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Biodegradation in water

Biodegradability of 4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid (CAS no. 87 -03 -6) is predicted using OECD QSAR toolbox version 3.4 (2017) with logKow as the primary descriptor. Test substance undergoes 0.5% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 4 -hydroxy-7 -[(5 -hydroxy-7 -sulfonaphthalen-2 -yl)amino]naphthalene-2-sulfonic acid was estimated to be not readily biodegradable in water.

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 4 -hydroxy-7 -[(5 -hydroxy-7 -sulfonaph thalen-2 -yl)amino]naphthalene-2-sulfonic acid (CAS No. 87 -03 -6). If released in to the environment, 2.41% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic 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-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid in sediment is estimated to be 337.5 days (8100 hrs). Based on this half-life value, it indicates that

4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid is persistent in sediment.

Biodegradation in soil

The half-life period of 4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid (CAS No. 87 -03 -6) 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, 44.3% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of

4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic 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.

Additional information

Biodegradation in water

Various predicted data for the target compound 4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid(CAS No. 87-03-6) and supporting weight of evidence studies for its read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a predicted data done by SSS (2017) using OECD QSAR toolbox version 3.4 with logKow as the primary descriptor, percentage biodegradability of test chemical 4-hydroxy-7-[(5- hydroxy-7 -sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid(CAS No. 87-03-6) was estimated.Test substance undergoes 0.5% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 4 -hydroxy-7 -[(5 -hydroxy-7 -sulfonaphthalen-2 -yl)amino]naphthalene-2-sulfonic acid was estimated to be not readily biodegradable in water.

 

In another prediction using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound 4 -hydroxy-7 -[(5 -hydroxy-7 -sulfonaphtha len-2 -yl)amino]naphthalene-2 -sulfonic acid(CAS No. 87-03-6) in the presence of mixed populations of environmental microorganisms was estimated.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 4 -hydroxy-7 -[(5 -hydroxy-7 -sulfonaphthalen-2 -yl)amino]naphthalene-2 -sulfonic acid is expected to be not readily biodegradable.

 

In a supporting weight of evidence study from peer reviewed journal (U. Pagga and O. Brown; 1986) for the read across chemical Tetrasodium 3,3'-[(3,3'-dimethoxy[1,1'-biphenyl] -4,4'-diyl)bis(azo)]bis[4,5-dihydroxynaphthalene-2,7-disulphonate] (CAS no. 4198-19-0), biodegradation experiment was carried out for 42 days for evaluating the percentage biodegradation of the read across chemical Tetrasodium 3,3'-[(3,3'-dimethoxy[1,1'-biphenyl]-4,4'-diyl)bis(azo) ]bis[4,5 -dihydroxynaphthalene-2,7 -disulphonate] using modified OECD Guideline 302B. Activated sludge was used as a test inoculum.The sources of the activated sludge were treatment plants conveniently located to the laboratories carrying out the test.These treatment plants received communal and/or industrial wastewater. Concentration of inoculum i.e, activated sludge used was 0.5 g/l and initial test substance conc. used in the study was 100 mg/l. Analytical methods involve the measurement of extinction at absorption maximum 412 nm and DOC (dissolved organic carbon). The percentage degradation of the test substance Tetrasodium 3,3'-[(3,3'-dimethoxy[1,1'-biphenyl] -4,4'-diyl)bis(azo)]bis[4,5 -dihydroxynaphthalene-2,7 -disulphonate] was determined to be -17% by using DOC removal parameter in 42 days. Thus, based on percentage degradation, the chemical Tetrasodium 3,3'-[(3,3'-dimethoxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[4,5-dihydroxy naphthalene-2,7-disulphonate] was considered to be not readily biodegradable in nature.

