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Short-term toxicity to fish

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Reference
Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
June 2012 - July 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Well conducted and well described study in accordance with GLP and OECD Guideline 201 without any major deviation
Reason / purpose:
reference to other study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
yes
Details on sampling:
- Concentrations: all groups
- Sampling method: in new and old media, volume of 1.0 mL
- Sample storage conditions before analysis: freezer (5°C, no more 48 h) or analysis performed directly after sampling
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Pre-experiments (non-GLP) were performed to assess stability of test substance under test coditions. The batch of Nerol used resulted in clear solution and appeared to be completely soluble and stable in test water at the test concentration.
- Stock solution for definitive concentration:
A stock solution 500 mg/L by addition of 2500 mg to 5 L of test water in sealed glass vessel. The mixing of the stock solution was performed for 24 h in the dark (magnetic stirrer). After 24 hours of gentle stirring, the solution was allowed to stand undisturbed for 1 hour. Then, the stock solution was diluted with test water to obtain the required test concentrations and filled into aquaria.
- No evidence of undissolved particle is reported
Test organisms (species):
Danio rerio (previous name: Brachydanio rerio)
Details on test organisms:
TEST ORGANISM
- Common name: Zebrafish
- Source: Elevage de la Grande Rivière - B. et C. Romano - La Fond Garel – 69490 SAINT FORGEUX
- Length at study initiation: 2.61 cm (range: 2.42 to 2.82 cm) for range-finding test, 2.75 cm (range: 2.60 to 2.94 cm) for final test
- Feeding during test: no

ACCLIMATION
- Acclimation period: >= 12 d
- Acclimation conditions: same as test
- Type and amount of food: pellets fish food
- Feeding frequency: daily
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Post exposure observation period:
None
Hardness:
250 mg/L (CaCO3)
Test temperature:
21.2-22.4°C (measured, whole test period)
pH:
7.35-7.95 (measured, whole test period)
Dissolved oxygen:
6.20-8.43 mg/L (measured, whole test period)
Salinity:
Not applicable
Nominal and measured concentrations:
Nominal: 14.4-16.4-18.7-21.2-24.2-27.6-31.5 mg/L
Measured: 13.69-16.77-18.45-21.21-NA-NA-NA mg/L (end 96h)
Details on test conditions:
TEST SYSTEM
- Test vessel: glass aquaria
- Closed by placing a glass plate on the aquarium and sealed with vaseline
- Fill volume: 3.5 L
- Headspace: ca. 1 cm
- Aeration: no
- Renewal rate of test solution: daily
- No. of organisms per vessel: 7
- No. of vessels per concentration: 1
- No. of vessels per control: 1
- Biomass loading rate: < 1 g/L

TEST MEDIUM / WATER PARAMETERS
- Reconstituted water according to OECD TG 203
- Intervals of water quality measurement: pH, nitrate and nitrite concentration, ammonia concentration, total water hardness and dissolved oxygen were measured once a week. Temperature was recorded every day.

OTHER TEST CONDITIONS
- Photoperiod: 16 h light : 8 h dark

EFFECT PARAMETERS MEASURED
- Mortality at 3, 6, 24, 48, 72 and 96 h following the start of exposure

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.14
- Range finding study: yes
- Test concentrations: 0.1-1.0-10.0-100 mg/L
- Results used to determine the conditions for the definitive study: mortatlity rate of 100% at 100 mg/L
Reference substance (positive control):
yes
Remarks:
Potasium dichromate
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
20.3 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: 95%CI: 18.9-21.8 mg/L
Details on results:
- Behavioural abnormalities: sublethal effects (lack of balance, erratic swimming, sudden quick movement, swimming on the back) observed at 14.4-16.4-18.7-21.2 mg/L nominal test concentrations
- Mortality of control: no
- Effect concentrations exceeding solubility of substance in test medium: no
- LC0 = 16.4 mg/L
- LC100 = 24.2 mg/L
Results with reference substance (positive control):
- Results with reference substance were valid
- LC50: 179 mg/L
Reported statistics and error estimates:
The software ToxRat® Professional was used for the determination of the effective concentrations. The LC50 value was determined by Probit analysis using linear max. likelihood regression.

ANALYTICAL RESULTS

- Concentrations measured in freshly prepared test solutions and in 24 -h old test solutions revealed that the concentration of the test item was satisfactorily maintained within ± 20 % of the initial concentration throughout the test

- Since exposure concentrations of the test substance were satisfactorily maintained, the results were expressed in terms of nominal concentrations

Validity criteria fulfilled:
yes
Conclusions:
The 96 h LC50 for Nerol is 20.3 (18.9-21.8) mg/L in zebrafish (Danio rerio).
Executive summary:

In an acute aquatic toxicity study performed according to OECD TG 203 and in compliance with GLP, groups (7/concentrations) of zebrafish (Danio rerio) were exposed to nerol at concentrations of 0 (blank), 14.4, 16.4, 18.7, 21.2, 24.2 -27.6 and 31.5 mg/L (nominal) for 96 h under semi-static conditions. Mortalities were recorded at 3, 6, 24, 48, 72 and 96 h. Exposure concentrations were satisfactorily maintained. The LC50 value, based on mortality, was 20.3 mg/L. Sublethal effects (lack of balance, erratic swimming, sudden quick movement, swimming on the back) were observed in the groups exposed to 14.4-16.4-18.7-21.2 mg/L nominal test concentrations.

This toxicity study is classified as acceptable and satisfies the guideline requirement for short-term toxicity to fish.

Description of key information

The substance exhibits a LC50 for freshwater fish of 20.3 mg/L.

Key value for chemical safety assessment

LC50 for freshwater fish:
20.3 mg/L

Additional information

One reliable study is available for nerol. The toxicity to freshwater fish was studied according to OECD TG No. 203 and GLP.

Fish (Danio rerio) were exposed to substance at nominal test concentrations of 14.4, 16.4, 18.7, 21.2, 24.2, 27.6 and 31.5 mg/L over a test period of 96 hours (semi-static test, daily renewal). Concentrations were analytically verified at the start and daily until the end of the test. Measured concentrations did not deviate from 20% of the initial concentrations. Thus the endpoints were based on nominal concentration.

The 96h-LC50 was determined to 20.3 mg/L, the LC0 and LC100 to 16.4 mg/l and 24.2 mg/L, respectively.