Midterm COPY Flashcards
Dose
Total amount of a substance administered to, taken, or absorbed by an organism.
What is a biomarker of dioxin exposure?
Induction of CYP1A4 and CYP1A5
Toxicant
Toxic substances that are produced by or are a by-product of human-made activities.
What is biotransport?
It is when a contaminant is able to move around an ecosystem because it is in an organism. Seabird guano is an example of this.
what is biomethylation
metal biotransformation whereby an ethyl or methyl group is added to a metal
what is selyean stress/general adaptation syndrome?
the non-specific response of the body to extraordinary demands made upon it: alarm, adaptation, exhaustion
what are the light isotopes
C12, N14, S32
What is the most toxic toxicant?
TCDD
What is the typical length of a chronic toxicity test?
Ideally minimum 10% of organism’s lifespan.
Boomerang Paradigm
What you throw away may come back to harm you” DDT, MeHg
What is R0?
net reproductive rate. number of females born to a female in her life time
What are four biological traits the contribute to higher concentrations in predators?
high lipid content, longer lifespan, larger body size, slower growth rates
Xenobiotic
A foreign substance that is not part of the normal biochemistry of the organism.
Define allometry and how it is related to ecotox
the size of an organism influences feeding rate, metabolic rate and thus uptake, biotransformation and elimination processes
what is lx?
age specific survival, proportion surviving to that age class
Mechanism of Action
A set of molecular targets of a drug or contaminant and the receptors and enzymes involved. eg. Acetylcholinesterase inhibitor.
what are two synonyms for biomagnification?
bioamplification and trophic enrichment
What is the formula for bioaccumulation factor?
concentration in organism / concetration in media
(at steady state)
What is the formula for daily dose of exposure?
Concentration in food x food intake rate x area use factors divided by body mass
What is the most toxic toxin?
Botulinum
Contaminant
Chemical or element that exceeds normal background levels; it may or may not cause environmental harm
What is the typical length of an acute toxicity test?
Less than 96 hours.
What is the theory of global fractionation?
most volatile chemicals, such as HCB, HCH, travel to the highest latitudes, while less volatile compounds, such as DDT, are less readily distilled and tend to remain near their source region
Pollutant
Chemical or element that exceeds normal background levels and causes environmental harm.
Bioaccumulation is the net consequence of ____ and ____.
uptake and elimination
what is depuration
the experimental procedure of placing an organism into a clean environment where the contaminant concentration will decrease
Dilution Paradigm
The solution to pollution is dilution
What is the formula for biomagnification factor
= [in organism] / [in diet]
>1 means biomagnifying
<1 means trophic dilution
does bioaccumulation usually increase or decrease with increasing pH?
it usually decreases with increasing pH
What is N15 used to indicate?
its the best indicator of trophic status and marine input. average increase of 3.4% per trophic level
ppm
mg/kg ug/g mg/L
For BCF, which source of accumulation does it exclude? Respiration, dermal, or diet?
Diet
What is phase 1 biotransformation
trying to make compound more hydrophilic by adding functional group
what is the common mode of action in dioxin-like compounds?
mediated by aryl hydrocarbon receptor
Name two chemical properties that contribute to biomagnifcation
persitence and lipophilicity
what is Tc?
Mean generation time
what information do vital rates provide?
life cycle events such as rates of birth, growth, fecundity, maturation and mortality
Do gases or liquids have higher vapour pressure?
Gases
what do p-glycoproteins pumps do? and what is its shorthand?
P-gp. it is a cell membrane protein that pumps many foreign substances out of cells
In Risk Characterization, what is the formula for Hazard Quotient
dose/toxicity reference value, greater than 1 means there’s a risk
Differentiate adsorb and absorb
Adsorption adheres to, absorption goes in
a collection of fragmented subpopulations is a __________
metapopulation
What are nutrient subsidies?
This has to do with the movement of material from one habitat to another. Emergent insects are nutrient subsidies because they take from aquatic environments and give them back to the terrestrial environment.
what does the exposure profile do?
it quantifies the magnitude, and spatial and temporal pattern of exposure for the scenarios developed during problem formation
what is dx
the number dying between x and x + 1
Name four routes of chemical uptake into cells
passive diffusion, active transport, phagocytosis, and facilitated diffusion
What the two physico-chemical properties influencing chemical fate?
Persistence and mobility.
Name three types of metal biotransformation
biomethylation, metallothionein binding, biomineralization
What formula is this
Logistic growth model
why does increased temperature typically increase bioaccumulation rate?
