Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate

Endpoint summary

Description of key information

Hydrolysis:
The half life for the substance Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate was estimated to be 306.28 days, indicating that it is very negligibly hydrolysable.

Biodegradation in water:
The test item disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate (CAS No. 4553-89-3) undergoes 2.80 % biodegradation after 28 days in the test condition. Thus, the test item can be inferred/considered as not readily biodegradable.

Biodegradation in water and sediment:
Half-life period of Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate), in water is observed to be 60 days (1440 hrs.) while in sediment it is 541.66 days (13000 hrs). Based on these half-life values of Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate), it is concluded that the chemical is persistent in water and sediment.

Biodegradation in soil:
EPI Suite has estimated Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate), is expected to be found predominantly in soil and it’s persistence estimate is based on its transformation in this medium. Its half-life in soil is estimated to be 120 days (2880 hrs). Therefore, Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate), is estimated to be persistent in the soil.

Bioaccumulation:
The estimated bioconcentration factor (BCF) for Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate) is 3.162 L/kg. This value does not exceed the bioconcentration threshold of 2000. Thus it is concluded that Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate) is not expected to bioaccumulate in the food chain because it does not exceed the BCF criteria.

Adsorption/desorption:
The partition coefficient of test substance disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate (CAS No.4553-89-3) was determined as per the HPLC method (OECD Guideline-12). The Log Koc value was found to be 3.259± 0.004 at 25°C.

Henry’s law constant:
The Henry's Law constant of the substance Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate is estimated to be 7.37E-38 atm m³/mol which is <0.000000001 atm m³/mol.

Additional information

Hydrolysis:
Hydrolysis of Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate was predicted using OECD QSAR toolbox version 3.3. The half life for the substance Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate was estimated to be 306.28 days, indicating that it is very negligibly hydrolysable.

Biodegradation in water:
Data available for target Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate for the endpoint Biodegradation in water are summarized as follows:

In key study, 28-days Manometric respirometry test following the OECD guideline 301F was conducted to determine the ready biodegradability of disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate(CAS No. 4553-89-3). 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 100mg/L, while that of inoculum was 10ml/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 BOD28value of disodium-4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate (CAS No. 4553-89-3) was observed to be 0.0385 mgO2/mg. ThOD was calculatedas 1.373 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was found to be 2.80%. Based on the results, the test item, under the test conditions, was found to be not readily biodegradable at 20 ± 1°C over a period of 28 days.

In supporting study, Estimation Programs Interface Suite (EPI suite, 2017) was run to predict the biodegradation potential of the test compound Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate), CAS No. 4553-89-3, 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 the test chemical Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate) is not expected to be readily biodegradable.

Thus based on available data for target it is concluded that Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate) is not expected to be readily biodegradable in water.

Biodegradation in water and sediment:
Half-life period of Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate), in water is observed to be 60 days (1440 hrs.) while in sediment it is 541.66 days (13000 hrs). Based on these half-life values of Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate), it is concluded that the chemical is persistent in water and sediment.

Biodegradation in soil:
EPI Suite has estimated Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate), is expected to be found predominantly in soil and it’s persistence estimate is based on its transformation in this medium. Its half-life in soil is estimated to be 120 days (2880 hrs). Therefore, Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate), is estimated to be persistent in the soil.

Bioaccumulation:
The estimated bioconcentration factor (BCF) for Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate) is 3.162 L/kg. This value does not exceed the bioconcentration threshold of 2000. Thus it is concluded that Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate) is not expected to bioaccumulate in the food chain because it does not exceed the BCF criteria.

Adsorption/desorption:
Data available for target Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate for the endpoint Adsorption are summarized as follows:

In key study, The partition Coefficient n-octanol/water of disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate (CAS No. 4553-89-3) was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The reference substances were chosen according to estimated Kocrange of the test substance and generalized calibration graph was prepared. The reference substances were 4 chloroaniline, 4 methylaniline, N methylaniline, 2 Nitrophenol, Nitrobenzene, 4-Nitrobenzamide , N,N-dimethylbenzamide , N-methylbenzamide , Benzamide , phenanthrene having Kocvalue ranging from 1.239 to 4.09. The Log Koc value was determined to be 3.259± 0.004 at 25°C. This value indicates the chemical has Strong sorption to soil and sediment and negligible to slow migration potential to ground water.

Further supporting the above data, Soil Adsorption Coefficient i.e Log Koc value of Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate) was estimated as 6.4217 (i.e. Koc:2640000 L/kg) by means of MCI method. This indicates that Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate) has very strong sorption to soil and sediment and negligible migration potential to groundwater.

Based on the above data, it is concluded that Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate) has Strong sorption to soil and sediment and negligible to slow migration potential to ground water.

Henry’s law constant:
The Henry's Law constant of the substance Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate is estimated to be 7.37E-38 atm m³/mol which is <0.000000001 atm m³/mol.

However due to restriction in above key value field, the value considered for CSR is 0.000000001 Pa m³/mol. This value indicates that the chemical has extremely low vapour pressure.