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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

readily biodegradable (OECD TG 301 B; RL1; GLP): 68% degradation after 11 days, 90% degradation after 28 days; read-across: C8-10 Alkylamidopropyl betaine 

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

No experimental data on biodegradation are available for the target substance Undecylenamidopropyl Betaine. However, relevant and reliable data are available for the closely related source substances C8 -10 Alkylamidopropyl betaine, C8-18 AAPB, C8-18 and C18 unsatd. AAPB and Formamidopropylbetaine. A justification for read-across is given below.

 

The biodegradation of C8-10 Alkylamidopropyl betaine (35% a.i.) was investigated over a 28-day period in a CO2 Evolution Test according to OECD guideline 301 B (1992). The test medium was inoculated with non-adapted activated sludge from a sewage treatment plant mainly fed with municipal wastewater. The rate of degradation was monitored by measuring the carbon dioxide produced over the 28-d period.

The test item was tested with a concentration of 45 mg/L in duplicates, corresponding to a carbon content (TOC) of 11.8 mg C/L in the test vessels.

The biodegradation of the test item was followed by titrimetric analyses of the quantity of CO2 produced by the respiration of bacteria. The degradation was finished on day 28 by acidification, the last titration was made on day 29. After the soluble CO2 was turned out over a period of 24 h.

The percentage CO2 production was calculated in relation to the theoretical CO2 (ThCO2) of the test item. The biodegradation was calculated for each titration time.

The 10% level (beginning of biodegradation of the test item) was reached after an adaptation phase of 3 days. The biodegradation was rapid, the pass level of 60% was reached already on day 11. The mean biodegradation came to a maximum of 90% after 28 days.

To check the activity of the test system sodium acetate was used as functional control. The percentage of degradation of the functional control reached the pass level of 60% after 10 days.

In the toxicity control containing both test and reference item a biodegradation rate of 63% occurred within 14 days and came to a maximum of 85% after 28 days. The biodegradation of the reference item was not inhibited by the test item in the toxicity control.

The test item C8-10 Alkylamidopropyl betaine is readily biodegradable in this CO2 evolution test and fulfills the 10 d window criterion. The substance is not inhibitory to microorganisms at a concentration of 45 mg/L.

 

C8-18 AAPB proved to be readily biodegradable and fulfilling the 10 -d window criterion in a a study conducted according to OECD Guideline 301 B (91.6% biodegradation after 28 d).

 

C8-18 and C18 unsatd. AAPB was readily biodegradable (87.2% biodegradation after 28 d) in a study conducted according to EPA OPPTS 835.3120 (Sealed Vessel Carbon Dioxide Production Test) and ISO/DIS 14593.

 

This is supported by a prediction using EpiSuite v4.11, BIOWIN v4.10: Undecylenamidopropyl Betaine is predicted to be readily biodegradable.

 

The source substance Formamidopropylbetaine is expected to be inherently biodegradable.

 

JUSTIFICATION FOR READ-ACROSS

Hypothesis for the analogue approach

This read-across is based on the hypothesis that source and target substances have similar environmental fate properties because

·        they are manufactured from similar / identical precursors under similar conditions

·        they share structural similarities with common functional groups:quaternary amines, amide bonds, carboxymethyl groups, and fatty acid chains, differing in length and degree of saturation.

Therefore, read-across from the existing environmental fate studies on the source substances is considered as an appropriate adaptation to the standard information requirements of the REACH Regulation for the target substance, in accordance with the provisions of Annex XI, 1.5 of the REACH Regulation.

The justification of the proposed read-across approach is elaborated in the next chapters.

 

1. Substance Identity

The target substance Undecylenamidopropyl Betaine is a monoconstituent substance manufactured from undecylenic acid and N, N-dimethylpropylenediamine (DMAPA) and further reacted with monochloroacetic acid.

