Biphenyl-2-ol

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)

Qualifier:

according to guideline

Guideline:

EU Method C.18 (Adsorption / Desorption Using a Batch Equilibrium Method)

Version / remarks:

cited as EU Council Directive 91/414/EEC, as amended by Commission Directive 95/36/EC of July 1995, Section 7, Sub-section 7.1.2

GLP compliance:

yes (incl. QA statement)

Type of method:

batch equilibrium method

Media:

soil

Radiolabelling:

yes

Test temperature:

20 ± 2 °C

Analytical monitoring:

yes

Details on matrix:

COLLECTION AND STORAGE
- Geographic location:
- A clay loam, 04/02, was collected from Shelley Field, Boarded Barns Farm, Fyfield Road, Ongar, Essex UK on the 23rd February 2004.
- A Sandy Loam, 04/03, was collected from Little Shelford, Whittlesford Road, Little Shelford, UK on the 24th February 2004.
- A sandy silt loam, 04/04, was collected from Aldhams Farm, Dead Lane, Lawford, Manningtree, Essex, UK on the 19th February 2004.
- A clay loam, 04/05, was collected from Lockington Grounds Farm, Lockington, Leicestershire, UK on the 23rd February 2004.
- Soil preparation: Were dried as required and passed through a 2 mm sieve

PROPERTIES
- Soil texture
- % sand: 21.93
- % silt: 51.2
- % clay: 26.88
- Soil taxonomic classification: Clay Loam
- Soil classification system: ADAS
- pH: 7.7
- Organic carbon (%): 1.9
- CEC (meq/100 g): 14.3
- Moisture (%): 15.59
- Organic matter: 3.4

- Soil texture
- % sand: 66.06
- % silt: 18.61
- % clay: 15.34
- Soil taxonomic classification: Sandy Loam
- Soil classification system: ADAS
- pH: 8.0
- Organic carbon (%): 2.4
- CEC (meq/100 g): 12.1
- Moisture (%): 18.39
- Organic matter: 4.1

- Soil texture
- % sand: 41.62
- % silt: 45.95
- % clay: 12.44
- Soil taxonomic classification: Sandy Silt Loam
- Soil classification system: ADAS
- pH: 5.9
- Organic carbon (%): 3.0
- CEC (meq/100 g): 11.7
- Moisture (%): 28.92
- Organic matter: 5.2

- Soil texture
- % sand: 36.66
- % silt: 33.19
- % clay: 30.14
- Soil taxonomic classification: Clay Loam
- Soil classification system: ADAS
- pH: 6.8
- Organic carbon (%): 2.8
- CEC (meq/100 g): 19.9
- Moisture (%): 27.99
- Organic matter: 4.8

Details on test conditions:

TEST SOLUTIONS
- Preliminary studies: A stock treatment solution was prepared by diluting an aliquot of the original stock solution in deionised water to give 0.49 mg/L of 14C-OPP. Treatment solutions for each phase of the preliminary experiment were prepared by removing a suitable volume of the stock solution and diluting to the required volume with 0.01 M calcium chloride solution.
- Definitive studies: A stock solution was prepared by dissolving approximately 19 mg of 14C-OPP in 10 mL acetonitrile. The actual concentration was determined to be 1.81 mg/L. For the definitive study the test solution was prepared by adding different treatment solutions in 25 mL of CaCl2, obtaining the following concentrations: 1.0, 0.33, 0.1, 0.03 and 0.01 mg a.i./L.
Conditions: darkness and temperature of 20 ± 1 °C

TEST SYSTEM
- Type, size and further details on reaction vessel: thick walled borosilicate glass tubes with external plastic coating, the tubes have a capacity of 125 ml and were sealed with screw caps
- Adsorption phase: The adsorption phase was carried out by shaking pre-equilibrated air dried soil (2g soil to 80 mL solution) with 2-phenylphenol at concentrations of 1.0, 0.33, 0.1, 0.03 and 0.01 mg a.i./L in darkness at 20 ± 1 °C for either 1 or 4 hours dependent upon the soil (approx. 1 h for the Manningtree and Lockington soils and 4 h for the Shelley Field and Little Shelford soils). 0.01 M aqueous CaCl2 solution was used as equilibration solution (soil/solution ratio: 1/40).
- Desportion phase: The desorption phase was carried out by treating pre-adsorbed soil samples with fresh 0.01 M aqueous CaCl2 solution for three desorption cycles.

