Ch.2a Flashcards
What are the three types of goals for ecotoxicology
- Scientific
- Technical
- Practical
Explain scientific goals for ecotoxicology
- to organize knowledge based on explanatory principles about contaminants in the biosphere
- goals are based on the development of scientific method
What is a precipitate explanation
- facts fit into ruling theory
- Ask an expert
- uncritical
- Its essentially just believing what the leader says
What is the model scientific goals used after precipitate explanation
The working hypothesis
- Never accepted as true
- Focus on falsification
What is a weakness of the working hypothesis
It tends to favor a central theory
Explain multiple working hypothesis
- Consider all plausible ideas simultaneously
- useful in questions with multiple explanations
- although a hypothesis is never assumed true, survival tends to enhance status
- must avoid weak hypotheses and imprecise/biased measurements
What are the three ways of learning new knowledge using the scientific goals
- precipitate explanation
- working hypothesis
- multiple working hypothesis
What is the next step for a hypothesis
-Becoming a paradigm
Define a paradigm
generally accepted concept that have survived vigorous testing
What is “normal science”
- incremental increase in facts and ideas reaffirm, revise or replace paradigms
- methodical fact gathering
what is “innovative science”
- questions paradigms and formulates new ones
- requires normal science
What are the two types of investigative behaviors
- normal science
- innovative science
do younger fields tend more towards normal or innovative science?
normal, but a balance is required
What are technological goals for ecotoxicology
to develop and apply tools and methods to acquire a better understanding of contaminant fate and effects in the biosphere.
What is the purpose of technological goals
a. Analytical instrumentation
b. Standard methods
c. Computational/analytical methods
What are some qualities aimed for in technological goals
- effectiveness
- precision
- accuracy
- appropriate sensitivity
- consistency
- clarity of results
- ease of use
What are practical goals in ecotoxicology
the application of available knowledge, tools and procedures to solving or documenting specific problems.
-Also called regulatory goals
What are some tools used in practical goals
- guidelines
- quality standards
- criteria
- step-by-step approaches
Are practical goals to further understanding?
No, they are to address a specific problem
What are some relevant terms with practical goals
- criteria
- standards
Define criteria
estimated [toxicant] based on current literature, that are considered protective for organisms or a defined purpose, if not exceeded
Define standards
legal limits thought sufficient to protect environment.
What is the value placed on in practical goals
- effectiveness
- precision
- accuracy
- sensitivity
- consistency
- clarity
- ease of use
- UNAMBIGUOUS RESULTS
Do all three goals (scientific/technical/practical) usually overlap
No, but ideally they should. A given lab/situation/study will usually emphasize one
What are toxicity Tests
Chemical and physical tests in the lab may not be enough to assess potential effects on live organisms
Why might organisms be used in toxicity tests
To see if:
- conditions support life
- what are good conditions (pH,DO,salinity,T)
- effect of env on toxicity
- tox to a specific species
- relative sensitivities of organisms
- amount and type of waste treatment to meet requirements
- monitor effectiveness of treatments
- monitor discharge rates
- Check compliance
Why use standard methods
They ensure:
- Uniformity
- Reproducibility
- utility
What are the different types of quality assurance/quality control procedures
- Guidelines for sampling/handling samples
- Source/condition of test organisms
- use of reference tests
- test procedures
Define Acclimate
to accustom test organisms to different environmental conditions
Define response
the measured biological effect of the variable tested
For acute toxicity its usually death/immobilization
Define control
treatment that duplicates all the conditions of the test but contains no test material
Define range-finding test
preliminary test to establish approximate toxicity
-Single replicates, multiple widely spaced concentrations (exposure for 8 to 26 hours)
Define screening test
toxicity test to determine if an impact is likely to be observed
- 1 concentration, lots of replicates
- exposure for 24 to 96 hrs
Define definitive test
toxicity test to establish concentration at which an end point occurs
-longer exposure, multiple concentration, close intervals, multiple replicates
Define Dose
The amount of toxin entering and organism
does does mean the same thing as concentration
no
Define Toxicity
potential of a test material to cause adverse effects on living organisms
- Result of dose or exposure concentration and exposure time
- May be effected by temperature, chemical form, availability
Define exposure time
time that test organism is in contact with the test solution
Define acute toxicity
relatively short term lethal or other effecttest
what is considered and acute exposure time for fish and other macroinvertebrates
4 days
what is the acute exposure time for organisms smaller than fish
2 days
define chronic toxicity
stimulus lasts 10% of life span or longer
-may involve reduced growth/reproduction/death
Define LC
Lethal concentration
-toxicant concentration estimated to produce death in a given proportion of organisms
Define EC
effective concentration
-toxicant concentration estimated to cause a specific effect in a given proportion of the population
Define IC
inhibition concentration
-toxicant concentration estimated to cause a specified percentage inhibition or impairment of a qualitative biological function
Define NOEC
No observed effect concentration
-In full or partial life cycle test, the highest toxicant concentration in which the values are not significantly different from control
Define LOEC
Lowest observed effect concentration
-In full or partial life cycle test, the lowest toxicant concentration in which the values for the measured response are significantly different from control
What is a static test
solutions + organisms in a container stay there for duration of test.
What is a Renewal test
organisms are exposed to solutions of the same composition which are renewed at intervals (24h)
What is a flow through test
solutions are continually replaced during the test
what should be some considerations when choosing an organism
- sensitivity to toxicant
- geographical distribution/abundance/availability
- recreational/economic/ecological importance
- abiotic requirements
- cultural methods
- knowledge of life cycle/nutrition
- physical condition
- health
how many concentrations and how many controls are needed in toxicity tests
- 5 conc
- 1 control
- duplicates for anaysis
- QA/QC
How should you distribute your organisms when making test solutions
- Randomly
- 1 at a time if <11/container
- 2 at a time if >12/container
How should organisms used for static tests be moved from an intermediate container
ALL AT ONCE
How many organisms must survive in the control for the test to be valid
90%
Are lower survival rates more acceptable in long or short exposure tests
long
what a good confidence interval for a toxicity test
-95% it should be less the +/- 30% of the mean
when might survival rates be lower than 90% in a toxicity test
- when there is not culture method
- in which case those values may not be attainable
- sometime when you just grab fish at random you grab only sick fish
