Fate of Contaminants

Question 1

How to contaminant tend to migrate in the environment?

Answer 1

From high to low concentration

Question 2

Point source

Answer 2

Toxicant come from a direct source
- industrial waste
- sewage discharge
- spills

Question 3

Non-point source discharge

Answer 3

Toxicant comes from an indirect source
- agricultural and urban runoff

Question 4

Exxon Valez

Answer 4

Accidental Spill
- 2-butoxyethanol used as surfactant
- elevated PAH still detected on beaches

Question 5

BP Oil disaster

Answer 5

Accidental spill
- large quantity of gaseous hydrocarbons
- high levels of PAH
- burn events leading to production of dioxins/furans (and PAHs)

Question 6

East Palestine Ohio

Answer 6

Accidental train derailment
- 2-butoxyethanol
- vinyl chloride (PVC)
- controlled burns released phosgene and HCl

Question 7

Chernobyl

Answer 7

Nuclear accident
- Iodine-131 (HL 8 days), caesium-137 (HL 30 yr) released in atmosphere and soil

Question 8

Alpha radiation

Answer 8

239-Plutonium, too big to enter skin, but can be ingested or breathed in

Question 9

Beta radiation

Answer 9

137-Caesium and 90-Strontium, limited range

Question 10

What does radiation cause

Answer 10

leads to break in DNA followed by incorrect DNA repair leading to mutation/cancer

Question 11

Times Beach

Answer 11

-Company making agent orange hired company which hired some guy to dispose of hit
- he mixed it with oil and spread it to control dust in fields
- spread it over dirt roads all over town
- river flooding, spreading dioxins, town evacuated

Question 12

Deliberate application

Answer 12

• fertilizers or pesticides directly applied to the land
• urban water or run off
• aerosols or gases
• combustion or incineration

Question 13

Volatile organic compounds (VOCs)

Answer 13

ex. paint

Question 14

Groundwater

Answer 14

Landfill - contaminants can leach into the soils/groundwater
-Pesticides, fertilizers, settle and adsorb to the land
- storage tanks leak

Question 15

Kow

Answer 15

measure of hte behaviour of a chemical between water and an organic solvent

Question 16

Kow depends on:

Answer 16

1. water solubility
2. hydophobility
3. vapour pressure
4. environmental half life

Question 17

Determining Kow:

Answer 17

• take equal vol water and octanol
• add chemical, mix well
• measure the concentration of chemical in water & octanol

Question 18

Kow =

Answer 18

concentration of chemical in octanol/concetration of chemical in water

Question 19

High Kow indicates:

Answer 19

Lipophilic/hydrophobic

Question 20

Low Kow indicates:

Answer 20

Lipophobic/hydrophilic

Question 21

Vapour pressure

Answer 21

ratio between vapour pressure to water solubility is the Henry’s law (H) coefficent

Question 22

H =

Answer 22

concentration of chemical in air/concentration of chemical in water

Question 23

Factors that affect persistence

Answer 23

• double bonds or oxygen containing functional groups - makes organics more susceptible to attack,
  - break down by enzymes and light (less persistent)
• replacement of hydrogen by halogens
  - protects organic compounds (more persistent)