Lecture 3

Question 1

Ecotoxicology = ___________ + ____________

Answer 1

Ecology + Toxicology

Question 2

Define ecotoxicology:

Answer 2

Branch of toxicology concerned with the study of toxic effects, caused by natural and synthetic pollutants, to the constituents of ecosystems - animals (including humans), vegetable, microbial - in an integrated context

Question 3

The study of harmful effects of chemicals on ecosystems =

Answer 3

ecotoxicology

Question 4

Substance present in greater than natural concentration as a result of human activity =

Answer 4

contaminant

Question 5

Substance that occurs in the environment at least in part of human activity and which has a deleterious effect on living organisms =

Answer 5

pollutant

Question 6

Foreign chemical not produced in nature and not considered a constitutive component of a biological system =

Answer 6

xenobiotic

Question 7

Processes at one level take their mechanisms from the level below and find their consequences to the level above =

Answer 7

SCALES

Question 8

SETAC:

Answer 8

Society of environmental toxicology and chemistry

Question 9

Give me some characteristics of legacy pollutants - ORGANICS

Answer 9

• Contain carbon and more than 1 C-H covalent bond
• C-H = low polarity, low water solubility
• Behaviour (fate/toxicity) dependent upon structure (size, shape, functional groups)
• Natural or anthropogenic sources

Question 10

PAHs =

Answer 10

Polycyclic Aromatic Hydrocarbons (PAHs)

Question 11

T or F: PAHs are natural chemicals that are present every time you burn something

Answer 11

T

Question 12

Describe some characteristics of PAHs:

Answer 12

• 2+ fused benzene rings
• decomposition, pyrolysis reactions
• exist as complex mixtures
• persistent (years to decades)
• natural and anthropogenic sources but mainly anthropogenic

Question 13

Benzo(a)pyrene is a ____

Answer 13

PAHs

Question 14

Name 3 natural sources of PAHs

Answer 14

1) Wildfires
2) Oil underground
3) Volcanoes

Question 15

Name 3 anthropogenic sources of PAHs

Answer 15

1) Burning trash
2) Deforestation (burn wood)
3) War, terrorism, vandalism, theft

Question 16

PAH fate: with an increased molecular weight the following occurs:

_________________ volatilization
_______________ bioaccumulation
________________ absorption to particles
_________________ solubility (increased Kow)
________________ environmental persistence

Answer 16

• decreased
• increased
• increased
• decreased
• increased

Question 17

What are some biological fates of PAHs in land (3)

Answer 17

• degradation by soil microbes
• metabolism by plants
• metabolism by soil invertebrates

Question 18

What are some biological fates of PAHs in water (3)

Answer 18

• degradation by microbes in water and sediment
• metabolism by algae
• metabolism by zooplankton, fish, mammals, and birds

Question 19

Physical effects of PAHs include:

Answer 19

smothering, reduced light (penetration will impact photosynthesis)

Question 20

Habitat change effects of PAHs:

Answer 20

• alter pH
• decrease oxygen
• decrease food availability

Question 21

Toxicity effects of PAHs:

Answer 21

• mainly on cellular membranes and enzyme-bound membranes (easily bind to lipids and penetrate the cells)
• metabolized PAHs are reactive, bind DNA and cause carcinogenesis

Question 22

PCBs =

Answer 22

POLYCHLORINATED BIPHENYLS *2 benzene rings not fused together

Question 23

Name some PCB industrial use:

Answer 23

• dielectric fluids in transformers and capacitors
• coolant
• lubricant
• PVC in electrical wires
• caulking sealant
• wood floor polish

Question 24

Name some PCB properties

Answer 24

• low water solubility (high in solvents/fats)
• low vapor pressure
• high dielectric constant
• high flashpoint

*chlorination impacts physical properties (increased chlorination = increased lipophilicity and reduced vapor pressure)

Question 25

What is the trade mark name for PCBs?

Answer 25

Aroclors

Question 26

T or F: PCBs bioaccumulate up food chains in fatty tissues; fatty-fish consumers are most at risk

Answer 26

T

Question 27

T or F: PCBs are persistent, resist breakdown; cycle between air, water and soil

Answer 27

T

Question 28

T or F: PCBs are considered a PBT substance

Answer 28

T persistent, bioaccumulative and toxic

Question 29

______ are chemical substances that persist in the environment, bioaccumulate through the food web, and pose a risk of causing adverse effects to human health and the environment

Answer 29

POPs

Question 30

Organophosphate insecticides are derivatives of _______________

Answer 30

orthophosphoric acid

Question 31

Organophosphate insecticides were initially developed as ___________

Answer 31

nerve gas agents to paralyze and kill people

Question 32

T or F: Organophosphate insecticides have a higher water solubility than PCBs, PAHs, etc

Answer 32

T

Question 33

Can organophosphate insecticides be considered DDT alternatives ?

Answer 33

Yes because the 1/2 life is shorter, days to weeks

Question 34

What is the mechanism of action of organophosphate insecticides?

Answer 34

They inhibit acetylcholinesterase activity which blocks acetylcholine metabolism which then causes muscular rigidity/paralysis in insects