Test 1 Flashcards
what is toxicology
the study of the ways poisons
interact with biological systems
toxicant
A substance that will cause a harmful effect when
administered to a living organism
toxin
a toxicant produced by a living organism (or by a biological process)
hazard
the ability of a chemical to produce
toxicity in receptor (harm, adverse response)
exposure
pathway for substance to be
transferred to a receptor (frequency, duration,
route)
risk
the probability that the hazard will occur
under defined conditions (incl. exposure)
calculation for risk
risk = hazard x exposure
Environmental toxicology
ecological effects of chemical toxicity
what started the modern environmental movement
Silent Spring by Rachel Carson
Xenobiotic
Foreign to the body
Anthropogenic
Human-made
acute exposure
less than 96 hours, single dose
chronic exposure
long duration, continuous exposure
dose-response x-axis
exposure
dose-response y-axis
response
quantal response examples
if the organism died, if the organism got cancer, etc. things you can know 100%
endpoint
quantifiable response related to exposure
NOEC
no observed effect concentration - highest concentration with no observable effects, not different from the control
LOEC
lowest observed effect concentration - lowest concentration that is significantly different than the control
what are the 2 ways to plot toxicity data
time-based plot, dose/concentration-based plot
biomarker / biochemical marker
The subcellular response of the living organisms is used to indicate the effect of a substance, departure from normal status
Lifetime
average time a toxicant spends in a particular compartment (AKA Residency Time)
Persistence
tendency of a toxicant to remain in a particular compartment
(Toxicant with a longer lifetime is more persistent)
Persistent Organic Pollutants (POPs)
organic molecule, toxicants featuring lifetime
(or half-life) greater than one year
Bioaccumulation
describes the fate of toxicants in the “biological organism compartment” - build up within an organism
2 factors of bioaccumulation
bioconcentration, biomagnification
bioconcentration
partition of toxicant into biological organism - concentration in tissue compared to in water
biomagnification
concentration amplified in the food web
BCF (bioconcentration factor) equation
BCF = (C_Tissue) / (C_water)
C_tissue
the level in the organism or lipid tissue
C_water
level in water
Bioaccumulation factor (BAF) equation
BAF = (C_tissue) / (C_water)
when in doubt of toxicant vs toxin
use toxicant. all toxins are toxicants but not all toxicants are toxins
Risk is the intersection of what 3 components
hazard, receptor, exposure
parties involved in environmental risk assessment
risk assessors, risk managers, stakeholders
PBT
Persistence, Bioaccumulation, Toxicity
best known POPs of the “dirty dozen”
PCBs
EDCs
Estrogenic compounds or Endocrine Disrupting Compounds. interfere with hormonal processes in the body
how were furans produced
unintentionally as a by-product
What does DDT become when it degrades
DDE
BAF
bioaccumulation factor
BCF
bioconcentration factor
K_OW
lipophilicity
K_OW equation
C_octanol / C_water
when/where does bioaccumulation occur
in food web and in organisms over time
PCB characteristics
Thermally stable, non-volatile, non-polar, extremely persistent
environmental risk assessment framework
- problem formulation
- exposure assessment
- exposure-response assessment
- risk characterization
