Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
biodegradation in water: screening tests
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Test procedures were carried out according to the German national standard, basic data given.
Reason / purpose:
reference to same study
Related information:
Composition 1
Reference:
Composition 0
Principles of method if other than guideline:
Test procedures were carried out according to the German national standard DIN 38409 Part 51 and 43, for BOD and COD respectively.
GLP compliance:
no
Remarks:
GLP for COD method: no
Test material information:
Composition 1
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Duration of test (contact time):
5 d
Initial conc.:
218 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation:
O2 consumption
Parameter:
BOD5
Value:
520 other: mg/L
Parameter:
COD
Value:
855 mg O2/g test mat.
Parameter:
BOD5*100/COD
Value:
61
Initial weight of the test substance: 1.0188 g/l
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study was performed in accordance to the EU guidelines, however no information was given on the purity of the test substance.
Reason / purpose:
reference to same study
Related information:
Composition 1
Reference:
Composition 0
Composition 0
Qualifier:
according to
Guideline:
other: EU Directive 79/831/EEC Annex V, part C
Principles of method if other than guideline:
Manometric respirometry test. This method is comparable to the OECD guideline 301 F.
GLP compliance:
no
Test material information:
Composition 1
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Municipal activated sludge from laboratory wastewater treatment plant fed with municipal sewage and synthetic wastewater. Final dry solids concentration: 30 mg/l
Duration of test (contact time):
28 d
Initial conc.:
85 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Reference substance:
aniline
Parameter:
% degradation (O2 consumption)
Value:
80 - 90
Sampling time:
28 d
Details on results:
Kinetic of test substance (in %):
< 10 after 4 day(s)
= 37 after 5 day(s)
= 72 after 14 day(s)
= 83 after 20 day(s)
= 90 after 28 day(s)
Kinetic of control substance (in %):
= 70 ... 80 after 28 day(s)
Interpretation of results:
readily biodegradable
Endpoint:
biodegradation in water: screening tests
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Test procedures were carried out according to the German national standard, basic data given.
Justification for type of information:
ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across is based on the hypothesis that source substances and target substance have similar physical-chemical properties and (eco)toxicological properties because they are either stereoisomers of the target substance, are hydrolysed to the same substance or their chemical structure differs only by an additional double bond. This prediction is supported by data on the substances themselves.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The target substance, L-Citronellol, is a mono-constituent substance (EC No. 231-415-7, CAS no. 7540-51-4 consisting of a C8 carbon backbone, methyl substituents at C3 and C7, one double bond and a hydroxyl group. The substance is optically active, comprising a single, pure enantiomeric laevo form.

The source substance, DL-Citronellol, is a mono-constituent substance (EC No. 203-375-0, CAS no. 106-22-9, consisting of a C8 carbon backbone, methyl substituents at C3 and C7, one double bond and a hydroxyl group. The substance is an equimolar mixture of two optical isomers (enantiomers).

The source substance, citronellyl acetate, is a mono-constituent substance (EC No. 205-775-0, CAS no. 150-84-5) consisting of a C8 carbon backbone, methyl substituents at C3 and C7, one double bond and an acetate group.

The source substance, geraniol and it’s isomer, consist of a C8 carbon backbone, methyl substituents at C3 and C7, two double bonds and a hydroxyl group. The only difference between the isomers is the position of the first double bond.

The source substance, geraniol and nerol, is a multi-constituent substance of E/Z isomers (EC No. 906-125-5). The constituents consist of a C8 carbon backbone, methyl substituents at C3 and C7, two double bonds and a hydroxyl group.

The source substance, geraniol, is a mono-constituent substance (EC No. 203-377-1, CAS no. 106-24-1), consisting of a C8 carbon backbone, methyl substituents at C3 and C7, two double bonds and a hydroxyl group. Geraniol is a pure form of the E-isomer.

The source substance, nerol, is a mono-constituent substance (EC No. 203-378-7, CAS no. 106-25-2), consisting of a C8 carbon backbone, methyl substituents at C3 and C7, two double bonds and a hydroxyl group. Nerol is a pure form of the Z-isomer.
The source and target substances are both of high purity with a low concentration of impurities.

3. ANALOGUE APPROACH JUSTIFICATION
The read across hypothesis is based on structural similarity where the source substances only differ in the enantiomeric ratio or an additional double bond. Another source substance is expected to be hydrolysed to the same structure as the target substance.
In a non-chiral environment the target and source chemical DL-Citronellol will have identical properties, but in the chiral environment of living organisms the enantiomers may possess different carcinogenicity and teratogenicity (in a chiral environment, stereoisomers might experience selective absorption, protein binding, transport, enzyme interactions and metabolism, receptor interactions, and DNA binding). All endpoints read-across from DL-Citronellol are considered to be acceptable for this substance assuming that 50% of the target compound is available in the test material.
The source substance citronellyl acetate is read-across from as part of a weight of evidence approach in the repeated dose toxicity endpoint. As this substance is hydrolysed to Citronellol within 2 hours, this read-across endpoint is acceptable in the weight of evidence approach used.
The source substances geraniol, nerol and the reaction mass of geraniol/nerol differ from the target substance only by an additional double bond at C2. These structures are considered to represent a worst case scenario due to the additional potential reactive feature of the second double bond. The genotoxicity, repeated dose and reproductive toxicity endpoints read-across from these substances are therefore acceptable as a worst case assumption.

