Isopropyl 4-hydroxybenzoate

Endpoint summary

Description of key information

Hydrolysis

HYDROWIN v2.00 program of Estimation Programs Interface (EPI Suite, 2017) prediction model was used to predict the hydrolysis half-life of test compound

isopropyl 4-hydroxybenzoate (CAS No. 4191 -73 -5). The estimated half-life of isopropyl 4-hydroxybenzoate was estimated to be 48.606 yrs and 4.861 yrs at pH 7 and 8 (at 25 deg C) respectively, indicating that it is not hydrolysable.

Biodegradation in water

28-days Closed Bottle test following the OECD guideline 301 D 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 as inoculum at concentration 10E7 to 10E8 CFU/ml. 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. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 76.5 %. Degradation of Sodium Benzoate exceeds 45.18% on 7 days & 70.48% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid. The BOD28 value of Isopropyl 4-hydroxybenzoate(CAS No.4191-73-5) was observed to be 1.25 mgO2/mg. ThOD was determined by calculation as 2.04 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle Test was found to be 61.27%. Based on the results, the test item, under the test conditions, was 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

Isopropyl 4-hydroxybenzoate (CAS No. 4191 -73 -5). If released in to the environment, 18.8% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of Isopropyl 4-hydroxybenzoate 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

Isopropyl 4-hydroxybenzoate in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical Isopropyl 4-hydroxybenzoate into the sediment is less than 1% (i.e, reported as 0.206%), indicates that Isopropyl 4-hydroxybenzoate is not persistent in sediment.

 

Biodegradation in soil:

The half-life period of Isopropyl 4-hydroxybenzoate (CAS No.4191-73-5) 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, 80.9% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of Isopropyl 4-hydroxybenzoate in soil is estimated to be 30 days (720 hrs). Based on this half-life value of Isopropyl 4-hydroxybenzoate , 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

From BCFBAF (v3.00) model of EPI suite Program, the estimated bio concentration factor (BCF) for Isopropyl 4-hydroxybenzoate is 38.37 L/kg whole body w.w which does not exceed the bio concentration threshold of 2000. Thus it is concluded that Isopropyl 4-hydroxybenzoate is not expected to bioaccumulate in the food chain.

Adsorption:

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 4 mg of test item and diluted with ACN up to 10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 6. 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 Benzoic acid methylester, Xylene, Ethylbenzene, Toluene, Naphthalene having Koc value ranging from 1.8 to 2.75. The Log Koc value was found to be 2.258 ± 0.000 at 25°C. Thus based on the result it is concluded that the test substance Isopropyl 4-hydroxybenzoate has a low sorption to soil and sediment and therefore has moderate migration potential to ground water.

Additional information

Hydrolysis

HYDROWIN v2.00 program of Estimation Programs Interface (EPI Suite, 2017) prediction model was used to predict the hydrolysis half-life of test compound

isopropyl 4-hydroxybenzoate (CAS No. 4191 -73 -5). The estimated half-life of isopropyl 4-hydroxybenzoate was estimated to be 48.606 yrs and 4.861 yrs at pH 7 and 8 (at 25 deg C) respectively, indicating that it is not hydrolysable.

Biodegradation in water

28-days Closed Bottle test following the OECD guideline 301 D 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 as inoculum at concentration 10E7 to 10E8 CFU/ml. 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. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 76.5 %. Degradation of Sodium Benzoate exceeds 45.18% on 7 days & 70.48% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid. The BOD28 value of Isopropyl 4-hydroxybenzoate(CAS No.4191-73-5) was observed to be 1.25 mgO2/mg. ThOD was determined by calculation as 2.04 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle Test was found to be 61.27%. Based on the results, the test item, under the test conditions, was 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

Isopropyl 4-hydroxybenzoate (CAS No. 4191 -73 -5). If released in to the environment, 18.8% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of Isopropyl 4-hydroxybenzoate 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

Isopropyl 4-hydroxybenzoate in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical Isopropyl 4-hydroxybenzoate into the sediment is less than 1% (i.e, reported as 0.206%), indicates that Isopropyl 4-hydroxybenzoate is not persistent in sediment.

 

Biodegradation in soil:

The half-life period of Isopropyl 4-hydroxybenzoate (CAS No.4191-73-5) 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, 80.9% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of Isopropyl 4-hydroxybenzoate in soil is estimated to be 30 days (720 hrs). Based on this half-life value of Isopropyl 4-hydroxybenzoate , 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:

Four different predicted results from validated models for bioaccumulation (BCF) endpoint of target chemical Isopropyl 4-hydroxybenzoate (Cas no. 4191-73-5) were summarized as follows:

 

First prediction done using BCFBAF (v3.00) model indicate the estimated bio concentration factor (BCF) for Isopropyl 4-hydroxybenzoate is 38.37 L/kg wet-wt which does not exceed the bioconcentration threshold of 2000.

 

Another validated prediction by ACD (Advanced Chemistry Development)/I-Lab; Algorithm Version: v5.0.0.184 using Bio-concentration Factor (v12.1.0.50374) module; 2017 indicate the bio-concentration Factor over the entire pH scale 1-14 of the test substance Isopropyl 4-hydroxybenzoate estimated to be in the range 1 to 71.6 (dimentionless).

 

Further, an estimation 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) indicate  the bioaccumulation i.e BCF for test substance Isopropyl 4-hydroxybenzoate to be 32.0 dimensionless. The predicted BCF result based on the 5 OECD principles.

 

Last study from Scifinder database indicate the Bioconcentration factor (BCF) for target chemical Isopropyl 4-hydroxybenzoate was predicted to be 1.80-71.8 at pH range 1-10 and temperature 25 deg.C.

 

Thus based on the above information for bioaccumulation endpoint, it can be concluded that the BCF of the test substance Isopropyl 4-hydroxybenzoate (Cas no. 4191-73-5) is expected to be in the range 1 - 71.8. This value indicates that the substance is likely to be non Bioaccumulative in aquatic environment as the BCF does not exceed the threshold of 2000.

Adsorption:

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 4 mg of test item and diluted with ACN up to 10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 6. 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 Benzoic acid methylester, Xylene, Ethylbenzene, Toluene, Naphthalene having Koc value ranging from 1.8 to 2.75. The Log Koc value was found to be 2.258 ± 0.000 at 25°C. Thus based on the result it is concluded that the test substance Isopropyl 4-hydroxybenzoate has a low sorption to soil and sediment and therefore has moderate migration potential to ground water.