Sodium 4-(4-(2-hydroxynaphthalenylazo)phenylazo)benzenesulphonate

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: data is from peer reviewed journal

Justification for type of information:

data is from peer reviewed journal

Qualifier:

according to guideline

Guideline:

other: refer principle below

Principles of method if other than guideline:

The Kb value of test chemical sodium 4-({4-[(2-hydroxy-1-naphthyl)diazenyl]phenyl}diazenyl)benzenesulfonate was determined on waste water solids by using spectroscopy method

GLP compliance:

not specified

Type of method:

other: spectroscopy

Media:

sewage sludge

Specific details on test material used for the study:

- Name of test material (IUPAC name): Sodium 4-(4-(2-hydroxynaphthalenylazo)phenylazo)benzenesulphonate
- Common name: Acid Red 151
- Molecular formula: C22H15N4O4S.Na
- Molecular weight: 455.448 g/mol
-Physical state: red to brown powder
- Smiles notation: c12c(\N=N\c3ccc(\N=N\c4ccc(S(O)(=O)=O)cc4)cc3)c(ccc1cccc2)O.[Na+]
- InChl: 1S/C22H16N4O4S.Na/c27-21-14-5-15-3-1-2-4-20(15)22(21)26-25-17-8-6-16(7-9-17)23-24-18-10-12-19(13-11-18)31(28,29)30;/h1-14,27H,(H,28,29,30);/q;+1/b24-23+,26-25+;
- Substance type: Organic

Radiolabelling:

not specified

Analytical monitoring:

not specified

Details on matrix:

Four separate samples of primary sludge, mixed-liquor solids, and digested sludge were collected for each test Compound in a series of 5-gal carboys. Solids were removed by centrifugation in a perforate bowl centrifuge containing a 6-pm fabric bag. Analysis of the sludge or mixed liquor and the centrate showed solids capture of 95 f 3% by centrifugation. The collected solids (approximately 10% on a dry weight basis) were stored at 4 OC until used.

Key result

Type:

Kd

Value:

8.3 dimensionless

Remarks on result:

other: other details not available

Type:

Koc

Value:

20.75 dimensionless

Matrix:

sewage sludge

Remarks on result:

other: log Koc= 1.3170

compound	n^a	K^b	m^c	r^d
Acid red 151	12	8.30	1.00	0.99

^an =number of data points in isotherm test.

^bK= sorption coefficient, which equals X/M (mg/gm dry solids) at C, = 1.0 mg/L.

m^c= slope of isotherm plot.

 ^dr, correlation coefficient.

^eK values extrapolated to C. = 1.0 mg/L for comparison purposes.

Validity criteria fulfilled:

not specified

Conclusions:

Adsorption coefficient of test chemical Sodium 4-(4-(2-hydroxynaphthalenylazo)phenylazo)benzenesulphonate was determined to be 8.30. On the basis of this this adsorption coeffiicent Koc value was determined to be 20.75 (log Koc=1.3170). On the basis of this log KOc value it is concluded that this test chemical has negligible sorption to sewage and has rapid migration potential to ground water.

Executive summary:

An experiment was performed to determine adsorption coefficient of test chemical Sodium 4-(4-(2-hydroxynaphthalenylazo)phenylazo)benzenesulphonate (CAS no. 6406-56-0) on Wastewater solids were collected from three different municipal wastewater treatment plants within a 50-mi radius of the Risk Reduction Engineering Laboratory, Cincinnati, Ohio and a stock slurry that contained purged distilled water and wastewater solids was prepared to give the desired concentration of solids for the isotherm test by using visible spectroscopy at 512 nm. The adsorption coefficient of test chemical Sodium 4-(4-(2-hydroxynaphthalenylazo)phenylazo)benzenesulphonate was determined to be 8.30.On the basis of this this adsorption coeffiicent Koc value was determined to be 20.75 (log Koc=1.3170). On the basis of this log KOc value it is concluded that this test chemical has negligible sorption to sewage sludge and has rapid migration potential to ground water.

