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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: data is from peer reviewed journal
Justification for type of information:
data is from peer reviewed journal
Reference:
Composition 0
Qualifier:
according to
Guideline:
other: refer principle below
Principles of method if other than guideline:
Biodegradability of test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one was determined by using Pseudomonas ovalis, strain 6-1 as inoculums for 4 days.
GLP compliance:
not specified
Test material information:
Composition 1
Specific details on test material used for the study:
- Name of test material: (+ )-carvone- IUPAC name: (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one- Molecular formula: C10H14O- Molecular weight: 150.22 g/mole- Smiles :C1[C@H](CC=C(C1=O)C)C(C)=C- Inchl: 1S/C10H14O/c1-7(2)9-5-4-8(3)10(11)6-9/h4,9H,1,5-6H2,2-3H3/t9-/m0/s1- Substance type: Organic- Physical state: Colorless to pale-yellow liquid
Oxygen conditions:
aerobic
Inoculum or test system:
other: Bacteria
Remarks:
Pseudomonas ovalis, strain 6-1,
Details on inoculum:
Ten milliliters of the cell suspension pre incubated for 24 hr in the growing medium containing 5 mg of ( + )-carvone and 0.1 ml of ethanol in a 30 ml test tube
Duration of test (contact time):
4 d
Initial conc.:
>= 600 - <= 1 000 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
test mat. analysis
Remarks:
GLC and TLC
Details on study design:
The growing medium contained 1 g,NH4N03 ; 0.5 g, KC1; 0.5 g, MgS04•7HzO; 0.5 g, dried extract of yeast; and 10 g, CaC03 in 1 liter of 1/30 M -KH2P04-Na,HP04 buffer (pH 7.2). Before cultivation, 60 to 100 mg of ( + )-carvone and 0.5 to 2.0 ml of ethanol were added to 90 ml of the above growing medium in a 500 ml flask.- Test temperature: 30 oC- pH: 8.0SAMPLING: No data CONTROL AND BLANK SYSTEM: no data
Key result
Parameter:
% degradation (test mat. analysis)
Remarks:
By GLC and TLC
Value:
100
Sampling time:
4 d
Remarks on result:
other: other details not available
Details on results:
The test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one undergoes 100 % degradation by considering test material analysis by GLC as parameter in 4 days.

The transformation products identified of test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one was (-)-isodihydrocarvone, (-)-isodihydrocarveol,( - )-neoisodihydrocarveol, (-) dihydrocarvone, (-)-neodihydrocarveol, and (+ )-dihydrocarveol,

Validity criteria fulfilled:
not specified
Interpretation of results:
readily biodegradable
Conclusions:
The test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one undergoes 100 % degradation by considering test material analysis by GLC as parameter and Pseudomonas ovalis, strain 6-1, as inoculum in 4 days. On the basis of percent degradability value it is concluded that test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one is readily biodegradable
Executive summary:

Biodegradation experiment of test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one was conducted by using Pseudomonas ovalis, strain 6-1, as inoculums for 4 days. In this experiment Ten milliliters of the cell suspension of Pseudomonas ovalis, strain 6-1 was pre incubated for 24 hr in the growing medium containing 5 mg of (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one and 0.1 ml of ethanol in a 30 ml test tube. Then it was added to 90 mL of growing medium containing 60-100 mg of test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one  in 500 mL flask. Then it was incubated at 30 oC temperature at 8.0 pH for 4 days. Then the culture broth was centrifuged at 8000 rpm for 10 mins. Then supernatant was subjected to ether extraction after that ether layer obtained was evaporated then GLC and Column chromatography was performed to determined transformation products. By using above techniques The test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one undergoes 100 % degradation by considering test material analysis by GLC as parameter and Pseudomonas ovalis, strain 6-1, as inoculum in 4 days. The transformation products identified of test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one was (-)-isodihydrocarvone, (-)-isodihydrocarveol,( - )-neoisodihydrocarveol, (-) dihydrocarvone, (-)-neodihydrocarveol, and (+ )-dihydrocarveol. On the basis of percent degradability value it is concluded that test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one is readily biodegradable.

