Cymbopogon nardus, ext.

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

other: Known constituent approach

Adequacy of study:

key study

Study period:

21 March 2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Citronella Nardus oil is a Natural Complex Substance (NCS), wIth 90.5% of its constituents identified. The substance can therefore be considered as a well defined NCS.

Justification for type of information:

No test result on the biodegradation of Citronella Nardus is available. According to the NCS Protocol (The Registration for REACH of Natural Complex Substances used as Fragrance Ingredients Revision 2, January 7, 2009 and EFEO/IFRA Guidelines on the Environmental Assessment of Natural Complex Substances (NCS) Version 01, May 26, 2016), the assessment of the biodegradability of a NCS can be based on a constituent approach.

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 C (Inherent Biodegradability: Modified MITI Test (II))

Qualifier:

according to guideline

Guideline:

OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)

Principles of method if other than guideline:

Assessment of the ready biodegradability of the known constituents: addition of the percentage of readily biodegradable constituents in the mixture gives the fraction of readily biodegradable substances.

GLP compliance:

no

Specific details on test material used for the study:

Assessment of constituents was based on using their CAS numbers for identification.

Oxygen conditions:

aerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Remarks:

several guideline tests with different inocula were used

Duration of test (contact time):

>= 28 - <= 63 d

Parameter followed for biodegradation estimation:

CO2 evolution

Parameter followed for biodegradation estimation:

O2 consumption

Key result

Parameter:

% degradation (O2 consumption)

Value:

>= 60

Sampling time:

28 d

Remarks on result:

other: Geraniol, Methyl eugenol, Methyl isoeugenol, borneol, citronellol, geranyl acetate, citronellal, Elemene beta, Elemol, Caryophyllene beta, Bornyl acetate

Key result

Parameter:

% degradation (CO2 evolution)

Value:

>= 60

Sampling time:

28 d

Remarks on result:

other: for Limonene, pinene alpha, cis and trans ocimene, terpineol alpha and citronellyl acetate

Key result

Parameter:

% degradation (O2 consumption)

Value:

>= 60

Sampling time:

63 d

Remarks on result:

other: Cadinene delta, camphene

Key result

Parameter:

% degradation (O2 consumption)

Value:

>= 60

Sampling time:

28 d

Remarks on result:

other: indirect evidence from other UVCB

Remarks:

