Lecture 5 Flashcards
Name 4 Factors Determining Movements & Distributions of Pollutants
- ) Polarity and Water Solubility
- ) Partition Coefficients
- )Vapor Pressure
- ) Molecular Stability & Recalcitrant Molecules
what are partition coefficients?
a measure of the difference in solubility of the compound in these two phases
(look at page 3!)
describe vapor pressure (2)
- Transition from liquid (or solid) to gaseous
* ↑Temperature = ↑Vapor pressure
what is Residence time? Give examples
how long does a chemical persist in an environment before being degraded by physical, chemical, or biological forces
ie: Weathering, hydrolysis, temperature changes, UV radiation, half-lives, metabolized
what does recalcitrant mean?
Of a substance that is degraded at an extremely slow rate if at all when released into the environment. Consequently, this type of material tends to accumulate in water, soil, and biota.
what are 2 different transport in water?
- directional currents
- density and temperature
describe transport in air
- Pollutants can be transported as gases or particles
- Relevant air currents operate up to 35 km above the earth’s surface
- Gases diffuse in the air
- Particles can precipitate in rain or snow
what are Models for Environmental Distribution of Chemicals?
Models that attempt to describe and predict distribution results
what does thermodynamic mean?
- when the pollutant is at equilibrium
- Closed systems; Kow
what does kinetic mean?
- movement through time
- Open systems
what is Fugacity?
- Describes the tendency of a pollutant to escape from one phase or compartment to another
- Equilibrium is when a chemical has the same fugacity in all phases
look at page 8 and 9 of lecture 5
yay the end of lecture 5:)
