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Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2001-12-05 to 2002-03-26
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
yes
Remarks:
The Test Guideline includes Part I - the 24h EC 50 acute immobilisation test and Part II - the reproduction test (at least 14 days). Accoding to this study the acute immobilisation test was conducted with a duration of 48 h, part II was not conducted.
GLP compliance:
yes
Analytical monitoring:
yes
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test chemical was refrigerated. 500mg test chemical was diluted in 500mL dilution water and which was used as 1,000mg/L test solution. Infrared absorption spectrum of the refrigerated test chemical was detected at the start and the end of the test, and both spectrums are not contradictory to each other.

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia Magna
-Strain: had been reproduced for 5 years.
- Source:National Institute for Environmental Studies, Ministry of Environment, .
- Age at study initiation (mean and range, SD): Juveniles less than 24 hours old
- Method of breeding: Subculture (maximum rearing period: four weeks, frequency of water exchange: at least twice a week)
- Feeding during test: no feeding


ACCLIMATION
- Acclimation period: December 19, 2001 to January 15, 2002, Parental daphnids were acclimated for 27 days on test condition before testing
- Acclimation conditions (same as test or not): same; water temperature 20+-1°C, 16-8 hours room light-dark photocycle
- Type and amount of food: Chlorella vulgaris, 0.15-0.2 mgC (organic carbon)/organism/day
- Health during acclimation (any mortality observed): death rate of parents was 5% or less in two weeks before exposure, no production of resting eggs or males was observed
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Hardness:
no data, artificially prepared water Elendt M4
Test temperature:
20.4-20.6°C +/- 1°C

pH:
8.1
Dissolved oxygen:
8 - 8.2 mg/L
Salinity:
no data, artificially prepared water Elendt M4
Nominal and measured concentrations:
measured concentration was within +/- 20% of the nominal value
Details on test conditions:
TEST SYSTEM
- Test vessel: 100 mL glass vessel with screw tubes
- Material, size, headspace, fill volume: 100 mL/container
- Aeration: not described
- No. of organisms per vessel: 5 fleas /container
- No. of vessels per concentration (replicates): 4 containers /concentration




TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Elendt M4


OTHER TEST CONDITIONS
- Adjustment of pH: no adjustment,but ph measurement
- Photoperiod: 16-8 hours light dark photocycle
- Light intensity: room light


TEST CONCENTRATIONS
- Justification for using less concentrations than requested by guideline: Based on the results of the preliminary test, the concentraion of 1000 mg/mL and control were set.
- Test concentrations: 1000 mg/L test solution

Reference substance (positive control):
yes
Remarks:
48 hour median immobilization concentration (EiC50) by potassium dichromate, special grade chemical was 0.67 mg/L (EiC50 value at our site is 0.49 - 1. 1 mg/L, n=5, since October 1999)
Duration:
48 h
Dose descriptor:
other: Highest concetration in 0% immobility
Effect conc.:
1 000 mg/L
Nominal / measured:
nominal
Duration:
48 h
Dose descriptor:
other: Lowest concentration in 100% immobility
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Basis for effect:
mobility
Details on results:
- Behavioural abnormalities:
- Observations on body length and weight:
- Other biological observations:
- Mortality of control:
- Other adverse effects control:
- Abnormal responses:
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values:
- Effect concentrations exceeding solubility of substance in test medium:


The immobility of the control group under 48 -hour exposure was 0% and the rate of the fleas that surfaced was 0% and it fulfilled the conditions for establishing the test.





Mortality or Immobility: No test organism was Immobilized
at any concentration.
-----------------------------------------------------------
       Cumulative Number of Dead or Immobilized
Daphnids
Nominal         (Percent Mortality or Immobility)
Conc.      
-----------------------------------------------------------
mg/L                  24 Hour         48 Hour
-----------------------------------------------------------
Control               0 ( 0 )         0 ( 0 )
1,000                 0 ( 0 )         0 ( 0 )
-----------------------------------------------------------


Validity criteria fulfilled:
not specified
Conclusions:
MMB was observed to cause no immobilizing effects on daphnia magnae after 48hrs at a concentration of 1,000 mg/L.
Executive summary:

The test on acute toxicity of 3-methoxy-3-methyl-1-butanol towards invertebrates was performed according to the OECD guideline 202 part I. The water flea (Daphnia magna), juveniles within 24 hours after birth, was used as the test organism. The study was conducted under static conditions over duration of 48 h. Each of 20 test organisms was exposed to the test concentration of 1000 mg/l s and the control. The concentration of the test substance was within +/- 20% of the nominal value, and each effect concentration was calculated, adopting the nominal value. MMB was found to cause no toxicity on daphnia magna after 24hours and after 48 hours at a concentration of 1,000 mg/L . The EC50 24h was > 1000 mg/L and the EC50 48 h was > 1000 mg/L.

Description of key information

A 48 hr daphnia magna LC50 >1000 mg/L is used in the chemical safety assessment for MMB. 

Key value for chemical safety assessment

Additional information