PUBH 6011 FINAL LATEST EXAM REAL EXAM QUESTIONS AND
ANSWERS
What are the 4 steps of an environmental risk assessment? - ANSWER: 1. Hazard
identification: which adverse effect?
2. Dose-response evaluation: how much does it take for adverse affect?
3. Exposure assessment: how much do people take in?
4. Risk characterization: estimate the magnitude of risk and uncertainty
What are the biological mechanisms of digestion? - ANSWER: (Big Flow Chart with
Ingestion, Inhalation, and Dermal contact)
What is the role of the liver in breaking down food, microbes, and chemical
toxicants? - ANSWER: The liver handles the majority of phase I and phase II reactions
(biotransformations):
1. Phase I reactions: expose or add polar groups
2. Phase II reactions: conjugation (make bigger and less reactive)
What is the difference in risk assessment logic for carcinogens and non-carcinogens?
- ANSWER: For carcinogens, unlike non-carcinogens, there is NO safe level of
exposure
What are the primary routes of human exposure? - ANSWER: Oral (lol): through the
mouth and GI tract
Inhalation: through the lungs
Dermal: through the skin
What is the difference between acute and chronic toxicity? - ANSWER: Acute
toxicity: sudden onset of toxic effect, usually from a single dose and often reversible
Chronic toxicity: toxic effect seen after long-term exposure
What are the pros/cons of toxicology and epidemiology in determining toxicity? -
ANSWER: Epidemiology:
-Pros:
-study species of interest
-free ranging subjects in their natural environment
-Cons:
-non-experimental/qualitative
-usually retrospective and subject to confounding /bias
Toxicology:
-Pros: experimental (animal studies)? prospective
-Cons: lack of generalization across species
, Why/How do people handle toxicants differently based enzymatic makeup? -
ANSWER: Enzymatic makeup will change how an individual's metabolism functions
-changes the amount of chemicals present in the body
-influences rate excretion
-influences reactivity and how toxic a chemical is
What is the "first pass" effect? - ANSWER: All blood flow from digestive system first
passes through the liver which has extensive metabolic capacity and may alert the
form and activity of ingested molecules, for better and worse
What are absorption, distributions, metabolism and excretion? (ADME) - ANSWER:
Absorption: intake of chemicals and molecules into the body through digestion
Distribution: When and how chemicals get moved around the body (by blood and
lymphatic system)
Metabolism (biotransformation): the enzymatic alteration of the chemical structure
of a molecule
Excretion: the removal of molecules from the body (poop)
Reference Dose (RfD) - ANSWER: An estimate of daily exposure that likely does not
have appreciable risks (EPA)
dose-response relationship - ANSWER: quantifies toxicity
LD50 - ANSWER: Dose that is lethal to 50% of test animals
LC50 - ANSWER: Concentration (ppm) that is lethal to 50% of tests
Average Daily Dose (ADD) - ANSWER: (Concentration x Intake rate) / body weight
Maximum Containment Level (MCL) - ANSWER: like a safety limit for contaminants in
drinking water
NOAEL (No observed adverse effect level) - ANSWER: Highest dose with NO effect
LOAEL (Lowest observed adverse effect level) - ANSWER: Lowest dose with adverse
effect
Threshold - ANSWER: Dose at which most sensitive people respond (reached at the
LOAEL and NOAEL)
Point of departure (POD) - ANSWER: Point on curve where no response ends
Effective Dose (ED lol) - ANSWER: Minimum dose to make response
ANSWERS
What are the 4 steps of an environmental risk assessment? - ANSWER: 1. Hazard
identification: which adverse effect?
2. Dose-response evaluation: how much does it take for adverse affect?
3. Exposure assessment: how much do people take in?
4. Risk characterization: estimate the magnitude of risk and uncertainty
What are the biological mechanisms of digestion? - ANSWER: (Big Flow Chart with
Ingestion, Inhalation, and Dermal contact)
What is the role of the liver in breaking down food, microbes, and chemical
toxicants? - ANSWER: The liver handles the majority of phase I and phase II reactions
(biotransformations):
1. Phase I reactions: expose or add polar groups
2. Phase II reactions: conjugation (make bigger and less reactive)
What is the difference in risk assessment logic for carcinogens and non-carcinogens?
- ANSWER: For carcinogens, unlike non-carcinogens, there is NO safe level of
exposure
What are the primary routes of human exposure? - ANSWER: Oral (lol): through the
mouth and GI tract
Inhalation: through the lungs
Dermal: through the skin
What is the difference between acute and chronic toxicity? - ANSWER: Acute
toxicity: sudden onset of toxic effect, usually from a single dose and often reversible
Chronic toxicity: toxic effect seen after long-term exposure
What are the pros/cons of toxicology and epidemiology in determining toxicity? -
ANSWER: Epidemiology:
-Pros:
-study species of interest
-free ranging subjects in their natural environment
-Cons:
-non-experimental/qualitative
-usually retrospective and subject to confounding /bias
Toxicology:
-Pros: experimental (animal studies)? prospective
-Cons: lack of generalization across species
, Why/How do people handle toxicants differently based enzymatic makeup? -
ANSWER: Enzymatic makeup will change how an individual's metabolism functions
-changes the amount of chemicals present in the body
-influences rate excretion
-influences reactivity and how toxic a chemical is
What is the "first pass" effect? - ANSWER: All blood flow from digestive system first
passes through the liver which has extensive metabolic capacity and may alert the
form and activity of ingested molecules, for better and worse
What are absorption, distributions, metabolism and excretion? (ADME) - ANSWER:
Absorption: intake of chemicals and molecules into the body through digestion
Distribution: When and how chemicals get moved around the body (by blood and
lymphatic system)
Metabolism (biotransformation): the enzymatic alteration of the chemical structure
of a molecule
Excretion: the removal of molecules from the body (poop)
Reference Dose (RfD) - ANSWER: An estimate of daily exposure that likely does not
have appreciable risks (EPA)
dose-response relationship - ANSWER: quantifies toxicity
LD50 - ANSWER: Dose that is lethal to 50% of test animals
LC50 - ANSWER: Concentration (ppm) that is lethal to 50% of tests
Average Daily Dose (ADD) - ANSWER: (Concentration x Intake rate) / body weight
Maximum Containment Level (MCL) - ANSWER: like a safety limit for contaminants in
drinking water
NOAEL (No observed adverse effect level) - ANSWER: Highest dose with NO effect
LOAEL (Lowest observed adverse effect level) - ANSWER: Lowest dose with adverse
effect
Threshold - ANSWER: Dose at which most sensitive people respond (reached at the
LOAEL and NOAEL)
Point of departure (POD) - ANSWER: Point on curve where no response ends
Effective Dose (ED lol) - ANSWER: Minimum dose to make response
