midterm 1

Question 1

what is toxicology

Answer 1

the study of the actual or potential danger presented by harmful effect of substances on living organisms

Question 2

define poison

Answer 2

substance which is taken in or formed within the organisms which imapreis the heath and may cause damage or kill the organisum

Question 3

weight of evidence approach

Answer 3

using indivudal lines of evidence to develop conculation regarding questions relating to the degree of impariment or risk

Question 4

explain DDT and its effects

Answer 4

was a chemical used to control insects and pests in the 1950s very widly used
had a trophic effect on the ecosystems as hawks specifically located at the top of the food chain would have the highest con of DDT in their system resluting in fragile egg shells. this was due to both bioaccumulation and biomagnification

Question 5

who is Rachel Carson

Answer 5

wrote silent spring which awoke the public to the threats of pollution to both humans and other animals.

Question 6

define persistence , bioaccumulation and biomagnification in respect to toxicology

Answer 6

p- the legnth of time that the sustance remains in the envoirment before it is physically removed or chemically transformed

BA- if the compound does not break down rapidly then it may begin to accumulate in organisms as it consumes more and more of the chemical(rate of removal is less then rate of uptake)

BM- higher contractions of the chemical are seen at high trophic levels as there is high levels of the chemicals in its prey.

Question 7

when was earth day set

Answer 7

1970

Question 8

what are the 3 pilers of sustainable development

Answer 8

social equity
econimiv viability
envoirmental protection

Question 9

what is the precautionary principle

Answer 9

when full scientific certainity does not fully back the threats of serious envirmental damge this should not be used as a post poning point
do it before its too late oretty much

Question 10

what was paracelsus influence on toxicology

Answer 10

he established the does response relationship

Question 11

what are the 3 factors by which toxicity are governed

Answer 11

the exposure
the duration
the response

Question 12

what are the keys for a toxicity test

Answer 12

many concentrations
fixted time
observervation of the response after the fixed time
this is what we did in the lab.

Question 13

what is a LC 50

Answer 13

the median lethal concentration
this is the con at which half of the population is dying and the other half is living.

Question 14

what is the point of using a probit

Answer 14

this is to creat a more linear relationship with the data set so that the LC50 can be more easily calaulated (more accurate)

Question 15

what is a probit

Answer 15

a standard deviation of a normal distribution

Question 16

when can probit analysis be used

Answer 16

only when dealing with quantal data (one has only 2 outcomes ei yes or no)

Question 17

what is a does response relationship

Answer 17

the association between a does and the incidence of a defined biological effect in a exposed population which is often expressed as a percentage

Question 18

what is a LD50

Answer 18

this is the median lethal DOSE

Question 19

what is a EC

Answer 19

EC stands for effect conentraction does not deal with mortaility rather is the exposoure at which 50% of the population shows a effect.

Question 20

define exposure in a toxicology context

Answer 20

exposure is contact with the contaminate

Question 21

what is a poison

Answer 21

a substance which is taken into or formed within the organism causing harm

Question 22

what is a xenobiotic

Answer 22

a foreign chemical or meterial which is not produced by nature and not considered part of normal biological systems which means this is a man made substance

Question 23

mutagen

Answer 23

a chemical which can cause mutation

Question 24

tertatogen

Answer 24

a chemical or physical agent capable of causing a development deformation

Question 25

genotoxicity

Answer 25

damage by chemical to DNA

Question 26

does duration curves what are some charteristics

Answer 26

only 2 variables one of which much be constant
there will be a con at which the does will not produce a effect and therefore it will apear as a astomtote therefore the endpoint is never reached

Question 27

the incipient lethal level

Answer 27

a LC50 value which is independent of time (when the dose is so small that there is no repose)

Question 28

what dose the threshold model describe

Answer 28

there is a point during a repose dose curve where is there seen to be a rapid increase in reposes same as a titration

Question 29

what is a monotonic curve

Answer 29

one which increase or decsease constaly w exposure

Question 30

what is a non-monotomic curve

Answer 30

one which seemingly share no relationship with the stim

Question 31

what is a sub-acute test duration

Answer 31

found between the times of acute and chronic

Question 32

what is the stochastic effect

Answer 32

an effect for which the probability of a adverse effect increase w exposure con

Question 33

what is the MATC

Answer 33

maximum allowable toxicant conc

Question 34

what are some uses of bioassays

Answer 34

determine which speceis is the most sensistive/ what is the most sensitive lifestage
compare effects of diffrent contaminates on various speceis
determine the minimum level of contamination which can occur without causing impact

Question 35

what kind of organisum would you use for a bio assay to detrmine the MATC

Answer 35

you would use the the most sensitive speceis which represents the ecosystem of intreset. you use the most sentive as the MATC for that will be lower for other memebers of the ecosystem as they will be less sensitive then the most sensitive member

Question 36

what is the threshold for deaths in a control

Answer 36

10%

Question 37

how do we set up a dilution series

Answer 37

we use a geometric set up not arithmetic
this means we cut in half each time not counting by tens

Question 38

what is the weber fechner law

Answer 38

the amm of change needed for sensory detection to occ increase w the intensity of a stim and is proportional to it pretty much the diffrence between arithmetic progression is that the diffrnce between the 2 numbers is the same which leads to problems at lower conc as you are more then halfing the value, whereas with a geometric seq you are using a fixed ration by halfing each time.

Question 39

what are the diffrent types of controls

Answer 39

pos- add a known chem w a known repose, this is used to validate the repose of the test system
neg- clean water w no contaminiate used to test health of the species
solvent- carrier, assets in exposure of test

Question 40

static exposures

Answer 40

the expsosure soloutions are prepded at the satrts of the study and remian for the duration of the study
this solutions undergo static renewal which means that over the duration of the exposure soultions are replaced at regular time intervals

Question 41

flow through exposure

Answer 41

the chemical is constantly supplied to the testing tank or vessel throughout the test
chemical in and chemical out

Question 42

LOEC

Answer 42

lowest obsered effect concetration
the lowets tested con w a noticeable adverse effect on the organisums

Question 43

NOEC

Answer 43

no obersved effect conc
highest tested conc that does not cause any obseved harm

Question 44

TEC

Answer 44

threshold effect conc
mean between LOEC and NOEC

Question 45

who is steven gilbeault

Answer 45

Minister of Environment and Climate Change of Canada