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Ecotoxicological information

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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
see deviations from guideline; however the assay evidenced significant toxicity and therefore acts as worst-case data enabling to classify the test item
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
yes
Remarks:
no negative control; missing details on test medium and oxygen; hardness 100 mg/L CaCO3 vs. 140-250 mg/L recommended; pH went below 6, possibly leading to pH-induced toxicity
Principles of method if other than guideline:
Daphnia magna neonates (<24h) from 2–3-week-old mothers were placed in a 50 ml glass beaker containing 40 ml of a test solution.
All experiments for exposure were made in four replcates and performed at 21 ± 0.3 °C under 16 h light: 8 h dark photoperiod.
Immobility was used as the endpoint for determining acute toxicity; the daphnids showing no movement within 15 s after gentle stirring were defined to be immobile.
After 24 and 48 h, the number of immobile daphnids was recorded to determine the concentration able to achieve 50% immobilization and it was indicated as EC50.
The EC50 values were calculated by Probit analyses (USEPA, 1993), based on nominal concentrations.
GLP compliance:
not specified
Analytical monitoring:
yes
Test organisms (species):
Daphnia magna
Details on test organisms:
Neonates (<24h)
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
100 mg CaCO3 / L
Test temperature:
21 ± 0.3°C
pH:
Initial pH 7.45 ± 0.05. No neutralisation during the assay.
Nominal and measured concentrations:
Tested concentration levels: 0.0625 to 1.0 mmol/L
Reference substance (positive control):
no
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
19.1 mg/L
Basis for effect:
mobility
Remarks on result:
other: 95% CI: 16.0-22.7 mg/L
Details on results:
The solution pH decreased below 6 at concentrations over 1 mmol/L 1 of benzoic acids when dissolved in the test medium employed, and daphnids exposed to these solutions showed 100% immobility. Consequently, the toxic effects of benzoic acids were not related to the exposed concentrations alone, under the non-neutralized condition.
Validity criteria fulfilled:
not applicable
Remarks:
no negative control and no data on dissolved oxygen
Conclusions:
Daphnia EC50-48h of the test item is 19.1 (95% CI: 16.0-22.7) mg/L.

Description of key information

Daphnia EC50-48h of the test item is 19.1 (95% CI: 16.0-22.7) mg/L.

Based on these endpoints, gallic acid is not classified for aquatic hazards.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
19.1 mg/L

Additional information