(S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one

Endpoint summary

Description of key information

Stability:

Hydrolysis:

According to Annex VIII column 2 the study does not need to be conducted because substance (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one (CAS no. 2244 -16 -8) is readily biodegradable.

Biodegradation:

Biodegradation in water:

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.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS No. 2244 -16 -8). If released in to the environment, 25.4 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is low whereas the half-life period of test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1 % (i.e, reported as 0.183 %), indicates that test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one is not persistent in sediment.

Biodegradation in soil:

The half-life period of test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS No.2244 -16 -8) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 74.3 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one in soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low.

Bioaccumulation:

Bioaccumulation: aquatic/sediments:

Using BCFBAF Program (v3.00) model of EPI suite (2017) the estimated bio concentration factor (BCF) for (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS No. 2244-16-8) is 28.51 L/kg wet-wt at 25 deg. c which does not exceed the bioconcentration threshold of 2000. Therefore it is concluded that test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one is non bioaccumulative in food chain.

Transport and distribution:

Adsorption/desorption:

The Soil Adsorption Coefficient i.e. Koc value of test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS No. 2244-16-8) was estimated using EPI suite KOCWIN Program (v2.00) as 136.2 L/kg (log Koc= 2.1314) by means of MCI method at 25 deg. C.  This log Koc value indicates that test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one has low sorption to soil and therefore test chemical has moderate migration potential to ground water.

Additional information

Stability:

Hydrolysis:

According to Annex VIII column 2 the study does not need to be conducted because substance (S)-2-methyl-5-(1-methylvinyl)cyclohex-2-en-1-one (CAS no. 2244 -16 -8) is readily biodegradable.

Biodegradation:

Biodegradation in water:

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.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS No. 2244 -16 -8). If released in to the environment, 25.4 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is low whereas the half-life period of test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1 % (i.e, reported as 0.183 %), indicates that test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one is not persistent in sediment.

Biodegradation in soil:

The half-life period of test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS No.2244 -16 -8) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 74.3 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one in soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low.

Bioaccumulation:

Bioaccumulation: aquatic/sediments:

Various predicted data for the target compound(5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS No. 2244-16-8)and supporting weight of evidence study for its structurally similar read across chemical were reviewed for the bioaccumulation end point which are summarized as below:

The first weight of evidence study was done by using BCFBAF Program (v3.00) model of Estimation Program Interface (EPI suite 2017) the estimated bio concentration factor (BCF) for (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS No. 2244-16-8) is 28.51 L/kg wet-wt at 25 deg. c

 

Second weight of evidence study was done by using Bio-concentration Factor (v12.1.0.50374) module of(ACD (Advanced Chemistry Development)/I-Lab predictive module, 2017) module in this study the Bio-concentration Factor at range pH 1-14  of the chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one(CAS no.2244 -16 -8) estimated to be 31.0 dimensionless.

 

Next weight of evidence study was done by using Scifinder database of American Chemical Society (ACS, 2017) in this study the Bioconcentration factor (BCF) of test substance (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one at pH 1-10 and temperature 25 °C was estimated to be 31.2 dimensionless.  This BCF value at pH 1-10 and temperature 25 °C suggests that the test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one is non bioaccumulative in aquatic organisms.

 

Another weight of evidence study was done by using Chemspider- ACD/PhysChem Suite of Royal Society of Chemistry (RCS, 2017) in this study the Bioconcentration factor (BCF) of test substance (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one at pH 5.5 and pH 7.4 was estimated to be 79.31 dimensionless. This BCF value suggests that the test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one is non bioaccumulative in aquatic organisms.

 

From CompTox Chemistry Dashboard using OPERA (OPEn (quantitative) structure-activity Relationship Application)  V1.02 model in which calculation based on PaDEL descriptors (calculate molecular descriptors and fingerprints of chemical)  the bioaccumulation i.e BCF for test substance(5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one(CAS no.2244 -16 -8) was estimated to be 4.53 dimensionless . The predicted BCF result was based on the 5 OECD principles.

 

The supporting weight of evidence study was done from authoritative database (HSDB, 2017) in this study the BCF value of read across chemical (5R)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS no. 99-49-0) estimated was 30 dimensionless by using log Kow of 3.07 and regression derived equation and it is far less than 2000 criteria so it is concluded that read across chemical (5R)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one is non bioaccumulative.

 

Last weight of evidence study was also experimental study done from same authoritative database (HSDB, 2017) as mentioned above in this study the BCF value of read across chemical 1,1,3-Trimethyl-3-cyclohexene-5-one ( CAS no. 78-59-1) estimated was 7.0 dimensionless in bluegill sunfish and it is far less than 2000 so it is concluded that this read across chemical is non bioaccumulative.

