List 5 considerations when applying rem techniques
Location, matrix, redox condition, properties of contaminants, and science
Define bioavailibitly
Amount of chem actually available to the tissues of living organisms after exposure. Adsorption/sorption of contam on soil solids reduces availability to receptors.
Decontamination vs remediation
Decontamination addresses substances on a site in order to minimize adverse affects on enviro now and into future. Concerned with specific area of a site. Where as, remediation applies to the whole site but same goal of minimizing adverse impacts.
List 3 considerations for biorem
- Type of contam
- Catabolic potential of microorgs ie does the microbe have the relevant functional gene to pair with contam
- Environmental conditions
Define biodegradation
Destruction or mineralization of materials by microorganisms of soils/sediments/water ect. Conversion of complex substances into simple products.
Define biotransformation
Modification (not destruction) of a molecule by a living organism. Applies to metals. May transform a substance from soluble and toxic to toxic and finally to solid particle and gas.
Briefly dfn risk, risk assessment, risk mgmt
Risk: measure of hazard to health and probability of exposure
Assessment: Characterization of adverse effects of exposure to harmful substances through routes of exposure
Mgmt: Application of control measures (rem/exposure control) to eliminate/reduce risk
Define contaminated site
Contamination of soil, sediments, ground/surface water above the bench criteria and/or pose a threat to human and enviro health
List steps of contaminated site mgmt (AB)
- Known release or suspected release
- Phase 1
- Phase 2
- Define rem/implement RAP
- Tier 1, Tier 2, remediation and rem certificate
OR exposure control, risk mgmt, and ongoing monitoring
List four processes w/in the soil-contaminant interaction
Volatization, adsorption, biodegradation/biotransformation, and migration/transport
What 3 factors control biodeg of organic contam in soil
- Properties of organic contaminants
- Properties of soil system
- Ability of microbes for biodegradation
List three properties of organic contaminants
- Hydrophobic/hydrophilic character
- Vapor pressure
- Henry’s Law
Why do clay particles have reactive surfaces? (Think physical aspects of clay)
- High surface area offers more interaction with contams hence high adsorption potential
- High volume of pore space but reduced water flow due to small pores
- Swelling cracking create erosion channels ^ movement of contam
- Pos or neg charge of clay plays role in adsorption and exchange reactions.
List a few points about phyllosilicates (2:1)
- Generally neg charge due to isomorphic substitution
- Charge is permanent > hold cations > contributes to cation exchange capacity
- Phyllo adsorb metal cations
What makes kaolinite unique
- 1:1 structure
- Has permanent charge and pH dependent charges due to exposed hydroxides
- Changes in soil pH determine charges (+/-) on kaolinite through protonation/deprotonation
What is PZC
Point zero charge: pH at which net charge on material is zero
List a few points about oxide minerals and the two categories
- Aluminum oxides and iron oxides
- Oxides possess pH dependent charges due to hydroxides (protonation/deprotonation)
- Have pos charge at neutral pH due to higher PZC
- Hold metal oxyanions
List a few points about soil organic matter
- Posses pH dependent charges due to functional groups
- Change in soil pH through protonation/deprotonation
- Can hold cations and oxyanions
- Strongly adsorbs organic compounds
List 4 functional groups of SOM
- Carboxyl COOH
- Hydroxyl OH
- Amine NH
- Carbonyl C=O
Langmuir Eqn
- Describes adsorption of a solute on homogeneous surfaces
- Monolayer of adsorbed solute on surface
- Max adsorption achieved as monolayer becomes saturated by absorbate
Linear partition theory
- Sorption of nonpolar, hydrophobic organic compounds
- Char by linear or constant partition of hydrophobic sorption
- Org compounds will dissolve into SOM
What is Kow related to?
- Water solubility
- Sediment/soil adsorption
- Bioconcentration factor for aquatic life
