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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:
14/5/91 - 16/5/91
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to
Guideline:
other: 40 CFR Part 797.1300, 9/27/85, "Daphnid acute toxicity test" USTC Procedure PRO/ST DAPHNIA 224-7
Deviations:
no
Principles of method if other than guideline:
Not relevant
GLP compliance:
no
Remarks:
Only signatures for GLP test plan available, GLP for test itself unclear
Specific details on test material used for the study:
Not relevant
Analytical monitoring:
yes
Details on sampling:
- Concentrations: 6.25, 12.5, 25, 50 and 100 mg/l (nominal)
- Sampling method: A two milliliter aliquot of each sample solution was withdrawn for analysis
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION:
- Method: No solvent was used
- Controls: Yes
Test organisms (species):
Daphnia pulex
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia pulex
- Source: USTC stock cultures
- Age at study initiation (mean and range, SD): <48 hours
- Method of breeding: Daphnid species are maintained as individual females lines; each female is transferred after releasing each of her first two broods, to new vessels twice, with fresh water and food. Third broods are used, in general, to start the next filial generation and for bioassays.
- No feeding during test

ACCLIMATION
- Acclimation conditions (same as test or not): same
- Type and amount of food: Food consists of a mixture of three algal species: Nitzchia frustulum, Ankistrodesmus convolutus and Chlamydomonas rheinhardi
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
Not relevant
Hardness:
80 - 90 mg/l CaCO3
Test temperature:
22 - 23 °C
pH:
7.6 - 7.8
Dissolved oxygen:
7.8 - 8.8 mg/l
Salinity:
Not relevant
Nominal and measured concentrations:
Nominal: 6.25, 12.5, 25, 50 and 100 mg/l
Measured: 2.4, 4.9, 9.8, 16.3 and 41.3 mg/l
Details on test conditions:
TEST SYSTEM
- Test vessel: test tube
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: glass, 18 x 150 mm containing 15 ml of test medium
- Aeration: Aerated by mixing of test solutions prior to test, no aeration during test
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water according to EPA 600/4-85/013 (Moderately-hard reconstituted water):
NaHCO3 - 96 mg/L
CaSO4.2H2O - 60 mg/L
MgSO4 - 60 mg/L
KCl - 4 mg/L

- Alkalinity: 70 - 100 mg/l CaCO3
- Conductivity: 233 - 238 umhos
- Culture medium different from test medium: no
- Intervals of water quality measurement: temperature, oxygen and pH measured at start and end of experiment

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours light, 8 hours dark
- Light intensity: fluorescent, 50 - 100 ft candles

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality, morbidity and appearance observed daily

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
Reference substance (positive control):
no
Duration:
24 h
Dose descriptor:
LC50
Effect conc.:
> 41.3 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
act. ingr.
Basis for effect:
mortality
Key result
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
22.5 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
act. ingr.
Basis for effect:
mortality
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
9.8 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
act. ingr.
Basis for effect:
mortality
Details on results:
- Mortality of control: 0%
Results with reference substance (positive control):
Not relevant
Reported statistics and error estimates:
Probit Analysis or Spearman - Karber Method when possible, otherwise, graphical interpolation.

For detailed results, see attached file "Results.doc".

Validity criteria fulfilled:
yes
Remarks:
Mortality in controls <10%, oxygen saturation >60%, pH differed less than 1 unit during the test
Conclusions:
The acute toxicity LC50 (48h) of Diacid 1550 potassium salt towards Daphnia pulex is 22.5 mg/l based on the active ingredient.
Executive summary:

The acute toxicity of Diacid 1550 potassium salt towards Daphnia pulex was investigated according to 40 CFR Part 797.1300, 9/27/85, "Daphnid acute toxicity test" USTC Procedure PRO/ST DAPHNIA 224-7 under GLP. Daphnids were exposed to nominal concentrations of 6.25, 12.5, 25, 50 and 100 mg/l and observed for 48 hours. Based on measured concentrations, the 24h- and 48h-LC50 and 48h-NOEC were found to be >41.3, 22.5 and 9.8 mg/l, respectively, based on the active ingredient.

Description of key information

The acute toxicity (48h-LC50) of Diacid 1550 potassium salt towards Daphnia pulex is 22.5 mg/l based on the active ingredient.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
22.5 mg/L

Additional information

 The acute toxicity of Diacid 1550 potassium salt towards Daphnia pulex was investigated according to 40 CFR Part 797.1300, 9/27/85, "Daphnid acute toxicity test" USTC Procedure PRO/ST DAPHNIA 224-7 under GLP. Daphnids were exposed to nominal concentrations of 6.25, 12.5, 25, 50 and 100 mg/l and observed for 48 hours. Based on measured concentrations, the 24h- and 48h-LC50 and 48h-NOEC were found to be >41.3, 22.5 and 9.8 mg/L respectively based on the active ingredient