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Description of key information

Hydrolysis

The half-life of Methyl methanesulfonate (CAS no. 66 -27 -3) was determined to be 4.56 h (at 20ᵒC), 9.66 hrs and 77 hrs (at 25ᵒC) respectively, indicates that the chemical Methyl methanesulfonate undergoes moderate to slow hydrolysis in water.

Biodegradation in water

Biodegradability of Methyl methanesulfonate (CAS no. 66 -27 -3) is predicted using QSAR toolbox version 3.3 (2017) with logKow as the primary descriptor. Test substance undergoes 29.2% degradation by BOD in 28 days.Thus, based on percentage degradation, the test chemical Methyl methanesulfonate was estimated to be not readily biodegradable in water.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound Methyl methanesulfonate (CAS No. 66 -27 -3). If released in to the environment, 40.7% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of Methyl methanesulfonate 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 moderate to low whereas the half-life period of Methyl methanesulfonate 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 0.0818%), indicates that Methyl methanesulfonate is not persistent in sediment.

Biodegradation in soil

The half-life period of Methyl methanesulfonate (CAS No. 66 -27 -3) 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, 51.3% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of Methyl methanesulfonate in soil is estimated to be 30 days (720 hrs). Based on this half-life value of Methyl methanesulfonate, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

Bioaccumulation: aquatic / sediment

The bioaccumulation study was conducted for estimating the BCF (bioaccumulation factor) value of test chemical Methyl methanesulfonate (CAS no. 66-27-3). The bioaccumulation factor (BCF) value was calculated using an estimated log Kow of -0.71 and a regression-derived equation. The estimated BCF (bioaccumulation factor) value of Methyl methanesulfonate was determined to be 3 dimensionless, which does not exceed the bioconcentration threshold of 2000, indicating that the chemical Methyl methanesulfonate is considered to be non-accumulative in aquatic organisms.

Adsorption / desorption

Adsorption study was conducted for estimating the adsorption coefficient (Koc) value of test chemical Methyl methanesulfonate (CAS no. 66-27-3). The adsorption coefficient (Koc) value was calculated using astructure estimation method based on molecular connectivity indices. The adsorption coefficient (Koc) value of test substance Methyl methanesulfonate was estimated to be 12 (Log Koc = 1.079). This Koc value indicates that the substance Methyl methanesulfonate has a negligible sorption tosoil and sediment and therefore have rapid migration potential to ground water.

Additional information

Hydrolysis

Experimental key studyfor the target chemical Methyl methanesulfonate (CAS no. 66-27-3) and supporting study for its structurally similar read across substance were reviewed for hydrolysis end point which are summarized as below:

 

In an experimental key study from peer reviewed journal (Arthur R et. al; 1987) and authoritative database (HSDB and PubChem, 2017), the half-life of Methyl methanesulfonate (CAS no. 66 -27 -3) was determined to be 4.56 h (at 20ᵒC), 9.66 hrs and 77 hrs (at 25ᵒC) respectively.

 

For the read across chemical Isopropyl methanesulfonate (CAS no. 926-06-7), the half-lives of chemical Isopropyl methanesulfonate was determined to be 4.56 hrs at 25°C and 77 hrs at 20°C respectively (HSDB, 2017).

 

Thus, based on the overall reported results for target chemical Methyl methanesulfonate (from authoritative database HSDB and PubChem, 2017& from peer reviewed journal) and the study for the read across chemical (from authoritative database HSDB, 2017), it can be concluded that the test substance Methyl methanesulfonate can be considered to undergoes moderate to slow hydrolysis in water.

Biodegradation in water

Various predicted data for the target compound Methyl methanesulfonate(CAS No. 66-27-3) and supporting weight of evidence studies for its closest read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction done by SSS (2017) using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor, percentage biodegradability of test chemical Methyl methane sulfonate(CAS No. 66 -27 -3) was estimated.Test substance undergoes 29.2% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemicalMethyl methanesulfonatewas estimated to be not readily biodegradable in water.

 

In another prediction using the Estimation Programs Interface Suite (EPI suite, 2018), the biodegradation potential of the test compound, Methyl methanesulfonate(CAS No. 66-27-3) in the presence of mixed populations of environmental microorganisms was estimated.The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that chemicalMethyl methanesulfonateis expected to be not readily biodegradable.

 

In a supporting weight of evidence study from authoritative database (J-CHECK, 2017) for the read across chemical Dimethyl disulfide (CAS no. 624-92-0),biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance Dimethyl disulphide. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of substance Dimethyl disulfide was determined to be 0% and 4% by BOD and HPLC parameter in 28 days. Thus, based on percentage degradation, Dimethyl disulphide is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical Methyl methanesulfonate (from OECD QSAR toolbox version 3.3 and EPI suite, 2017) and for its read across substance (from authoritative database J-CHECK, 2017), it can be concluded that the test substance Methyl methanesulfonate can be expected to be not readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound Methyl methanesulfonate (CAS No. 66 -27 -3). If released in to the environment, 40.7% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of Methyl methanesulfonate 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 moderate to low whereas the half-life period of Methyl methanesulfonate 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 0.0818%), indicates that Methyl methanesulfonate is not persistent in sediment.

