INTERACTIONS AND TRANSPORT Paul D. Capel, U.S. Geological Survey - - PowerPoint PPT Presentation

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Sep 30, 2023 247 likes •536 views

CLEAN WATER SUMMIT 2012 Green Infrastructure for Clean Water: The Essential Role of Soil CHEMICALS AND SOILS: INTERACTIONS AND TRANSPORT Paul D. Capel, U.S. Geological Survey WATER TRANPORT MANY CHEMICALS ! Fe +2 Fe +3 Cl - Zn +2 As +3 THE

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CLEAN WATER SUMMIT 2012 Green Infrastructure for Clean Water: The Essential Role of Soil

CHEMICALS AND SOILS: INTERACTIONS AND TRANSPORT

Paul D. Capel, U.S. Geological Survey

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WATER TRANPORT

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Fe+3 Cl- Zn+2 As+3 Fe+2

MANY CHEMICALS !

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THE “OLIVE THEORY” OF THE BEHAVIOR AND TRANSPORT OF CHEMICALS IN THE ENVIRONMENT Properties of the Environment

temperature
pH
salinity
kind of solids
amount of solids
amount of water
bacteria

.... Properties of the Chemical

water solubility
vapor pressure
Henry’s Law
acid / base
charge
size
reactivity

.....

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One Meter Deep Profiles of Various Minnesota Soils

SOILS ARE COMPOSED OF SOLIDS, AIR, AND WATER

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SOIL AGGREGATE

Mineral surface Roots Organic matter Pore

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Mineral surfaces Organic matter Air Water Chemical

SOIL-CHEMICAL INTERACTIONS

Photo: Karnok, 2003, Australian Turfgrass Management

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CHEMICAL CONTROLS ON SOIL-CHEMICAL INTERACTIONS

Water Solubility (S) Charge and reactivity Henry’s Law constant (~V/S) Vapor pressure (V)

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EQUATIONS – FOR THE ENGINNERS !

Solids-Water Distribution concentration of the chemical on solid (mg/kg) concentration of the chemical in water (mg/L) Air-Water Distribution concentration of the chemical in air (mg/m3) concentration of the chemical in water (mg/L)

Kd = Kaw =

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Capel et al., USGS, in review

EQUILIBRIUM DISTRIBUTIONS OF CHEMICALS AMOUNG SOLIDS, WATER, AND AIR

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Capel et al., USGS, in review

EQUILIBRIUM DISTRIBUTIONS OF CHEMICALS AMOUNG SOLIDS, WATER, AND AIR

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CHEMICALS ALSO UNDERGO TRANSFORMATIONS

Microorganism-induced Plant-induced Chemical-induced Light-induced “Half-life”: time for 50% to be transformed “Environmental lifetime” of a chemical = 6 half-lives (~1% remains)

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Capel et al., USGS, in review

CHEMICAL LIFETIME AND DISTRIBUTION

Legacy Chemicals

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EXAMPLES: GLYPHOSATE and VOCs

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GLYPHOSATE Competes with phosphorous for solid interactions Strongly interacts with mineral surfaces (Ca, Mg, Fe, Al) Weakly interacts with organic matter Kd ranges from 1 to > 1000 L/kg (depending on soil)

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GLYPHOSATE IN AN AGRICULTURAL STREAM

 Transported largely in runoff associated with soil particles

Coupe et al., 2012, Pest. Manage.

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GLYPHOSATE IN AN AGRICULTURAL DRAIN

 Quickly transported through soil after rain after application ???

Velkoverh and Capel, in review

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GLYPHOSATE: COMPLEX INTERATIONS WITH SOIL

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EXTENT OF GLYPHOSATE ASSOCIATED WITH SOLIDS

Streams Soil Runoff

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VOLATILE ORGANIC CHEMICALS (VOCs)

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VOCs IN PRINCIPAL AQUIFERs – DETECTION FREQUENCY

Zogorski et al., USGS Circular 1292

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VOCs IN PRINCIPAL AQUIFERs – CONCENTRATIONS

Zogorski et al., USGS Circular 1292

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Pankow et al., 1997, ES&T

TRANSPORT OF VOCs THROUGH THE SOIL TO GW

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Capel et al., USGS, in review

CHEMICAL LIFETIME AND DISTRIBUTION

Legacy Chemicals

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URBAN AND AGRICULTURAL AREAS Similarities: soil foundation, same transport processes water and solids, sometime similar engineering, ... Differences: permanent vegetation, tillage, exposed soil, ...

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