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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Reference
Endpoint:
toxicity to soil macroorganisms except arthropods: short-term
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
see "General Justification for Read-Across" attached to IUCLID section 13

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
Mutual read across from the AAPBs to one another is justified:

a) Based on the information given in section 1, it can be concluded that all AAPBs mentioned above are similar in structure, since they are manufactured from similar resp. identical precursors under similar conditions and all contain the same functional groups. Thus a common mode of action can be assumed.
b) The content of minor constituents in all products are comparable and differ to an irrelevant amount.
c) The only deviation within this group of substances is a minor variety in their fatty acid moiety, which is not expected to have a relevant impact on intrinsic toxic or ecotoxic activity and environmental fate. Potential minor impact on specific endpoints will be discussed in the specific endpoint sections.

The read-across hypothesis is based on structural similarity of target and source substances. Based on the available experimental data, including key physico-chemical properties and data from toxicokinetic, acute toxicity, irritation, sensitisation, genotoxicity and repeated dose toxicity studies, the read-across strategy is supported by a quite similar toxicological profile of all five substances.
The respective data are summarised in the data matrix; robust study summaries are included in the Technical Dossier in the respective sections.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
see "General Justification for Read-Across" attached to IUCLID section 13

3. ANALOGUE APPROACH JUSTIFICATION
see "General Justification for Read-Across" attached to IUCLID section 13

4. DATA MATRIX
see "General Justification for Read-Across" attached to IUCLID section 13
Reason / purpose:
read-across: supporting information
Reason / purpose:
read-across source
Reason / purpose:
read-across source
Key result
Duration:
14 d
Dose descriptor:
LC0
Effect conc.:
>= 846 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
mortality
Duration:
14 d
Dose descriptor:
LC0
Effect conc.:
>= 380 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
mortality
Conclusions:
As there were no effects observed in both studies, it is justified to use the LC0 of 846 mg a.i./kg soil dw for chemical safety assessment. The obtained results were considered to be valid for the AAPBs.

Description of key information

Two acute toxicity studies towards the earthworm Eisenia fetida are available.

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:
846 mg/kg soil dw

Additional information

No experimental data are available for C12-14 AAPB. However, adequate and reliable data on the acute toxicity towards soil macroorganisms (Eisenia fetida) are available for the closely related source substances C8-18 AAPB and C8-18 and C18 unsatd. AAPB.

A justification for read-across is given below.

 

The acute toxicity of C8-18 AAPB towards the earthworm Eisenia fetida was investigated in a study conducted according to OECD Guideline 207 (Earthworm, Acute Toxicity Tests) and EU Method C.8 (Toxicity for Earthworms: Artificial Soil Test). At total 40 animals per concentration step were exposed to nominal concentrations of 0 (control), 63, 125, 250, 500, and 1000 mg product/kg dry soil for 14 d. No mortality and no effects on body weight were observed even in the highest concentration tested (14 d LC0 ≥ 1000 mg product/kg dry soil; 14 d LC0 ≥ 380 mg a. i /kg dry soil assuming an active matter content of 38 %). Moreover, no abnormal behaviour of the test organisms or other symptoms of toxicity were recorded in worms at any of the test treatments.

 

A second study, conducted as limit test, the acute toxicity of C8-18 and C18 unsatd. AAPB towards Eisenia fetida was investigated according to EU Method C.8 (Toxicity for Earthworms: Artificial Soil Test). 40 Animals were exposed to 1000 mg/kg dry residue of test material (sole concentration tested) over a 14-d period. The 14 d LC0was determined to be ≥ 1000 mg dry residue/kg soil dry weight (corresponding to ≥ 846 mg active matter/kg soil dry weight and ≥ 2857 mg product/kg soil dry weight.

 

Conclusion

As there were no effects observed in both studies, it is justified to use the LC0 of 846 mg a.i./kg soil dw for chemical safety assessment. The obtained results were considered to be valid for the AAPBs.

 

Justification for read-across

For details on substance identity and detailed (eco)toxicological profiles, please refer also to the general justification for read-across attached as pdf document to IUCLID section 13.

 

This read-across approach is justified based on structural similarities. All AAPBs contain the same functional groups. Thus a common mode of action can be assumed.

