Barium 3-hydroxy-4-[(4-methyl-2-sulphonatophenyl)azo]-2-naphthoate

Endpoint summary

Description of key information

Hydrolysis

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate can be expected to be range from 51 days to 1.4 yrs, respectively (at pH 7 and 8) and the second order hydrolysis rate constant of test chemical can be considered to be 0.16 L/mol-sec. Test chemical was reported to be hydrolytically stable at pH 4, 7 and 9, respectively and at a temperature of 50⁰C. Thus, based on this, test chemical barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate is considered to be not hydrolysable in water.

Biodegradation in water

Estimation Programs Interface Suite was run to predict the biodegradation potential of the test compound barium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate (CAS no. 17852 -98 -1) in the presence of mixed populations of environmental microorganisms. 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 chemical barium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl) diazenyl]-2 -naphthoate is expected to be not readily biodegradable.

Bioaccumulation: aquatic / sediment

BCFBAF model (v3.01) of Estimation Programs Interface was used to predict the bioconcentration factor (BCF) of test chemical barium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate (CAS No. 17852 -98 -1). The bioconcentration factor (BCF) of barium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate was estimated to be 10 L/kg whole body w.w (at 25 deg C) which does not exceed the bio concentration threshold of 2000, indicating that the chemical barium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate is not expected to bioaccumulate in the food chain.

Adsorption / desorption

KOCWIN model (v2.00) of Estimation Programs Interface was used to predict the soil adsorption coefficient i.e Koc value of test chemical barium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate (CAS No. 17852 -98 -1). The soil adsorption coefficient i.e Koc value of barium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate was estimated to be 8320 L/kg (log Koc=3.92) by means of MCI method (at 25 deg C). This Koc value indicates that the substance barium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2-naphthoate has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

Additional information

Hydrolysis

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the half-life of the test chemical barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate.The studies are as mentioned below:

The half-life of the test chemical was determined at different pH range. The study was performed according to OECD Guideline 111 (Hydrolysis as a Function of pH) at a temperature of 50°C. Although, half-life value of test chemical is not known, but chemical was reported to be hydrolytically stable at pH 4, 7 and 9, respectively and at a temperature of50⁰C. Based on this, it is concluded that test chemical is not hydrolysable.

In an another study, the half-life and base catalyzed second order hydrolysis rate constant was determined using a structure estimation method of the test chemical. The second order hydrolysis rate constant of test chemical was determined to be 0.16L/mol-sec with a corresponding half-lives of 1.4 yrs and 51 days at pH 7 and 8, respectively. Based on the half-life values, it is concluded that test substance is not hydrolysable.

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate can be expected to be range from  51 days to 1.4 yrs, respectively (at pH 7 and 8) and the second order hydrolysis rate constant of test chemical can be considered to be 0.16 L/mol-sec. Test chemical was reported to be hydrolytically stable at pH 4, 7 and 9, respectively and at a temperature of 50⁰C. Thus, based on this, test chemical barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate is considered to be not hydrolysable in water.

Biodegradation in water

Predicted data for the target compound barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate (CAS No. 17852-98-1) and supporting weight of evidence studies for its structurally and functionally similar read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compoundbarium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate(CAS No. 17852-98-1) in the presence of mixed populations of environmental microorganisms was estimated.

 

In a supporting weight of evidence study from study report (2016) for the test chemical, 28-days Manometric respirometry testfollowing the OECD guideline 301Fto determine the ready biodegradability of the test item. The test system included control, test item and reference item. The concentration of test and reference item ( Sodium Benzoate) chosen for both the study was 30 mg/L, while that of inoculum was 10 ml/l. 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 BOD28 value of test chemical was observed to be mgO2sup>/mg. ThOD was calculated as mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was determined to be 12.807 %.Based on the results, the test item, under the test conditions, was considered to be not readily biodegradable at 20± 1°C over a period of 28 days.

 

Another biodegradation study of 28-days Closed Bottle test following the OECD guideline 301D was conducted for determining the ready biodegradability of the test chemical (Experimental study report, 2017). The test system included control, test item and reference item. The concentration of test and reference item (Sodium Benzoate) chosen for the study was 32 mg/l and 32mg/l, while that of inoculum was 32ml/l. 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 BOD28value of test substance was observed to be 0.475mgO2/mg. ThOD was calculated as 1.465 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 32.42%. Based on the results, the test item, under the test conditions, was considered to be not readily biodegradable at 20 ± 1°C over a period of 28 days.

 

For the test chemical from peer reviewed journal (Yasuhide TONOGAI et. al., 1978), Biodegradation study was conducted under aerobic conditions for evaluating the percentage biodegradability of test substance. Activated sludge was used as a test inoculumobtained from the municipal sewage treatment plant, Nakahama, Osaka.The return sludge was acclimated to the synthetic sewage for a week or longer, and it was used for the aerobic and anaerobic decomposition experiments.Synthetic sewage was prepared by dissolving Glucose, peptone and potassium dihydrogen phosphate, 30g each, in 1 liter water and the pH was adjusted to pH 7.0 with sodium hydroxide. Concentration of inoculum used for the study was3000 mg/l. Percentage degradation of chemical was determined by measuring the absorbance (test material analysis), oxygen uptake and BOD parameter. For theaerobic decomposition of dyes with sludge, 250 ml of O.03 M dye solution was added to 750ml of sludge (MLSS ca, 3,000 ppm), and bubbled with air sufficiently at 20°C. 5ml sample was taken out once a day. After sampling 5ml of synthetic sewage was added to the mixture. Each sample was filtered through filter paper and diluted twenty times prior to the spectrophotometric measurement at the absorption maximum within the visible range. The decrease of dyes concentration was expressed in terms of percent to the initial absorption whereas measurement oxygen uptake by sludge involve 2.0 ml of sludge, 0.2 ml of 1,000 ppm dye solution, and O.2 ml of 20% potassium hydroxide were pipetted into the vessel, the side arm and central well, respectively. The sludge and the dye solution were mixed and the vessel was shaken at 25"C. The oxygen uptake was measured. The oxygen uptake by sludge alone was subtracted from the the by dye addition. For determining the BOD values, test chemical solutions (10, 20 and 40 ppm) were prepared with the seeded dilution water and kept at 20°C. The dissolved oxygen contents were then measured by using a dissolved oxygen meter.The percentage degradation of test chemical was determined to be 20% in 10 days by using the test material analysis parameter. From the oxygen uptake by Warburg’s manometer, the low activity of the sludge to dye was obtained and by using the dissolved oxygen meter, the dissolved oxygen contents on the 5th day were essentially the same to initial ones. Thus, based on percentage degradation, test chemical was considered to be not readily biodegradable in nature.

