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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
9 July 2012 to 15 Sept 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Study conducted according to GLP and in accordance with OECD 121 and EC council regulation No. 440/2008 Method C.19
Qualifier:
according to
Guideline:
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
Deviations:
no
Qualifier:
according to
Guideline:
other: Council reg 440/2008 Method C.19
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Specific details on test material used for the study:
Biphenyl-4,4’-diol / CAS 92-88-6
Radiolabelling:
no
Test temperature:
21 +/- 0.1°C
Details on study design: HPLC method:
EQUIPMENT
- Apparatus and model: HPLC AGILENT 1100 consisting of:
Auto sampler - G1329A
Auto sampler thermostat - G1330B
Degasser - G1322A
Column oven - G1316A
Detector (test system) - G1315B
Pump - G1312A (flow rate 1.0 mL/min
Software - Empower 2 (Build no: 2154), waters
- Type, material and dimension of analytical column: Cyano 12 mm, S-5 µm, 250 x 4.0 mm, serial number 110930 20031, Lot 8330, YMC Europe GMBH.
- Detection system: HPLC in combination with DAD (diode array detection)

MOBILE PHASES
- Type: 55% methanol / 45% citrate buffer (20 mmol/L - adjusted to pH 6 with 1 N NaOH) (v/v)
- Experiments with additives carried out on separate columns: no
- pH: 6
- Solutes for dissolving test and reference substances: methanol and citrate-buffer to mobile phase ratio

DETERMINATION OF DEAD TIME
- Method: by threefold injection of a solution of 10 mg/L sodium nitrate (NaNO3)
- NaNO3 stock solution: 100 mg/L in water
- Test concentration: 10 mg/L (diluton of NaNO3 stock solution with methanol and citrate-buffer to mobile phase ratio)

TEST ITEM
- Dissolved in methanol and diluted with methanol and citrate-buffer to mobile phase ratio

REFERENCE SUBSTANCES
- Identity: Acetanilide, Atrazine, 3-Nitrobenzamid, Linuron, Benzoic acid phenylester, Fenthion, Phenanthrene
- Stock solutions: 100 mg/L each in methanol
- Test concentration: 5 mg/L of each (diluton of the stock solution with methanol and citrate-buffer to mobile phase ratio)

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 1.25 µg (50 µL of 25 mg/L standard)
- Quantity of reference substances: 0.25 µg (50 µL of 5 mg/L standard)
- Intervals of calibration: Performed once, before and after analysis of the test item, respectively.

REPETITIONS
- Number of determinations: Triplicate

EVALUATION
- Calculation of capacity factors k': The capacity k' was calculated according to the following equation:

k'=(tR-t0)/t0
tR = Retention time (min)
t0 = Dead time (min)
k' = Capacity factor

- Calculation of retention times: The retention time of each of the reference items was determined. The retention time of the test item was then determined in triplicate.
- Determination of the log Koc value: calculated using the obtained function of the linear regression of the calibration graphs log Koc soil versus log k' and the log Koc sewage sludge versus log k' of the reference substances and the calculated capacity factor k' of the test item.
Analytical monitoring:
yes
Details on sampling:
Single sample at a test item concentration equivalent to 25 mg/L was analysed in triplicate.
Details on matrix:
Sample under analysis pure reference item dissolved in methanol.
Details on test conditions:
TEMPERATURE:
The mean temperature of the column during the test was 21.0 °C

PH:
The mobile phase pH was adjusted to 6 for the study.
Computational methods:
Adsorption coefficient of the test item was calculated using the function of linear regression of the calibration graph log Koc soil versus log k' and log Koc sewage works sludge versus log k' of the reference substances and calculated capacity factor k' of the test item.
Key result
Type:
Koc
Remarks:
soil
Value:
>= 79 - <= 126 dimensionless
pH:
6
Temp.:
21 °C
Remarks on result:
other: Min: 79 / Max: 126 / Mean: 100
Key result
Type:
log Koc
Value:
ca. 2 dimensionless
pH:
6
Temp.:
21 °C
Remarks on result:
other: 2.0 ± 0.1
Key result
Type:
Koc
Remarks:
sewage works sludge
Value:
>= 79 - <= 200 dimensionless
pH:
6
Temp.:
21 °C
Remarks on result:
other: Min: 79 / Max: 200 / Mean: 123
Key result
Type:
log Koc
Value:
ca. 2.1 dimensionless
pH:
6
Temp.:
21 °C
Remarks on result:
other: 2.1 ± 0.2
Details on results (HPLC method):
Calibration data of the reference items for soil and sewage sludge