Description of key information

The test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one undergoes 100 % degradation  by considering test material analysis by GLC  as parameter and Pseudomonas ovalis, strain 6-1, as inoculum in 4 days. On the basis of percent degradability value it is concluded that test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one is readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

One Experimental study and one predicted data study for target chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one  and three supporting experimental studies for its structurally similar read across chemicals have been conducted for biodegradation in water endpoint and their results are summarized below.

 

In first study the biodegradation experiment of test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one was conducted by using Pseudomonas ovalis, strain 6-1, as inoculums for 4 days. In this experiment Ten milliliters of the cell suspension of Pseudomonas ovalis, strain 6-1 was pre incubated for 24 hr in the growing medium containing 5 mg of (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one and 0.1 ml of ethanol in a 30 ml test tube. Then it was added to 90 mL of growing medium containing 60-100 mg of test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one  in 500 mL flask. Then it was incubated at 30 oC temperature at 8.0 pH for 4 days. Then the culture broth was centrifuged at 8000 rpm for 10 mins. Then supernatant was subjected to ether extraction after that ether layer obtained was evaporated then GLC and Column chromatography was performed to determined transformation products. By using above techniques The test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one undergoes 100 % degradation by considering test material analysis by GLC as parameter and Pseudomonas ovalis, strain 6-1, as inoculum in 4 days. The transformation products identified of test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one was (-)-isodihydrocarvone, (-)-isodihydrocarveol,( - )-neoisodihydrocarveol, (-) dihydrocarvone, (-)-neodihydrocarveol, and (+ )-dihydrocarveol. On the basis of percent degradability value it is concluded that test chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one is readily biodegradable.

 

In next supporting experimental study the Biodegradability of test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS no. 2244 -16 -8) was estimated by using OECD QSAR tool box v3.3 by considering six closest read across chemicals with log Kow as primary descriptor. The percent degradation of test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one was estimated to be  86.71 % by considering BOD as parameter and microorganisms as inoculums in 28 days. On the basis of percent degradability value it can be concluded that test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one is readily biodegradable.

 

In another supporting experimental study which is done from CLH report of Committee for Risk Assessment RAC –ECHA (2013) for structurally similar read across chemical biodegradation of read across chemical (5R)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one was determined by using test guideline OECD 301 D. The initial read across chemical concentration used was 1 mg/L and 3 mg/L. The read across chemical (5R)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one undergoes 68% and 62% biodegradability in 28 days at 1 mg/L and 3 mg/L initial read across substance concentration respectively.60% degradation was reached within the 14-day window,(5R)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-oneis considered readily biodegradable.

 

Further in one more experimental study which is done from authoritative database (HSDB, 2017) for same read across chemical as mentioned in above study Biodegradation was determined by using Manometric Respirometry test. The initial concentration of read across chemical used was 100 mg/L. The read across chemical (5R)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one undergoes 90% biodegradation using activated sludge as inoculums in aerobic conduction in 28 days. On the basis of percent biodegradability value it is concluded that read across chemical (5R)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one is readily biodegradable.

 

Last experimental study was also done from authoritative database (HSDB, 2017) in this study the biodegradation of test chemical 1,1,3-Trimethyl-3-cyclohexene-5-one (CAS no. 78 -59 -1) was determined by using 7 days static incubation in dark and settled domestic wastewater as inoculums. The initial test chemical concentration used was 5 and 10 mg/L. The test chemical 1,1,3-Trimethyl-3-cyclohexene-5-one undergoes 100% biodegradation using settled domestic waste as inoculums in 7 days. On the basis of % biodegradability value it is concluded that test chemical (5R)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one is readily biodegradable.

 

One the basis of all the studies mentioned above it is concluded that test chemical chemical (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one is expected to be readily biodegradable.