 

The source substance C8 -10 Alkylamidopropyl betaine is a UVCB substance manufactured from fatty acids (C8 and C10) and N, N-dimethylpropylenediamine (DMAPA) and further reacted with sodium monochloroacetate.

The source substances C8-18 AAPB and C8 -18 and C18 unsatd. AAPB are UVCB substances manufactured from natural fatty acids or oils with N, N-dimethylpropylenediamine (DMAPA) and further reacted with sodium monochloroacetate. As their origin is from natural sources, the used fatty acids may have a mixed slightly varying composition with an even numbered chain length from C8 to C18. Unsaturated C18 amounts may be included.

 

The source substance Formamidopropylbetaine is a monoconstituent substance manufactured from formic acid and N, N-dimethylpropylenediamine (DMAPA) and further reacted with sodium monochloroacetate.

 

Table 1: Substanceidentities

 

Target substance

Sourcesubstances

Undecylenamidopropyl Betaine

C8-10 Alkylamidopropyl betaine

C8-18 AAPB

C8-18 and C18 unsatd. AAPB

Formamidopropylbetaine

IUPAC name

Carboxymethyl)dimethyl[3-[(1-oxoundecenyl)amino]propyl]ammonium hydroxide

1-Propanaminium, 3-amino-N-(carboxymethyl)-N,N-dimethyl-, N-C8-10 (even numbered) acyl derivs., hydroxides, inner

1-Propanaminium, 3-amino-N-(carboxymethyl)-N,N-dimethyl-, N-(C8-18(even numbered) acyl) derivs., hydroxides, inner salts

 

1-Propanaminium, 3-amino-N-(carboxymethyl)-N,N-dimethyl-, N-(C8-18(even numbered) and C18 unsaturated acyl) derivs., hydroxides, inner salts

(3-(Formylamino)propyl)dimethylammonioacetate

EC number

n.a.

n.a.

931-296-8

931-333-8

480-680-7

CAS number

98510-75-9

n.a.

97862-59-4

 

147170-44-3

120128-90-7

Molecular formula:

C18H34N2O3

UVCB substance, not applicable

UVCB substance, not applicable

UVCB substance, not applicable

C8H16N2O3

Molecular weight:

327.48

286.4-314.5g/mol

weighted mean: 297 g/mol

286.4 - 426.7 g/mol

weighted mean: 355 g/mol

286.4 - 426.7 g/mol

weighted mean: 355 g/mol

188.226 g/mol

Chain length distribution

C11

C6: <= 2 %

C8: 53-64 %

C10: 36-47 %

C12: <= 2 %

C8: <= 10 %

C10: <= 10 %

C12: 40-65 %

C14: 10-26 %

C16: 6-14 %

C18: 2-24 %

C18 unsatd.: <= 2

C6:         <=2%

C8: <= 10%

C10: <= 10%

C12: 40 - 65%

C14: 14 - 21%

C16: 5 - 12%

C18: 1 - 14%

C18 unsatd.:  2 - 20%

C1: 100%

Minor consti-tuents

ca. 15.3% sodium chloride

 

ca. 0.6% glycollic acid

 

ca. 0.8% N-[3-(dimethylamino)propyl]-10-Undecenamide

 

 

11-21% sodium chloride

 

0-3% water

 

0-2% glycollic acid

 

0-0.3% alkylamido-propylamine

 

0-0.0005% DMAPA

5-15% sodium chloride

 

0-3% glycollic acid

 

0-10% glycerol

 

0-2% water

 

0-0.005%DMAPA

 

0-1% alkylamido-propylamine

<20% sodiumchloride

 

<3% glycollic acid

 

< 0.005%DMAPA

 

<1% alkylamido-propylamine

 

ca. 26% sodium chloride

 

ca. 1.5% glycolic acid

 

ca. 1% formamido-propylamine

 

</=0.02% DMAPA

 

Figure 1: Molecular structures of the target substance Undecylenamidopropyl Betaine and the source substances C8-10 Alkylamidopropyl betaine,Formamidopropylbetaine, C8-18 AAPB, C8-18 and C18 unsatd. AAPB (see attachment)

 

2. Analogue approach justification

The read-across hypothesis is based on structural similarity of target and source substances. Based on available experimental data, including water solubility, eye irritation, ecotoxicity, genotoxicity and repeated dose toxicity studies, the read-across strategy is supported by a similar toxicological profile of the target and source substances.

