Disodium 4-hydroxynaphthalene-2,7-disulphonate

Endpoint summary

Description of key information

Biodegradation in water:

Biodegradability of target chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) ( CAS no. 20349 -39 -7) was determined by using OECD QSAR tool box v3.4 with log Kow as primary descriptor. The target chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2)  undergoes 0.6285 % biodegradation in 28 days by considering BOD as parameter and microorganisms as inoculum. On the basis of percent biodegradability value it is concluded that target chemical

2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) is not readily biodegradable.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS No: 20349 -39 -7) .If released in to the environment, 16.3 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of the chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) 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 low whereas the half-life period of 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) in sediment is estimated to be 135 days (3240 hrs).  However, as the percentage release of test chemical into the sediment is less than 1 % (i.e, reported as 0.553 %), indicates that test chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) is not persistent in sediment.

Biodegradation in soil:

The half-life period of 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS No: 20349 -39 -7) 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, 83.2 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) in soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2), 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 compound2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) ( CAS no. 20349-39-7)and supporting weight of evidence studies for its read acros substance were reviewed for the biodegradation end point which are summarized as below:

Biodegradability of target chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS no. 20349-39-7) was determined by using OECD QSAR tool box v3.4 with log Kow as primary descriptor. The target chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2)  undergoes 0.6285 % biodegradation in 28 days by considering BOD as parameter and microorganisms as inoculum. On the basis of percent biodegradability value it is concluded that target chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) is not readily biodegradable.

Another prediction done by using Estimation Programs Interface Suite (EPI suite, 2017) to estimate the biodegradation potential of the test chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS No: 20349 -39 -7) 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 chemical  2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) is not readily biodegradable.

In a supporting weight of evidence study done from authoritative database ( J check, 20170 the read across chemical dipotassium 7-hydroxynaphthalene-1, 3-disulfonate (CAS no. 842-18-2) was subjected to biodegradation test by taking sludge as inoculums at 30 mg/L concentration. Biodegradation was analysed by using BOD parameter. The initial concentration of read across chemical was 100 mg/L and study design is of standard type. After 4 weeks of incubation the read across chemical showed 0% biodegradation by BOD parameter so it is concluded that it is not readily biodegradable.

Similarly, in another supporting weight of evidence study done from authoritative database ( J check, 2017) the read across chemical Sodium 5-amino-4-hydroxy-7-sulfonaphthalene-2-sulfonate (CAS no. 5460-09-3) was subjected to biodegradation test by taking sludge as inoculums at 30 mg/L concentration. Biodegradation was analyzed by using O2 consumption (BOD), TOC removal and test material analysis by UV vis parameter. The initial concentration of read across chemical was 100 mg/L and study design is of standard type. After 2 weeks (14 days) read across chemical Sodium 5-amino-4-hydroxy-7-sulfonaphthalene-2-sulfonate showed 0% biodegradation by O2 consumption (BOD) parameter, 5 % biodegradation by TOC removal parameter and less than 0 % biodegradation by test material analysis by UV Vis parameter in 14 days. So it is concluded that this read across chemical is not readily biodegradable.

On the basis of results of above mentioned studies for target chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) ( CAS no. 20349 -39 -7) (from OECD QSAR tool box v3.4 and EPI suite) and supporting weight of evidence study ( from J Check, 2017). It is concluded that the test chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) can be expected to be not readily biodegradable.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS No: 20349 -39 -7) .If released in to the environment, 16.3 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of the chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) 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 low whereas the half-life period of 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) in sediment is estimated to be 135 days (3240 hrs).  However, as the percentage release of test chemical into the sediment is less than 1 % (i.e, reported as 0.553 %), indicates that test chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) is not persistent in sediment.

Biodegradation in soil:

The half-life period of 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) (CAS No: 20349 -39 -7) 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, 83.2 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2) in soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemical 2,7-Naphthalenedisulfonic acid, 4-hydroxy-, sodium salt (1:2), 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.