Diphenyl sulphide

Endpoint summary

Description of key information

Hydrolysis

In accordance with column 2 of Annex VIII of the REACH regulation, testing for this endpoint is scientifically not necessary and does not need to be conducted since the substance Diphenyl sulphide is readily biodegradable.

Biodegradation in water

Biodegradation study was conducted for 100 h (4.166 days) for evaluating the percentage biodegradability of test substance Diphenyl sulphide (CAS no. 139-66-2) by using desulfurizing bacteriumMycobacterium sp.ZD-19 at a temperature of 30°C (Han Chen, et. al; 2008).Mycobacterium sp.Strain ZD-19 was isolated from oil-contaminated sludge samples that near different petroleum refineries or mining areas. One gram of the sample was suspended in 10 ml of BSM, supplemented with 0.5 mM DBT as sole sulfur source and shaken in rotary shaker at 180 rpm for 48 h at 30°C. After being centrifuged at 500g for 2 min to separate solid, the culture was transferred into the fresh medium. After 4 days cultivation, single-colony isolation was repeated on the plate of the same medium containing 1.5% agar, and isolated colonies were streaked on the plate. Selection of strain ZD-19 among 20 isolated strains was based on the high activity to degradedibenzothiophene (DBT) as well as to produce 2-HBP (2-hydroxylbiphenyl).Basal salt medium was used as a test medium for the study.The basic salt medium (BSM) for the bacteria growth contains following components per liter of solution: 5 g of K2HPO4.3H2O, 2 g of NaH2PO4.2H2O, 0.2 g of MgCl2.6H2O, 5 g of NH4Cl, 1 ml of mineral solution. Glycerol was added as the carbon source at a concentration of 5 g/l. The mineral solution contained (per liter of deionized water): 0.1 g of CuCl2.2H2O, 0.4 g of CoCl2.6H2O, 0.2 g of ZnCl2, 20 g of CaCl2, 0.05 g of H3BO3, 0.2 g of NaMoO4.2H2O, 4 g of FeCl3.7H2O, 0.1 g of AlCl3.6H2O and 0.8 g of MnCl2.4H2O. BSM supplemented with 0.5 mM DBT was used as enrichment culture. Cells in the medium were harvested by centrifugation at 2500gfor 10 min and washed twice with 0.1 mM phosphate buffer (pH 7.0).BSM supplemented with 0.5 mM DBT was used as an enrichment culture. For desulfurization/degradation test, resting cells were prepared. Test compound diphenyl sulfide (DPS) was added separately with an initial concentration of 0.5 mM in 3 ml resting cells suspension (initial cell concentration of 15 g dry cell weight (DCW)/L). All reactions were carried out in 25 ml flasks in duplicate at 30°C and 180 rpm in rotary shaker within 3 h.Cell growth was measured turbidimetrically at 620 nm. The concentration of cells was determined from a calibration curve for correlating OD620 to dry cell weight.Test compound Diphenyl sulphide was determined by gas chromatography (GC).The dead control (without bacterium) has also been setup during the study.The percentage degradation of test substance Diphenyl sulphide was determined to 60 and 80% degradation after 50 hrs (2.083 days) and 90 hrs (3.75 days), respectively.The specific desulfurization rate (first 3 h reaction) of test chemical by ZD-19 resting cells is calculated as 8.58.Thus, based on percentage degradation, Diphenyl sulphide is considered to be 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 Diphenyl sulphide (CAS No. 139 -66 -2). If released in to the environment, 21.3% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of Diphenyl sulphide 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 ismoderate to low whereas the half-life period of Diphenyl sulphide in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 6% (i.e, reported as 5.84%), indicates that Diphenyl sulphide is not persistent in sediment.

 

Biodegradation in soil

The half-life period of Diphenyl sulphide (CAS No. 139 -66 -2) 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, 71.9% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of Diphenyl sulphide in soil is estimated to be 30 days (720 hrs). Based on this half-life value of Diphenyl sulphide, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals ismoderate to low.

Bioaccumulation: aquatic / sediment

BCFBAF model (v3.01) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the bioconcentration factor (BCF) of test chemical Diphenyl sulphide (CAS No. 139 -66 -2). The bioconcentration factor (BCF) of Diphenyl sulphide was estimated to be 401 L/kg whole body w.w (at 25 deg C) which does not exceed the bio concentration threshold of 2000, indicating that the chemical Diphenyl sulphide is not expected to bioaccumulate in the food chain.

Adsorption / desorption

KOCWIN model (v2.00) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the soil adsorption coefficient i.e Koc value of test chemical Diphenyl sulphide (CAS No. 139 -66 -2). The soil adsorption coefficient i.e Koc value of Diphenyl sulphide was estimated to be 9161 L/kg (log Koc=3.9619) by means of MCI method (at 25 deg C). This Koc value indicates that the substance  Diphenyl sulphide has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

Additional information

Hydrolysis

In accordance with column 2 of Annex VIII of the REACH regulation, testing for this endpoint is scientifically not necessary and does not need to be conducted since the substance Diphenyl sulphide is readily biodegradable.

Biodegradation in water

Various experimental key and supporting studies for the target compound Diphenyl sulphide (CAS No. 139-66-2) were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study from peer reviewed journal (Han Chen, et. al; 2008), biodegradation experiment was conducted for 100 h (4.166 days) for evaluating the percentage biodegradability of test substance Diphenyl sulphide (CAS no. 139-66-2) by using desulfurizing bacterium Mycobacterium sp.ZD-19 at a temperature of 30°C.Mycobacterium sp. Strain ZD-19 was isolated from oil-contaminated sludge samples that near different petroleum refineries or mining areas. One gram of the sample was suspended in 10 ml of BSM, supplemented with 0.5 mM DBT as sole sulfur source and shaken in rotary shaker at 180 rpm for 48 h at 30°C. After being centrifuged at 500g for 2 min to separate solid, the culture was transferred into the fresh medium. After 4 days cultivation, single-colony isolation was repeated on the plate of the same medium containing 1.5% agar, and isolated colonies were streaked on the plate. Selection of strain ZD-19 among 20 isolated strains was based on the high activity to degradedibenzothiophene (DBT) as well as to produce 2-HBP (2-hydroxylbiphenyl).Basal salt medium was used as a test medium for the study.The basic salt medium (BSM) for the bacteria growth contains following components per liter of solution: 5 g of K2HPO4.3H2O, 2 g of NaH2PO4.2H2O, 0.2 g of MgCl2.6H2O, 5 g of NH4Cl, 1 ml of mineral solution. Glycerol was added as the carbon source at a concentration of 5 g/l. The mineral solution contained (per liter of deionized water): 0.1 g of CuCl2.2H2O, 0.4 g of CoCl2.6H2O, 0.2 g of ZnCl2, 20 g of CaCl2, 0.05 g of H3BO3, 0.2 g of NaMoO4.2H2O, 4 g of FeCl3.7H2O, 0.1 g of AlCl3.6H2O and 0.8 g of MnCl2.4H2O. BSM supplemented with 0.5 mM DBT was used as enrichment culture. Cells in the medium were harvested by centrifugation at 2500gfor 10 min and washed twice with 0.1 mM phosphate buffer (pH 7.0).BSM supplemented with 0.5 mM DBT was used as an enrichment culture. For desulfurization/degradation test, resting cells were prepared. Test compound diphenyl sulfide (DPS) was added separately with an initial concentration of 0.5 mM in 3 ml resting cells suspension (initial cell concentration of 15 g dry cell weight (DCW)/L). All reactions were carried out in 25 ml flasks in duplicate at 30°C and 180 rpm in rotary shaker within 3 h.Cell growth was measured turbidimetrically at 620 nm. The concentration of cells was determined from a calibration curve for correlating OD620 to dry cell weight.Test compound Diphenyl sulphide was determined by gas chromatography (GC).The dead control (without bacterium) has also been setup during the study.The percentage degradation of test substance Diphenyl sulphide was determined to 60 and 80% degradation after 50 hrs (2.083 days) and 90 hrs (3.75 days), respectively.The specific desulfurization rate (first 3 h reaction) of test chemical by ZD-19 resting cells is calculated as 8.58.Thus, based on percentage degradation, Diphenyl sulphide is considered to be readily biodegradable in nature.

 

Another biodegradation study from peer reviewed journal (Kim, et. al; 1990) was conducted for 5 days for evaluating the percentage biodegradability of test substance Diphenyl sulphide (CAS no. 139-66-2) by using sulphate reducing bacterium Desulfovibrio desulfuricans M6 under anaerobic conditions at a temperature of 30°C.Test inoculum Desulfovibrio desulfuricans M6 was isolated from soil. Desulfovibrio desulfuricans M6 was cultivated at 30°C using medium C for 3 days.Cultures were grown in an anaerobic pressure tube or in a serum vial with a 5 % inoculum.After 3 days of growth about 70 ml culture was harvested anaerobically and suspended in 65.1 ml of sulphate free medium C (Postgate medium C without sodium sulfate). The cell suspension was added with 1.4 ml of 100 mM methyl viologen solution and 3.5 ml of 2 % organic sulfur compound solution in dimethylformamide. The headspace of the vial was filled with hydrogen gas and the reaction mixture was reduced using 2.5 % sodium sulfide solution before the vial was incubated at 30°C for 5 days. The concentrations of organic sulfur compounds were determined by gas chromatographic method using a Varian 3700 (Sunnyvale, CA) with a flame ionization detector and a glass column (2 m X 2 mm) packed with 10 % OV-101 chromosorb WHP. Nitrogen was used as the carder gas (20 ml/min). The temperatures of injector, column and detector were 220, 200 and 250°C, respectively. The scanning rate was 0.5 scan/sec with an ionization voltage of about 1500 V. Infrared spectrum was recorded using a Perkin Elmer Model 621 IR spectrophotometer with a KBr disk.The percentage degradation of test substance Diphenyl sulphide was determined to 73% degradation after 5 days. Thus, based on percentage degradation, Diphenyl sulphide is considered to be readily biodegradable in nature.

In a supporting study, biodegradation experiment was conducted for 80 h (3.33 days) for evaluating the percentage biodegradability of test substance Diphenyl sulphide (CAS no. 139-66-2) by using desulfurizing bacterium Mycobacterium sp.ZD-M2 at a temperature of 30°C (Wei Li, et. al; 2005). Mycobacterium sp. Strain ZD-M2 was isolated from oil-contaminated sludge samples. One gram of the sample was suspended in 10 ml of MSM, supplemented with 0.2 mM DBT as sole sulfur source and shaken in rotary shaker for 48 h at 30°C. After being centrifuged at 1000 rpm for 2 min to separate solid, the culture was transferred into the fresh medium. After 4 days cultivation, single-colony isolation was repeated on the plate of the same medium containing 1.5% agar, and finally, isolated colonies were streaked on the plate. Selection of strain ZD-M2 among 15 isolated strains was based on the activity and selectivity to degrade DBT and to produce 2-HBP with high rates.Test compound diphenyl sulfide (DPS) was dissolved in ethanol, and each was added with an initial concentration of 0.2 mM to the sterilized BSM as a sole sulfur source for bacterial growth. Cultures were shaken at 30°C at 180 rpm. During the course of bacterial growth, aliquots of the culture were removed and acidified to pH≤2.0 by the addition of 10% HCl. After 30 min of extraction with the same volume of methyl acetate and 10 min centrifugation at 4800 rpm, a portion of the ethyl acetate layer was used to determine the concentration of organic sulfur compounddiphenyl sulfide (DPS)by gas chromatography (GC) equipped with a FID. A 1µl filtered sample was injected into a 0.32 mm interior diameter, 30 m column with a 0.015 mm film SE-54 column operated at 2.07 ml/min – volume velocity of nitrogen carrier gas. The injector and detector temperatures were both maintained at 280°C. The column temperature was remained at a certain degree according to the different organic sulfur compounds till the character peak appeared. Diphenyl sulfide possessed the lowest desulfurization efficiencies with 70% being transformed within 72 h. Thus, based on percentage degradation, Diphenyl sulphide is considered to be readily biodegradable in nature.

 

Additional biodegradation study from peer reviewed journal (Magda Constanti, et. al; 1996) was conducted for 14 days for evaluating the percentage biodegradability of test substance Diphenyl sulphide (CAS no. 139-66-2) by Agrobacterium MC501 and a mixed culture at a temperature of 30°C. Agrubucterium MC501 was isolated from a coal mine area by an enrichment culture with DBT. The mixed cultured XACO consists of Agrobacterium MC501, Xanthomonas MC701, Corynebacteriumsp. MC401, and Corynebacterium sp. MC402 with all cultures individually isolated with the same procedure as described above. Basal salt medium was used as a test medium for the study. The basic salt medium (BSM)contained per liter of distilled water the following:1 g of K2HPO4, 1 g of MgCl2.6H2O, 2 g of NH4Cl, 0.001 g of CaCl2, and 0.001 f of FeCl3.6H2O. Glucose (6 mM) was added as the main carbon source (BSG medium).pH of the test medium was adjusted to 7.0 using NaOH. Diphenyl sulphide (DS)was finely ground and added to BSG in powder form. Cultures were grown in capped Erlenmeyer flasks in a Gallenkamp gyratory shaker at 30°C and 150 rpm. Ail glassware was scrupulously cleaned with HCl to prevent spurious growth on contaminant sulfur. Chemicals used to prepare growth medium were of the highest degree of purity.AgrobacteriumMC501 and the mixed culture XACO were incubated, in duplicate, in 40 ml BSG plus several organic and inorganic sulfur compounds. In this study, test chemical Diphenyl sulphide (DS)(0.161 mmol/l) was used as a sole source of sulfur in growth experiments. Glucose was the carbon source. A flask without any source of sulfur was used as negative control of growth. Growth was followed for several days. Bacterial growth was quantified by direct microscopic counts using a Neubauer chamber. It was also monitored by measuring the absorbance at 440 mn in a Hitachi U-2000 spectrophotometer. Maximum growth of Agrobacterium MC501 and a mixed culture was achieved in 8 and 14 days, respectively. This indicates that the chemical Diphenyl sulphideis utilized for growth by the test inoculum Agrobacterium MC501 and a mixed culture, respectively. Thus, based on this, Diphenyl sulphide is considered to be biodegradable in nature.

 

In an another supporting study, biodegradation experiment was conducted for evaluating the percentage biodegradability of test substance Diphenyl sulphide (CAS no. 139-66-2) by desulfurizing bacterial strain Gordona strain CYKS1 under aerobic conditions (Sung-Keun, et. al; 1998). Gordona strain CYKS1 (Bacteria) was used as a test inoculums for the study.Strain CYKS1 was grown aerobically in 50-ml test tubes containing 5 ml of MSM with organic sulfur compound Diphenyl sulphide(0.3 mM) as the sole sulfur source. Butyl rubber stoppers were used. Cell growth was determined by measuring optical density of culture broth samples at 600 nm. Sulfur-free MSM was used as a negative control. Growth of Gordona Strain, CYKS1 was observed when Diphenyl sulphide was used as a sole sulfur source. This indicates that the chemical Diphenyl sulphide is utilized for growth by the test inoculum Gordona Strain, respectively. Thus, based on this, Diphenyl sulphide is considered to be biodegradable in nature.

 

On the basis of above results for target chemical Diphenyl sulphide (from peer reviewed journals), it can be concluded that the test substance Diphenyl sulphide can be expected to be 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 Diphenyl sulphide (CAS No. 139 -66 -2). If released in to the environment, 21.3% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of Diphenyl sulphide 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 ismoderate to low whereas the half-life period of Diphenyl sulphide in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 6% (i.e, reported as 5.84%), indicates that Diphenyl sulphide is not persistent in sediment.

 

Biodegradation in soil

The half-life period of Diphenyl sulphide (CAS No. 139 -66 -2) 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, 71.9% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of Diphenyl sulphide in soil is estimated to be 30 days (720 hrs). Based on this half-life value of Diphenyl sulphide, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals ismoderate to low.

On the basis of available information, the test substanceDiphenyl sulphide can be considered to be readily biodegradable in nature.

Bioaccumulation: aquatic / sediment

Various predicted data for the target compound Diphenyl sulphide (CAS No. 139-66-2) and supporting weight of evidence study for its structurally similar read across substance were reviewed for the bioaccumulation end point which are summarized as below:

 

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 Diphenyl sulphide (CAS No. 139 -66 -2). The bioconcentration factor (BCF) of Diphenyl sulphide was estimated to be 401 L/kg whole body w.w (at 25 deg C).

 

In an another prediction done by using Bio-concentration Factor (v12.1.0.50374) moduleACD (Advanced Chemistry Development)/I-Lab predictive module, 2017), theBio-concentration Factor (BCF) over the entire pH scale of the test substance Diphenyl sulphide (CAS no. 139 -66 -2) was estimated to be 1419.

 

Bioconcentration Factor (BCF) of test chemical Diphenyl sulphide was estimated using Chemspider database(ChemSpider, 2017). The bioconcentration factor of test substance Diphenyl sulphide was estimated to be 877.81 at pH both 5.5 and 7.4, respectively.

 

Another predicted data was estimated usingSciFinder database (American Chemical Society (ACS), 2017) was used for predicting the bioconcentration factor (BCF) of test chemical Diphenyl sulphide (CAS No. 139 -66 -2). The bioconcentration factor (BCF) of Diphenyl sulphide was estimated to be 137 at pH range 1-10, respectively (at 25 deg C).

 

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 Diphenyl sulphide was estimated to be 542 dimensionless . The predicted BCF result based on the 5 OECD principles. Thus based on the result it is concluded that the test substance Diphenyl sulphide is non-bioaccumulative in nature.

 

In a supporting weight of evidence study from authoritative database (J-CHECK, 2017) for the read across chemical (phenyldisulfanyl)benzene (CAS no. 882-33-7),bioaccumulation experiment was conducted on test organism Cyprinus carpio for 28 days for evaluating the bioconcentration factor (BCF value) of (phenyldisulfanyl)benzene (CAS no. 882-33-7).The study was performed according to ‘OECD Guideline 305 (Bioconcentration: Flow-through Fish Test)’ orother guideline"Bioaccumulation test of a chemical substance in fish or shellfish" provided in "the Notice on the Test Method Concerning New Chemical Substances", respectively. Cyprinus carpio was used as a test organism for the study. Test chemical nominal conc. used for the study were0.005 mg/l and 0.0005 mg/l, respectively. Test chemical solution was prepared in HCO-40.Analytical method involve the recovery ratio: Test water : 96.7 %, Fish : 78.0 %, - Limit of quantitation : Test water : 1st concentration area : 0.13 microg/L, 2nd concentration area : 0.013 microg/L, Fish : 12 ng/g. Range finding study involve theLC50(96h) 0.0743 mg/L(w/v) onRice fish (Oryzias latipes). Lipid content of the test organism Cyprinus carpio was determined to be1.64% and 1.7% at the start and end of the exposure. The bioconcentration factor (BCF value) of substance (phenyldisulfanyl)benzene on Cyprinus carpio was determined to be in the range of ≤ 2.5 L/Kg at a conc. of 0.005 mg/l and ≤ 26 L/Kg at a conc. of 0.0005 mg/l, respectively.

 

For the read across chemical 1,1'-Oxybis-benzene (CAS no. 101-84-8),bioaccumulation study was conducted on test organism Cyprinus carpio for 8 weeks for evaluating the bioconcentration factor (BCF value) of 1,1'-Oxybis-benzene (J-CHECK and HSDB, 2017 and EnviChem, 2014).The study was performed according to other guideline "Bioaccumulation test of a chemical substance in fish or shellfish" provided in "the Notice on the Test Method Concerning New Chemical Substances", respectively. Cyprinus carpio was used as a test organism for the study. Test chemical nominal conc. used for the study were 0.3mg/land 0.03mg/l, respectively. Test chemical solution was prepared in HCO-20 or HC0-100.Range finding study involve the TLm (48h) 4.6 mg/l (w/v)on Rice fish (Oryzias latipes).The bioconcentration factor (BCF value) of substance 1,1'-Oxybis-benzene on Cyprinus carpio was determined to bein the range of 112-583 L/Kg at a conc. of 0.3 mg/l and 49-594 L/Kg at a conc. of 0.03 mg/l, respectively.

 

On the basis of above results for target chemical Diphenyl sulphide (from EPI suite, ACD labs,ChemSpider, SciFinder database and CompTox Chemistry Dashboard,  2017) and for its read across substance (from authoritative database J-CHECK, HSDB and EnviChem), it can be concluded that the BCF value of test substance Diphenyl sulphide ranges from 137 – 1419 which does not exceed the bioconcentration threshold of 2000, indicating that the chemical Diphenyl sulphide is not expected to bioaccumulate in the food chain.

Adsorption / desorption

Various predicted data for the target compound Diphenyl sulphide (CAS No. 139-66-2) and supporting weight of evidence study for its structurally similar read across substance were reviewed for the adsorption end point which are summarized as below:

 

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 Diphenyl sulphide (CAS No. 139 -66 -2). The soil adsorption coefficient i.e Koc value of Diphenyl sulphide was estimated to be 9161 L/kg (log Koc=3.9619) by means of MCI method (at 25 deg C). This Koc value indicates that the substance Diphenyl sulphide has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

 

The Soil Adsorption Coefficient i.e Koc value of test substance Diphenyl sulphide (CAS no. 139 -66 -2) was estimated using Adsorption Coefficient module (v12.1.0.50374) program as Koc 6278 (log Koc = 3.8 ± 1.0) at pH range 1-14 respectively(ACD (Advanced Chemistry Development)/I-Lab predictive module, 2017). This Koc value indicates that the substance  Diphenyl sulphide has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

 

In an another prediction done by using ChemSpider Database (2017),the Soil Adsorption Coefficient i.e Koc value of test substance Diphenyl sulphide (CAS no. 139 -66 -2) was estimated. The adsorption coefficient (Koc) value of test substance Diphenyl sulphide was estimated to be 4451.31 (Log Koc = 3.648) at both pH 5.5 and 7.4, respectively. This Koc value indicates that the substance Diphenyl sulphide has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

 

Additional soil adsorption coefficient i.e Koc value of test chemicalDiphenyl sulphide (CAS No. 139 -66 -2)was estimated using the SciFinder database (American Chemical Society (ACS), 2017).The soil adsorption coefficient i.e Koc value of Diphenyl sulphide was estimated to be 1180 at pH range 1-10, respectively (at 25 deg C). This Koc value indicates that the substance Diphenyl sulphide has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

 

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 Diphenyl sulphide was estimated to be 1600 L/kg (log Koc = 3.204).The predicted KOC result based on the 5 OECD principles. This Koc value indicates that the substance Diphenyl sulphide has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

In a supporting weight of evidence study from authoritative database (HSDB, 2017) for the read across chemical 1,1'-Oxybis-benzene (CAS no. 101-84-8), adsorption experiment was conducted for estimating the adsorption coefficient (Koc) value of read across chemical 1,1'-Oxybis-benzene. The adsorption coefficient (Koc) value was determined in an Australian soil using a measured soil/water partition coefficient (Kd) of 12.4. The adsorption coefficient (Koc) value of substance 1,1'-Oxybis-benzene was determined to be 1950 (Log Koc = 3.29). This Koc value indicates that the substance 1,1'-Oxybis-benzene has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

 

For the read across chemical Phenothiazine (CAS no. 92-84-2), adsorption study was conducted for estimating the adsorption coefficient (Koc) value of read across chemical Phenothiazine (HSDB, 2017). The adsorption coefficient (Koc) value was calculated using an experimental logKow of 4.15 and a regression derived equation. The adsorption coefficient (Koc) value of substance Phenothiazine was estimated to be 4300 (Log Koc = 3.633). This Koc value indicates that the substance Phenothiazine has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

 

On the basis of above overall results for target chemicalDiphenyl sulphide(from EPI suite, ACD labs,ChemSpider, SciFinder database and CompTox Chemistry Dashboard,2017) and for its read across substance (from authoritative database HSDB, 2017), it can be concluded that the Koc value of test substance Diphenyl sulphide ranges from1180–9161 indicating that the test chemical Diphenyl sulphide has a moderate to strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.