Phosphonic acid, mixed C12-20-alkyl and C14-18-unsatd. alkyl derivs.

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:

Between 03 November 2011 and 10 November 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Valid and conclusive guideline study under GLP

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))

Version / remarks:

Commission Regulation (EC) No. 440/2008

Deviations:

no

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:

2001

Deviations:

no

GLP compliance:

yes

Remarks:

Department of Health of Government of the U.K., inspection 19-21 July 2011

Type of method:

HPLC estimation method

Radiolabelling:

no

Test temperature:

30 °C (column temperature)

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Agilent Technologies 1100, incorporating autosampler and workstation
- Analytical column: Luna 5µ CN 100Å (150 ∙ 4.6 mm id)
- Detection system: UV detector wavelength for dead time and reference standards 210 nm and for the sample 230 nm

MOBILE PHASES
- Type: Methanol : Water (55 : 45 v/v), for the sample, the mobile phase was altered to 100 % tetrahydrofuran after the elution time of DDT to enable elution of the highly retained test item. The flow rate was set to 10 mL/min
- Experiments with additives carried out on separate columns: No
- pH: 6.1
- Solutes for dissolving test and reference substances: Solutions of reference standards were prepared in methanol, while the test item (1001.4 mg) was diluted to 100 mL with tetrahydrofuran (concentration 10,014 mg/L).

DETERMINATION OF DEAD TIME
- Method: By inert substance (formamide, purity according to the supplier 99.94 % at 693 mg/L in the mobile phase) which is not retained by the column

REFERENCE SUBSTANCES
- Identity: Acetanilide, Phenol, Atrazine, Isoproturon, Triadimenol, Linuron, Naphthalene, Endosulfan-diol, Fenthion, α-Endosulfan, Phenanthrene, Diclofop-methyl and DDT

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: Injection volume 10 µL with a concentration of 10.014 g/L, i.e. 100.14 µg
- Quantity of reference substances: Injection volume 10 µL with concentrations between 103 and 160 mg/L (see table below ), i.e. 1.03 to 1.6 µg
- Intervals of calibration: Log Koc 1.25, 1.32, 1.81, 1.86, 2.40, 2.59, 2.75, 3.02, 3.31, 4.09, 4.20, 4.09 and 5.63

REPETITIONS
- Number of determinations: 2

EVALUATION
- Calculation of capacity factors: k = (tr-t0)/t0, where t0 = Dead time [min] and tr = Retention time [min]
- Determination of the log Koc value: Log Koc = ((Log k)-A)/B, where A = intercept of the calibration curve, B = slope of the calibration curve

Type:

Koc

Value:

> 426 580 dimensionless

Temp.:

30 °C

Type:

log Koc

Value:

> 5.63 dimensionless

Temp.:

30 °C

Details on results (HPLC method):

- Retention times of reference substances used for calibration: 2.477, 2.437, 2.741, 2.978, 3.155, 3.467, 4.304, 3.45, 5.166, 5.963, 6.344, 6.923 and 14.905 min
- Details of fitted regression line (Log k' versus. Log Koc): Intercept of the calibration curve: A = -1.0672; Slope of the calibration curve: B = 0.3402, Coefficient of determination of the calibration curve: R² = 0.9615
- Graph of regression line attached as illustration
- Average retention data for test substance: 30.463 min; the test item eluted in a distinctive peak.

Table 2: Dead time determination, retention times of formamide

Dead Time	Retention Time [min]		Mean Retention Time [min]
	Injection 1	Injection 2
Formamide	2.052	2.052	2.052

Table 3: Retention times, capacity factors (k) and Log Koc values for the reference standards

Standard	Retention Time [min]		Mean Retention Time [min]	Capacity Factor (k)	Log k	Log Koc
	Injection 1	Injection 2
Acetanilide	2.477	2.477	2.477	0.207	-0.684	1.25
Phenol	2.436	2.438	2.437	0.187	-0.727	1.32
Atrazine	2.741	2.741	2.741	0.336	-0.474	1.81
Isoproturon	2.982	2.974	2.978	0.451	-0.346	1.86
Triadimenol	3.164	3.147	3.155	0.537	-0.270	2.40
Linuron	3.472	3.462	3.467	0.689	-0.162	2.59
Naphthalene	4.306	4.301	4.304	1.097	0.0402	2.75
Endosulfan-diol	3.452	3.447	3.45	0.681	-0.167	3.02
Fenthion	5.165	5.167	5.166	1.517	0.181	3.31
a-Endosulfan	5.966	5.961	5.963	1.905	0.280	4.09
Diclofop-methyl	6.342	6.346	6.344	2.091	0.320	4.20
Phenanthrene	6.926	6.919	6.923	2.373	0.375	4.09
DDT	14.905	14.905	14.905	6.262	0.797	5.63