 

For the read across chemical disodium 7-amino-4-hydroxy-3-[(E)-2-(4-{4-[(E)-2-(1-hydroxy-4-sulfonatonaphthalen-2-yl)diazen-1-yl]-3-methoxyphenyl}-2-methoxyphenyl)diazen-1 -yl]naphthalene-2-sulfonate (CAS no. 6449-35-0), biodegradation study was carried out for 42 days for evaluating the percentage biodegradation of the read across chemical disodium 7 -amino-4 -hydroxy-3 -[(E)-2 -(4 -{4 -[(E)-2 -(1 -hydroxy-4 -sulfonatonaphthalen-2 -yl)diazen-1 -yl]-3 -methoxyphenyl}-2 -methoxyphenyl)diazen-1 -yl]naphthalene-2-sulfonate using modified OECD Guideline 302B (U. Pagga and O. Brown; 1986). Activated sludge was used as a test inoculum.The sources of the activated sludge were treatment plants conveniently located to the laboratories carrying out the test.These treatment plants received communal and/or industrial wastewater. Concentration of inoculum i.e, activated sludge used was 0.5 g/l and initial test substance conc. used in the study was 100 mg/l. Analytical methods involve the measurement of extinction at absorption maximum 412 nm and DOC (dissolved organic carbon).The percentage degradation of the test substance disodium 7 -amino-4 -hydroxy-3 -[(E)-2 -(4 -{4 -[(E)-2 -(1 -hydroxy-4 -sulfonatonaphthalen-2 -yl)diazen-1 -yl]-3 -methoxyphenyl}-2 -methoxyphenyl)diazen-1 -yl]naphthalene-2 -sulfonate was determined to be 44% by using DOC removal parameter in 42 days. Thus, based on percentage degradation, the chemical disodium 7 -amino-4 -hydroxy-3 -[(E)-2 -(4 -{4 -[(E)-2 -(1 -hydroxy-4 -sulfonatonaphthalen-2 -yl)diazen-1 -yl]-3 -methoxyphenyl}-2 -methoxyphenyl)diazen-1 -yl]naphthalene-2 -sulfonate was considered to be not readily biodegradable in nature.

In a supporting weight of evidence study from authoritative database (J-CHECK, 2017) for the read across chemical disodium 4-hydroxy-7-{[(5-hydroxy-7-sulfonato-2-naphthyl)carba moyl]amino}naphthalene-2-sulfonate (CAS no. 20324-87-2), biodegradation experiment was conducted for 14 days for evaluating the percentage biodegradability of read across substance disodium 4 -hydroxy-7 -{[(5 -hydroxy-7 -sulfonato-2 -naphthyl)carbamoyl]amino}naphthalene-2 -sulfonate. 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 substance disodium 4 -hydroxy-7 -{[(5 -hydroxy-7 -sulfonato-2 -naphthyl) carbamoyl]amino}naphthalene-2 -sulfonate was determined to be 0 and 1.3% by BOD and TOC removal parameter in 14 days. Thus, based on percentage degradation, disodium 4 -hydroxy-7 -{[(5 -hydroxy-7 -sulfonato-2 -naphthyl)carbamoyl]amino}naphthalene-2 -sulfonate is considered to be not readily biodegradable in nature.

 

Another biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of read across substance Tetrasodium 3,3'-[(3,3'-dimethoxy[1,1'-biphenyl] -4,4'-diyl)bis(azo) ]bis[5 -amino-4 -hydroxynaphthalene-2,7 -disulphonate] (CAS no. 2429 -74 -5) (J-CHECK and HSDB, 2017). The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)) under aerobic conditions. 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 substance Tetrasodium 3,3'-[(3,3'-dimethoxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[5-amino-4-hydroxy naphthalene-2,7-disulphonate] was determined to be 4, 1 and 2% by BOD, TOC removal and HPLC parameter in 28 days. Thus, based on percentage degradation, Tetrasodium 3,3'-[(3,3'-dimethoxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)] bis[5-amino-4-hydroxynaphthalene-2,7-disulphonate] is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical 4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid(from OECD QSAR toolbox version 3.4 and EPI suite, 2017) and for its read across substance (from peer reviewed journal and authoritative databases J-CHECK & HSDB), it can be concluded that the test substance 4 -hydroxy-7 -[(5 -hydroxy-7 -sulfonaphthalen-2 -yl)amino]naphthalene-2 -sulfonic acid can be expected to be not 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 4 -hydroxy-7 -[(5 -hydroxy-7 -sulfonaph thalen-2 -yl)amino]naphthalene-2-sulfonic acid (CAS No. 87 -03 -6). If released in to the environment, 2.41% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic 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-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid in sediment is estimated to be 337.5 days (8100 hrs). Based on this half-life value, it indicates that 4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid is persistent in sediment.

Biodegradation in soil

The half-life period of 4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid (CAS No. 87 -03 -6) 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, 44.3% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of 4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic 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-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid can be considered to be not readily biodegradable in nature.