4. DATA MATRIX
Please refer to the data matrix included in the read-across justification document attached in Section 13.2.
Reason / purpose:
read-across source
Related information:
Composition 1
Reference:
Composition 0
Principles of method if other than guideline:
Test procedures were carried out according to the German national standard DIN 38409 Part 51 and 43, for BOD and COD respectively.
GLP compliance:
no
Remarks:
GLP for COD method: no
Test material information:
Composition 1
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Duration of test (contact time):
5 d
Initial conc.:
218 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation:
O2 consumption
Parameter:
BOD5
Value:
520 other: mg/L
Parameter:
COD
Value:
855 mg O2/g test mat.
Parameter:
BOD5*100/COD
Value:
61
Initial weight of the test substance: 1.0188 g/l
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study was performed in accordance to the EU guidelines, however no information was given on the purity of the test substance.
Justification for type of information:
ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across is based on the hypothesis that source substances and target substance have similar physical-chemical properties and (eco)toxicological properties because they are either stereoisomers of the target substance, are hydrolysed to the same substance or their chemical structure differs only by an additional double bond. This prediction is supported by data on the substances themselves.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The target substance, L-Citronellol, is a mono-constituent substance (EC No. 231-415-7, CAS no. 7540-51-4 consisting of a C8 carbon backbone, methyl substituents at C3 and C7, one double bond and a hydroxyl group. The substance is optically active, comprising a single, pure enantiomeric laevo form.

The source substance, DL-Citronellol, is a mono-constituent substance (EC No. 203-375-0, CAS no. 106-22-9, consisting of a C8 carbon backbone, methyl substituents at C3 and C7, one double bond and a hydroxyl group. The substance is an equimolar mixture of two optical isomers (enantiomers).

The source substance, citronellyl acetate, is a mono-constituent substance (EC No. 205-775-0, CAS no. 150-84-5) consisting of a C8 carbon backbone, methyl substituents at C3 and C7, one double bond and an acetate group.

The source substance, geraniol and it’s isomer, consist of a C8 carbon backbone, methyl substituents at C3 and C7, two double bonds and a hydroxyl group. The only difference between the isomers is the position of the first double bond.

The source substance, geraniol and nerol, is a multi-constituent substance of E/Z isomers (EC No. 906-125-5). The constituents consist of a C8 carbon backbone, methyl substituents at C3 and C7, two double bonds and a hydroxyl group.

The source substance, geraniol, is a mono-constituent substance (EC No. 203-377-1, CAS no. 106-24-1), consisting of a C8 carbon backbone, methyl substituents at C3 and C7, two double bonds and a hydroxyl group. Geraniol is a pure form of the E-isomer.

The source substance, nerol, is a mono-constituent substance (EC No. 203-378-7, CAS no. 106-25-2), consisting of a C8 carbon backbone, methyl substituents at C3 and C7, two double bonds and a hydroxyl group. Nerol is a pure form of the Z-isomer.
The source and target substances are both of high purity with a low concentration of impurities.

3. ANALOGUE APPROACH JUSTIFICATION
The read across hypothesis is based on structural similarity where the source substances only differ in the enantiomeric ratio or an additional double bond. Another source substance is expected to be hydrolysed to the same structure as the target substance.
In a non-chiral environment the target and source chemical DL-Citronellol will have identical properties, but in the chiral environment of living organisms the enantiomers may possess different carcinogenicity and teratogenicity (in a chiral environment, stereoisomers might experience selective absorption, protein binding, transport, enzyme interactions and metabolism, receptor interactions, and DNA binding). All endpoints read-across from DL-Citronellol are considered to be acceptable for this substance assuming that 50% of the target compound is available in the test material.
The source substance citronellyl acetate is read-across from as part of a weight of evidence approach in the repeated dose toxicity endpoint. As this substance is hydrolysed to Citronellol within 2 hours, this read-across endpoint is acceptable in the weight of evidence approach used.
The source substances geraniol, nerol and the reaction mass of geraniol/nerol differ from the target substance only by an additional double bond at C2. These structures are considered to represent a worst case scenario due to the additional potential reactive feature of the second double bond. The genotoxicity, repeated dose and reproductive toxicity endpoints read-across from these substances are therefore acceptable as a worst case assumption.

4. DATA MATRIX
Please refer to the data matrix included in the read-across justification document attached in Section 13.2.
Reason / purpose:
read-across source
Related information:
Composition 1
Reference:
Composition 0
Composition 0
Qualifier:
according to
Guideline:
other: EU Directive 79/831/EEC Annex V, part C
Principles of method if other than guideline:
Manometric respirometry test. This method is comparable to the OECD guideline 301 F.
GLP compliance:
no
Test material information:
Composition 1
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Municipal activated sludge from laboratory wastewater treatment plant fed with municipal sewage and synthetic wastewater. Final dry solids concentration: 30 mg/l
Duration of test (contact time):
28 d
Initial conc.:
85 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Reference substance:
aniline
Parameter:
% degradation (O2 consumption)
Value:
80 - 90
Sampling time:
28 d
Details on results:
Kinetic of test substance (in %):
< 10 after 4 day(s)
= 37 after 5 day(s)
= 72 after 14 day(s)
= 83 after 20 day(s)
= 90 after 28 day(s)
Kinetic of control substance (in %):
= 70 ... 80 after 28 day(s)
Interpretation of results:
readily biodegradable

Description of key information

This endpoint was read across from Citronellol (3,7-dimethyl-6-Octen-1-ol, CAS 106 -22 -9). The substance is readily biodegradable according to OECD criteria.

Two guideline studies investigating the ready biodegradability of Citronellol are available. The biodegradation of the substance was tested in a Manometric Respirometry Test according to EU Directive 79/831/EEC Annex V, part C using domestic activated sludge as inoculum. At test termination after 28 days Citronellol was degraded by 80 - 90 % (BASF AG, 1986). In a BOD5 test according to German standard DIN 38409 part 51 and 43 a BOD5*100/COD of 61 was determined. The results demonstrate that Citronellol is readily biodegradable according to OECD criteria.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

[Type of water: freshwater]