MT 2

Question 1

What is the soil half life of imidacloprid?

Answer 1

1-2 years

Question 2

What is the water half-life of imidacloprid?

Answer 2

30-160 days

Question 2

What molecular effect do neonicotinoids have?

Answer 2

agonize nicotinic acetylcholine receptors and take ACh’s place on receptors, preventing its breakdown by acetylcholine esterase

Question 3

What biological effect do neonicotinoids have?

Answer 3

causes neurotoxicity like tremors, paralysis and death by constantly activating receptors (irreversible)

Question 3

What Kow value does imidacloprid have and how is it interpreted?

Answer 3

Kow = 0.57
Not bioaccumulative (hydrophilic instead)

Question 4

What concentrations of imidacloprid, clothianidin and thiamethoxam are acutely toxic in bees?

Answer 4

<2 ug

Question 5

What are some effects neonicotinoids have in bees?

Answer 5

• learning
• memory
• olfactory/gustation
• flight navigation/orientation
• foraging

Question 6

How did neonicotinoids affect songbirds in Saskatchewan?

Answer 6

caused weight loss and delays in migration

Question 7

What is a potential issue when creating neonicotinoid guidelines from lab tests?

Answer 7

lab species’ sensitivity may be lower than species in the ecosystem, so creating guidelines that protects a wide range of species may be challenging

Question 8

What are Species Sensitivity Distributions and what are they used for?

Answer 8

plots the sensitivities of different number of species onto a curve

used to predict a concentration that can safely protect a given proportion of species (i.e 50%)

Question 9

How did neonicotinoids affect salmon eggs during acute testing?

Answer 9

15 ug/L exposure to thiamethoxam caused 25% decrease in fertilization, overall exposure caused abnormal growth

no effect from clothianidin or mixture of neonics

Question 10

How did neonicotinoids affect salmon eggs during chronic testing?

Answer 10

imidacloprid caused increase in estrogen/thyroid receptors

clothianidin caused decrease in glucacorticoid receptor 2, increase in estradiol at 0.15 ug/L (affects gonad development, causes feminization)

no effect from thiamethoxam exposure

Question 11

How do neonicotinoids affect non-fish species?

Answer 11

rats = imidacloprid caused abnormal LH/FSH levels, ovarian damage; clothianidin in low doses altered male gonad development

birds = general exposure lowered fertilization success, decreased egg thickness and size, lowered offspring survival

mammals = increased aromatase (testosterone –> estrogen enzyme) activity

Question 12

What is a toxicity modifying factor?

Answer 12

environmental (i.e pH), chemical or biological (i.e age, nutrition, sex) factors that may affect the toxicity of a substance

Question 13

What did the PMRA review into different pesticides find?

Answer 13

varying impacts on bees/pollinators, and suggested altering practices (i.e no application of fruiting plants during bloom) but all three (imidacloprid, clothianidin and thiamethoxam) are still registered for use

Question 13

What are some sources of PAHs?

Answer 13

• crude oil
• burning of oil/gas/coal
• burning of trees/houses
• using cigarettes

Question 13

Give some examples for PAHs

Answer 13

• benzene
• naphthalene
• benzo[a]pyrene

Question 14

How are PAHs classified in Canada and what does it mean?

Answer 14

• Schedule 1
• means there is a toxic risk to both human (Health Canada) and non-human (Environment Canada) health

Question 15

What are OSPWs?

Answer 15

Oilsand process-affected water

Any water in contact with oilsands

Question 16

How can oil spills affect wildlife?

Answer 16

• acutely through death via suffocation (gills/lungs), drowning, hypothermia, inhalation of toxic vapours
• chronically through altering reproductive and immune systems, metabolism of PAHs into harmful intermediate molecules that can damage DNA/RNA, can cause cancer, can affect development

Question 17

What is an endocrine axis?

Answer 17

a specific pathway of a given hormone and all the organs involved in its expression

Question 18

What responses does the pituitary gland initiate?

Answer 18

ACTH (in adrenal gland) = production of glucocorticoids

FSH/LH (in testes/ovaries) = production of sex hormones

GH (in various tissues) = growth

PRL (in mammary glands) = production of milk

TSH (in thyroid) = production of thyroid hormones

Question 19

How did atrazine affect frogs?

Answer 19

male frogs had mutated testes, had ovaries and eggs, and some were completely feminized

Question 20

What is the mechanism behind atrazine?

Answer 20

activates aromatase (testosterone –> estrogen)

Question 21

What are the water quality guidelines in the US and Canada for atrazine?

Answer 21

Canada: drinking water = 5 ug/L, freshwater = 1.8 ug/L

US: drinking water = 3 ug/L, freshwater = 10 ug/L

Question 22

What two Canadian regulations set requirements for toxicity tests?

Answer 22

Federal = Pulp and Paper Effluent regulations

Provincial = Metal and Mining Effluent

Question 23

What is the purpose of toxicity identification evaluations (TIE)

Answer 23

to identify causes of toxicity and attempt to reduce their toxicity by improving treatment methods of effluents

Question 24

What are the three phases of TIEs?

Answer 24

phase 1 = ID the toxicant class based on chemical and physical properties
Phase 2 = ID the specific toxicant
Phase 3 = confirm findings of Phase 2