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

Endpoint summary

Description of key information

Biodegradation in water

Biodegradability of disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate (CAS no. 5858 -81 -1) is predicted using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor. Test substance undergoes 1.28% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate was estimated to be not readily biodegradable in water.

Biodegradation in water & sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound disodium 4 -[(E)-2 -(4 -methyl-2 -sulfphenyl)diazen-1 -yl]-3 -oxidonaphthalene-2 -carboxylate (CAS No. 5858 -81 -1). If released in to the environment, 14.7% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate 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 isnot persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of disodium 4 -[(E)-2 -(4 -methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate in sediment is estimated to be 377.5 days (8100 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.562%), indicates that disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate is not persistent in sediment.

 

Biodegradation in soil

The half-life period of disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate (CAS No. 5858 -81 -1) 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, 84.5% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate, 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

Predicted data for the target compounddisodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate(CAS No. 5858-81-1) and various supporting weight of evidence studies for its read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction done by SSS (2017) using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor, percentage biodegradability of test chemicaldisodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate(CAS No. 5858-81-1) was estimated.Test substance undergoes 1.28% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate was estimated to be not readily biodegradable in water.

 

In a supporting weight of evidence study from study report (Sustainability Support Services (Europe) AB, Report no. 4548-53-2/01/2016/RBD, 2016) for the read across chemical Disodium 3-[(2,4-dimethyl-5-sulphonatophenyl)azo]-4-hydroxynaphthalene-1-sulphonate (CAS no. 4548-53-2), 28-days Manometric respirometry testfollowing the OECD guideline 301F to determine the ready biodegradability of the read across item disodium 3- [(2,4 -dimethyl-5 -sulphonatophenyl)azo]-4 -hydroxynaphthalene-1 -sulphonate. 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 disodium 3-[(2,4-dimethyl-5- sulphonatophenyl)azo]-4-hydroxynaphthalene-1-sulphonate, CAS No. 4548-53-2 was observed to be mgO2sup>/mg. ThOD was calculated as mgO2/mg. Accordingly, the % degradation of the read across item Disodium 3-[(2,4-dimethyl-5-sulphonatophenyl)azo]-4-hydroxynaphthalene-1-sulphonate 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 read across item disodium 3 -[(2,4 -dimethyl-5 -sulphonatophenyl)azo]-4 -hydroxynaphthalene-1 –sulphonate (CAS no. 4548-53-2) (Sustainability Support Services (Europe) AB, Report no. 4548-53-2/01/2016/CBT, 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 BOD 28value of Disodium 3 -[(2,4 -dimethyl-5 -sulphonatophenyl)azo]-4 -hydroxynaphthalene-1 –sulphonate was observed to be 0.475 mgO2/mg. ThOD was calculated as 1.465 mgO2/mg. Accordingly, the % degradation of the read across item Disodium 3-[(2,4-dimethyl-5-sulphonatophenyl)azo]-4-hydroxynaphthalene-1-sulphonate 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 disodium3 -[(2,4 -dimethyl-5 -sulphonatophenyl)azo]-4 -hydroxynaphthalene-1 -sulphonate, under the test conditions, was considered to be not readily biodegradable at 20 ± 1°C over a period of 28 days.

 

In a supporting weight of evidence study from peer reviewed journal (Yasuhide TONOGAI et. al, 1978) for read across substancetrisodium (4E)-3-oxo-4-[2-(4-sulfonatonaphthalen-1-yl)hydrazin-1-ylidene]-3,4-dihydronaphthalene-2,7-disulfonate (CAS no. 915-67-3),biodegradation study was conducted under aerobic conditions for evaluating the percentage biodegradability of read across substance trisodium (4E)-3-oxo-4-[2-(4-sulfonatonaphthalen-1-yl)hydrazin-1-ylidene]-3,4-dihydronaphthalene-2,7-disulfonate. Activated sludge was used as a test inoculum obtained 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 the aerobic 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 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 chemicaltrisodium (4E)-3-oxo-4-[2-(4-sulfonatonaphthalen-1-yl)hydrazin-1-ylidene]-3,4-dihydronaphthalene-2,7-disulfonatewas 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, the chemical trisodium (4E)-3-oxo-4-[2-(4-sulfonatonaphthalen-1-yl)hydrazin-1-ylidene]-3,4-dihydronaphthalene-2,7-disulfonate was considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate (from OECD QSAR toolbox version 3.3, 2017) and for its read across substance (from peer reviewed journals and study report), it can be concluded that the test substance disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate can be expected to be not readily biodegradable in nature.

Biodegradation in water & sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound disodium 4 -[(E)-2 -(4 -methyl-2 -sulfphenyl)diazen-1 -yl]-3 -oxidonaphthalene-2 -carboxylate (CAS No. 5858 -81 -1). If released in to the environment, 14.7% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate 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 isnot persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of disodium 4 -[(E)-2 -(4 -methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate in sediment is estimated to be 377.5 days (8100 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.562%), indicates that disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate is not persistent in sediment.

 

Biodegradation in soil

The half-life period of disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate (CAS No. 5858 -81 -1) 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, 84.5% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate, 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 disodium 4-[(E)-2-(4-methyl-2-sulfophenyl)diazen-1-yl]-3-oxidonaphthalene-2-carboxylate can be considered to be not readily biodegradable in nature.