Type:

Koc

Value:

252 - 393

Type:

log Koc

Value:

2.4 - 2.6

Transformation products:

no

Details on results (Batch equilibrium method):

- Material balance: Mean recoveries within the acceptable range of 90-105% of applied radioactivity
- In all soils there was a non-linear relationship between the concentration in solution and the amount adsorbed to the soil, with values for 1/n ranging from 0.78 to 0.87

Table 1: Parameter for the adsorption of the test substance in the four soils

Soil	Freundlich adsorption coefficients and constants
	KF[mL/g]	Koc[mL/g]	1/n	r^2
Shelley Field Little Shelford Manningtree Lockington Mean	7.47 8.53 11.66 7.04 8.68	393 355 389 252 347	0.809 0.821 0.870 0.784 0.82	0.999 1.000 0.996 0.993 0.997

Table 2: Parameter for the desorption of the test substance in the four soils

Soil	Freundlich desorption coefficients and constants
	Kdes[mL/g]	Koc des[mL/g]	1/n	r^2
Desorption 1 Shelley Field Little Shelford Manningtree Lockington	16.42 16.78 18.62 9.36	864 699 621 334	0.797 0.792 0.886 0.697	0.992 0.997 0.998 0.950
Desorption 2 Shelley Field Little Shelford Manningtree Lockington	40.08 40.12 35.78 11.21	2109 1672 1193 400	0.814 0.806 0.886 0.627	0.989 0.992 0.993 0.828
Desorption 3 Shelley Field Little Shelford Manningtree Lockington	85.28 127.82 88.19 12.93	4488 5326 2940 462	0.823 0.881 0.915 0.588	0.973 0.988 0.982 0.666

Reference 2

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study, reliable with restrictions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))

Version / remarks:

new proposal

GLP compliance:

yes

Type of method:

HPLC estimation method

Radiolabelling:

no

Test temperature:

40 °C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: HPLC
- Type, material and dimension of analytical (guard) column: length: 250 mm; inner diameter: 4 mm
- Detection system: UV, 220 nm

STATIONARY PHASE
- Type: LiChropher 100 CN; particel diameter 5 µm

MOBILE PHASES
- Type: 500 mL acetonitrile : 85 mL buffer solution pH 6 : 415 mL water
- pH: 6

DETERMINATION OF DEAD TIME: with sodium nitrate the dead time is 1.673 min

REFERENCE SUBSTANCES
- Identity: 2-nitrobenzamide; N,N-dimethylbenzamide; Acetanilide, Methylbenzoate, Naphthalene, 1,2,3.trichlorobenzene

REPETITIONS
- Number of determinations: 3

Type:

Koc

Value:

346.7

Type:

log Koc

Value:

2.54

HPLC retention time data and determination of K_ocfor OPP and reference substances according to OECD guideline 121

Substance	Mean Retention Time [min]	Mean Dead Time [min]	Mean k’ (Capacity factor)	Mean log k’	Mean Koc(Distribution coefficient based on organic C)	Mean log Koc
2-Nitrobenzamide	2.783	1.673	0.664	-0.178	28.18	1.45
N, N-dimethylbenzamide	2.964	1.673	0.771	-0.133	33.11	1.52
Acetanilide	3.000	1.673	0.793	-0.101	17.78	1.25
Methylbenzoate	3.597	1.673	1.150	0.061	63.10	1.80
Naphtalene	4.540	1.673	1.714	0.234	562.34	2.75
1,2,3-trichlorobenzene	4.773	1.673	1.853	0.268	1445.44	3.16
Preventol O	4.071	1.673	1.434	0.157	346.7	2.54

Description of key information

For OPP a moderate adsorption potential is expected (Koc = 247).

Key value for chemical safety assessment

Koc at 20 °C:

347

Additional information

To assess the adsorption/desorption behavior of OPP (CAS-No. 90-43-7) two guideline studies are available. In the first study, which was carried out according to OECD guideline 106 and in GLP compliance, the adsorption/desorption behavior of OPP in four different soils, which comprised two times clay loam, a sandy loam and a sandy silt loam were tested. In all soils a non-linear relationship between the concentration in solution and the amount adsorbed to the soil was observed, with values for 1/n ranging from 0.78 to 0.87. Additionally, there was no significant correlation between pH and adsorption for the investigated soils. The Koc values obtained ranged from 252 to 393 mL/g (mean = 347 mL/g). No degradation product was observed during ad- and desorption by HPLC in the supernatant of the selected soils. Therefore it can be concluded that no significant degradation of OPP occurred during the duration of the study (Oddy and Jacob, 2005).

These Koc values are supported by another study estimated using High Performance Liquid Chromatography (HPLC). The test was performed according to OECD guideline 121 (Proposal for New Guideline, 2001). Six reference standards of known Koc values and OPP were analysed on a HPLC system. The Koc value for OPP was estimated by interpolation from the reference substance regression line. The estimated Koc value for OPP is 346.7 (Erstling, 2001).

In conclusion, it can be assumed that the adsorption potential of OPP is moderate.

[LogKoc: 2.54]