Farnesene alpha, Germacrene D

Data matrix for ready biodegradation

Constituent	Typical Concentration (% w/w)	Results of Biodegradation Assessment
Geraniol CAS# 106-24-1	25	READILY BIODEGRADABLE   - Modified OECD 301B (sealed CO2 test): 101% (94.5% - 106.3%) in 28 d (Quest 1994) - OECD 301F: test 86% in 28 d (Haarmann& Reimer 2001) - OECD 301F: 94% (Givaudan, 1994) - OECD 301F: 100% (DOC) in 28 d - OECD 301F: 94% in 28 d (ECHA database) -OECD 301D (Closed Bottle test): 73% in 14 d (BBA 1992, in IUCLID (http://esis.jrc.ec.europa.eu/doc/IUCLID /data_sheets/106241.pdf)
(S)-Limonene CAS# 138-86-3/5989-54-8	8	READILY BIODEGRADABLE   - Modified OECD301B (sealed vessels): 71.4% (Quest 1993). The biodegradability of perfume ingredients in the sealed vessel test. - MITI (I) / OECD 301C, improved for volatile substance: Limonene 14d - BOD: 41, 81, 98% Direct analysis: GC: 100%; TOC 50, 73, 81% (MITI 1980 http://www.safe.nite.go.jp/sitemap/db_map_e.html) - Readily biodegradable (Misra, G.; Pavlostathis, S. G.; Perdue, E. M.; Araujo, R. Applied Microbiology and Biotechnology (1996), 45(6), 831-838.)
Camphene CAS# 79-92-5	8	Inherently biodegradable   - OECD 302C: 66% (28d); 76% (61 d) (Givaudan 2010)
Methyl isoeugenol CAS# 93-16-3	8	Expected to be READILY BIODEGRADABLE   Based on the structural similarity of the skeleton with   Methyl eugenol CAS# 93-15-2 (See below)   As it can been seen from the chemical structures of the both constituents, Methyl isoeugenol and Methyl eugenol are very similar: they have the same aromatic structure, the only difference is the position of the double bond in the aliphatic tail. Physical chemical properties of the chemicals are summarized below: The predicted Log Kowvalues are very close (almost equal: 2.95 for Methyl isoeugenol versus 3.03 for Methyl eugenol) indicating that they are comparable. Likewise, the difference in the water solubilities and the vapour pressures for both of the constituents can be considered as comparable.   Chemical / CAS# Log Kow^1 Water Solubility^2 Vapour Pressure^3 Methyl isoeugenol / 93-16-3 E^4: NA C: 2.95 E: NA C: 37.64 E: NA C: 1.20 Methyl eugenol / 93-15-2 E: 2.4 (as Log Powat 30°C) C: 3.03 E: NA C: 17.61 E: NA C: 0.46 ^1C: Predicted value (dimensionless) using KOWWIN v1.68 available inEPI Suite program v4.11. ^2C: Predicted value (mg/L at 25 °C) using WATERNT v1.01 available inEPI Suite program v4.11. ^3Predicted value (Pa at 25 °C) using MPBPVP v1.43 available inEPI Suite program v4.11. ^4E: Experimental value in ECHA Database. NA: Not available.
Borneol CAS# 464-45-9	5	READILY BIODEGRADABLE   - 301F: 99% (28d) (Givaudan 1999) (Borneol Crystals, purity 95.9%, sum of 2 isomers) - 301F: 83% (28d) (Symrise, 2000) (L-Borneol (CAS 464-45-9)
Citronellol CAS# 106-22-9	5	READILY BIODEGRADABLE - OECD 301C (Modified MITI) 65% (Givaudan-Roure 1989, unpublished report to FMA) - DOC (Method F from Blue book series 1991) 100% after 15 days (BBA 1990)
Geranyl Acetate CAS# 105-87-3	5	READILY BIODEGRADABLE   - OECD 301D: 68% (Symrise 1999) - OECD 301D: 91% (Symrise 2000) - Modified OECD 301B, sealed CO2 test: 82.2% (Quest1994) - OECD 301F: 85% (Givaudan 1998)
Citronellal CAS# 106-23-0	4.5	READILY BIODEGRADABLE   - OECD 301F: 61% (28d), 51% in 10d-window (Givaudan 1994)
Farnesene alpha CAS# 26560-14-5	4	Predicted as not readily biodegradable, however potentially (readily) biodegradable   SMILES: C=CC(C)=CCC=C(C)CCC=C(C)C   Probability of Rapid Biodegradation (BIOWIN v4.10): Biowin1 (Linear Model): 0.6503 Biowin2 (Non-Linear Model): 0.5267 Expert Survey Biodegradation Results: Biowin3 (Ultimate Survey Model):2.7476 (weeks-months) Biowin4 (Primary Survey Model) :3.5529 (days-weeks ) MITI Biodegradation Probability: Biowin5 (MITI Linear Model): 0.2912 Biowin6 (MITI Non-Linear Model): 0.1374 Anaerobic Biodegradation Probability: Biowin7 (Anaerobic Linear Model): 0.1546 Ready Biodegradability Prediction: NO   In addition, Farnesene alpha is a major constituent (≥ 10%) in Ylang Ylang III oil. The Ylang Ylang III oil was shown to be readily biodegradable (86% in 28d in 301D, ref. REACH dossier on ECHA website), suggesting (ready) biodegradation of Farnesene alpha to be highly likely.
