disodium 4-amino-6-((4-((4-(2,4-diaminophenyl)azo)phenylsulfamoyl)phenyl)azo)-5-hydroxy-3-((4-nitrophenyl)azo)naphthalene-2,7-disulfonate

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

October 10, 2011-October 17, 2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
-the substance is in its salt form
log Kow= -1.73

Test temperature:

25°C

Details on study design: HPLC method:

Column: Eclipse XDB-CN, 150 x 4.6 mm, 5µm
Mobile phase 1: A: 550 mL of MeOH was mixed with 450 mL of citrate buffer solution of pH 4.2
Mobile phase 2: B: 550 mL of MeOH was mixed with 450 mL of citrate buffer solution of pH 6.0
Detection: 210 nm - NaNO3
240 nm - reference compounds
600 nm - test substance
Flow: 1.0 mL / min
Injection volume: 10 uL
Column temp.: 25°C
Autosampler tem.: 25°C

Type:

log Koc

Remarks:

soil, pH=5.6

Value:

ca. 2.42

Temp.:

25 °C

Type:

log Koc

Remarks:

sludge, pH=5.6

Value:

ca. 2.39

Temp.:

25 °C

Type:

log Koc

Remarks:

soil, pH=7.4

Value:

ca. -0.07

Temp.:

25 °C

Type:

log Koc

Remarks:

sludge, pH=7.4

Value:

ca. -0.52

Temp.:

25 °C

Details on results (HPLC method):

The study gives the following values for the estimation of adsorption coefficient (KOC) on soil and sewage sludge for Acid Black 210

Estimation of the adsorption coefficient (KOC) on soil and sewage sludge at given pH of mobile phase and set temperature:


log Koc, soil= 2.42 +/- 0.31 (pH = 5.6, 25°C)

log Koc, sludge= 2.39 +/- 0.65 (pH = 5.6, 25°C)

log Koc, soil = -0.07 +/- 0.58 (pH = 7.4, 25°C)

log Koc, sludge = -0.52 +/- 1.28 (pH = 7.4, 25°C)

In the case of mobile phase of pH 7.4, the test substance was less retained on the column than any of reference standard. The results were obtained by extrapolation of the given calibration curve.

Validity criteria fulfilled:

no

Conclusions:

The study gives the following values for the estimation of adsorption coefficient (KOC) on soil and sewage sludge for Acid Black 210:
Estimation of the adsorption coefficient (KOC) on soil and sewage sludge at given pH of mobile phase and set temperature:

log = 2.42 +/- 0.31 (pH = 5.6, 25°C)

log = 2.39 +/- 0.65 (pH = 5.6, 25°C)

log = -0.07 +/- 0.58 (pH = 7.4, 25°C)

log = -0.52 +/- 1.28 (pH = 7.4, 25°C)

In the case of mobile phase of pH 7.4, the test substance was less retained on the column than any of reference standard. The results were obtained by extrapolation of the given calibration curve.

Executive summary:

The estimation of the adsorption coefficient Koc of Acid Black 210 on soil and sewage sludge was tested following Method C.19, Estimation of the adsorption coefficient (Koc) on soil and sewage sludge using high performance liquid chromatography (HPLC) at pH 5.6 and 7.4. The mobile phase were citric buffer solutions since the tested substance is ionisable. The temperature was set at 25°C.

Estimation of the adsorption coefficient (KOC) on soil and sewage sludge at given pH of mobile phase and set temperature:

log = 2.42 +/- 0.31 (pH = 5.6, 25°C)

log = 2.39 +/- 0.65 (pH = 5.6, 25°C)

log = -0.07 +/- 0.58 (pH = 7.4, 25°C)

log = -0.52 +/- 1.28 (pH = 7.4, 25°C)

In the case of mobile phase of pH 7.4, the test substance was less retained on the column than any of reference standard. The results were obtained by extrapolation of the given calibration curve.

Description of key information

log Koc, soil, pH 5.6, 25°C= 2.42

log Koc, sludge, pH 5.6, 25°C=2.39

log Koc, soil, pH 7.4, 25°C = -0.07

log Koc, sludge, pH 7.4, 25°C = -0.52

Key value for chemical safety assessment

Koc at 20 °C:

1.1

Other adsorption coefficients

Type:

log Kp (solids-water in raw sewage sludge)

Value in L/kg:

0.059

at the temperature of:

25 °C

Other adsorption coefficients

Type:

log Kp (solids-water in settled sewage sludge)

Value in L/kg:

0.059

at the temperature of:

25 °C

Other adsorption coefficients

Type:

log Kp (solids-water in activated sewage sludge)

Value in L/kg:

0.072

at the temperature of:

25 °C

Other adsorption coefficients

Type:

log Kp (solids-water in effluent sewage sludge)

Value in L/kg:

0.072

at the temperature of:

25 °C

Additional information

A study (Karel Cizek, 2011) was performed to estimate the adsorption coefficient Koc of Acid Black 210 on soil and sludge by means of HPLC method, following EU C.19. Log Koc for both soil and sludge are less than 3 for pH 5.6 at 25°C and negative at pH 7.4, showing very low potential of adsorption of the tested substance. No significant influence of the potassium counterion can be estimated on this result

The value of 1.1 has been set as the minimum Koc value accepted by EUSES to perform the risk assessment.

Partitioning constants in the sewage plant have been set to QSAR "Non hydrophyilic" substances, in order to reproduce what it really happens in the sewage plant, where precipitation of the dye is provoqued by modulation of pH. In this way the dye is removed completely from the aqueous phase and the sludge sent to external special dedicated treatment ( eventually incineration)