Because the increase in temperature usually causes increased feeding and growth, thus increased uptake
what does the glutathione s-conjugate export pump do?
it removes glutathione conjugates from cells
what is qx
mortality rate between x and x + 1
Which species’ LD50 indicates greatest sensitivity? Guinea pigs = 0.61 Rat = 22 Mice = 283 Rabbit = 115 Monkey = 50
Guinea pigs with 0.61.
what is bioavailability?
the fraction of contaminant that is available for uptake by organisms and capable of exerting a toxic effect; also, the fraction of a contaminant that is absorbed across biological membranes and assimilated into tissues
what is λ? When is it used? whats the formula?
the finite growth rate, functions in discrete time steps, when you want to know what is happening between years
Nt+1 = λNt
lambda = 1 = no growth
lambda > 1 = growth
lambda < 1 = decline
ppb
ug/kg ng/g ug/L
what is the most widespread sublethal effect?
behaviour
what is an isotopic fingerprint?
its the ratio of heavy vs. lighter stable isotopes compared against a standard (C-13/C-12, N-15/N-14, O-18/O-16)
Differentiate “in suspension” and “in solution”
Something in suspension will fall to the bottom, something in solution is dissolved.
What are they heavy isotopes?
C13, N15, S34
Do higher or lower trophic levels have higher assimilation efficiencies?
Higher trophic leves
define autoecology
the study of an individual organism or species and its relationship to the physical, chemcial and and biological environment
Life Table Response Experiments (LTRE) provide a measure of effects on ______ ________ _______
population growth rate
does toxicity and bioavailabilty usually increase or decreases with increasing water hardness?
it decreases
which has higher absorption and distribution? inorganic mercury or organic mercury?
organic mercury
Concentration
Quantity of a material or substance contained in unit quantity of a given medium or system.
What are contaminant subsidies?
Similar to nutrient subsidies, but with contaminants. Salmon are contaminant subsidies because they bring contaminants from the ocean into pristine Alaskan lakes
name three types of elimination pumps
glutathione s-conjugate export pump, OAT, p-glycoprotein pump
Mode of Action
Broad set of biological responses involving processes or biochemical pathways that are affected in an organism. e.g. cell signalling, DNA synthesis, oxidative phosphorylation.
What is r? how is it calculated?
r is the intrinsic growth rate, it is relative to 0
r = (birth rate - death rate)
r = 0 = no growth
r > 0 = population growth
r < 0 = population decline
what is S34 used to indicate?
its a good indicator of food source, rather than trophic level
what is assimilation efficiency?
the proportion retained of total ingested.
= mass in tissue / mass in food
what is mx?
age specific fecundity, mean number females born to a female in that age class
what is biomineralization
metal biotransformation whereby, for example, lead or cadmium are incorporated inertly into bone or exoskeleton
What are five disadvantages to behaviour based endpoints?
- the dose-response relationship isn’t great
- extrapolation from lab to field isn’t great
- large individual variation in response
- some behavioural effects may not be directly related to fitness
- difficult to relate effects to specific chemical(s)
Toxin
Substance produced naturally, i.e. by a plant or animal/ Protein based
what is the difference between a leslie and a leftkovitch matrix?
a leslie matrix is age structured, a leftkovitch is life stage structured
Which LC50 is most toxic? a) 280 b) 0.41 c) 5.3 d) 0.003 e) 35
d) 0.003.
What is arctic haze
its a mixture of aerosols containing acidifying SOx, NOx, coarse particles of soot, heavy metals PAHs and PCBs
what is the relationship between r and λ?
r = ln λ
or
λ = er
What are the two most useful ways of classifying contaminants?
By chemical structure and mechanism of action.
Explain how increasing organic carbon content in water can both increase and decrease bioavailabilty
it can increase bioavailabilty because the turbid water will have less light penetration, less photolysis.
it can decrease bioavailability because the organic matter can complex with the contaminants
Define population within the realm of ecotoxicology
a group of contemporaneous individuals of the same species occupying a habitat with patches differing markedly in the capability to foster survival, growth, and reproduction
what are two enzymes are affected by dioxin responsive genes?
CYP1a4 and CYP1a5, which are involved in phase I and phase II metabolism
ppt
ng/kg pg/g ng/L
What are the three types of life tables?
Cohort, horizontal, and survival
what is isotopic discrimination?
lighter isotopes (C12, N14, S32) are eliminated from organisms more readily during trophic exchange than heavier isotopes (C13, N15, S34)
So we find heavier isotopes up the food web
Name this formula:
Nt = Noert
exponential growth formual
What are the three major classes of contaminants?
Metals and metalloids, organic contaminants, and radionuclides.
what is C13 used to indicate?
it can be used as an indicator of trophic structure and carbon input
