Mentha arvensis, 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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Cornmint oil is a Natural Complex Substance (NCS). With 98.8% of the constituents of Cornmint Oil known, this NCS can be considered as a well defined NCS. The constituents of Cornmint oil are predominantly cyclic monoterpene alcohols (menthol) and ketones (menthone). In the typical Cornmint oil, these constituents form 87% of total. If the constituents of the NCS are readily biodegradable, the NCS itself is considered to be readily biodegradable as well.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

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

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 F (Ready Biodegradability: Manometric Respirometry Test)

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 biodegrabable constituents in the mixture gives the fraction of ready biodegradable substances. If this fraction exceeds 75%, the NCS is classified as 'readily biodegradable'.

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Remarks:

several guideline tests with different inocula were used

Parameter followed for biodegradation estimation:

CO2 evolution

Parameter followed for biodegradation estimation:

O2 consumption

Key result

Parameter:

% degradation (O2 consumption)

Value:

> 60

Remarks on result:

other: L-menthol, iso- Menthone, 1,8-cineole, Sabinene, beta-carophyllene, L-limonene

Key result

Parameter:

% degradation (CO2 evolution)

Value:

> 60

Remarks on result:

other: Menthone, alpha-Pinene, beta-Myrcene

Key result

Parameter:

not specified

Value:

> 60

Remarks on result:

other: Based on read across from structural analogy and BIOWWIN prediction

Remarks:

Neo- Menthol, Menthyl Acetate, Pulegone, Iso-pulegol, beta-pinene, Piperitone, Octan-3-ol, Neo-iso Menthol, Neo-iso pulego

Parameter:

% degradation (O2 consumption)

Value:

< 60

Remarks on result:

other: Germacrene D

Details on results:

Details for all constituents are summarised in window "Any other information on results" and in attached document

Assessment of the biodegradability of Cornmint oil:

Each of the identified constituents, totalling 95 -98% of the composition, is readily biodegradable, see underlying data in table below.

Constituent	Results of biodegradation assessment
L-menthol C10 H20 O	READILY BIODEGRADABLE: - OECD 301D (Closed Bottle test): 79 – 92 % (TNO 2003 /Haarmann & Reimer)
Menthone C10H18O	READILY BIODEGRADABLE: - OECD 301B: 99.5% under CAS 89-80-5 (Quest 1996)
Iso-Menthone C10H18O	READILY BIODEGRADABLE: - OECD 301D (Closed bottle test): 63% (Symerise 1999)
L-Limonene C10H16	READILY BIODEGRADABLE: - Headspace CO2: 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.)
Neo-Menthol C10 H20 O	Expected to be READILY BIODEGRADABLE Isomer of l-menthol CAS 2216-51-1 (see row 1 in this table)
Menthyl Acetate C12H22O2	Expected to be READILY BIODEGRADABLE Ester cleavage by hydrolysis to acetic acid and menthol Both transformation products are readily biodegradable   Supported by SRC-BIOWWIN prediction
Pulegone C10H16O	Expected to be READILY BIODEGRADABLE Structural analogy with isomenthone & menthone (row 3 and row 2 in this table) Both are readily biodegradable   Expected Pathway: Oxidation of cyclic keton to cyclic ester (mono-oxygenase), next ester cleavage and further degradation (UM-PPS)
Iso-pulegol C10H18O	Expected to be READILY BIODEGRADABLE Structural analogy with menthol (row 1 in this table, readily biodegradable)   Supported by SRC-BIOWWIN prediction
Alpha-Pinene C10H16	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: 91, 90, 95% Direct analysis: GC: 100, 100, 100% (MITI 2007: http://www.safe.nite.go.jp/sitemap/db_map_e.html)
beta-pinene C10H16	READILY BIODEGRADABLE: Read-across froma-Pinene, based on structural analogy Supporting evidence from: - OECD301B, sealed vessels Gum turpentine (50.9% alpha-pinene, 36.8% beta-pinene): 52% mineralisation in 28d (Astra Zeneca, 2001, ECB PBT#84). This high level of biodegradation cannot be caused by degradation only of a-pinene, so also b-pinene is degraded.
Piperitone C10H16O	Expected to be READILY BIODEGRADABLE Structural analogy with isomenthone & menthone (row 3 and row 2 in this table) Both are readily biodegradable   Expected Pathway: Oxidation of cyclic keton to cyclic ester (mono-oxygenase), next ester cleavage and further degradation (UM-PPS)
Octan-3-ol C8H18O	READILY BIODEGRADABLE structural analogues: 1-octanol: MITI-I (OECD 301C), 28d 89% BOD, DIrect analysis TOC 99%, GC 100% (2002) octan-2-ol: MITI-I (OECD 301C), 14d 76% BOD, DIrect analysis TOC 96%, GC 100% (2000) 2-ethylhexanol: MITI-I (OECD 301C), 14d 99.9 & 79 % BOD, DIrect analysis TOC 100%, GC 100% (1977) http://www.safe.nite.go.jp/sitemap/db_map_e.html
Neo-iso menthol C10 H20 O	Expected to be READILY BIODEGRADABLE Isomer of l-menthol CAS 2216-51-1 (see row 1 in this table)
Neo-iso pulegol C10H18O	Expected to be READILY BIODEGRADABLE Structural analogy with menthol (row 1 in this table, readily biodegradable)   Supported by SRC-BIOWWIN prediction
Germacrene D C15H24	Not 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).
1,8-cineole C10H18O	READILY BIODEGRADABLE: - OECD 301B, sealed CO2: 91% (Quest 1995);   - OECD 301F:82% (Givaudan 1997)
beta-Myrcene C10H16O	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/sitemap/db_map_e.html)
Sabinene C10H16	READILY BIODEGRADABLE: - OECD 301F: 76% in 28d (Givaudan 2010) Sabinene (72% pure with 27% beta-pinene)
beta-caryophyllene C15H24	READILY BIODEGRADABLE: - OECD301F - 75% (REF: Givaudan, 2007)
Fraction of NCS readily biodegradable (tests) Including constituents expected to be readily biodegradable

