox library (https://comptox.epa.gov/#/) lists the half-life for most organic contaminants, from which the daily maximum decay rate constant can be calculated and specified for this parameter. Users can enter the specified half-life value into an online calculator to calculate the decay constant. For example, see https://www.calculator.net/half-life-calculator.html?type=2&chalflife=4&cmeanlifetime=&cdecayconstant=&x=35&y=16. Note that decomposed contaminant amounts are not tracked by the simulation and not reported in its results. This is because contaminants almost always make up an insignificant fraction of the total amount of organic matter within soils. |
Microbial efficiency of decomposition ?Comment:Constant value determined by the class variable; Contaminant. The unitless microbial efficiency (range [0.0, 1.0]) of decomposition of organic contaminants in soil, that is, the ratio of carbon assimilated/total carbon consumed, whereby the difference is that respired as carbon dioxide. Typical microbial efficiencies range from 0.45 to 0.55. |
Molar mass ?Comment:Constant determined by the class variable: Contaminant. Comptox provides the molecular weight for all contaminants in its library. Users need to enter this so that VELMA can calculate solubility. |
Octanol-water partition coefficient ?Comment:Kow (log10) is the experimentally determined ratio of a contaminant's concentration in the octanol (C8H17OH) phase of a two-phase octanol-water system. Kow is a standard indicator of a contaminant’s affinity for adsorption by organic matter. Higher KOW values indicate strongly sorbed, less mobile (hydrophobic) chemicals. User enters KOW value into VELMA based on EPA Comptox website, https://comptox.epa.gov/dashboard. Note that Comptox expresses KOW as KP, a confusing use of terminology. This variable is a constant determined by the class variable; Contaminant. |
Slope intercept of linear regression correlating log(octanol-water partition coefficient) to carbon normalized sorption coefficient ?Comment:This variable is a constant determined by the class variable; Contaminant. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Contaminant-specific regression parameters for calculating KOC can often be applied to chemically similar contaminants, with the caveat that soil organic matter concentrations and mineralogy are within the range of experimental conditions for which the regression was developed (Piwoni and Banerjee 1989; Ho et al. 2005). |
Slope of linear regression correlating log(octanol-water partition coefficient) to carbon normalized sorption coefficient ?Comment:This variable is a constant determined by the class variable; Contaminant. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Contaminant-specific regression parameters for calculating KOC can often be applied to chemically similar contaminants, with the caveat that soil organic matter concentrations and mineralogy are within the range of experimental conditions for which the regression was developed (Piwoni and Banerjee 1989; Ho et al. 2005). |
Solubility in water ?Comment:Constant determined by the class variable; Contaminant. Contaminant solubility values can be found in EPA’s Comptox library (https://comptox.epa.gov/#/). |
Carbon normalized sorption coefficient ?Comment:With the specified survey-based spatial estimates of soil organic carbon (humus), VELMA internally calculates the carbon normalized sorption coefficient, KOC. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Typically expressed as log KOC. |
Gram solubility coefficient ?Comment:VELMA calculates a gramSolubilityCoefficent value “behind the scenes” as: gramSolubilityCoefficient = molarMass * molSolubilityCoefficient, with units, g/L = g/mol * mol/L |
Soil-water partition coefficient | Chemical transfer amount | |
Temporal Extent
variable.detail.tempExtentHelp
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Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not applicable | Not applicable | Not applicable | Not applicable |
Temporally Distributed?
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Yes | Yes | Yes | Yes | Yes | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Yes | Yes | Yes | Yes |
Regular Temporal Grain?
