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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:
1992-08-17 to 1993-06-11
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
2004
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Concentrations: 0 and 100 mg TOS/L
- Sampling method: At the start of the test, three samples (10 mL) were taken from freshly prepared control and test meida. After 48h,the contents of the test vessels from each group were pooled and further samples taken for nalysis.
- Sample storage conditions before analysis: frozen
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test substance (957.4 mg) was dissolved in dilution medium (Elendt M4) to provide the test medium at a nominal concentration of 100 mg TOS/L. The contents of the flask were shaken vigorousley before being poured in the test vessels.
- Controls: dilution medium ( Elendt M4)
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia
- Strain: Daphnia magna Straus
- Source: Institute National de Recherche Chimique Appliqué (IRChA), France
- Age at study initiation (mean and range, SD): less than 24 hours
- Feeding during test: no



Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Hardness:
260 mg CaCO3/L
Test temperature:
20.8 - 21.2°C
pH:
6.16 - 6.68
Dissolved oxygen:
72 - 100% ASV
Nominal and measured concentrations:
nominal: 0 and 100 mg TOS/L
Measured: 92.5% of the nominal activity
Details on test conditions:
TEST SYSTEM
- Test vessel: glass dishes
- Type (delete if not applicable): loosely covered
- Material, size, fill volume: : glass, 120 mL, 100 mL
- 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: Elendt M4 medium. The medium was prepared in deionised, reversed osmosis water. The dilution medium was adjusted to pH 6.0 ± 0.2 to maintain the stability of the test substance.
- Culture medium different from test medium: no


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


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The numbers of mobile, immobile and floating daphnia were counted approximately 24 and 48h after the start of the study.

TEST CONCENTRATIONS
- 0 and 100 mg TOS/L corresponding to 0 and 22.2 mg active enzyme protein/L

Reference substance (positive control):
no
Key result
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
>= 22.2 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Remarks:
active enzyme protein
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 22.2 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Remarks:
active enzyme protein
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
other: TOS
Basis for effect:
mobility
Remarks on result:
other:
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
other: TOS
Basis for effect:
mobility
Details on results:
- Mortality of control: 0
- Other adverse effects control:no
- Abnormal responses: no
Validity criteria fulfilled:
yes
Conclusions:
Xylanase was not toxic towards Daphnia magna under the given conditions and hence no EC50 value could be determined. The NOEC is thus the highest exposure concentration i.e. 100 mg TOS/L corresponding to 22.2 mg aep/L.
Executive summary:

The acute toxicity of Xylanase, PPQ 30189 to Daphnia magna was assessed under static exposure conditions. The active component of the test substance is an enzyme, which was known to be pH sensitive with reduced enzymatic activity under alkaline conditions. In order to maintain the stability of the enzyme the dilution medium used in the study was adjusted to pH 6 before use.

The study was conducted in accordance with EC Methods for Determination of Ecotoxicity, Annex to Commission Regulation (EC) No 440/2008 (O.J. No. L142/456, 2008) Part C, Method 2 “Daphnia sp. Acute Immobilisation Test” and the OECD Guideline for Testing of Chemicals No. 202, “Daphnia Acute Immobilisation Test” (2004).

A group of twenty Daphnia, less than 24 hours old, was exposed for 48 hours to Xylanase, PPQ 30189 at a nominal concentration of 100 mg TOS (Total Organic Solids)/L. The test medium was prepared in Elendt M4 medium by the direct addition of the test substance to the dilution medium.

At the request of the Sponsor, the test concentrations were verified by analysis of the enzyme concentrations, which was performed at the Sponsor’s laboratory.

Observations of the Daphnia in each control and test vessel were made after 24 and 48 hours.

No immobilisation or adverse effects on the Daphnia were noted at a nominal concentration of 100 mg TOS/L (22.2 mg aep/L).

Based on these findings the following values have been estimated:

  • 48-hour EC50 value : >100 mg TOS/L corresponding to 22.2 mg aep/L
  • “No observed effect concentration” : 100 mg TOS/L corresponding to 22.2. mg aep/L

Description of key information

Xylanase was not toxic towards daphnia magna and hence the 48 h EC50 value for xylanase could not be determined and is above > 100 mg TOS/L corresponding to 22.2 mg aep/L. The NOEC value was determined to be >=100 mg TOS/L or 22.2 mg aep/L. The NOEC is >= 100 mg TOS/L equivalent to 22.2 mg aep/L.

Key value for chemical safety assessment

Additional information