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Biodegradation in water: screening tests

Biodegradation study was carried out for 28 days for evaluating the percentage biodegradability of the test substance 4 -Amino-3 -methylbenzenesulfonic acid (CAS no. 98 -33 -9). The study was performed according to OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test) under aerobic conditions. The percentage degradation of test substance was determined to be 22% by DOC removal parameter in 28 days. Thus, based on percentage degradation, 4 -Amino-3 -methylbenzenesulfonic acid was considered to be inherently biodegradable in nature.

Biodegradation in water and sediment: simulation tests

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 4 -Amino-3 -methylbenzenesulfonic acid (CAS No. 98 -33 -9). If released in to the environment, 35% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 4 -Amino-3 -methylbenzenesulfonic acid 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 4 -Amino-3 -methylbenzenesulfonic acid in sediment is estimated to be 337.5 days (8100 hrs). However, as the percentage release of test chemical into the sediement is less than 1% (i.e, reported as 0.0835%), it indicates that the chemical 4 -Amino-3 -methylbenzenesulfonic acid is not persistent in sediment. 

Biodegradation in soil

The half-life period of 4-Amino-3-methylbenzenesulfonic acid (CAS No. 98 -33 -9) 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, 64.9 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 4-Amino-3-methylbenzenesulfonic acid in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of 4 -Amino-3 -methylbenzenesulfonic acid, 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 Program (v3.00) model of EPI suite the estimated bio concentration factor (BCF) for 4-amino-3-methylbenzenesulfonic acid is 3.162 L/kg wet-wt which does not exceed the bioconcentration threshold of 2000.Thus it is concluded that chemical 4-amino-3-methylbenzenesulfonic acid is not expected to be bioaccumulative in fish and the food chain.

Adsorption / desorption:

The Soil Adsorption Coefficient i.e Koc value of 4-amino-3-methylbenzenesulfonic acid  was estimated using EPI suite  KOCWIN Program (v2.00) as Koc 10 L/kg (log Koc = 1)  by means of MCI method at 25 deg.C. This Koc value indicates that the substance 4-amino-3-methylbenzenesulfonic acid  has a Negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

Additional information

Biodegradation in water: screening tests

Various study and predicted data for the target compound 4 -Amino-3 -methylbenzenesulfonic acid (CAS no. 98 -33 -9) and the study for its read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study (D. Brown and B. Hamburger, 1987), biodegradation experiment was carried out for 28 days for evaluating the percentage biodegradability of the test substance 4 -Amino-3 -methylbenzenesulfonic acid (CAS no. 98 -33 -9). The study was performed according to OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test) under aerobic conditions. The percentage degradation of test substance was determined to be 22% by DOC removal parameter in 28 days. Thus, based on percentage degradation, 4 -Amino-3 -methylbenzenesulfonic acid was considered to be inherently biodegradable in nature.

 

In a supporting study for test substance 4 -Amino-3 -methylbenzenesulfonic acid (CAS no. 98 -33 -9) from peer reviewed journal (D. Brown and B. Hamburger, 1987), biodegradation study was carried out for 28 days for evaluating the percentage biodegradability of the test substance 4 -Amino-3 -methylbenzenesulfonic acid (CAS no. 98 -33 -9). The study was performed according to EPA OTS 796.3180 (Ready Biodegradability: Modified AFNOR Test) under aerobic conditions. The percentage degradation of test substance was determined to be 2 and 12% by DOC removal parameter in 28 days. Thus, based on percentage degradation, 4 -Amino-3 -methylbenzenesulfonic acid was considered to be not readily biodegradable in water.

 

Another supporting biodegradation study (D. Brown and B. Hamburger, 1987) was carried out for evaluating the percentage biodegradability of the test substance 4 - Amino-3 -methylbenzenesulfonic acid (CAS no. 98 -33 -9). Activated sludge was used as an inoculum and the study was performed under anaerobic conditions at a temperature of 35°C for a period of approx. 100 days. Samples of the aqueous phase were analyzed either qualitatively or quantitatively by an appropriate chromatographic method for the presence of certain of the expected aromatic amine metabolites. The percentage degradation of test substance was determined to be 0% by appropriate chromatography method and DOC analysis in approx. 100 days. Thus, based on percentage degradation, 4 -Amino-3 -methylbenzenesulfonic acid was considered to be not readily biodegradable in nature.

 

Estimation Programs Interface Suite (EPI suite, 2017) was run to predict the biodegradation potential of the test compound 4-Amino-3-methylbenzenesulfonic acid (CAS no. 98 -33 -9) 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 4 -Amino-3 -methylbenzenesulfonic acid is expected to be not readily biodegradable.

For read across substance 2-amino-5-methylbenzene sulfonic acid (CAS no. 88 -44 -8) (J-CHECK, 2016), biodegradation study was conducted for 14 days for evaluating the percentage biodegradability of substance 2-amino-5-methylbenzene sulfonic acid. Concentration of inoculum i.e, activated sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of substance was determined to be <0 and 0% by BOD, O2 consumption, TOC removal, Test mat. analysis and UV-Vis parameter in 14 days. Thus, based on percentage degradation, 2-amino-5-methylbenzene sulfonic acid is considered to be not readily biodegradable in water.

 

On the basis of above results for target chemical 4 -Amino-3 -methylbenzenesulfonic acid (frompeer reviewed journal and EPI Suite) and read across substance from authortiative database (J-CHECK, 2016), it can be concluded that the test substance 4 -Amino-3 -methylbenzenesulfonic acid can be expected to be not readily biodegradable in nature.