The only deviation within this group of substances is a minor variety in their fatty acid moiety (chain length and degree of unsaturation), which is not expected to have a relevant impact on intrinsic ecotoxicological properties.

 

a. Structural similarity and functional groups

Alkylamidopropyl betaines (AAPBs) are – with the exception of C12 AAPB - UVCB substances (Substances of Unknown or Variable composition, Complex reaction products or Biological materials), which are defined as reaction products of natural fatty acids or oils with dimethylaminopropylamine and further reaction with sodium monochloroacetate. AAPBs are amphoteric surfactants, which are characterized by both acidic and alkaline properties.

 

Their general structure is:

 

R-C(O)-NH-(CH2)3-(N(CH3)2)+-CH2-C(O)O-

R = fatty acid moiety

 

The fatty acids have a mixed, slightly varying composition with an even numbered chain length from C8 to C18. Unsaturated C18 may be included. Consequently, the AAPBs differ by their carbon chain length distribution and the degree of unsaturation in the fatty acid moiety. However, Lauramidopropyl betaine (C12 fatty acid derivate) is the major ingredient of all AAPBs covered by this justification as listed in table 1 “Substance identities” of the general justification for read-across.

 

The substances under evaluation share structural similarities with common functional groups (quaternary amines, amide bonds and carboxymethyl groups), and fatty acid chains with differences in chain length and degree of saturation.

 

b. Differences

Differences in ecotoxicity of the AAPBs could potentially arise from the following facts:

-Different amounts of different carbon chain lengths (carbon chain length distribution):

Higher amounts of higher chain lengths and corresponding lower amounts of lower chain length could result in a rising average lipophilicity. However, the main component for all AAPBs is C12 AAPB. Relevant effects on ecotoxicity are not to be expected.

- Different amounts of unsaturated fatty ester moieties:

Effects may be expected for e.g. physical state, but are not considered to be of relevance for ecotoxicity.

 

Comparison of toxicity datato soil macroorganisms

 

Endpoints

Source substances

Target substance

 

C8-18 AAPB

C8-18 and C18 unsatd. AAPB

C12-14 AAPB

Toxicity to soil macroorganisms except arthropods

key_Toxicity to soil macroorganisms except arthropods.97862-59-4_9.4.1_Acute Earthworm_Unilever-A23-KAW030412_OECD 207


key study

 

EU Method C.8 (Toxicity for Earthworms: Artificial Soil Test), Eisenia fetida, laboratory study,
short-term toxicity

 
14 d LC0 >= 1000 mg/kg soil dw, test mat.
(nominal) based on: mortality
14 d LC0 >= 380 mg/kg soil dw,
act. ingr. (nominal) based on: mortality

 

Reliability: 1 (reliable without restriction), GLP

key Toxicity to soil macroorganisms except arthropods: 61789-40-0_9.4.1_Hüls_1995_EEC 88-302 C8

 

key study

 

EU Method C.8 (Toxicity for Earthworms: Artificial Soil Test), Eisenia fetida, laboratory study,
short-term toxicity

 
14 d LC0 >= 846 mg/kg soil dw,
act. ingr. (nominal) based on: mortality

 

Reliability: 2 (reliable with restrictions), GLP

No data, read-across

 

No effects were observed in both studies. The 14 d LC0 was >/=846 mg a.i./kg soil dw(nominal).

 

 

Quality of the experimental data of the analogues:

The available data are adequate and sufficiently reliable to justify the read-across approach.

The studies were performed according to EU Method C.8 and werereliable or reliable with restrictions (RL1-2, GLP).

The test materials used in the respective studies represent the source substance as described in the hypothesis in terms of substance identity and minor constituents.

Overall, the study results are adequate for the purpose of classification and labelling and risk assessment.

 

Conclusion

Based on structural similarities of the target and source substancesas presented above and in more detail in the general justification for read across, it can be concluded that the available data from the source substances C8-18 AAPB and C8-18 and C18 unsatd. AAPBare also valid for the target substance C12-14 AAPB.

The 14 d LC0 of AAPBs to the earthworm Eisenia fetida was >/=846 mg a.i./kg soil dw(nominal).