Elemene beta CAS# 33880-83-0 / 515-13-9	2.5	Expected to be READILY BIODEGRADABLE   Based on the structural similarity of the skeleton with Elemol CAS# 639-99-6 (See below)   As it can been seen from the chemical structures of the both constituents, Elemene beta and Elemol are similar: they have the same ring structure with the same branching and substituents. Physical chemical properties of the chemicals are summarized below: The predicted Log Kowvalues are comparable, both are higher than 4 indicating that they are structurally comparable. The differences between the water solubilities and the vapour pressures for both of the constituents are due to the hydrogen bonding ability of the -OH group present in Elemol.   Chemical / CAS# Log Kow^1 Water Solubility^2 Vapour Pressure^3 Elemene beta / 33880-83-0 / 515-13-9 E^4: NA C: 7.04 E: NA C: 0.27 E: NA C: 12.3 Elemol / 639-99-6 E: NA C: 5.54 E: NA C: 10.50 E: NA C: 0.05 ^1C: Predicted value (dimensionless) using KOWWIN v1.68 available inEPI Suite program v4.11. ^2C: Predicted value (mg/L at 25 °C) using WATERNT v1.01 available inEPI Suite program v4.11. ^3Predicted value (Pa at 25 °C) using MPBPVP v1.43 available inEPI Suite program v4.11. ^4E: Experimental value in ECHA Database. NA: Not available.
Caryophyllene beta CAS# 87-44-5	2	READILY BIODEGRADABLE   - OECD301F - 75% (REF: Givaudan, 2007)
Pinene alpha CAS# 80-56-8	2	READILY BIODEGRADABLE   - OECD301B, sealed vessels: 62% (28d), 70% (42d) (Astra Zeneca, 2001, ECB PBT#84 http://ecb.jrc.ec.europa.eu/documents/PBT_EVALUATION/PBT_sum084_CAS_91770-80-8.pdf ).                                                 - MITI (I) / OECD 301C: 28d - BOD: 92% Direct analysis: GC: 100% (MITI 2007: http://www.safe.nite.go.jp/english/sougou/view/TotalSrchInput_en.faces)
cis Ocimene CAS# 3338-55-4	2	Expected to be READILY BIODEGRADABLE   Based on the structural similarity of the skeleton with b-Myrcene CAS# 123-35-3, a constituent of another substance (Cymbopogon winterianus), which is READILY BIODEGRADABLE - OECD 310 Carbon Dioxide Headspace test: CO2 production: 73% (Van Ginkel 2009) - MITI (I) / OECD 301C, improved for volatile substance: 14d - BOD: 86% Direct analysis: GC: 99%; TOC: 97% (MITI 1987: http://www.safe.nite.go.jp/english/sougou/view/TotalSrchInput_en.faces)  (See below)   As it can been seen from the chemical structures of the both constituents, cis Ocimene andb-Myrcene are very similar: they both have 8-carbon skelaton and three double bonds, the only difference is the position of one of the double bonds. Physical chemical properties of the chemicals are summarized below: The predicted Log Kowvalues are very close (almost equal: 4.80 versus 4.88) indicating that they are comparable. Likewise, the difference in the water solubilities and the vapour pressures for both of the constituents can be considered as comparable   Chemical / CAS# Log Kow^1 Water Solubility^2 Vapour Pressure^3 cis Ocimene / 3338-55-4 E^4: NA C: 4.80 E: NA C: 38.09 E: NA C: 358.00 b-Myrcene / 123-35-3 E^4: 4.82 (as Log Powat 30°C) C: 4.88 E: NA C: 17.81 E: 251 (Pa at 25°C) C: 320.00 ^1C: Predicted value (dimensionless) using KOWWIN v1.68 available inEPI Suite program v4.11. ^2C: Predicted value (mg/L at 25 °C) using WATERNT v1.01 available inEPI Suite program v4.11. ^3Predicted value (Pa at 25 °C) using MPBPVP v1.43 available inEPI Suite program v4.11. ^4E: Experimental value in ECHA Database. NA: Not available.
Elemol CAS# 639-99-6	1.8	READILY BIODEGRADABLE   - OECD 301F: 71% BOD (28d) (Givaudan 2011)
Germacrene D CAS# 23986-74-5 / 37839-63-7	1.6	Not readily biodegradable, however complete primary degradation and in addition potentially readily biodegradable   - OECD301F - 19% 28d, 24% 63d, specific analysis at the end of the test provided evidence of complete primary degradation of Germancrene-D (Givaudan, 2008). Sample: essential oil fraction of Ylang-Ylang, enriched in Germacrene D. 71.1% Germacrene-D, 12.7% beta-carypohyllene, 3.8% delta-cadinene, rest – sesquiterpenes.   In addition, Germacrene D is a major constituent (≥ 15%) in Ylang Ylang III oil. The Ylang Ylang III oil was shown to be readily biodegradable (86% in 28d in 301D, ref. REACH dossier on ECHA website), suggesting (ready) biodegradation of Germacrene D to be highly likely.
Terpineol alpha CAS# 98-55-5	1.5	READILY BIODEGRADABLE:   - OECD 310 (CO2Headspace test, CO2production): 80% degradation for Isomeric terpineol mixtures [CAS 8000-41-7] e.g. mixture containing 86% alpha, 11% gamma & 1% beta (Van Ginkel 2008).   Primary degradation and complete mineralisation demonstrated using soil inoculum under aerobic conditions (Misra, G.; Pavlostathis, S. G.; Perdue, E. M.; Araujo, R. Applied Microbiology and Biotechnology (1996), 45(6), 831-838.)