The respective reliable data (RL 1 or 2) are summarized in the data matrix; robust study summaries are included in the Technical Dossier in the respective sections.

 

The read-across from the source substances is justified:

 

a)    Based on the information given in section 1, it can be concluded that the substances are similar in structure, since they are manufactured from similar or 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 carboxylic acid moiety, which is not expected to have a relevant impact on intrinsic toxic or ecotoxic activity and environmental fate. Potential impact on specific endpoints will be discussed in the specific endpoint sections.

 

 

2.1 Structural similarity

a. Structural similarity and functional groups (Table 1, Figure 1)

The target substance Undecylenamidopropyl Betaine is a monoconstituent substance manufactured from undecylenic acid and N, N-dimethylpropylenediamine (DMAPA) and further reacted with monochloroacetic acid.

 

The source substance C8-10 Alkylamidopropyl betaine is a UVCB substance manufactured from fatty acids (C8 and C10) and N, N-dimethylpropylenediamine (DMAPA) and further reacted with sodium monochloroacetate.

 

The source substances C8-18 AAPB and C8-18 and C18 unsatd. AAPB are UVCB substances manufactured from natural fatty acids or oils with N, N-dimethylpropylenediamine (DMAPA) and further reacted with sodium monochloroacetate. As their origin is from natural sources, the used fatty acids may have a mixed slightly varying composition with an even numbered chain length from C8 to C18. Unsaturated C18 amounts may be included.

 

The source substance Formamidopropylbetaine is a monoconstituent substance manufactured from formic acid and N, N-dimethylpropylenediamine (DMAPA) and further reacted with sodium monochloroacetate.

 

b. Differences

Differences in chemical and other intrinsic properties of the target and source substances 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 lead to a rising average lipophilicity as can be seen from the increasing log Kow from Formamidopropylbetaine (log Kow: -3.3), Undecylenamidopropyl Betaine (log Kow: -1.38), C8-10 Alkylamidopropyl betaine (log Kow: 2.2), C8-18 AAPB (4.23).

A higher log Kow and thereby higher Koc might lead to a lower availability of the substance to degrading microorganisms. In that case, the source substances would represent a worst case.

 

- Different amounts of unsaturated fatty ester moieties:

The source substance C8-18 and C18 unsatd. AAPB contains considerable amounts of unsaturated C18 chains, which represents a worst case with respect to some toxicological endpoints, mainly local effects (e.g. irritation, sensitisation). No relevant influence on biodegradation is expected.

 

The provided structural similarities and impurity profiles support the proposed read-across hypothesis with high confidence.

 

 

3. Physicochemical properties

Table 2: Physicochemical properties

 

 

Target substance

Source substances

 

 

 

 

 

 

End-points

Undecylenamidopropyl Betaine

C8-10 Alkylamidopropyl betaine

C8-18 AAPB

C8-18 and C18 unsatd. AAPB

Formamidopropylbetaine

Physical state at 20°C / 1013 hPa

Solid

 

Reliability: 1 (reliable without restrictions)

Solid

 

Reliability: 2 (reliable with restrictions)

Solid

 

Reliability: 2 (reliable with restrictions)

Solid

 

Reliability: 2 (reliable with restrictions)

Liquid

 

Reliability: 1 (reliable without restrictions)

Melting point

144 -158 °C

 

OECD TG 102

 

Reliability: 1 (reliable without restrictions)

No data

Not identifiable due to decomposition in the range between 208 and 280°C

 