variable.detail.regularTempGrainHelp
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Yes | Yes | Yes | Yes | Yes | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Yes | Yes | Yes | Yes |
Temporal Grain Size Value
variable.detail.tempGrainSizeValHelp
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1 | 1 | 1 | 1 | 1 | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | 1 | 1 | 1 | 1 |
Temporal Grain Size Units
variable.detail.tempGrainSizeUnitHelp
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Day | Day | Day | Day | Day | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Day | Day | Day | Day |
Temporal Density
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Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not applicable | Not applicable | Not applicable | Not applicable |
Contaminant ?Comment:Class variable |
Contaminant concentration |
Soil moisture (layer 1,2,3,4) ?Comment:Computed as part of the VELMA hydro model. |
Soil organic carbon (layer 1,2,3,4) ?Comment:In VELMA, users specify initial humus (soil organic matter) values (g C/m2) according to soil survey or other data, for example, NRCS soil survey map data. VELMA then calculates initial foc values and subsequent daily changes in foc in response to environmental and management drivers. VELMA calculates foc per soil layer per grid cell per day. |
Water flow ?Comment:Derived as output from the VELMA hydro model. |
Decay rate (maximum) ?Comment:Constant value determined by the class variable; Contaminant. The maximum daily decay rate constant (fraction per day) of a specified contaminant. The Comptox library (https://comptox.epa.gov/#/) lists the half-life for most organic contaminants, from which the daily maximum decay rate constant can be calculated and specified for this parameter. Users can enter the specified half-life value into an online calculator to calculate the decay constant. For example, see https://www.calculator.net/half-life-calculator.html?type=2&chalflife=4&cmeanlifetime=&cdecayconstant=&x=35&y=16. Note that decomposed contaminant amounts are not tracked by the simulation and not reported in its results. This is because contaminants almost always make up an insignificant fraction of the total amount of organic matter within soils. |
Microbial efficiency of decomposition ?Comment:Constant value determined by the class variable; Contaminant. The unitless microbial efficiency (range [0.0, 1.0]) of decomposition of organic contaminants in soil, that is, the ratio of carbon assimilated/total carbon consumed, whereby the difference is that respired as carbon dioxide. Typical microbial efficiencies range from 0.45 to 0.55. |
Molar mass ?Comment:Constant determined by the class variable: Contaminant. Comptox provides the molecular weight for all contaminants in its library. Users need to enter this so that VELMA can calculate solubility. |
Octanol-water partition coefficient ?Comment:Kow (log10) is the experimentally determined ratio of a contaminant's concentration in the octanol (C8H17OH) phase of a two-phase octanol-water system. Kow is a standard indicator of a contaminant’s affinity for adsorption by organic matter. Higher KOW values indicate strongly sorbed, less mobile (hydrophobic) chemicals. User enters KOW value into VELMA based on EPA Comptox website, https://comptox.epa.gov/dashboard. Note that Comptox expresses KOW as KP, a confusing use of terminology. This variable is a constant determined by the class variable; Contaminant. |
Slope intercept of linear regression correlating log(octanol-water partition coefficient) to carbon normalized sorption coefficient ?Comment:This variable is a constant determined by the class variable; Contaminant. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Contaminant-specific regression parameters for calculating KOC can often be applied to chemically similar contaminants, with the caveat that soil organic matter concentrations and mineralogy are within the range of experimental conditions for which the regression was developed (Piwoni and Banerjee 1989; Ho et al. 2005). |
Slope of linear regression correlating log(octanol-water partition coefficient) to carbon normalized sorption coefficient ?Comment:This variable is a constant determined by the class variable; Contaminant. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Contaminant-specific regression parameters for calculating KOC can often be applied to chemically similar contaminants, with the caveat that soil organic matter concentrations and mineralogy are within the range of experimental conditions for which the regression was developed (Piwoni and Banerjee 1989; Ho et al. 2005). |
Solubility in water ?Comment:Constant determined by the class variable; Contaminant. Contaminant solubility values can be found in EPA’s Comptox library (https://comptox.epa.gov/#/). |
Carbon normalized sorption coefficient ?Comment:With the specified survey-based spatial estimates of soil organic carbon (humus), VELMA internally calculates the carbon normalized sorption coefficient, KOC. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Typically expressed as log KOC. |
Gram solubility coefficient ?Comment:VELMA calculates a gramSolubilityCoefficent value “behind the scenes” as: gramSolubilityCoefficient = molarMass * molSolubilityCoefficient, with units, g/L = g/mol * mol/L |
Soil-water partition coefficient | Chemical transfer amount | |
Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | |
Min Value
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Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable |
Max Value
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Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable |
Other Value Type
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Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable |
Other Value
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Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not applicable |
Contaminant ?Comment:Class variable |
Contaminant concentration |
Soil moisture (layer 1,2,3,4) ?Comment:Computed as part of the VELMA hydro model. |
Soil organic carbon (layer 1,2,3,4) ?Comment:In VELMA, users specify initial humus (soil organic matter) values (g C/m2) according to soil survey or other data, for example, NRCS soil survey map data. VELMA then calculates initial foc values and subsequent daily changes in foc in response to environmental and management drivers. VELMA calculates foc per soil layer per grid cell per day. |
