Environmental Toxicology

Question 1

what is biomonitoring?

Answer 1

measurement in people of a chemical or the products it akes when it breaks down

• this measurement (level of concentration) usually taken in blood and urine and sometimes in other tissues and fluids
• this measurement indicates how much of a chemical is present in a person

Question 2

wh conduct biomionitoring studies?

Answer 2

determine which chemicals at which conctns are present in the general popln

determine if there are dfferences in exposure among popln groups

track temporal trends in exposure

asess the effectiveness of public health interventions

establish reference ranges
determine the occurrence of exposures above kown toxicity levels

prioritize future research

Question 3

biological media

Answer 3

whole blood or serum (most common)

urine (noninvasive, metabolites often measured)

hair (exposure to certain metals, few comparison studies)

breast milk (fat soluble chemicals)

nails, teeth, adipose tissue, oral fluid (not widely used)

Question 4

charactertistic molecule or biological property that can be detected and measured in the body

Answer 4

biomarkers

Question 5

biomarker of exposure

Answer 5

chemicals or metabpites that can be measured to determine level of exposure

ex: pesticides in bloodm phthalate metabolites in urine
= won’t give us health info??? (LISTEN AGAN)

Question 6

biomarker of effectr

Answer 6

indicarors of a change in biologic function in response to an exposure

ex: cholinesterase, carbohydrate deficient transferrin

measuring the effects of an exposure, not the exposure itself

Question 7

biomarker of suscpetibility

Answer 7

factors that make some individuals more sensitive to chemical exposure
ex: genetic factors, age, nutirtional sratus

Question 8

what is the concern with personal care products?

Answer 8

may contain endocrine disrupting chemicals such as some phtalates or phenols
- regulated by Health Canada
- shampoos, moisturizers, facuak tussyes, etc.

Question 9

mimic estrogen

Answer 9

bisphenol A

Question 10

inhibits hormines

Answer 10

phthalates

Question 11

T or F. Phthalates exposure is higher in children than adults

Answer 11

T

Question 12

this replaced DEHP

Answer 12

MHNCH

Question 13

T or F. pesticides are not regulated by Health Canada

Answer 13

F! It is ; toxicity info is well-known

Question 14

factors that affect internal dose

Answer 14

chemical properties = is it lipophilic? (Kow)

route of administration = if inhaled or absorbed through skin, quickly distributed but if infested, the chemical can be metabolized by liver

ADME

frequency and duration of exposure = continuous, intermittent, cyclic, random, concentrated

Question 15

why is it important to include children in biomonitoring studies?

Answer 15

• same exposure does not MEAN same internal dose (everyone has dfferent biomarkers of availability)
• children are NOT little adults = they have different, sometimes uninque exposures to environmental chemicals (placenta, breast milk)
• developmental physiology often have higher exposures to chemicals inair, food, water
• higher surface to volume ratio than adults
• longer life expectancy
• ingest more dust and soil

Question 16

these have been reported to penetrate the fetal system

Answer 16

POPs
persistent organic pollutants

placenta= potentially enhanced vulnerability although it plays a protective role

Question 17

the dose below which no toxicity is observed

Answer 17

threshold dose
- there is a safe level of exposure for most chemicals

Question 18

aim of a risk assessment

Answer 18

to provide estimates of the likelihood of illnesses and injury as a consequence of exposure to various hazards

Question 19

what is a biomonitoring equivalent (BEs)?

Answer 19

developed in 2008

tools to interret biomonitoring data

concentration of a biomarker in bio medium that is consistent with existing exposure guidelines such as reference doses, total daily intakes (TDIs)

screening tools to assess biomarker levels with respect to existing ruis assessments and exposure to guidance values

Question 20

biomonitoring limitations

Answer 20

• cannot reveal what health effects, if any may arise from exposure
• absence of chemical doesn’t necessarily mean a person has not been exposed
• cannot determine the source or route of exposure
• increased analytical sensitivity = is what being detected meaningful?