Fate and Behavior of Chemicals

Question 1

Factors affecting movement of chemicals

Answer 1

toxicity
physiochemical properties
persistence
mobility

Question 2

Physical parameters affecting fate and behavior of chemicals

Answer 2

molecular weight
melting/boiling point
solubility in water
volatility
n-octanol/water partition coefficient

Question 3

Tests to determine fate and behavior of chemicals

Answer 3

hydrolysis as a function of pH
Adsorption/Desorption
Photolysis studies
Degradation in natural water/sediment

Question 4

Chemical contaminants

Answer 4

TPH total petroleum hydrocarbons
organochlorines
DDT

Question 5

Most significant degradation Process

Answer 5

microbial degradation

photodegradation

Question 6

Abiotic process enhancing the degradation process

Answer 6

elevated temperature
increased sunlight
aerobic conditions

Question 7

how to determine organic content

Answer 7

combustion techniques

Question 8

OC content of mobile chemicals

Answer 8

less than 500

Question 9

mobility of negative ions

Answer 9

more mobile in silt/clay systems (negatively-charged clay repels negative ion)

Question 10

persistence

Answer 10

ability to resist breakdown

Question 11

n-Octanol/water partition coefficient

Answer 11

used to predict if a chemical is likely to bioaccumulate in plant and animal tissue

Question 12

n-octanol/water partition coefficient >3

Answer 12

chemical is more likely to concentrate in the food chain

Question 13

bioconcentration

Answer 13

compounds enter the organisms directly and concentrate in tissue

Question 14

bioaccumulation

Answer 14

uptake of residues through the food chain

Question 15

biomagnification

Answer 15

total process in which tissue concentrations of a lipophilic chemical increase through two or more trophic levels

Question 16

hydrolysis as a function of pH

Answer 16

chemicals are tested against several pH levels to assess its stability to different environmental conditions

Question 17

adsorption/desorption

Answer 17

chemicals that are strongly bound to soil or sediment will not be mobile except by a physical transportation and will not be available for uptake

test:
:test chemical added to different soil types
:amount of free and bound chemical is determined

Question 18

Factors affecting adsorption

Answer 18

particle size
type of soil
organic matter
cation exchange capacity
water solubility
octanol/water partition coefficient

Question 19

Photolysis studies

Answer 19

determine the stability of chemical in the presence of light

Question 20

degradation in natural water/sediment

Answer 20

test chemical is added to sediment plus water from river or stream