Cadinene delta CAS# 483-76-1	1.3	Biodegradable in prolonged test but Not readily biodegradable   d-Cadinene: OECD 301F respirometry test (100 mg substance/l): 28d 50% BOD, 63d: > 60% BOD (prolonged test). This implies completely mineralisation after 63 d. Jenner et al 2011 (Environm. Tox. Chem. 30:1096-1108).   According to the UM-BBD prediction, first hydrogenation of the ring structure will occur and next the rings will be cleaved for further degradation http://umbbd.ethz.ch/predict/   SMILES: C(=C(CC1)C)C(C1=C(C2)C)C(C2)C(C)C
trans Ocimene CAS# 3779-61-1	1	Expected to be READILY BIODEGRADABLE   Based on the structural similarity of the skeleton with b-Myrcene CAS# 123-35-3, a constituent of another substance (Cymbopogon winterianus), which is READILY BIODEGRADABLE - OECD 310 Carbon Dioxide Headspace test: CO2 production: 73% (Van Ginkel 2009) - MITI (I) / OECD 301C, improved for volatile substance: 14d - BOD: 86% Direct analysis: GC: 99%; TOC: 97% (MITI 1987: http://www.safe.nite.go.jp/english/sougou/view/TotalSrchInput_en.faces)  (See below)   As it can been seen from the chemical structures of the both constituents, trans Ocimene andb-Myrcene are very similar: they both have 8-carbon skelaton and three double bonds, the only difference is the position of one of the double bonds. Physical chemical properties of the chemicals are summarized below: The predicted Log Kow, water solubility and the vapour pressure values are exactly equal indicating that they are structurally similar.   Chemical / CAS# Log Kow^1 Water Solubility^2 Vapour Pressure^3 trans Ocimene / 3779-61-1 E^4: NA C: 4.88 E: NA C: 17.81 E: NA C: 320.00 b-Myrcene / 123-35-3 E^4: 4.82 (as Log Powat 30°C) C: 4.88 E: NA C: 17.81 E: 251 (Pa at 25°C) C: 320.00 ^1C: Predicted value (dimensionless) using KOWWIN v1.68 available inEPI Suite program v4.11. ^2C: Predicted value (mg/L at 25 °C) using WATERNT v1.01 available inEPI Suite program v4.11. ^3Predicted value (Pa at 25 °C) using MPBPVP v1.43 available inEPI Suite program v4.11. ^4E: Experimental value in ECHA Database. NA: Not available.
Bornyl acetate CAS# 76-49-3	1	Expected to be READILY BIODEGRADABLE: Based on structural similarity with Borneol CAS# 464-45-9 which is readily biodegradable (see above)   As it can been seen from the chemical structures of the both constituents, Bornyl acetate and Borneol are similar: they have the same ring structure with the same branching and substituents, Borneol is an alcohol and Bornyl acetate is an methyl-esterified version of it. Physical chemical properties of the chemicals are summarized below: The predicted Log Kowvalues are comparable, both are smaller than 4 indicating that they are structurally comparable. The differences between the water solubilities and the vapour pressures for both of the constituents are due to the hydrogen bonding ability of the -OH group present in Borneol.   Chemical / CAS# Log Kow^1 Water Solubility^2 Vapour Pressure^3 Bornyl acetate / 76-49-3 E^4: 3.74 (as Log Powat 20°C) C: 3.86 E: 62.60 (mg/L at 20°C) C: 42.51 E: NA C: 14.30 Borneol / 464-45-9 E: 2.75 (as Log Powat 20°C) C: 2.85 E: 585.70 (mg/L at 20°C) C: 742.39 E: NA C: 0.06 ^1C: Predicted value (dimensionless) using KOWWIN v1.68 available inEPI Suite program v4.11. ^2C: Predicted value (mg/L at 25 °C) using WATERNT v1.01 available inEPI Suite program v4.11. ^3Predicted value (Pa at 25 °C) using MPBPVP v1.43 available inEPI Suite program v4.11. ^4E: Experimental value in ECHA Database. NA: Not available.
Citronellyl acetate CAS# 150-84-5	1	READILY BIODEGRADABLE:   OECD 301 B and 301 F, respectively using activated sludge as inoculum. At test termination after 28 days Unilever reported a degradation rate of 82.1 % and the 10-day window criteria was fulfilled. However, due to technical deficiencies, both studies have been disregarded. To cover the information requirements, a third study on ready biodegradability according to OECD guideline 310 (Headspace Test) for testing volatile substances was performed. The degree of biodegradation after an exposure period of 28 days was 93 ± 7 %. The results in this study are consistent with all validity criteria and the test is valid according to the guideline of this study. Accordingly, citronellyl acetate is considered readily biodegradable according to OECD criteria.
Methyl eugenol CAS# 93-15-2	0.3	READILY BIODEGRADABLE   GLP study according to OECD Guideline 301 C. Based on a degradation of 89% (O2 consumption) within 28 d, the substance is readily biodegradable according to OECD criteria.
Readily biodegradable (experiment): 61.1% Inherently biodegradable (experiment): 8.0% Ultimately biodegradable (experiment): 1.3% Expected to be readily biodegradable (read-across): 14.5% Potentially (readily) biodegradable (major constituent analysis): 5.6%