The complete asssessment is added attached to this study record. Studies mentioned by Company Name are included in the RIFM database.

Validity criteria fulfilled:

not applicable

Interpretation of results:

readily biodegradable

Conclusions:

Cornmint oil is considered to be readily biodegradable.

Executive summary:

Cornmint oil is a Natural Complex Substance (NCS) for which > 90% of the constituents is identified. The main constituents in Cornmint oil are predominantly cyclic monoterpene alcohols (like menthol) and ketones (like menthone). As no valid empirical results from a test for the ready biodegradation of Cornmint oil are available, the assessment is based on its constituents. The assumption is that if the constituents of the NCS are readily biodegradable, the NCS itself is readily biodegradable as well.

83 % of the volume of constituents are shown to be readily biodegradable based in experimental results of the constituents. For 6 constituents (15 %) the ready biodegradability is based on structurally related substances.

 

Thus 98% of the composition of this NCS is in the category of ready biodegradable substances. Therefore, Cornmint oil is considered as readily biodegradable.

Description of key information

Cornmint oil is a Natural Complex Substance (NCS) for which > 98% of the constituents is identified. The asssessment of the biodegradation of Cornmint oil is based on its constituents. 83 % and probably up to 98% of constituents forming this NCS are in the category of ready biodegradable substances. Therefore, Cornmint oil is considered as readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Cornmint oil is a Natural Complex Substance (NCS) for which > 98% of the constituents is identified. The main constituents in Cornmint oil are predominantly cyclic monoterpene alcohols (like menthol) and ketones (like menthone) comprising more then 85% of the composition. As no valid empirical results from a test for the ready biodegradation of Cornmint oil are available, the assessment is based on its constituents. The assumption is that if the constituents of the NCS are readily biodegradable, the NCS itself is readily biodegradable as well.

83 % of the volume of constituents are shown to be readily biodegradable based in experimental results of the constituents. For 6 constituents (15 %) the ready biodegradability is based on structurally related substances.

 

The constituents, comprising 83 % and probably up to 98% of the composition of this NCS, are in the category of ready biodegradable substances. Therefore, Cornmint oil is considered as readily biodegradable.