Tris(pentane-2,4-dionato-O,O')vanadium

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption, other

Remarks:

Batch test with samples from 5 european topsoils (Spain, Sweden, Belgium)

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

please refer to Read-across statement attached in section 13

Reason / purpose for cross-reference:

read-across source

Radiolabelling:

no

Sample No.:

#1

Type:

other: KF

Remarks:

Freundlich coefficient

Value:

177.76 L/kg

pH:

8.15

Temp.:

20 °C

Matrix:

Guadalajara. Spain: Calcic Cambisol (used as olive orchard)

% Org. carbon:

0.5

Remarks on result:

other: Result concerted to VAA

Remarks:

KF is the Freundlich coefficient, which was calculated with the concentration units mg/kg and mg/L tor n and c (see Freundlich equation)

Sample No.:

#2

Type:

other: KF

Value:

255.7 L/kg

pH:

6.33

Temp.:

20 °C

Matrix:

Pustnäs, Sweden: Eutric Regosol (used as grassland)

% Org. carbon:

1.1

Remarks on result:

other: Result concerted to VAA

Remarks:

KF is the Freundlich coefficient, which was calculated with the concentration units mg/kg and mg/L tor n and c (see Freundlich equation)

Sample No.:

#3

Type:

other: KF

Value:

1 285.33 L/kg

pH:

5.88

Temp.:

20 °C

Matrix:

Säby, Sweden: Eutric Cambisol, used as arable land

% Org. carbon:

2.5

Remarks on result:

other: Result concerted to VAA

Remarks:

KF is the Freundlich coefficient, which was calculated with the concentration units mg/kg and mg/L tor n and c (see Freundlich equation)

Sample No.:

#4

Type:

other: KF

Value:

218.78 L/kg

pH:

6.66

Temp.:

20 °C

Matrix:

Ter Munck, Belgium: Haplic Luvisol, used as arable land

% Org. carbon:

0.9

Remarks on result:

other: Result concerted to VAA

Remarks:

KF is the Freundlich coefficient, which was calculated with the concentration units mg/kg and mg/L tor n and c (see Freundlich equation)

Sample No.:

#5

Type:

other: KF

Value:

90.93 L/kg

pH:

5.7

Temp.:

20 °C

Matrix:

Zwijnaarde, Belgium: Haplic Podzol, used as arable land

% Org. carbon:

1.6

Remarks on result:

other: Result concerted to VAA

Remarks:

KF is the Freundlich coefficient, which was calculated with the concentration units mg/kg and mg/L tor n and c (see Freundlich equation)

Sample No.:

#1

Phase system:

other: Organic carbon fraction of solid soil phase / soil water phase

Type:

other: Koc

Remarks:

KF normalised to the organic carbon content of soil

Value:

35 551.7 dimensionless

Temp.:

20 °C

pH:

8.15

Matrix:

Guadalajara. Spain: Calcic Cambisol (used as olive orchard)

% Org. carbon:

0.5

Remarks on result:

other: Result concerted to VAA

Remarks:

Koc values calculated (as defined in OECD Guideline 121)

Sample No.:

#2

Phase system:

other: Organic carbon fraction of solid soil phase / soil water phase

Type:

other: Koc

Remarks:

KF normalised to the organic carbon content of soil

Value:

23 245.3 dimensionless

Temp.:

20 °C

pH:

6.33

Matrix:

Pustnäs, Sweden: Eutric Regosol (used as grassland)

% Org. carbon:

1.1

Remarks on result:

other: Result concerted to VAA

Sample No.:

#3

Phase system:

other: Organic carbon fraction of solid soil phase / soil water phase

Type:

other: Koc

Remarks:

KF normalised to the organic carbon content of soil

Value:

51 413.2 dimensionless

Temp.:

20 °C

pH:

5.88

Matrix:

Säby, Sweden: Eutric Cambisol, used as arable land

% Org. carbon:

2.5

Remarks on result:

other: Result concerted to VAA

Sample No.:

#4

Phase system:

other: Organic carbon fraction of solid soil phase / soil water phase

Type:

other: Koc

Remarks:

KF normalised to the organic carbon content of soil

Value:

24 387.1 dimensionless

Temp.:

20 °C

pH:

6.66

Matrix:

Ter Munck, Belgium: Haplic Luvisol, used as arable land

% Org. carbon:

0.9

Remarks on result:

other: Result concerted to VAA

Remarks:

Koc values calculated (as defined in OECD Guideline 121)

Sample No.:

#5

Phase system:

other: Organic carbon fraction of solid soil phase / soil water phase

Type:

other: Koc

Remarks:

KF normalised to the organic carbon content of soil

Value:

5 683.5 dimensionless

Temp.:

20 °C

pH:

5.7

Matrix:

Zwijnaarde, Belgium: Haplic Podzol, used as arable land

% Org. carbon:

1.6

Remarks on result:

other: Result concerted to VAA

Details on results (HPLC method):

HPLC study design not applied.