OECD TG 102

 

Reliability: 1 (reliable without restrictions)

No data

-50 °C to -20 °C

 

OECD TG 102

 

Reliability: 1 (reliable without restrictions)

Boiling point

decomposition >220°C

 

OECD Guideline 103

 

Reliability: 1 (reliable without restrictions)

No data

decomposition in the range between 208 and 280°C

 

OECD Guideline 103

 

Reliability: 1 (reliable without restrictions)

No data

decomposition >250°C

 

OECD Guideline 103

 

Reliability: 1 (reliable without restrictions)

Density

No data, read-across

No data

relative density D (4/20): 1.15 at 20°C

 

ISO 1183-1

 

Reliability: 1 (reliable without restrictions)

No data

relative density D (4/20):1.14 at 20°C

 

OECD TG 109

 

Reliability: 1 (reliable without restrictions)

Vapour pressure

1.52E-12 Pa at 25°C

 

Calculation: Modified Grain Method; Episuite v4.11, MPBMWIN v 1.43

 

Reliability: 4 (not assignable)

2E-11 Pa at 25°C (calculation C8 derivative)

 

EPIWIN v3.11, MPBPWIN v1.4

 

Reliability: 4 (not assignable)

No data

<=0.0031 hPa at 20°C, C8/10-fraction

 

OECD

Guideline 104

 

Reliability: 2 (reliable with restrictions)

2758 Pa at 20°C

 

OECD

Guideline 104

 

Reliability: 1 (reliable without restrictions)

Log Kow

-1.38 at 20°C

 

Calculation (ACD/Labs v12)

 

Reliability : 2 (reliable with restrictions)

2.2 at 20°C (weighted mean)

 

Calculation (ACD/Labs v12)

 

Reliability : 2 (reliable with restrictions)

4.2317 at 20°C, mean

 

Calculation (ACD/Labs v12)

 

Reliability : 2 (reliable with restrictions)

4.2317 at 20°C, mean

 

Calculation (ACD/Labs v12)

 

Reliability : 2 (reliable with restrictions)

-3.3 at 20.1°C, pH 7.1

 

OECD

TG 107

 

Reliability: 1 (reliable without restrictions)

Water solubili-ty

CMC: 3.1 g/L at 20°C

 

OECD

TG 115

 

Reliability: 1 (reliable without restrictions)

CMC: 4.9 g/L at 20°C

 

OECD

TG 115

 

Reliability: 1 (reliable without restrictions)

400 mg/L at 20°C

 

CMC determination

 

Reliability : 2 (reliable with restrictions)

No data

> 2160 g/L at 20.2 ± 0.6 °C, pH 5.8

 

OECD

TG 105

 

Reliability: 1 (reliable without restrictions)

Surface tension

28.9 mN/m(surface active)

 

OECD

TG 115

 

Reliability: 1 (reliable without restrictions)

24.4 mN/m(surface active)

 

OECD

TG 115

 

Reliability: 1 (reliable without restrictions)

No data

30.9 ± 0.2 mN/m at 20°C (surface active)

 

DIN EN 14370 (Wilhelmy plate method)

 

Reliability: 1 (reliable without restrictions)

72.9 mN/m at 20°C and 2.77 g/L (not surface active)

 

OECD TG 115

 

Reliability: 1 (reliable without restrictions)

Experimental data on melting point, boiling point, water solubility and surface tension are available for the target substance as well as calculated values for vapour pressure. All other endpoints are read across from the source substances as indicated in the table above.

There are differences in molecular weight among the target and source substances – especially the source substance Formamidopropylbetaine differs from the other substances. But as it represents an extreme with the shortest possible C-chain within this group of substances, it can be regarded as a worst case in terms of reactivity (e.g. for the flammability endpoints). The differences in molecular weights also results in differences in physical state, melting and boiling point and vapour pressure. The shorter C-chain further leads to higher hydrophilicity and thereby a lower log Kow and may also explain the absence of surface activity.