Reference item tR (min) tR Mean (min) k’ log k’ log Koc log Koc sewage sludge
Acetanilide 3.112 3.113 0.449 -0.348 1.26 1.52
3.114
Atrazine 3.546 3.547 0.651 -0.186 1.81 1.66
3.547
Linuron 5.113 5.114 1.381 0.140 2.59 2.43
5.114
Benzoic acid phenylester 5.267 5.268 1.453 0.162 2.87 3.26
5.269
Fenthion 7.736 7.734 2.601 0.415 3.31 3.75
7.732
Phenanthrene 7.865 7.866 2.662 0.425 4.09 4.35
7.867
Transformation products:
not specified

 Results of Test Item Analysis at pH 6 for soil

 

tR

k’

log k’

KOC, soil

log KOC, soil

log KOC
95% Cl

koc

4,4-Biphenol

3.862

0.7980

-0.0980

106.57

2.0276

2.0±0.1
(1.634 to 2.419)

100

3.861

0.7975

-0.0983

106.38

2.0268

3.859

0.7966

-0.0988

105.98

2.0252

 

 

 

 

Mean

2.027

 

 

 

 

 

 

SD

0.001

 

 

 

 

 

 

log Koc

0.002

 

 

 

 Results of Test Item Analysis at pH 6 for Sewage works sludge

 

 

tR

k’

log k’

KOC, soil

log KOC, soil

log KOC
95% CI

koc

4,4-Biphenol

3.862

0.7980

-0.0980

136.05

2.1337

2.1±0.2
(1.593 to 2.673)

126

3.861

0.7975

-0.0983

135.78

2.1328

3.859

0.7966

-0.0988

135.21

2.1310

 

 

 

 

Mean

2.133

 

 

 

 

 

 

SD

0.001

 

 

 

 

 

 

log Koc

0.003

 

 

 

tR = Retention time, SD = Standard deviation, CI = Confidence Interval

Validity criteria fulfilled:
yes
Conclusions:
The mean measured Koc of biphenyl-4,4'-diol in soil from an OECD 121 test was 100 L/kg (log Koc = 2.0).
The mean measured Koc of biphenyl-4,4'-diol in sewage works sludge in the same test was 126 L/kg (log Koc = 2.1).
These results indicate that the substance has a low affinity for organic matter and it may be expected to be moderately mobile in soil (Log Koc between 2 and 3).

Executive summary:

A study of the adsorption/desorption behaviour of biphenyl-4,4 '-diol was conducted according to guideline OECD 121 and Council Regulation (EC) No. 440/2008, Method C.19.

Under test conditions the retention time of biphenyl-4,4'-diol was found to be 3.861 +/- 0.001 minutes at pH 6.0. Based on the calibrations for soil and sewage works sludge the following log Koc and Koc values were obtained. For the Koc minimum and maximum values are given under consideration of the standard deviation for the log Koc.

 

Soil

Sewage Works Sludge

log Koc, soil

Koc, soil (L/kg)

log Koc, sewage sludge

Koc, sewage sludge (L/kg)

2.0 +/- 0.1

Min.: 79

2.1 +/- 0.2

Min.: 79

Mean: 100

Mean: 126

Max.: 126

Max.: 200

 

The validity criteria for guideline OECD 121 and Council Regulation (EC) No. 440/2008, Method C.19 were fulfilled. The calculated values for log Koc of the injections for the test item did not differ more than +/- 0.25.

Description of key information

The mean measured Koc of biphenyl-4,4'-diol in soil from an OECD 121 test was 100 L/kg (log Koc = 2.0).
The mean measured Koc of biphenyl-4,4'-diol in sewage works sludge in the same test was 126 L/kg (log Koc = 2.1).
These results indicate that the substance has a low affinity for organic matter and it may be expected to be moderately mobile (Log Koc = 2 -3).

Key value for chemical safety assessment

Koc at 20 °C:
100

Additional information

A study of the adsorption/desorption behaviour of biphenyl-4,4'-diol was conducted according to guideline OECD 121 and Council Regulation (EC) No. 440/2008, Method C.19.

Under test conditions the retention time of biphenyl-4,4'-diol was found to be 3.861 +/- 0.001 minutes at pH 6.0. Based on the calibrations for soil and sewage works sludge the following log Koc and Koc values were obtained. For the Koc minimum and maximum values are given under consideration of the standard deviation for the log Koc. In soil, the minimum measured Koc was 79 L/kg, while the maximum measured Koc was 126 L/kg. The mean measured Koc value was 100 L/kg. In sewage works sludge the minimum measured Koc was 79 L/kg and the maximum measured Koc was 200 L/kg. The mean measured Koc was 126 L/kg.

[LogKoc: 2.0]