Models for Predicting Volatilization of Soil‐Incorporated Pesticides

Mayer, R.; Letey, J.; Farmer, W. J.

doi:10.2136/sssaj1974.03615995003800040015x

Cited by 50 publications

(17 citation statements)

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“…The environmental fate and transport of organic chemicals including volatilization and leaching losses has been used to explore the distribution of agricultural pesticides in soils (Mayer et al 1974, and Jury et al 1980). These models were primarily intended to simulate specific circumstances.…”

Section: Screening Modelmentioning

confidence: 99%

Environmental fate and transport of chemical signatures from buried landmines -- Screening model formulation and initial simulations

Phelan¹,

Webb²

1997

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The fate and transport of chemical signature molecules that emanate from buried landmines is strongly influenced by physical chemical properties and by environmental conditions of the specific chemical compounds. Published data have been evaluated as the input parameters that are used in the simulation of the fate and transpon processes. A one-dimensional model developed for screening agricultural pesticides was modified and used to simulate the appearance of a surface flux above a buried landmine, estimate the subsurface total concentration. and show the phase specific concentrations at the ground surface. The physical chemical properties of T N T cause a majority of the mass released to the soil system to be bound to the solid phase soil particles. The majority of the transport occurs in the liquid phase with diffusion and evaporation driven advection of soil water as the primary mechanisms for the flux to the ground surface. The simulations provided herein should only be used for initial conceptual designs of chemical pre-concentration subsystems or complete detection systems, The physical processes modeled required necessary simplifying assumptions to allow for analytical solutions. Emerging numerical simulation tools will soon be available that should provide more realistic estimates that can be used to predict the success of landmine chemical detection surveys based on knowledge of the chemical and soil properties, and environmental conditions where the mines are buried. Additional measurements of the chemical properties in soils are also needed before a fully predictive approach can be confidently applied.

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Section: Screening Modelmentioning

confidence: 99%

Environmental fate and transport of chemical signatures from buried landmines -- Screening model formulation and initial simulations

Phelan¹,

Webb²

1997

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“…volatilization of soil-incorporated organic chemicals ia controlled by their rate of movement away from the surface, their effective vapor pressure at the surface or within the soil, and their rate of movement through the soil to the vaporizing surface. Models developed for estimating volatilization rates are based on equations describing the rate of movement of the chemical to the surface by diffusion and/or by convection, and away from the surface through the air boundary layer by diffusion Mayer et al, 1974;Jury et al, 1980Jury et al, , 1983. Additionally, the proportion of the chemical in soil that will be lost by volatilization depends on the resistance of the chemical to degradation.…”

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confidence: 99%

Volatilization of Organic Chemicals from Soil as Related to Their Henry's Law Constants

et al. 1988

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Volatilization and air transport are the principal means for widespread dispersion of pesticides and other organic chemicals in the environment. The importance of volatilization in transport of pesticides from treated areas has been established by direct field measurements (Taylor, 1978; Glotfelty et al., 1984). Laboratory research established that the rate of volatilization from soil is controlled by rate of movement of the organic chemical to the soil surface by mass flow in water and by diffusion . The output from a pesticide screening model (Jury et al., 1984a) indicated that rate of movement to the soil surface relative to movement of the pesticide through the stagnant air boundary ,layer above the surface can also control volatilization and accumulation at the soil surface.Volatilization rate from a surface deposit depends only on the rate of movement of the chemical away from the evaporating surface and its vapor pressure. In contrast, . volatilization of soil-incorporated organic chemicals ia controlled by their rate of movement away from the surface, their effective vapor pressure at the surface or within the soil, and their rate of movement through the soil to the vaporizing surface. Models developed for estimating volatilization rates are based on equations describing the rate of movement of the chemical to the surface by diffusion and/or by convection, and away from the surface through the air boundary layer by diffusion Mayer et al., 1974;Jury et al., 1980Jury et al., , 1983. Additionally, the proportion of the chemical in soil that will be lost by volatilization depends on the resistance of the chemical to degradation.In a series of papers, Jury et al. (1983Jury et al. ( , 1984a, b, c) described and applied a model for assessing relative volatility, mobility, and persistance of pesticides and other trace organics in soil. The model allows the organica to be present in the soil in the adsorbed, solution, and

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“…b From Grover et al (1978). Vapor pressures of pesticides in soil are useful for estimating volatility from soil and are needed for predicting rates of vapor phase diffusion through soil (Ehlers et al 1969, Shearer et al 1973 and for predicting vaporization rates of pesticides from soil based on diffusion models (Mayer et al 1974). The apparatus and procedures described above for vapor pressure measurement by the gas saturation method can be adapted for measuring vapor pressures of pesticides in various soils.…”

Section: C) Resultsmentioning

confidence: 99%