Description of key information

In a batch equilibrium study adsorption of vanadium to samples of five european top-soils with contrasting properties was investigated. Sodium metavanadate (NaVO3) was used as vanadium compound.
Calculated adsorption coefficients (KF) for the 5 soils are in a range of 13.3 to 188 L/kg (base: vanadium) or 90.93 to 1285.33 L/kg based on VAA. Average KF value based on VAA: 405.7 L/kg.

Calculated distribution coefficients (Koc) for the 5 soils are in a range of 831.3 to 7520 (base: vanadium) or 5683.5 to 51413.2 baseed on VAA. Average Koc value based on VAA: 28040.2.

Key value for chemical safety assessment

Koc at 20 °C:

28 040.16

Other adsorption coefficients

Type:

other: KF (Freundlich adsorption coefficient)

Value in L/kg:

405.7

at the temperature of:

20 °C

Additional information

In a batch equilibrium study adsorption of vanadium to samples of five european top-soils with contrasting properties was investigated. Sodium metavanadate (NaVO3) was used as vanadium compound. In brief. 2 ± 0.05 g of air-dried soil were added to polypropylene bottles together with a 30-mL solution containing 0.01 M NaNO3, and 7 different concentrations of vanadate (ranging 0 to 15 mg V/L). The vanadate stock solution was made using NaVO3 salt. The tubes were equilibrated in room temperature in an end-over-end shaker for 6 days and the samples were thereafter centrifuged at 4000g for 15 mm. The supernatant was then removed, and a subsample was taken to measure its pH. The remaining supernatant was filtered (0.2 µm) and analyzed tor vanadium with ICP mass spectroscopy (Varian-Vista Australia). The results were fitted to the Freundlich equation (n = KF x c^m). Here, n (milligrams per kilogram) is the total concentration of sorbed vanadium, which is the sum of the vanadium sorbed during the experiment (nsorb) and the initially sorbed vanadium (nini). In addition, c (milligrams per liter) is the measured dissolved vanadium concentration, whereas KF (the Freundlich coefficient) and m (nonideality parameter) are adjustable parameters. The value of nini was fitted. In the the fitting procedure nini, KF and m were optimized through trial-and-error, which involved linear regression on log-transformed values using the trendline tool in Microsoft Excel.

Results: The vanadium sorption properties differed among the 5 soils as shown by the Freundlich sorption isotherms. In each soil, die pH value remained constant with a difference smaller than 0.2 units in response to the different vanadium additions. Furthermore, the vanadium concentrations in solution for samples without added vanadium were low, ranging from 0.003 mg V/L (Guadalajara) to 0.054 mg V/L (Zwijnaarde). To compare the vanadium sorption properties of the soils, the "Freundlich sorption strength" was determined, which was defined as the amount of sorbed vanadium expected when the dissolved vanadium concentration was 2.5 mg/L. The concentration was chosen to comply with the median soil solution EC50 of 2.6 mg V/L. The sorption strength varied about 10-fold between the soils, with the Saby soil having the highest sorption strength and Zwijnaarde the lowest. Saturation of the sorption sites (as would be evidenced by flattening of the Freundlich log n - log c graph at high concentrations) was not reached in the vanadium concentration range tested. Calculated adsorption coefficients (KF) for the 5 soils are in a range of 13.3 to 188 L/kg (based on V). KF is the Freundlich coefficient, which was calculated with the concentration units mg/kg and mg/L tor n and c (see Freundlich equation). Based on the KF values and the organic fraction of soil (Corg), Koc values were calculated for the 5 soil matrices (Koc = Distribution coefficient between organic carbon fraction of solid soil phase of soil and the soil water phase, following the equations given in OECD Guideline 121). Calculated distribution coefficients (Koc) for the 5 soils are in a range of 831.3 to 7520 (based on V).