Biodegradation in water and sediment: simulation tests

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 4 -Amino-3 -methylbenzenesulfonic acid (CAS No. 98 -33 -9). If released in to the environment, 35% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 4 -Amino-3 -methylbenzenesulfonic acid 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 4 -Amino-3 -methylbenzenesulfonic acid in sediment is estimated to be 337.5 days (8100 hrs). However, as the percentage release of test chemical into the sediement is less than 1% (i.e, reported as 0.0835%), it indicates that the chemical 4 -Amino-3 -methylbenzenesulfonic acid is not persistent in sediment. 

Biodegradation in soil

The half-life period of 4-Amino-3-methylbenzenesulfonic acid (CAS No. 98 -33 -9) 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, 64.9 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 4-Amino-3-methylbenzenesulfonic acid in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of 4 -Amino-3 -methylbenzenesulfonic acid, 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 substance 4 -Amino-3 -methylbenzenesulfonic acid can be considered to be not readily biodegradable in nature.

 

Bioaccumulation: aquatic / sediment:

Four different studies including those from validated prediction databases and experimental study for bioaccumulation endpoint of target chemical 4-amino-3-methylbenzenesulfonic acid (Cas no. 98-33-9)and relevant read across which is structurally similar to target chemical are summarized as followed:

 

First study from prediction report by BCFBAF (v3.00) model of EPI Suite program indicated the estimated bio concentration factor (BCF) for 4-amino-3-methylbenzenesulfonic acid as 3.162 L/kg wet-wt which does not exceed the bioconcentration threshold of 2000.

 

And predicted database PBT profiler propose the Bioaccumulation factor (BCF) was predicted to be 3.2 L/kg wet-wt at 25 deg.C for test chemical 4-amino-3-methylbenzenesulfonic acid.

 

Above both studies are supported by another reliable predicted data sources i.e Chemspider - ACD/PhysChem Suite and Scifinder database which indicate the Bioconcentration factor (BCF) for target chemical 4-amino-3-methylbenzenesulfonic acid was predicted to be 1 at pH 1-10 and temperature 25 deg.C.

Finally an experimental study of read across chemical 4-amino-3-methylbenzenesulfonic acid (Cas no.121-57-3) give assistance to all predicted results of target substance which suggest Bioaccumulation test was conducted for 28 days for determination the bioconcentration factor (BCF) and lipid content of substance 4-aminobenzenesulfonic acid (Cas no.121-57-3) on test organism Cyprinus carpio. The recovery ratio is given- Fish: 87.5 %  and Nominal concentrations used in the study as - 1st concentration area: 1 mg/L, 2nd concentration area: 0.1 mg/L and Range finding study was carried out on Rice fish (Oryzias latipes) and the 96 hr LC50 value was found to be 270 mg/L.By analytical methods, the limit of quantification was found to be- Test water: (Fish: 340 ng/g) ;1st concentration area: 31 µg/l and 2nd concentration area: 3.1µg/l .Whereas the lipid content at the start and end of exposure was found to be 2.14% and 2.05%, respectively. Thus according to guideline OECD Guideline 305 (Bioconcentration: Flow through Fish Test) the BCF value for test substance 4-aminobenzenesulfonic acid (Cas no.121-57-3) was observed to be <= 0.34 L/kg at dose concentration 1 mg/L and <= 3.5 L/kg at dose concentration 0.1 mg/L on test organism Cyprinus carpio during 28 day period. These values indicate that the substance is not bioaccumulative in fish and food chain. (J-check database;2017)

All values for bioaccumulation is in the range of <=0.34 -3.5 (L/kg or dimensionless) conclude that the target chemical 4-amino-3-methylbenzenesulfonic acid (Cas no. 98-33-9) isnot expected to be bioaccumulative in fish and the food chain.

Adsorption / desorption:

Three different studies from validated predicted databases and experimental study for adsorption endpoint of target chemical 4-amino-3-methylbenzenesulfonic acid (Cas no. 98-33-9) with relevant read across which is structurally similar to target chemical are summarized as followed:

 

First study from prediction report using EPI suite KOCWIN model (v2.00) indicate the Soil Adsorption Coefficient i.e Koc value of 4-amino-3-methylbenzenesulfonic acid was estimated as Koc 10 L/kg (log Koc = 1) by means of MCI method at 25 deg.C. This Koc value indicates that the substance 4-amino-3-methylbenzenesulfonic acid has negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

 

Whereas Chemspider - ACD/PhysChem Suite prediction model and Scifinder database indicate the soil adsorption coefficient i.e Koc value of test substance 44-amino-3-methylbenzenesulfonic acid was estimated to be 1 (Log koc-0) at pH 1-10 (including pH range 5.5 and 7.4 from Chemspider data source)and temperature 25 deg.C. This Koc value at all range of pH condition indicates that the substance 4-amino-3-methylbenzenesulfonic acid has negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

 Above both predicted values of target chemical are further supported by experimental study of read across chemical 4-aminobenzenesulfonic acid (also reported as Sulfanilic acid; CAS no. 121-57-3) which suggest the adsorption coefficient (Koc) of substance Sulfanilic acid was found to be 10 using a structure estimation method based on molecular connectivity indices.This Koc value suggests that sulfanilic acid is expected to have very high mobility in soil.(HSDB database;2017)

All values for adsorption is in the range of log Koc 1-0 (L/kg or dimensionless) which gives common conclusion as target chemical 4-amino-3-methylbenzenesulfonic acid (Cas no. 98-33-9) has high mobility in soil/sediment compartment.