 

On the basis of above overall results for target chemical barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate (from modelling database,2017), it can be concluded that the test substance barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate can be considered to be not readily biodegradable in nature.

Bioaccumulation: aquatic / sediment

Various predicted data for the target compound barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate (CAS No. 17852-98-1) and supporting weight of evidence study for its structurally and functionally similar read across substance 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 (modelling database, 2017) was used to predict the bioconcentration factor (BCF) of test chemical barium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate (CAS No. 17852 -98 -1). The bioconcentration factor (BCF) of barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate was estimated to be 10 L/kg whole body w.w (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 barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate (CAS no. 17852 -98 -1) was estimated to be 8.51 dimensionless . The predicted BCF result based on the 5 OECD principles.

 

For the test chemical fromauthoritative databases (2017),bioaccumulation study was conducted on test organism Cyprinus carpio for 28 days for evaluating the bioconcentration factor (BCF value) of test substance. 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". Cyprinus carpio was used as a test organism for the study. Details on analytical methods involve the recovery ratio: Test water: 100% (The test solution were input analytical equipment directly), Fish: 82.4%, - Limit of quantitation: Test water: 1st concentration area : 21µg/l, 2nd concentration area : 2.1µg/l, Fish: 260 ng/g. Test chemical nominal conc. used for the study were 0.474mg/land 0.0474 mg/l, respectively. Range finding study involve the LC50 (96 hr) > 200 mg/l onRice fish (Oryzias latipes).The bioconcentration factor (BCF value) of test substance on Cyprinus carpio was determined to be ≤ 0.55 L/Kg at a conc. of 0.474 mg/l and ≤ 5.6 L/Kg at a conc. of 0.0474 mg/l, respectively.

 

Another bioaccumulation study was conducted for estimating the BCF (bioaccumulation factor) value of test chemical (authoritative database, 2017). The bioaccumulation factor (BCF) value was calculated using a measured water solubility of 80,000 mg/l and a recommended regression-derived equation. The estimated BCF (bioaccumulation factor) value of test chemical was determined to be 1.0 dimensionless.

 

In a supporting weight of evidence study, bioaccumulation experiment was conducted for estimating the BCF (bioaccumulation factor) value of test chemical (authoritative database, 2017). The bioaccumulation factor (BCF) value was calculated using a log Kow and a regression-derived equation. The estimated BCF (bioaccumulation factor) value of test substance was determined to be 3 dimensionless.

 

On the basis of above overall results for target chemical barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate (from modelling databases, 2017), it can be concluded that the BCF value of test substance barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoateranges from 8.51 –10 which does not exceed the bioconcentration threshold of 2000, indicating that the chemicalbarium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate is not expected to bioaccumulate in the food chain.

Adsorption / desorption

Predicted data for the target compound barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate(CAS No. 17852-98-1) and various supporting weight of evidence studies for its structurally and functionally similar read across substance 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 (modelling database, 2017) was used to predict the soil adsorption coefficient i.e Koc value of test chemical barium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate (CAS No. 17852 -98 -1). The soil adsorption coefficient i.e Koc value of barium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate was estimated to be 8320 L/kg (log Koc=3.92) by means of MCI method (at 25 deg C).

 

For the test chemical fromstudy report (2016), the adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The solutions of the test substance and reference substances were prepared in appropriate solvents. A test item solution was prepared by accurately weighing 50mg of test item and diluted with mobile phase up to 100ml. Thus, the test solution concentration was 500mg/l. The pH of test substance was 6.24. Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed. Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k(Annex - 2).The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor. The reference substances were chosen according to structural similarity with the test substance and calibration graph was prepared. The reference substances were Phenol, Aniline, Nitrobenzene, naphthalene, Phenanthrene and DDT having Koc value ranging from 1.32 to 5.63.The Log Koc value of test chemical was determined to be 3.679 ± 0.076 at 25°C.

 

In a supporting weight of evidence study,adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals (Experimental study report, 2016). The solutions of the test substance and reference substances were prepared in appropriate solvents. A test item solution was prepared by accurately weighing 50mg of test item and diluted with mobile phase up to 100ml. Thus, the test solution concentration was 500mg/l. The pH of test substance was 7.33. Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed. Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k(Annex - 2).The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor. The reference substances were chosen according to estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances were Phenol, 4 methyl aniline, nitrobenzene, toluene, Ethylbenzene, Phenanthrene, and DDT having Koc value ranging from 1.32 to 5.63. The Log Koc value of test chemical was determined to be 3.6 ± 0.06 at 25°C.

 

On the basis of above overall results for target chemical barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate (from modelling database,2017), it can be concluded that the Koc value of test substance barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate was estimated to be 8320 L/kg (log Koc=3.92) indicating that the test chemical barium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.