 

Under standard conditions the substances are solid (described as waxy or soapy), with the exception of the source substance Formamidopropylbetaine which is liquid. A melting range of 144 -158 °C was determined for the target substance; a boiling point was not identified due to decomposition >200°C. A melting and a boiling point were not identifiable via DSC measurements with the source substance C8-18 AAPB due to decomposition of the test substances. The source substance Formamidopropylbetaine has a melting range of -50 °C to -20 °C and undergoes decomposition at >250°C.

The density of the source substances is in the same range (1.14 to 1.15 g/cm³). Based on the available data, it can be assumed that the differences chain length distribution of the fatty acid chains have no or at the most a minor impact on density. Thus, a similar density can be assumed for the target substance.

The log Kow increases within this group of substances with increasing C-chain length, the presence of double bonds decreases the log Kow, which is in line with the expectations.

 

 

4. Comparison of environmental fate data

The available biodegradation data are summarised in the data matrix below.

No experimental data are available for the target substance Undecylenamidopropyl Betaine. Nevertheless, Undecylenamidopropyl Betaine is predicted to be readily biodegradable based on a calculation using EpiSuite v4.11, BIOWIN v4.10.

 

Biodegradation tests with the source substances C8-10 Alkylamidopropyl betaine, C8-18 AAPB and C8-18 and C18 unsatd. AAPB showed their ready biodegradability. The source substance Formamidopropylbetaine is expected to be inherently biodegradable.

 

5. Quality of the experimental data of the analogues:

All available studies have been conducted according to or comparable with OECD guidelines and have been assigned a reliability of 1 or 2 as documented in the data matrix.

 

Overall, the study design of the respective source studies is adequate and reliable for the purpose of this read-across. The results are adequate for classification and labelling and for risk assessment purposes.

 

6. Conclusion

The structural similarities between the substances as presented above support the read-across hypothesis. Further support is given by the prediction on biodegradability using EpiSuite v4.11, BIOWIN v4.10.

The results of the studies conducted with the source substances are likely to predict the environmental fate properties of the target substance Undecylenamidopropyl Betaine and are considered as adequate to fulfil the respective information requirements. Undecylenamidopropyl Betaine is expected to be readily biodegradable.

 

The read-across is acceptable with high confidence. There are no uncertainties in the read-across approach used that need to be addressed.

 


Table 4 Data matrix

 

Target substance

Source substances

 

 

 

Endpoint

Undecylenamidopropyl Betaine

C8-10 Alkylamidopropyl betaine

C8-18 and C18 unsatd. AAPB

C8-18 AAPB

Formamidopropylbetaine

Bio

degradation

sup_Biodegradation in water: screening tests: 98510-75-9_9.2.1.1._2016_Evonik_EpiSuite

 

calculation with EpiSuite v4.11, BIOWIN v4.10

 

predicted to be readily biodegradable

 

Reliability: 2 (reliable with restrictions), no GLP

WoE_Biodegradation in water: screening tests: 73772-45-9 / 73772-46-0_9.2.1.1._2005_Evonik_OECD 301 B

 

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test), ready biodegradability, aerobic

 

activated sludge, domestic, non-adapted

 

% Degradation of test substance: 68 after 11 d / 81 after 28 d(CO2 evolution)

 

readily biodegradable

 

Reliability: 1 (reliable without restrictions), GLP

WoE_RA_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 restrictions), no GLP

WoE_RA_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 restrictions), GLP

sup_RA_NOTOX 454051 Biodegradation in water: screening tests

 

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test), ready biodegradability, aerobic

 

activated sludge, domestic, non-adapted

 

% Degradation of test substance: 35% after 28 d (CO2 evolution)

 

Not readily biodegradable; inherently biodegradable

 

Reliability: 1 (reliable without restrictions), GLP