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Appendix E: Chemical- and Site-Specific Factors That May Affect Contaminant Transport

Transport Mechanism Factors Affecting Transport
Chemical-specific considerations Site-specific considerations
Groundwater
Movement within and across aquifers and to surface water
  • Density (more or less dense than water)
  • Water solubility
  • KOC (organic carbon partition coefficient)
  • Site hydrogeology
  • Precipitation
  • Infiltration rate
  • Porosity
  • Hydraulic conductivity
  • Groundwater flow direction
  • Depth to aquifer
  • Groundwater/surface water recharge and discharge zones
  • Presence of other compounds
  • Soil type
  • Geochemistry of site soils and aquifers
  • Presence and condition of wells (well location, depth, and use; casing material and construction; pumping rate)
  • Conduits, sewers
Volatilization (to soil gas, ambient air, and indoor air)
  • Water solubility
  • Vapor pressure
  • Henry's Law Constant
  • Diffusivity
  • Depth to water table
  • Soil type and cover
  • Climatologic conditions
  • Contaminant concentrations
  • Properties of buildings
  • Porosity and permeability of soils and shallow geologic materials
Adsorption to soil or precipitation out of solution
  • Water solubility
  • KOW (octanol/water partition coefficient)
  • KOC
  • Presence of natural carbon compounds
  • Soil type, temperature, and chemistry
  • Presence of other compounds
Biologic uptake
  • KOW
  • Groundwater use for irrigation and livestock watering
Soil (Surface and Subsurface), Sediment, Sludge, Waste Materials (Site-specific factors for Waste Materials are at the conclusion of this table)
Runoff (soil erosion)
  • Water solubility
  • KOC
  • Presence of plants
  • Soil type and chemistry
  • Precipitation rate
  • Configuration of land and surface condition
Leaching
  • Water solubility
  • KOC
  • Soil type
  • Soil porosity and permeability
  • Soil chemistry (especially acid/base)
  • Cation exchange capacity
  • Organic carbon content
Volatilization
  • Vapor pressure
  • Henry's Law Constant
  • Physical properties of soil
  • Chemical properties of soil
  • Climatologic conditions
Biologic uptake
  • Bioconcentration factor
  • Bioavailability
  • Soil properties
  • Contaminant concentration
Surface Water
Overland flow (via natural drainage or man-made channels)
  • Water solubility
  • KOC
  • Precipitation (amount, frequency, duration)
  • Infiltration rate
  • Topography (especially gradients and sink holes)
  • Vegetative cover and land use
  • Soil/sediment type and chemistry
  • Use as water supply intake areas
  • Location, width, and depth of channel; velocity; dilution factors; direction of flow
  • Floodplains
  • Point and nonpoint source discharge areas
Volatilization
  • Water solubility
  • Vapor pressure
  • Henry's law constant
  • Climatic conditions
  • Surface area
  • Contaminant concentration
Hydrologic connection between surface water and groundwater
    • Density
  • Groundwater/surface water recharge and discharge
  • Stream bed permeability
  • Soil type and chemistry
  • Geology (especially Karst conditions)
Adsorption to soil particles and sedimentation (of suspended and precipitated particles)
  • Water solubility
  • KOW
  • KOC
  • Density
  • Particle size and density
  • Geochemistry of soils/sediments
  • Organic carbon content of soils/sediment
Biologic uptake
  • KOW
  • Bioconcentration factor
  • Chemical concentration
  • Presence of fish, plants, and other animals
Air
Aerosolization
  • Water solubility
  • Chemicals stored under pressure
Atmospheric deposition
  • Particle size
  • Rainfall/wind
Volatilization
  • Henry's law constant
  • Presence of open containers, exposed surfaces, or leaking equipment
Wind NA
  • Speed, direction, atmospheric stability
Biota
Bioaccumulation
  • KOW
  • Persistence/half-life
  • Presence of plants and animals
  • Consumption rate
Migration NA
  • Commercial activities (farming, aquaculture, livestock, dairies)
  • Sport activities (hunting, fishing)
  • Migratory species
Vapor sorption NA
  • Soil type
  • Plant species
Root uptake NA
  • Contaminant depth
  • Soil moisture
  • Plant species
Waste Materials (Site-Specific Factors only)
Surface water runoff NA
  • Waste type
  • Integrity of contaminant
  • Integrity of containers, impoundments, and other structures
  • Climatic conditions
Leaching
Groundwater movement
Volatilization

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Appendix F       List of Appendices


 
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