 

On the basis of above results for target chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS No. 2244-16-8)(from EPI suite, ACD labs, Sci Finder database, Chemspider and CompTox Chemistry Dashboard 2017) and for its structurally similar read across chemicals (From HSDB) it can be concluded that the BCF value of test substance(5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-oneranges from 4.53 to 79.31 dimensionless which does not exceed the bioconcentration threshold of 2000, indicating that the chemical(5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-oneis expected to be nonbioaccumulative in the food chain.

Transport and distribution:

Adsorption/desorption:

Various predicted data for the target compound of(5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS No. 2244-16-8)and supporting weight of evidence study for its structurally similar read across chemicals were reviewed for the Adsorption end point are summarized as below.

In first weight of evidence study the Soil Adsorption Coefficient i.e. Koc value of test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS No. 2244-16-8) was estimated using Estimation Program Interface (EPI suite, 2017) KOCWIN Program (v2.00) as 136.2 L/kg (log Koc= 2.1314) by means of MCI method at 25 deg. C.  This log Koc value indicates that test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one has low sorption to soil and therefore test chemical has moderate migration potential to ground water.

 

In next weight of evidence study the Soil Adsorption Coefficient i.e Koc value of test substance (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one(CAS no.2244 -16 -8) was estimated using Adsorption Coefficient module (v12.1.0.50374) program of(ACD (Advanced Chemistry Development)/I-Lab predictive module, 2017) moduleas Koc 407 dimensionless (log Koc= 2.6095). This log Koc value indicates that the test substance (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-onehas a moderate sorption to soil and therefore has slow migration potential to groundwater.

Third weight of evidence study was done by using Sci Finder database of American Chemical Society (ACS, 2017) in this study the soil adsorption co-efficient i.e., Koc value of test chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one was estimated to be 408 dimensionless ( log Koc = 2.6106) at pH 1-10 at temperature 25 deg.c. this value suggests that this test chemical has moderate sorption to soil therefore has slow migration potential to ground water.

 

Another weight of evidence study was done by using Chemspider-ACD/Phy chem suite of Royal Society of Chemistry (RCS, 2017) in this study the soil adsorption co-efficient i.e., Koc value of test substance (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one was estimated to be 796.41 dimensionless (log Koc= 2.9011) at pH 5.5 and 7.4 and temperature 25 deg.C . This Koc value at different pH indicates that the chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one has moderate sorption to soil and sediments and therefore test chemical has slow migration potential to ground water.

 

Next weight of evidence study was done from CompTox Chemistry Dashboard using OPERA (OPEn (quantitative) structure-activity Relationship Application)  V1.02 model in which calculation based on PaDEL descriptors (calculate molecular descriptors and fingerprints of chemical)  the adsorption coefficient i.e KOC for test substance(5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one(CAS no. 2244 -16 -8) was estimated to be 226 L/kg (log Koc = 2.3541) .The predicted KOC result based on the 5 OECD principles. Thus based on the result it is concluded that the test substance (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-onehas a low sorption to soil and sediment and therefore has moderate migration potential to ground water.

 

The supporting experimental weight of evidence study was done from authoritative database HSDB, 2017 in this study the Koc value for read across chemical (5R)-2-Methyl-5-prop-1-en-2-ylcyclohex-2-en-1-one (CAS no.99-49-0) was estimated by using a structure estimation method based on molecular connectivity indices. The estimated Koc value was 140 dimensionless and log Koc is 2.1461 this log Koc value suggests that (5R)-2-Methyl-5-prop-1-en-2-ylcyclohex-2-en-1-one is expected to have low sorption to soil and sediment and therefore have moderate migration potential to ground water.

 

Last weight of evidence study was also experimental study done from same authoritative database (HSDB, 2017) in this study the Koc value for read across chemical 1,1,3-Trimethyl-3-cyclohexene-5-one (CAS no.78-59-1) was estimated by using a log Kow of 1.7 and a regression-derived equation. The estimated Koc value is 200 dimensionless and log Koc is 2.3010 this log Koc value suggests that 1,1,3-Trimethyl-3-cyclohexene-5-one is expected to have low sorption to soil and sediment and therefore have moderate migration potential to ground water.

 

On the basis of above results for target chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS No. 2244-16-8) (from EPI suite, ACD labs, Sci Finder database, Comptox chemistry dashboard and Chemspider 2017) and for its read across chemicals (From authoritative database HSDB) it can be concluded that the log Koc value of (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-oneranges from 2.1341 to 2.9011 indicating that the chemical (5S)-2-methyl-5-(prop-1-en-2-yl)cyclohex-2-en-1-one (CAS No. 2244-16-8) has low to moderate sorption to soil and sediment and therefore it has moderate to slow migration potential to ground water.