Description of key information

Adsorption coefficient of test chemical Sodium 4-(4-(2-hydroxynaphthalenylazo)phenylazo)benzenesulphonate was determined to be 8.30. On the basis of this this adsorption coeffiicent Koc value was determined to be 20.75 (log Koc=1.3170). On the basis of this log KOc value it is concluded that this test chemical has negligible sorption to sewage and has rapid migration potential to ground water.

Key value for chemical safety assessment

Koc at 20 °C:

20.75

Additional information

One predicted data study and one experimental study for target chemical Sodium 4-(4-(2-hydroxynaphthalenylazo)phenylazo)benzenesulphonate (CAS no. 6406-56-0) and two experimental studies for its structurally similar read across chemical have been conducted from different sources and results of all the studies are summarized below for adsorption endpoint.

 

The first study was done from Environ. Sci. Techno. 1989, 23, 1092-1097 by Richard A. Dobbs, Leping Wang, and Rakesh Govind in this study an experiment was performed to determine adsorption coefficient of test chemical Sodium 4-(4-(2-hydroxynaphthalenylazo)phenylazo)benzenesulphonate (CAS no. 6406-56-0) on Wastewater solids were collected from three different municipal wastewater treatment plants within a 50 -mi radius of the Risk Reduction Engineering Laboratory, Cincinnati, Ohio and a stock slurry that contained purged distilled water and wastewater solids was prepared to give the desired concentration of solids for the isotherm test by using visible spectroscopy at 512 nm. The adsorption coefficient of test chemical Sodium 4-(4-(2-hydroxynaphthalenylazo)phenylazo)benzenesulphonate was determined to be 8.30. On the basis of this this adsorption coeffiicent Koc value was determined to be 20.75 (log Koc=1.3170). On the basis of this log KOc value it is concluded that this test chemical has negligible sorption to sewage sludge and has rapid migration potential to ground water.

 

Next study was predicted data studyin this study the Soil Adsorption Coefficient i.e Koc value of test substance sodium 4-({4-[(2-hydroxy-1-naphthyl)diazenyl]phenyl}diazenyl)benzenesulfonate (CAS no. 6406 -56 -0) was estimated using Adsorption Coefficient module (v12.1.0.50374) program of Advanced Chemistry Development (ACD) /I –lab predictive module as Koc 1.99 dimensionless (log Koc= 0.3). This log Koc value indicates that the test substance sodium 4-({4-[(2-hydroxy-1-naphthyl)diazenyl]phenyl}diazenyl)benzenesulfonate has a negligible sorption to soil and show rapid migration potential to groundwater.

 

Another study was experimental study done from UERL labaoratory (2017) in this study the adsorption coefficient Koc in soil and in sewage sludge read across chemical Sodium 3-(panilinophenylazo) benzenesulphonate (CAS No.587-98-4) 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 functional similarity with the read across substance and calibration graph prepared. The reference substances were N-methylaniline, 2 - nitrophenol, Nitrobenzene, 4 -Nitrobenzamide, N,N-dimethylbenzamide, N-methylbenzamide, Benzamide having Koc value ranging from 1.239 to 2.47 The Log Koc value was determined to be 1.697 ± 0.002at 25°C.

This value indicates that the read across substance has low sorption to soil and sediment, moderate migration to ground water.

 

Based on the study from an authoritative database [HSDB(Hazardous Substances Data Bank) (2017)], the Koc of another read across chemical C.I. Acid Red 18 is estimated as approximately 9, using an experimental water solubility of 80,000 mg/l and a regression-derived equation. According to a recommended classification scheme, the estimated Koc value of 9 suggests that C.I. Acid Red 18 has very high mobility in soil.

 

 By compiling results of all the studies mentioned above it is concluded that target chemical Sodium 4-(4-(2-hydroxynaphthalenylazo)phenylazo)benzenesulphonate (CAS no. 6406-56-0)has negligible sorption to soil and has rapid migration potential to ground water.

[LogKoc: 1.317]