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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:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Justification for type of information:
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
Data for 2-aminoethanol (ethanolamine; CAS No. 141-43-5) and propionic acid (CAS No. 79-09-4) will be used to address the ecotoxicological data requirements for 2-ethyl-2-oxazoline (CAS No. 10431-98-8) in an analogue read-across approach. The basis for this read-across approach is that the test species are expected to rapidly transform the target substance into ethanolamine and propionic acid. The ecotoxicity of the ethanolamine transformation product will be assessed using information on ethanolamine, and the ecotoxicity of the propionic acid transformation product will be assessed using information on propionic acid.

2. SOURCE AND TARGET CHEMICAL(S)
The target substance is known to be of high purity (typically 99.5 % w/w), and to contain up to 1 % w/w (typically 0.5 % w/w) of its 2-methyl analogue as impurity. The impurity is expected to undergo the same transformation steps as the target substance, producing exactly the same ethanolamine transformation product but an analogous acetic acid transformation product in place of the propionic acid transformation product. On this basis, the source substances effectively represent typically >99.5 % w/w of the target substance. The purities of the samples of source substances that were tested are not specifically known, but it is assumed that they would not have been sufficiently impure as to substantially affect the study results. On this basis, the applicability of the data on the source substance to the target substance is not expected to be compromised by the presence of impurities in any of the substances.
See attached report for further details.

3. ANALOGUE APPROACH JUSTIFICATION
The basis for this read-across approach is that the target substance is expected to be rapidly transformed by the test species into ethanolamine and propionic acid according to the scheme presented in the attached report.
This transformation that is expected to occur in man is expected also to occur in the aquatic test species.
The ethanolamine transformation product is clearly identical to the first source substance, and the amount produced will be equivalent to 62% w/w of the loading of target substance.
The propionic acid transformation product is clearly identical to the second source substance, and the amount produced will be equivalent to 75% w/w of the loading of target substance.
The sum of the above values exceeds 100% due to the mass added by the incorporation of water of hydrolysis.
See attached report for further details.

4. DATA MATRIX
See attached report for further details.
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across: supporting information
Specific details on test material used for the study:
The short term toxicity of 2-ethyl-2-oxazoline to aquatic invertebrates is predicted based on the results of 2-aminoethanol and propionic acid.
Test organisms (species):
Daphnia magna
Key result
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
ca. 67 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: Predicted value
Validity criteria fulfilled:
not applicable
Conclusions:
No test data to address the ecotoxicity of the target substance are available. On the basis of available data on the two source substances, aquatic organisms are more sensitive to propionic acid than to 2-aminoethanol. The short-term toxicity to daphnid (24-hr LC50) of 2-aminoethanol was shown to be 140 mg/L, which is less toxic than that for propionic acid which was 50 mg/L (48-hr LC50). During metabolism the target substance produces 62% 2-aminoethanol and 75% propionic acid. As such, based on these values the target substance predicted aquatic toxicity values are: 48-hr LC50 (daphnid) 226 mg/L based on 2-aminoethanol and 67 mg/L based on propionic acid. For risk assessment the conservative 48-hr LC50 (daphnid) = 67 mg/L.

Description of key information

No test data to address the ecotoxicity of the target substance are available. On the basis of available data on the two source substances, aquatic organisms are more sensitive to propionic acid than to 2-aminoethanol. The short-term toxicity to daphnid (24-hr LC50) of 2-aminoethanol was shown to be 140 mg/L, which is less toxic than that for propionic acid which was 50 mg/L (48-hr LC50). During metabolism the target substance produces 62% 2-aminoethanol and 75% propionic acid.  As such, based on these values the target substance predicted aquatic toxicity values are: 48-hr LC50 (daphnid) 226 mg/L based on 2-aminoethanol and 67 mg/L based on propionic acid.  For risk assessment the conservative 48-hr LC50 (daphnid) = 67 mg/L will be utilised.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
67 mg/L

Additional information

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