Biodegradation in soil

The half-life period of Methyl methanesulfonate (CAS No. 66 -27 -3) 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, 51.3% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of Methyl methanesulfonate in soil is estimated to be 30 days (720 hrs). Based on this half-life value of Methyl methanesulfonate, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

On the basis of available information, the test substance Methyl methanesulfonate can be considered to be not readily biodegradable in nature.

Bioaccumulation: aquatic / sediment

Experimental study and various predicted data for the target compound Methyl methanesulfonate (CAS No. 66-27-3) and various supporting studies for its structurally similar read across substance were reviewed for the bioaccumulation end point which are summarized as below:

 

In an experimental key study from authoritative database (HSDB and PubChem, 2017), bioaccumulation experiment was conducted for estimating the BCF (bioaccumulation factor) value of test chemical Methyl methanesulfonate (CAS no. 66-27-3). The bioaccumulation factor (BCF) value was calculated using an estimated log Kow of -0.71 and a regression-derived equation. The estimated BCF (bioaccumulation factor) value of Methyl methanesulfonate was determined to be 3 dimensionless.

 

In aprediction done using theBCFBAF Program(v3.01) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the bioconcentration factor (BCF) of test chemical Methyl methanesulfonate (CAS No. 66 -27 -3). The bioconcentration factor (BCF) of Methyl methanesulfonate was estimated to be 3.162 L/kg whole body w.w (at 25 deg C).

 

In a supporting study from authoritative database (HSDB, 2017) for the read across chemical Isopropyl methanesulphonate (CAS no. 926-06-7), the bioaccumulation study in fish was conducted for estimating the BCF (bioaccumulation factor) value of read across chemical isopropyl methanesulphonate. The bioaccumulation factor (BCF) value was calculated using an estimated log Kow of 0.25 and a regression-derived equation. The estimated BCF (bioaccumulation factor) value of isopropyl methanesulphonate was determined to be 3 dimensionless.

 

For the read across chemical Methanesulphonyl chloride (CAS no. 124-63-0), bioaccumulation study was conducted for estimating the BCF (bioaccumulation factor) value of read across chemical methanesulphonyl chloride (HSDB, 2017). The bioaccumulation factor (BCF) value was calculated using an estimated log Kow of 1.3 and a regression-derived equation. The estimated BCF (bioaccumulation factor) value of methanesulphonyl chloride was determined to be 1.9 dimensionless.

 

On the basis of above results for target chemical Methyl methanesulfonate (from authoritative database HSDB,PubChemand EPI suite,2017) and for its read across substance (from authoritative database HSDB, 2017), it can be concluded that the BCF value of test substance Methyl methanesulfonate ranges from 3.0 – 3.162 which does not exceed the bioconcentration threshold of 2000, indicating that the chemical Methyl methanesulfonate is not expected to bioaccumulate in the food chain.

Adsorption / desorption

Experimental study and various predicted data for the target compound Methyl methanesulfonate (CAS No. 66-27-3) and various supporting studies for its structurally similar read across substance were reviewed for the adsorption end point which are summarized as below:

 

In an experimental key study from authoritative database (HSDB andPubChem, 2017),adsorption experiment was conducted for estimating the adsorption coefficient (Koc) value of test chemical Methyl methanesulfonate (CAS no. 66-27-3). The adsorption coefficient (Koc) value was calculated using astructure estimation method based on molecular connectivity indices. The adsorption coefficient (Koc) value of test substance Methyl methanesulfonate was estimated to be 12 (Log Koc = 1.079).

 

In aprediction done using theKOCWIN Program(v2.00) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the soil adsorption coefficient i.e Koc value of test chemical Methyl methanesulfonate (CAS No. 66 -27 -3). The soil adsorption coefficient i.e Koc value of Methyl methanesulfonate was estimated to be 4.332 L/kg (log Koc= 0.6367) by means of MCI method (at 25 deg C).

 

In a supporting study from authoritative database (HSDB, 2017) for the read across chemical Methanesulphonyl chloride (CAS no. 124-63-0),adsorption experiment was conducted for estimating the adsorption coefficient (Koc) value of read across chemical methanesulphonyl chloride. The adsorption coefficient (Koc) value was calculated using as tructure estimation method based on molecular connectivity indices. The adsorption coefficient (Koc) value of test substance methanesulphonyl chloride was estimated to be 6.1 (Log Koc = 0.785).

 

For the read across chemical Methanesulphonic acid (CAS no. 75-75-2),adsorption study was conducted for estimating the adsorption coefficient (Koc) value of read across chemical methanesulphonic acid (CAS no. 75-75-2). The adsorption coefficient (Koc) value was calculated using astructure estimation method based on molecular connectivity indices. The adsorption coefficient (Koc) value of test substance methanesulphonic acid was estimated to be 1 (Log Koc = 0).

 

On the basis of above overall results for target chemical Methyl methanesulfonate (from authoritative database HSDB,PubChemand EPI suite,2017) and for its read across substance (from authoritative database HSDB, 2017), it can be concluded that the Koc value of test substanceMethyl methanesulfonateranges from4.332–12indicating that the test chemical Methyl methanesulfonate has a negligible sorption to soil and sediment and therefore have rapid migration potential to ground water.

 

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