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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2001
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
GLP compliance:
yes
Vehicle:
no
Test organisms (species):
Daphnia magna
Total exposure duration:
48 h
Details on test conditions:
29.6, 44.4, 66.7, 100, and 150 mg/l
Key result
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
70 mg/L
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
EC100
Effect conc.:
100 mg/L
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
LOEC
Effect conc.:
66.7 mg/L
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
At 66.7, 100, and 150 mg/l, a significant reduction in pH was recorded.
Validity criteria fulfilled:
not specified
Conclusions:
2-Ethylbutyric acid was determined to have an LC50, EC100, and LOEC of 70, 100, and 66.7 mg/l, respectively, in a 48-hour aquatic acute toxicity experiment in Daphnia magna.
Executive summary:

An experiment was performed according to Good Laboratory Practise (GLP) and OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test) in order to determine the acute toxicity of 2-ethylbutyric acid to the aquatic invertebrate Daphnia magna. The experiment ran for a 48-hour period, at the start of which Daphnia magna were exposed to 29.6, 44.4, 66.7, 100, and 150 mg/l. Although 2-ethylbutyric acid was considered to be acidic, the pH of the test system was not adjusted and, therefore, any negative effect observed relative to the control may be a result of the low pH as well as potential toxicity. The immobilisation of Daphnia magna was selected as a reliable indicator of toxicity. At the end of the 48-hour experiment, an LC50, EC100, and LOEC of 70, 100, and 66.7 mg/l, respectively, had been calculated. The LC50 of 70 mg/l is outside of the range considered to be hazardous to the aquatic environment under CLP Regulation (EC) No 1272/2008. This data was not published.

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
2000
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Insufficient information for an assessment of reliability.
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
GLP compliance:
not specified
Test organisms (species):
Daphnia magna
Total exposure duration:
48 h
Test temperature:
20 ± 1 °C
Nominal and measured concentrations:
29.6, 44.4, 66.7, 100, and 150 mg/l
Key result
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
44.4 mg/L
Conc. based on:
test mat.
Basis for effect:
not specified
Key result
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
71.7 mg/L
Conc. based on:
test mat.
Basis for effect:
not specified
Key result
Duration:
48 h
Dose descriptor:
LC100
Effect conc.:
100 mg/L
Conc. based on:
test mat.
Basis for effect:
not specified
Validity criteria fulfilled:
not specified
Conclusions:
2-Ethylbutyric acid was concluded to have a NOEC, LC50, and LC100 of 44.4, 71.7, and 100 mg/l, respectively, in the aquatic invertebrate Daphnia magna following a 48-hour exposure period.

Description of key information

An LC50, EC100, and LOEC value of 70, 100, and 66.7 mg/l, respectively, was concluded as part of a 48-hour aquatic acute toxicity experiment in Daphnia magna exposed to 29.6 - 150 mg/l 2-ethylbutyric acid. As the 70 mg/l LC50 is outside of the range considered to be hazardous to the aquatic environment (CLP Regulation (EC) No 1272/2008), the registered substance can be regarded as being non-acutely toxic to aquatic invertebrates under the conditions of the test. A supporting study that involved 48-hour exposure of Daphnia magna to 2-ethylbutyric provided a relatively similar NOEC, LC50, and LC100 of 44.4, 71.7, and 100 mg/l, respectively. The LC50 of 70 mg/l was selected as the key value for chemical safety assessment given that this was derived from a key study (Klimisch score = 2) and is most conservative.  

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
70 mg/L

Additional information