Hexakis[μ-(acetato-O:O')]-μ3-oxo-triangulo-triruthenium acetate

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Tier 1 only

GLP compliance:

yes

Type of method:

batch equilibrium method

Media:

soil

Radiolabelling:

no

Test temperature:

25 + 2°C (preliminary study)

Analytical monitoring:

yes

Details on sampling:

Samples were analysed after a 24 hour equilibration period.

Details on matrix:

Soil 2:
Particle size
53 µm – 2 mm: 37.56%
2 µm – 53 µm: 29.37%
<2 µm: 33.08%
pH (1:5 soil to 0.01 M CaCl2 ratio): 7.5
Cation exchange capacity (mEq/100g): 31.1
Organic carbon content (%): 2.4
Total nitrogen (mg/kg): 1693.9

Soil 3:
Particle size
53 µm – 2 mm: 25.88%
2 µm – 53 µm: 46.98%
<2 µm: 17.14%
pH (1:5 soil to 0.01 M CaCl2 ratio): 6.3
Cation exchange capacity (mEq/100g): 26.0
Organic carbon content (%): 3.2
Total nitrogen (mg/kg): 1749.8

Soil 4:
Particle size
53 µm – 2 mm: 55.72%
2 µm – 53 µm: 26.81%
<2 µm: 17.47%
pH (1:5 soil to 0.01 M CaCl2 ratio): 5.6
Cation exchange capacity (mEq/100g): 25.8
Organic carbon content (%): 3.4
Total nitrogen (mg/kg): 2869.7

Soil 5:
Particle size
53 µm – 2 mm: 71.78%
2 µm – 53 µm: 18.90%
<2 µm: 9.32%
pH (1:5 soil to 0.01 M CaCl2 ratio): 5.8
Cation exchange capacity (mEq/100g) 17.5:
Organic carbon content (%): 1.6
Total nitrogen (mg/kg): 1231.8

Soil 7:
Particle size
53 µm – 2 mm: 85.23%
2 µm – 53 µm: 11.94%
<2 µm: 2.83%
pH (1:5 soil to 0.01 M CaCl2 ratio): 2.9
Cation exchange capacity (mEq/100g): 49.2
Organic carbon content (%): 12.0
Total nitrogen (mg/kg): 4367.9

Details on test conditions:

5 soil types were tested, ranging in organic carbon content (2.4 - 12.0%), in a tier 1 assessment, with the aim of selecting the optimal soil / solution ratio. Soil / solution ratios of 1:1, 1:10 and 1:25 were used. Aliquots of 0.01M calcium chloride solution were added to the soil in glass centrifuge tubes.Samples were shaken at 28.5 +- 2.5⁰C in the dark for 18.5 hours, or at 21 +- 1⁰C for 17.5 hours, depending on the soil. Stock solution of the test material was then added to each soil, after which the samples were shaken 21.0 +- 1.0⁰C in the dark for 24 hours, before they were analysed by ICP.

Sample No.:

#1

Type:

Kd

Remarks on result:

not determinable

Remarks:

No determination of the adsorption coefficient was possible as the adsorption properties of the test material exceeded the scope of OECD method 106. No significant trend was observed between percentage test material adsorbed and nominal soil to solution ratio, with the exception of soil 4 and to a lesser extent soil 3. As adsorption was not proportional to to the quantity of soil present, calculation of a Kd value was not considered valid.

Adsorption and desorption constants:

No determination of the adsorption coefficient was possible as the adsorption properties of the test material exceeded the scope of OECD method 106. No significant trend was observed between percentage test material adsorbed and nominal soil to solution ratio, with the exception of soil 4 and to a lesser extent soil 3. As adsorption was not proportional to to the quantity of soil present, calculation of a Kd value was not considered valid.

However, it can be concluded that the test material does not adsorb strongly to the organic carbon content of the soil as when given the opportunity to adsorb to an increased quantity of soil / organic carbon as the nominal soil / solution ratio altered there was no significant further adsorption.

Recovery of test material:

Mean percentage recoveries for control solutions with respect to the theoretical fortified concentration ranged from 86.2 to 111%.

Validity criteria fulfilled:

not applicable

Conclusions:

No determination of the adsorption coefficient was possible as the adsorption properties of the test material exceeded the scope of OECD method 106.

However, it can be concluded that the test material does not adsorb strongly to the organic carbon content of the soil as when given the opportunity to adsorb to an increased quantity of soil / organic carbon as the nominal soil / solution ratio altered there was no significant further adsorption.

Executive summary:

This is a GLP study following OECD 106. However, only a tier 1, 24 hour assessment was conducted, carried out in order to select the optimal soil / solution ratio. No determination of the adsorption coefficient was possible as the adsorption properties of the test material exceeded the scope of OECD method 106. No significant trend was observed between percentage test material adsorbed and nominal soil to solution ratio, with the exception of soil 4 and to a lesser extent soil 3. As adsorption was not proportional to the quantity of soil present, calculation of a Kd value was not considered valid.

However, it can be concluded that the test material does not adsorb strongly to the organic carbon content of the soil as when given the opportunity to adsorb to an increased quantity of soil / organic carbon as the nominal soil / solution ratio altered there was no significant further adsorption.

Description of key information

No determination of the adsorption coefficient was possible as the adsorption properties of the test material exceeded the scope of OECD method 106. However, it can be concluded that the test material does not adsorb strongly to the organic carbon content of the soil as when given the opportunity to adsorb to an increased quantity of soil / organic carbon as the nominal soil / solution ratio altered there was no significant further adsorption.

Additional information

O'Connor and Mullee (2006) is a GLP study following OECD 106. However, only a tier 1, 24 hour assessment was conducted, carried out in order to select the optimal soil / solution ratio. No determination of the adsorption coefficient was possible as the adsorption properties of the test material exceeded the scope of OECD method 106. No significant trend was observed between percentage test material adsorbed and nominal soil to solution ratio, with the exception of soil 4 and to a lesser extent soil 3. As adsorption was not proportional to the quantity of soil present, calculation of a Kd value was not considered valid.

However, it can be concluded that the test material does not adsorb strongly to the organic carbon content of the soil as when given the opportunity to adsorb to an increased quantity of soil / organic carbon as the nominal soil / solution ratio altered there was no significant further adsorption.