High temperature calcination products of titanium dioxide, calcium carbonate, calcium fluoride, quartz and antimony oxide containing lewisite and wollastonite

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

no guideline followed

Principles of method if other than guideline:

Partition coefficient values were determined using a batch procedure using a single point soluble metal/metalloid spike on the spectrally representative subset of approximately 500 soils of the Geochemical Mapping of Agricultural Soils of Europe (GEMAS).

GLP compliance:

no

Remarks:

The study is not-GLP compliant but generally well documented and was published in a peer-reviewed journal.

Type of method:

other: batch procedure using a single point soluble metal/metalloid or radioactive isotope spike on the spectrally representative subset of approximately 500 GEMAS soils.

Media:

soil

Specific details on test material used for the study:

Values of Kd were measured for antimonate (Sb[OH]6–).

Analytical monitoring:

yes

Details on sampling:

Total of 4813 soils from the GEMAS sampling program were collected from arable land (0–20 cm depth) and land under permanent grass cover (0–10 cm; 1 sample/2500 km2). The samples were air dried, and sieved to <2 mm prior to analysis. Soils were oven dried at 40 ᵒC for 12 h and cooled in a desiccator prior to MIR analysis of all the samples, and experimental Kd values were determined for a spectrally representative set of approximately 500 soils (the calibration samples).

Details on matrix:

Approximately 500 spectrally representative soils of the Geochemical Mapping of Agricultural Soils of Europe (GEMAS) program were used to determine the partition coefficient values. These calibration soils represented the major properties of the entire 4813 soils of the GEMAS project.

Details on test conditions:

Approximately 2.0±0.05 g of <2-mm sieved soils were weighed into 50mL centrifuge tubes and mixed end-over-end for 48 h with 20 mL of 0.01M calcium chloride. After this initial equilibration period, the pH of the suspension was measured, and samples were spiked individually with a soluble metal/metalloid to achieve final spike concentrations per sample of 5mg Sb(V) / kg as antimony oxide (Sb2O5). The Sb(V) stock solution was prepared by shaking excess solid in a 50 mL centrifuge tube with ultrapure deionized water and syringe filtering to < 0.2 µm.

The spiked samples were mixed end-over-end for a further 72 h. After the spike equilibration period, samples were centrifuged at 1200 g for 20 min, and supernatants were filtered to <0.2 µm. The pH of soil suspension was again determined after equilibrium with the spike.

Computational methods:

The Kd values were determined using the following equation:

Kd = Iadd – Fmea/ SPmea

where, Kd values are in L/kg;
Iadd is the initial metal/metalloid concentration added (mg/kg)
Fmea is the final metal/metalloid concentration in solution (mg/kg)
and SPmea is the final solution phase concentration (mg/L)

The Fmea (mg /kg) and SPmea (mg/L) values were both corrected for background metal/metalloid concentrations.

Phase system:

solids-water in soil

Type:

Kp

Value:

69 L/kg

pH:

6

Matrix:

approx. 500 GEMAS soils

% Org. carbon:

>= 0.5 - <= 49

Remarks on result:

other: median; range: 2.8 - 5494 L/kg

Validity criteria fulfilled:

not specified

Conclusions:

The median Kd value for antimony was 69 L/kg (range: 2.8 – 5494 L/kg).

Executive summary:

Partition coefficient values were determined using a batch procedure using a single point soluble metal/metalloid spike on the spectrally representative subset of approximately 500 GEMAS soils.

The median Kd value for antimony was determined to be 69 L/kg (range: 2.8 – 5494 L/kg).

The study does not follow the standard guideline but is generally well documented and was published in a peer-reviewed journal. This is a non-GLP experimental study and there are minor restrictions in reporting but it is otherwise acceptable as the key study for this endpoint.

Reference 2

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

summer 1997 and summer 1998

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Reason / purpose for cross-reference:

read-across: supporting information

Principles of method if other than guideline:

Water samples were collected from 54 rivers at 119 locations in the Czech Republic during the summers of 1997 and 1998. Partitioning between suspended matter and water was determined based on measurements of Ti concentrations in solution and in corresponding suspended matter.