Table 4: Retention times, capacity factors and Log Koc values determined for the test item

Peak	Retention Time [min]			Capacity Factor (k)	Log k	Log Koc
	Injection 1	Injection 2	Mean
1	30.463	30.463	30.463	> 6.26	> 0.797	> 5.63

Validity criteria fulfilled:

yes

Conclusions:

Strong adsorption to organic matter, Koc >> 427,000 and Log Koc >> 5.63 at 30 °C

Executive summary:

The adsorption of the test item to organic matter was determined in a GLP-compliant study using HPLC comparison according to the EU C.19 (2008) and OECD TG 121 (2001) protocols. The experiment is deemed valid, conclusive and thus suitable for assessment without restrictions.

The column temperature was 30 °C. Atrazine, Isoproturon, Triadimenol, Linuron, Naphthalene, Fenthion, α-Endosulfan, Phenanthrene, Diclofop-methyl and DDT were used as standard references. The correlation of fit of the established calibration curve (R²) was 0.9615 demonstrating the reliability of the method in the calibration range from Log Koc 1.25 to 5.63. The column temperature was 30 °C.

The test item eluted in one distinctive peak out of the calibration range, after ca. 30 min, while the last standard DDT (Log Koc 5.63) was detected after about 15 min. Accordingly the adsorption of the submission item can be described by Koc >> 427,000 and Log Koc >> 5.63 at 30 °C.

Description of key information

Strong adsorption to organic matter, Koc >> 426,000 and Log Koc >> 5.63 at 30 °C (OECD 121)

Strong adsorption to organic matter has been demonstrated, Koc >> 426,000 and Log Koc >> 5.63 at 30 °C. However, water insolubility and ready biodegradation in combination with the strong adsorption mean no relevant concentrations in any compartment can be expected.

Key value for chemical safety assessment

Koc at 20 °C:

426 580

Additional information

The adsorption to organic matter was determined in a GLP-compliant study (Fox & White 2012, Harlan Report no. 41103279) using HPLC comparison according to the EU C.19 (2008) and OECD TG 121 (2001) protocols. The experiment is deemed valid, conclusive and thus suitable for assessment without restrictions.

The submission item eluted in one distinctive peak out of the calibration range, after ca. 30 min, while the last standard DDT (Log Koc 5.63) was detected after about 15 min. Accordingly the adsorption of the submission item can be described by Koc >> 427,000 and Log Koc >> 5.63 at 30 °C.

According to classification schemes, the Koc value suggests that the submission item is expected to fall into the “immobile” mobility class (Koc > 5000) according to McCall et al (1981) and Swann et al (1983) or to be “non-mobile” (Koc > 4000) according to Hollis (1991).

Further testing as demanded by the Corrigendum to Regulation (EC) No 1907/2006 of the European parliament and of the council of 18 December 2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), Annex IX, 9.3.3., p L 136/115, published 2007-05-29 in the Official Journal of the European Union can be waived in accordance with column 2 restrictions as:

“The study need not be conducted if:

- the substance and its degradation products decompose rapidly.”

Given the ready biodegradability (Clarke 2011, Harlan Report no. 41103271) of the submission item rapid decomposition is soils seems likely. Therefore further testing can be waived.

• Hollis JM (1991). Mapping the vulnerability of aquifers and surface waters to pesticide contamination at the national/regional scale. Pesticides in Soils and Water: Current Perspectives (Walker A ed), BCPC Monograph 47:165-74.
• McCall PJ, Laskowski DA, Swann RL, Dishburger HJ (1981). Measurement of sorption coefficients of organic chemicals and their use, in environmental fate analysis pages 94-109 IN Test Protocols for Environmental Fate and Movement of Toxicants: 94th annual meeting, October 21, 22, 1980, Washington, DC, U.S.A. ISBN-10 093558420X ISBN-13 978-0935584202. 330 p.
• Swann RL, Laskowski DA, McCall PJ, Vanderkuy K, Dishburger HJ (1983). A rapid Method for the Estimation of the Environmental Parameters Octanol Water Partition-Coefficient, Soil Sorption Constant, Water to Air Ratio, and Water Solubility. ISSN 0080 -181X Residue Reviews 85:17-28.