Midterm 2

Question 1

What does PMRA stand for?

Answer 1

Pest Management Regulatory Agency

Question 2

Where are pesticides found?

Answer 2

• In air, water, soil, sediment and food

- In the tissues of many aquatic species

Question 3

How are pesticides transported to groundwater?

Answer 3

-mostly by recharge resulting from rainfall or irrigation within agricultural and urban areas where they are used

Question 4

How do pesticides get to the atmosphere?

Answer 4

Transfer after application via volatization, spray drift and wind erosion

Question 5

What happens to pesticides in the atomosphere?

Answer 5

-they are returned to earth by precipitation and dry deposition and can reach streams and ground water

Question 6

What regulate the use of pesticides?

Answer 6

-there are provincial and municipal laws regarding the use of pesticides

Question 7

What is a pesticide?

Answer 7

-any substance or mixture of substances used to destroy, suppress or alter the life cycle of any pest

Question 8

What are the most common categories of pesticides?

Answer 8

-bactericides, fungicides, herbicides, insecticides, rodenticides and repellents

Question 9

Where are pesticides used?

Answer 9

-in commercial, domestic and urban environments

Question 10

What is a popular organochlorine?

Answer 10

DDT

Question 11

When were neonicotinoids introduced?

Answer 11

In the 1990s

Derived from nicotine

Question 12

How are neonicotinoids used?

Answer 12

• applied onto seeds or soil prior to planting

- and or sprayed onto foliage

Question 13

What is the target pest for neonicotinoids?

Answer 13

• piercing-sucking insects (aphids, leafhoppers and whiteflies)
• also has a broad spectrum toxicity to a wide range of pests

Question 14

Who gave the ted talk on bees?

Answer 14

-Marla Spivak, University of Minnesota

Question 15

What is the mode of action of neonicotinoids?

Answer 15

-binds to nAChR(nicotine acetylcholine receptor) in postsynaptic neurons

Question 16

What do neonicotinoids do when it is in the host?

Answer 16

• acts as a false neurotransmitter

- causes continuous activation of the receptor, leading to symptoms of neurotoxicity

Question 17

What are the effects of receptor binding? (Neonics)

Answer 17

-receptor binding is irreversible so permanent effects are cumulative with time, and delayed toxicity exhibited

Question 18

What class seems to be the most sensitive to neonicotinoids?

Answer 18

-class insecta

Question 19

What is one of the biggest impacts of insect loss?

Answer 19

-cascading effects on insect eating species (birds, reptiles, amphibians and fish)

Question 20

How do we know the amount of pesticide use in canada?

Answer 20

• pesticide reporting is confidential

- estimated via application rates and crop type

Question 21

What is biotransformation?

Answer 21

The sum of the chemical reactions that occur within the body to alter the structure of a xenobiotic/endogenous compound

Question 22

What is part of phase 1 of biotransformation?

Answer 22

• oxidation, hydrolysis, reduction

- make it hydrophilic to be excreted

Question 23

What is phase 2 of biotransformation?

Answer 23

• conjugation/synthetic reactions

- something like a surface group is added to make it more excretable

Question 24

What is the problem with using commonly used lab species for neonicotinoid testing?

Answer 24

• lab species used in standard toxicity tests are not always the most sensitive to neonicotinoids
• wide range of differences in sensitivities between invertebrate taxa

Question 25

What are environmental quality guidelines based on?

Answer 25

-data for lab species

Question 26

What is more useful for deriving environmental quality guidelines for neonicotinoids?

Answer 26

Species Sensitivity Distributions (SSDs)

Question 27

What does a Species Sensitivity Distribution do?

Answer 27

-models the variation in sensitivity of a species to a particular stressor

Question 28

How are species sensitivity distributions generated?

Answer 28

-by fitting a statistical function to the proportion of species affected as a function of toxicant concentration or dose

Question 29

What is the goal of a species sensitivity distribution?

Answer 29

To predict the concentration that will protect a given percentage of species in the environment

Question 30

What are the impacts of neonicotinoids on ecosystems?

Answer 30

- moderate to high acute toxicity to most invertebrates - chronic low level exposure in water bodies and in plants - birds and fish may have indirect effects because there are fewer insects to eat

Question 31

What are three major neonicotinoid pesticides?

Answer 31

- imidacloprid - thiamethoxam - clothianidin

Question 32

What is the toxicity modifying factor?

Answer 32

-when toxicity of a substance is affected by some environmental, chemical or biological factor

Question 33

What are the basic components of the endocrine system?

Answer 33

1. Endocrine gland/cell 2. Hormone 3. Target organ

Question 34

What does the endocrine gland/cell do?

Answer 34

- secretes hormones | - effects distal target

Question 35

What is the path of thyroid hormones?

Answer 35

- Higher brain center - Hypothalamus - TRH - Pituitary - TSH - Thyroid - T4, T3 - Target Tissues

Question 36

What is the process of metamorphisis controlled by?

Answer 36

-thyroid hormone

Question 37

What is an endocrine disrupting substance?

Answer 37

-exogenous substance or mixture that alter function of the endocrine system and consequently cause cause adverse health effects in an intact organism, or its progeny or (sub)populations

Question 38

What are the critical windows of exposure for endocrine disrupting substance?

Answer 38

-exposure during early life stages may cause irreversible effects on organisms

Question 39

What are the possible causes for sockeye salmon decline?

Answer 39

- climate change - fishing pressures - habitat destruction - disease/ parasites - environmental contaminants/ pollutants

Question 40

Why are sockeye important?

Answer 40

- culturally important - economically important - ecologically important

Question 41

What are neonicotinoids?

Answer 41

-class of neurotoxic, systemic, broad spectrum insecticides used in agriculture, around the home and on pets

Question 42

What are the fates of neonicotinoids?

Answer 42

- uptake by plant - enter waterways via runoff, leeching and spray drift - soil - target pests - nontarget organisms

Question 43

What did previous marlatt lab results show?

Answer 43

- increased whole body concentration of estradiol - neonics could be a slight endocrine system disruptor - possibility of feminization of gonads