1-Propanaminium, 3-amino-N-(carboxymethyl)-N,N-dimethyl-, N-(C12-18(even numbered) acyl) derivs., hydroxides, inner salts

Endpoint summary

Additional information

AAPBs are readily biodegradable, biodegradable under anaerobic conditions and under different environmental conditions (water, seawater, sewage treatment plants). The ultimate biodegradation was proven and a mean elimination of 99 % was calculated. Therefore further investigation on biodegradation in soil does not need to be conducted in accordance with REACH Regulation Annex IX, 9.2.1.3.

 

Conclusion

Experimental results from several guideline studies (e.g. OECD 301 A, 301 B, 301 D, 301 E) on the aerobic biodegradation of C8-18 and C18 unsatd. AAPB, C12 AAPB and C8 -18 AAPB are available. Based on the results, C8-18 and C18 unsatd. AAPB, C12 AAPB, and C8 -18 AAPB can be regarded as readily biodegradable. The inherent biodegradability of C12-18 AAPB was proven in a Zahn-Wellens Test. Based on these results, the AAPBs can be regarded as readily biodegradable.

The anaerobic biodegradability of C8-18 and C18 unsatd. AAPB and C8-18 AAPB was investigated in studies conducted similar to OECD guideline 311. Based on the results of these studies, the AAPBs are considered to be biodegradable under anaerobic condition.

 

Furthermore, the ultimate biodegradation of the AAPBs was proven; a mean elimination of 99% was calculated for the AAPBs. Based on the results of the biodegradation study in seawater, the AAPBs are considered as readily biodegradable in the marine environment.

 

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.

Moreover, in several biodegradation screening tests ready or at least inherent biodegradability was shown for all substances under invesitigation.

 

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 biodegradability 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 biodegradability 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 biodegradability.

 

Comparison of biodegradation data

Endpoints	Source substances			Target substance
	C8-18 AAPB	C8-18 and C18 unsatd. AAPB	C12 AAPB	C12-18 AAPB
Biodegradation: key studies (further supporting studies are presented in the General Justification for Read-Across)	key.Biodegradation in water: screening tests.97862-59-4_9.2.1.1_EOC_Hydrotox_1992_OECD 301 B   OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test), ready biodegradability, aerobic   activated sludge (adaptation not specified)   % Degradation of test substance: 91.6 after 28 d (CO2 evolution)   readily biodegradable   Reliability: 1 (reliable without restriction), GLP	key.Biodegradation in water: screening tests.61789-40-0_9.2.1.1_Stepan_2000_ISO/DIS 14593   ISO/DIS 14593, ready biodegradability, aerobic   activated sludge (adaptation not specified)   % Degradation of test substance: 87.2 after 28 d (CO2 evolution)   readily biodegradable   Reliability: 1 (reliable without restriction), no GLP	key.Biodegradation in water: screening tests.4292-10-8_9.2.1.1_DAC_1996_EEC 92-69 C4f EU Method C.4-F (Determination of the "Ready" Biodegradability - MITI Test), ready biodegradability, aerobic   inoculum taken from a purifying plant for municipal and industrial effluents, from an industrial effluent purifying plant and surface water and surface soil from a river bank % Degradation of test substance:82 after 28 d (O2 consumption) (biodegradation based on ThOD) 95 after 28 d (O2 consumption) (biodegradation based on COD) readily biodegradable   Reliability: 2 (reliable with restrictions), no GLP	key.Biodegradation in water: screening tests: 63641-59-8_9.2.1.1a_Hoechst_1986_OECD 302B equivalent to OECD TG 302 B (Zahn-Wellens/EMPA Test), inherent biodegradability, aerobic activated sludge, industrial, non-adapted   % Degradation of test substance: 89.4 after 15 d (DOC removal) inherently biodegradable   Reliability: 2 (reliable with restrictions), no GLP
	key(anaerobic)_Biodegradation in water: screening tests: 97862-59-4_9.3.4_THG_2000_ECETOC TG 28 ECETOC Anaerobic Biodegradation (Technical Report No. 28),anaerobic biodegradability digested sludge   % Degradation of test substance: ca. 80 after 62 d (DOC removal) well biodegradable under anaerobic conditions   Reliability: 2 (reliable with restrictions), no GLP	key (anaerobic).Biodegradation in water: screening tests: 61789-40-0_9.3.4_Colgate-Palmolive_2002_ISO 11734 ISO 11734,anaerobic biodegradability % Degradation of test substance: 80 — 90 after 60 d (biogas production and TIC) anaerobic sludge biodegradable under anaerobic conditions   Reliability: 1 (reliable without restriction), no GLP
Biodegradation in water and sediment: simulation tests	No data	key(seawater).Biodegradation in water and sediment: simulation tests.61789-40-0_9.2.1_Stepan_2007_JC_OECD 306-CONF   key study similar to OECD Guideline 306 (Biodegradability in Seawater),aerobic   aged seawater % Degradation of test substance: 76 after 28 d (O2 consumption) Reliability: 2 (reliable with restrictions), GLP	No data	No data, read-across
		WoE.Biodegradation in water and sediment: simulation tests.61789-40-0_9.2.1.4_Biodeg_Unilever_A20_TR-474-01   weight of evidence   similar to OECD Guideline 303 A (Simulation Test - Aerobic Sewage Treatment. A: Activated Sludge Units), aerobic   aged seawater   sewage, domestic   % Degradation of test substance: 96.8 — 105.2 after 161 d (DOC removal)   Reliability: 2 (reliable with restrictions), GLP
		WoE.Biodegradation in water and sediment: simulation tests: 61789-40-0_9.2.1.4_Henkel_2001_OECD 303A   weight of evidence   OECD Guideline 303 A (Simulation Test - Aerobic Sewage Treatment. A: Activated Sludge Units), aerobic   activated sludge (adaptation not specified)   % Degradation of test substance: 97 after 35 d (DOC removal) Reliability: 2 (reliable with restrictions), no GLP
		sup(seawater).Biodegradation in water and sediment: simulation tests.61789-40-0_9.2.1_Stepan_2003_JC_OECD 306-CONF   supporting study   similar to OECD Guideline 306 (Biodegradability in Seawater), aerobic   aged seawater   % Degradation of test substance: 54 after 28 d (O2 consumption)   Reliability: 2 (reliable with restrictions), GLP

 

For the target substance C12-18 AAPB, inherent biodegradability was shown.

C8-18 AAPB, C8-18 and C18 unsatd. AAPB and C12 AAPB were shown to be readily biodegradable under aerobic conditions. For C8-18 AAPB as well as C8-18 and C18 unsatd. AAPB the biodegradation under anaerobic conditions was proved as well.

C8-18 and C18 unsatd. AAPB was shown to be ultimately biodegradable in seawater as well as in a simulation test with seage.

 

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 or similar toguidelines and werereliable or reliable with restrictions (RL1-2).

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 substances as presented above and in more detail in the general justification for read across as well ason the similar results from the screening tests, it can be concluded that the available data on ready biodegradation from the source substances C12 AAPB, C8-18 AAPB, and C8-18 and C18 unsatd. AAPB and the data on ultimate biodegradation from the source substance C8-18 and C18 unsatd. AAPB are also valid for the target substance C12-18 AAPB.