GLP compliance:

no

Type of method:

other: Water samples were analysed by AAS, or ICP-MS, and suspended particulate matter samples by PIXE and NAA

Media:

suspended matter

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Water samples (filtered and unfiltered) were collected from 54 rivers at 119 locations in the Czech Republic during summer of 1997 and 1998.

For the analysis of suspended particulate matter (SPM), a volume of 200 mL of river water was filtered and another 100 mL was used for analysis.

Details on matrix:

COLLECTION AND STORAGE
- Geographic location: samples were collected from 54 rivers at 119 locations in the Czech Republic over the whole state territory
- Collection procedures: The water samples were filtrated in the field immediately after collection (polycarbonated filter, 0.4 µm). For the analysis of suspended particulate matter (SPM), a volume of 200 mL of river water was filtered and another 100 mL was used for analysis.

Computational methods:

The values of Kd were calculated by dividing the total concentration of the element in suspended particulate matter by its concentration in filtered water according to the following formula:
Kd = Cs/Cl (g/L)
where:
Cs is the overall concentration in the solid phase, and
Cl is the overall concentration in the liquid phase.

Phase system:

solids-water in suspended matter

Type:

log Kp

Value:

2.36 other: L/g

Remarks on result:

other: The median Kd value calculated from data from 54 rivers in 119 locations

Validity criteria fulfilled:

not applicable

Conclusions:

For titanium, the median log Kd was determined to be 2.36 L/g.

Executive summary:

Partitioning between suspended matter and water was determined based on measurements of titanium concentrations in water samples and in corresponding suspended matter. Water samples were collected from 54 rivers at 119 locations in the Czech Republic during the summers of 1997 and 1998. The samples were analysed to determine the concentration of 41 elements in suspended particulate matter and in filtrate. The partitioning coefficients (Kd values) were calculated by dividing the total concentration of the element in suspended particulate matter by its concentration in filtered water.

The median log Kd value for titanium was determined to be 2.36 L/g.

 

The study does not follow the standard guideline but is generally well documented and was published in a peer-reviewed journal. This is a non-GLP experimental study and there are minor restrictions in reporting but it is otherwise acceptable as the key study for this endpoint.

Description of key information

The adsorption/ desorption endpoint is completed by read across from antimony and titanium.

The median log Kd value for titanium was determined to be 2.36 L/g and the median Kd value for antimony was determined to be 69 L/kg.

Additional information

The adsorption/ desorption endpoint is completed by read across from antimony and titanium. Titanium oxide and antimony oxide are the main components of uverithe and therefore it is considered appropriate to use data on antimony and titanium for assessing the behaviour of uverithe in the environment.

 

Monitoring data on titanium and antimony in the environment were used to derive adsorption / desorption partition coefficients for these elements.

 

Vesely et al. (2001) investigated water samples and suspended matter from 54 rivers in the Czech Republic. Partitioning coefficients between suspended matter and water were determined based on measurement of Ti concentrations in solution and in corresponding suspended matter. The median log Kd value for titanium was determined to be 2.36 L/g. The study reported the partition coefficient of titanium in suspended matter, therefore this study was chosen as a key study for this endpoint.

Roychoudhury and Starke. (2007) evaluated partitioning of trace metals between surface water and sediments and their fate within the sediments of a river in South Africa. Samples of surface water and sediment were collected from 20 randomly chosen locations the East Rand near Johannesburg, South Africa. In the study, the median log Kd value for titanium was determined to be 4.61 L/kg. 

For antimony, partition coefficient values were determined using a batch procedure using a single point soluble metal/metalloid spike on the spectrally representative subset of approximately 500 soils of the Geochemical Mapping of Agricultural Soils of Europe (GEMAS) program (Janik et al. 2015). The Kd values ranged from 2.8 to 5494 L/kg and the median Kd value for antimony was determined to be 69 L/kg.

The studies were not conducted according to standard guidelines and are not GLP-compliant. However, they are well-reported and were published in a peer-reviewed journals, therefore are reliable with restrictions (Klimisch 2) and are considered suitable for use for this endpoint.