OECD 203 Flashcards
What are OECD Testing Guidelines updated to reflect?
Scientific advances, regulatory changes, and animal welfare concerns.
What methods are introduced to reduce or avoid animal use in fish toxicity testing?
- QSAR
- Read-across
- Fish embryos
- Cell lines
- Threshold approach
- Limit tests
Is testing for 100% and 0% mortality concentrations mandatory?
No, it is not mandatory.
What is the purpose of the OECD Fish Toxicity Testing Framework?
To provide guidelines for fish acute toxicity testing.
How long are fish exposed to a test chemical in the OECD acute toxicity test?
96 hours.
What must be recorded during the fish acute toxicity test?
Mortality and visible abnormalities.
What is LC50?
Lethal concentration for 50% of fish.
What prior knowledge is essential for meaningful test design?
Chemical properties such as molecular weight, pKa, solubility, and vapor pressure.
What is the control mortality limit for the validity of the test?
Must not exceed 10% or one fish if fewer than 10 are tested.
What type of materials should test vessels be made of?
Chemically inert materials (e.g., glass, stainless steel).
What is the maximum fish loading for static/semi-static tests?
0.8 g fish/L.
What is the recommended photoperiod intensity for light during the test?
10–20 μE/m²/s (540–1000 lux).
What is the minimum number of fish required per concentration in the test?
At least 7 fish.
What is the preferred method for preparing test solutions?
Diluting a stock solution in test water, preferably by stirring or sonication.
What must be maintained during the exposure conditions in the test?
Oxygen must be ≥60% air saturation.
What is a limit test?
A test conducted at 100 mg/L or solubility/threshold limit for 96 hours.
What type of statistical methods can be used for LC50 estimation?
- Probit/logit models
- Spearman-Karber method
- Binomial method
- Moving average method
- Graphical method
What is the definition of a flow-through test?
A test with continued flow of test solutions through the test system during the duration of exposure.
What should be reported about the test chemical for mono-constituents?
Appearance, solubility, relevant properties, chemical IDs (IUPAC/CAS name, number, SMILES/InChI).
What are UVCBs?
Substances of Unknown or Variable composition, Complex reaction products or Biological materials.
What is the purpose of the Annex 4 in the OECD guidelines?
To describe sublethal clinical signs in fish.
What is a critical observation time frame for fish during the test?
Minimum of 2 observations in the first 24 hours.
What is the definition of total length (TL) in fish measurement?
Length from the tip of the snout to the tip of the longer lobe of the caudal fin.
What is the acclimatization period for fish before testing?
At least 9 days.