Water flow ?Comment:Derived as output from the VELMA hydro model. |
Decay rate (maximum) ?Comment:Constant value determined by the class variable; Contaminant. The maximum daily decay rate constant (fraction per day) of a specified contaminant. The Comptox library (https://comptox.epa.gov/#/) lists the half-life for most organic contaminants, from which the daily maximum decay rate constant can be calculated and specified for this parameter. Users can enter the specified half-life value into an online calculator to calculate the decay constant. For example, see https://www.calculator.net/half-life-calculator.html?type=2&chalflife=4&cmeanlifetime=&cdecayconstant=&x=35&y=16. Note that decomposed contaminant amounts are not tracked by the simulation and not reported in its results. This is because contaminants almost always make up an insignificant fraction of the total amount of organic matter within soils. |
Microbial efficiency of decomposition ?Comment:Constant value determined by the class variable; Contaminant. The unitless microbial efficiency (range [0.0, 1.0]) of decomposition of organic contaminants in soil, that is, the ratio of carbon assimilated/total carbon consumed, whereby the difference is that respired as carbon dioxide. Typical microbial efficiencies range from 0.45 to 0.55. |
Molar mass ?Comment:Constant determined by the class variable: Contaminant. Comptox provides the molecular weight for all contaminants in its library. Users need to enter this so that VELMA can calculate solubility. |
Octanol-water partition coefficient ?Comment:Kow (log10) is the experimentally determined ratio of a contaminant's concentration in the octanol (C8H17OH) phase of a two-phase octanol-water system. Kow is a standard indicator of a contaminant’s affinity for adsorption by organic matter. Higher KOW values indicate strongly sorbed, less mobile (hydrophobic) chemicals. User enters KOW value into VELMA based on EPA Comptox website, https://comptox.epa.gov/dashboard. Note that Comptox expresses KOW as KP, a confusing use of terminology. This variable is a constant determined by the class variable; Contaminant. |
Slope intercept of linear regression correlating log(octanol-water partition coefficient) to carbon normalized sorption coefficient ?Comment:This variable is a constant determined by the class variable; Contaminant. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Contaminant-specific regression parameters for calculating KOC can often be applied to chemically similar contaminants, with the caveat that soil organic matter concentrations and mineralogy are within the range of experimental conditions for which the regression was developed (Piwoni and Banerjee 1989; Ho et al. 2005). |
Slope of linear regression correlating log(octanol-water partition coefficient) to carbon normalized sorption coefficient ?Comment:This variable is a constant determined by the class variable; Contaminant. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Contaminant-specific regression parameters for calculating KOC can often be applied to chemically similar contaminants, with the caveat that soil organic matter concentrations and mineralogy are within the range of experimental conditions for which the regression was developed (Piwoni and Banerjee 1989; Ho et al. 2005). |
Solubility in water ?Comment:Constant determined by the class variable; Contaminant. Contaminant solubility values can be found in EPA’s Comptox library (https://comptox.epa.gov/#/). |
Carbon normalized sorption coefficient ?Comment:With the specified survey-based spatial estimates of soil organic carbon (humus), VELMA internally calculates the carbon normalized sorption coefficient, KOC. This requires user input of published empirical regression parameters describing the relationship between KOW and KOC. Typically expressed as log KOC. |
Gram solubility coefficient ?Comment:VELMA calculates a gramSolubilityCoefficent value “behind the scenes” as: gramSolubilityCoefficient = molarMass * molSolubilityCoefficient, with units, g/L = g/mol * mol/L |
Soil-water partition coefficient | Chemical transfer amount | |
Variability Expression Given?
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Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not applicable | Not applicable | Not applicable | Not applicable |
Variability Metric
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None | None | None | None | None | None | None | None | None | None | None | None | None | None | None | None |
Variability Value
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None | None | None | None | None | None | None | None | None | None | None | None | None | None | None | None |
Variability Units
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None | None | None | None | None | None | None | None | None | None | None | None | None | None | None | None |
Resampling Used?
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Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not applicable | Not applicable | Not applicable | Not applicable |
Variability Expression Used in Modeling?
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Not applicable | Not applicable | Not applicable | Not applicable | Not applicable | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not recorded for Constant or Parameter Variables | Not applicable | Not applicable | Not applicable | Not applicable |
Chemical transfer amount | |
Variable ID
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22099 |
Validated?
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Not applicable |
Validation Approach (within, between, etc.)
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None |
Validation Quality (Qual/Quant)
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None |
Validation Method (Stat/Deviance)
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None |
Validation Metric
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None |
Validation Value
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None |
Validation Units
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None |
Use of Measured Response Data
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None |