More detail can be found in the attached document

Validity criteria fulfilled:

not applicable

Interpretation of results:

inherently biodegradable

Conclusions:

Citronella nardus oil is considered as a worst case to be inherently biodegradable. However ≥ 75% of the known constituents are indicated to be readily biodegradable. The UVCB substance is not persistent.

Executive summary:

Citronella Nardus is a Natural Complex Substance (NCS) of which 90.5% of the constituents are identified. An assessment of the biodegradability of Citronella Nardus was made based on the degradability of its constituents and the underlying assumption that if the constituents of the NCS are readily biodegradable, the NCS itself should also be readily biodegradable. Data on constituents were either derived from experimental or non-testing data to asses biodegradability. Based on available data obtained in experimental ready biodegradability tests, 61.1% of the known constituents indicated to be biodegradable. For some constituents (14.5% of the NCS), the ready biodegradability was based on available data on the ready biodegradability of structurally related substances. Thus, 75.6% of the composition of the known constituents of Citronella Nardus is in the category of readily biodegradable substances. For 5.6 % of the composition, a biodegradability conclusion was drawn indirectly based on results from another UVCB substance in which these constituents were present as the major constituent. In conclusion there is sufficient information to conclude that none of the constituents appears persistent. For classification and labelling purposes, Citronella Nardus oil can be classified at least as inherently biodegradable and not persistent.

Description of key information

Citronella Nardus is a Natural Complex Substance (NCS) of which 90.5% of the constituents are identified. An assessment of the biodegradability of Citronella Nardus was made based on the degradability of its constituents and the underlying assumption that if the constituents of the NCS are readily biodegradable, the NCS itself should also be readily biodegradable. Data on constituents were either derived from experimental or non-testing data to asses biodegradability. Based on available data obtained in experimental ready biodegradability tests, 61.1% of the known constituents indicated to be biodegradable. For some constituents (14.5% of the NCS), the ready biodegradability was based on available data on the ready biodegradability of structurally related substances. Thus, 75.6% of the composition of the known constituents of Citronella Nardus is in the category of readily biodegradable substances. For 5.6 % of the composition, a biodegradability conclusion was drawn indirectly based on results from another UVCB substance in which these constituents were present as the major constituent. In conclusion there is sufficient information to conclude that none of the constituents appears persistent. For classification and labelling purposes, Citronella Nardus oil can be classified at least as inherently biodegradable and not persistent.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater