Sodium 3-nitrobenzenesulphonate

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 test chemical is readily biodegradable.

Biodegradation in water

28-days Closed Bottle test following the OECD guideline 301 D was performed to determine the ready biodegradability of the test item. The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used for this study. 1 polyseed capsule were added in 500 ml D.I water and then stirred for 1 hour for proper mixing and functioning of inoculum. This gave the bacterial count as 10E7 to 10E8 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/L . OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test item and reference item. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 75.3 %. Degradation of Sodium Benzoate exceeds 49.39 % on 7 days & 75.3 on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 0.77 mgO2/mg. ThOD was calculated as 0.78 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 98.71 %. Based on the results, the test item, under the test conditions, was considered to be readily 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 chemical. If released in to the environment, 31.3% 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 37.5 days (900 hrs). The half-life (37.5 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 test chemical in sediment is estimated to be 337.5 days (8100 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.083%), indicates that test chemical is not persistent in sediment.

Biodegradation in soil

The half-life period of test chemical 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, 68.6% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of test chemical, 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

Bioaccumulation study was conducted on test organism Cyprinus carpio for 6 weeks for evaluating the bioconcentration factor (BCF value) of test chemical.The study was performed according to OECD Guideline 305 C "Bioaccumulation: Test for the Degree of Bioconcentration in Fish" andother guideline"Bioaccumulation test of a chemical substance in fish or shellfish" provided in "the Notice on the Test Method Concerning New Chemical Substances", respectively under flow through conditions at a temperature of25°C and pH range 6.0-8.5, respectively.Cyprinus carpio was used as a test organism for the study. Test chemical nominal conc. used for the study were 1 mg/l and 0.1 mg/l, respectively. Range finding study involve the TLm(48h) > 1000 mg/L on Rice fish (Oryzias latipes).The bioconcentration factor (BCF value) of test chemical on Cyprinus carpio was determined to be in the range of 0.5-1.6 L/Kg at a conc. of 1 mg/l and ≤ 5 L/Kg at a conc. of 0.1 mg/l, respectively, which does not exceed the bioconcentration threshold of 2000, indicating that the test chemical is not expected to bioaccumulate in the food chain.

Adsorption / desorption

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 chemical was estimated to be 25.7 L/kg (log Koc = 1.409).The predicted KOC result based on the 5 OECD principles. This Koc value indicates that the test chemical haas a negligible sorption to soil and sediment and therefore have rapid 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 chemical is readily biodegradable.

Biodegradation in water:

Various experimental key and supporting studies for the target compound were reviewed for the biodegradation end point and their results are summarized as below:

The first study was experimental study in this study the 28-days Closed Bottle test following the OECD guideline 301 D was performed to determine the ready biodegradability of the test item. The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used for this study. 1 polyseed capsule were added in 500 ml D.I water and then stirred for 1 hour for proper mixing and functioning of inoculum. This gave the bacterial count as 10E7 to 10E8 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/L. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test item and reference item. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 75.3 %. Degradation of Sodium Benzoate exceeds 49.39 % on 7 days & 75.3 on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 0.77 mgO2/mg. ThOD was calculated as 0.78 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 98.71 %. Based on the results, the test item, under the test conditions, was considered to be readily in nature.

In next experimental key study from peer reviewed journal (GREIM H, et. al; 1994), biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of test chemical. The study was performed according to OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test). The percentage degradation of test chemical was determined to be >70% by DOC removal or COD parameter in 28 days. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in water.

Another biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test chemical (IUCLID dataset, 2000). The study was performed according to OECD Guideline 302 B "Inherent biodegradability: Modified Zahn–Wellens Test" under aerobic conditions. The percentage degradation of test chemical was determined to be >90% by DOC removal or COD parameter in 28 days. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

In next supporting study from secondary source (IUCLID dataset, 2000), biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of test chemical. The study was performed according to "Modified Zahn–Wellens Test" under aerobic conditions. Activated sludge was used as a test inoculum for the study. Initial test substance conc. used in the study was 200 mg/l based on Dissolved Organic Carbon (DOC), respectively. Lag phase and beginning of the plateau phase was determined to be 1 and 3 days, respectively. The percentage degradation of test chemical was determined to be 100% by DOC removal or COD parameter after 5 days. Thus, based on percentage degradation, of test chemical is considered to be readily biodegradable in nature.

Additional biodegradation study from authoritative database (J-CHECK and Envichem, 2017) and secondary source (IUCLID dataset, 2000) was conducted for 14 days for evaluating the percentage biodegradability of test chemical. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I) under aerobic conditions. Activated sludge (non-adapted) was used as a test inoculums for the study. 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 test chemical was determined to be 0, 4.6 and 1% by BOD, TOC removal and UV-Vis parameter in 14 days. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

In an another supporting study, biodegradation experiment was conducted for 6 hrs for evaluating the percentage biodegradability of test chemical by using acclimated activated sludge as a test inoculum (Sarvottam D. Deshpande, et. al; 1987). Activated sludge obtained from an oxidation ditch treating domestic waste water was used as a test inoculum for the study. For acclimation of activated sludge, activated sludge was exposed to test chemical. The organic loading in each case was maintained at 0.11 g of total organic carbon (TOC)/g of mixed liquor volatile suspended solids (MLVSS). Diammonium orthophosphate (200 mg/L) provided the required nitrogen and phosphorus. The fill and draw technique was employed, and acclimation was determined from the rate of TOC utilization by the respective sludges. Biodegradation experiment was carried out by exposing the activated sludge to the test chemical.The organic loading in each case was maintained at 0.11 g of total organic carbon (TOC)/g of MLVSS in batch reactors of 1 l capacity and equipped with sintered glass diffusers. The experiments were conducted for a period of 6 h, and the TOC of 0- and 6-h samples in each case was monitored with a Beckman TOC analyzer (Model 915 A). The organic components present in samples were quantified with the help of high-performance liquid chromatography (HPLC) (Model 204, Water Associates Inc., Milford, MA) in a system equipped with M-6000 and M-45 pumps, a u6K septumless injector, a Model 440 UV absorption detector with a 254-nm primary filter, and an HPLC recorder (Houston Instrument Series B-5000 dual pen, Austin, TX). Solvents used were double-distilled spectroscopic-grade dioxane and water in the ratio of 1:24 in the case of catechol-resorcinol system and only water in the case of all other systems investigated. The column used for HPLC analyses was µBondapac C-18. Samples filtered through Millipore membrane filter were analysed by reverse-phase chromatography. Operating conditions were (i) chart speed, 25cm/h; (ii) flow rate, 2mL/min; and (iii) column temperature, ambient. Analytical-grade standards were run with each experiment. The TOC removal of the test chemical by using acclimated activated was determined to be 16.9 mg after a period of 6 hrs. Thus, based on this, test chemical is considered to be biodegradable in nature.

On the basis of above results for target (from study report and peer reviewed journals and secondary source), most of the studies show test chemical is readily biodegradable therefore it can be concluded that the test chemical is 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 chemical. If released in to the environment, 31.3% 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 37.5 days (900 hrs). The half-life (37.5 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 test chemical in sediment is estimated to be 337.5 days (8100 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.083%), indicates that test chemical is not persistent in sediment.

Biodegradation in soil

The half-life period of test chemical 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, 68.6% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of test chemical, 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 chemical can be considered to be readily biodegradable in nature.

Bioaccumulation: aquatic / sediment

Experimental study and predicted data for the target chemical and various supporting studies for its structurally similar read across substances were reviewed for the bioaccumulation end points which are summarized as below:

 In an experimental key study from authoritative database (J-CHECK & BCF database, 2017 and EnviChem, 2014) and secondary source (IUCLID dataset, 2000) for the target chemical, bioaccumulation experiment was conducted on test organism Cyprinus carpio for 6 weeks for evaluating the bioconcentration factor (BCF value) of test chemical .The study was performed according to OECD Guideline 305 C "Bioaccumulation: Test for the Degree of Bioconcentration in Fish" and 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 under flow through conditions at a temperature of25°C and pH range 6.0-8.5, respectively. Cyprinus carpio was used as a test organism for the study. Test chemical nominal conc. used for the study were 1 mg/land 0.1 mg/l. Range finding study involve the TLm(48h) > 1000 mg/L on Rice fish(Oryzias latipes).The bioconcentration factor (BCF value) of test chemical on Cyprinus carpio was determined to be in the range of 0.5-1.6 L/Kg at a conc. of 1 mg/l and ≤ 5 L/Kg at a conc. of 0.1 mg/l, respectively.

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 chemical was estimated to be 5.05 dimensionless . The predicted BCF result was based on the 5 OECD principles.

In a next weight of evidence study from authoritative database (J-CHECK, 2017) for the test chemical, bioaccumulation experiment was conducted on test organism Cyprinus carpio for 6 weeks for evaluating the bioconcentration factor (BCF value) of test chemical. The study was performed according to OECD Guideline 305 C (Bioaccumulation: Test for the Degree of Bioconcentration in Fish) and 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 0.5mg/land 0.05 mg/l, respectively. Analytical method involve the recovery ratio: Test water: Fish: 91.0 %, - Limit of quantitation: Test water: 1st concentration area : 0.018 mg/L, 2nd concentration area : 0.0018 mg/L, Fish : 0.20 microg/g. Range finding study involve theLC50 (48h) 326 mg/L on Rice fish (Oryzias latipes). Lipid content of the test organism Cyprinus carpio was determined to be 4.1% at the start of exposure. The bioconcentration factor (BCF value) of test chemical on Cyprinus carpio was determined to be ≤ 0.4 L/Kg at a conc. of 0.5 mg/l and ≤ 4.1 L/Kg at a conc. of 0.05 mg/l, respectively.

In another weight of evidence study for test chemical, the bioaccumulation study was conducted on test organism Cyprinus carpio for 6 weeks for evaluating the bioconcentration factor (BCF value) of test chemical (J-CHECK, 2017). Cyprinus carpio was used as a test organism for the study. Test chemical nominal conc. used for the study were 1mg/land 0.1 mg/l, respectively. Range finding study involves the TLm (48 hr) ˃ 1000 mg/l (w/v) on Rice fish (Oryzias latipes). The bioconcentration factor (BCF value) test chemical on Cyprinus carpio was determined to be in the range of 0.2-0.5 L/Kg at a conc. of 1 mg/l and ≤ 2 L/Kg at a conc. of 0.1 mg/l, respectively.

On the basis of above results for target chemical (from authoritative J-CHECK, BCF database, EnviChem, secondary source & modelling database CompTox Chemistry Dashboard,2017) it can be concluded that the BCF value of test chemical ranges from 0.5–5.05 which does not exceed the bioconcentration threshold of 2000, indicating that the test chemical is not expected to bioaccumulate in the food chain.

Transport and distribution:

Adsorption / desorption

Predicted data for the target compound and supporting experimental study for its read across substances were reviewed for the adsorption end point which is summarized as below:

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 was estimated to be 25.7 L/kg (log Koc = 1.409).The predicted KOC result was based on the 5 OECD principles.

In a supporting study from authoritative database (HSDB, 2017) for the test chemical, adsorption experiment was conducted for estimating the adsorption coefficient (Koc) value of test chemical. The adsorption coefficient (Koc) value was calculated using an experimental water solubility of 80,000 mg/l and a regression derived equation. The adsorption coefficient (Koc) value of test chemical was estimated to be 9 (Log Koc = 0.954). This Koc value indicates that the test chemical has a negligible sorption to soil and sediment and therefore has rapid migration potential to ground water.

In next supporting study the Koc of test chemical was estimated to be approximately 54 , the log Koc was calculated to be 1.732 . Hence, based on the log Koc value the test chemical is considered to have Low sorption to soil and sediment, moderate migration to ground water.

On the basis of above overall results for target chemical (from modelling database CompTox Chemistry Dashboard, 2017and authoritative database HSDB, 2017), it can be concluded that the Koc value of test chemical was estimated to be 9 to 54 indicating that the test chemical has a negligible to low sorption to soil and sediment and therefore have rapid to moderate migration potential to ground water.