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

Endpoint summary

Description of key information

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

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.