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Endpoint:
adsorption / desorption, other
Remarks:
field method
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
Principles of method if other than guideline:
Report summarizes soil and sediment solid/liquid partition coefficients (Kd) computed from indigenous stable element concentrations measured at the Forsmark and Laxemar-Simpevarp sites. The measured values were then compared to Kd values from literature.
GLP compliance:
no
Remarks:
GLP was not indicated in the published data.
Type of method:
other: monitoring data of samples
Media:
soil
Radiolabelling:
no
Analytical monitoring:
no
Matrix no.:
#1
Matrix type:
other: clayey silty till (Site A)
% Clay:
12.2
% Silt:
30.3
% Sand:
42.9
% Org. carbon:
0.29
pH:
6.5
Bulk density (g/cm³):
2 140
Matrix no.:
#2
Matrix type:
other: peat (Site B)
% Clay:
57
% Org. carbon:
56
pH:
3.5
Bulk density (g/cm³):
120
Matrix no.:
#3
Matrix type:
other: sandy till (Site C)
% Clay:
2.9
% Silt:
6.9
% Sand:
46
% Org. carbon:
3.8
pH:
5
Bulk density (g/cm³):
1 160
Matrix no.:
#4
Matrix type:
other: clay gyttja (Site D)
% Silt:
91.3
% Sand:
8.7
% Org. carbon:
25.6
pH:
5
Bulk density (g/cm³):
310
Matrix no.:
#5
Matrix type:
other: peat (Site E)
% Clay:
29
% Org. carbon:
28
pH:
4
Bulk density (g/cm³):
260
Matrix no.:
#6
Matrix type:
other: clay gyttja (Site F)
% Silt:
96.8
% Sand:
3.2
% Org. carbon:
33.9
pH:
5.5
Bulk density (g/cm³):
310
Matrix no.:
#7
Matrix type:
other: clayey silty till (Site G)
% Clay:
6.7
% Silt:
34.3
% Sand:
41.3
% Org. carbon:
2.3
Bulk density (g/cm³):
1 520
Details on matrix:
COLLECTION AND STORAGE
- Geographic location: 3 sites in Forsmark (Site A, B, G) and 4 sites in Laxemar-Simpevarp (Site C, D, E, F)
- Collection procedures: 10 sub samples were randomly taken for each site from an area of around 30 m²; 3 additional samples were taken from each site using steel cylinders (for bulk density determination)
- Sampling depth (cm): 30 cm
- Storage conditions: in a plastic bag in a cold room
- Soil preparation: Steel cylinders were dried at 105 °C. The 10 sub samples were mixed to result in one general sample. Five samples (Site A, C, D, F, G) were used for grain size analysis and content of calcite (CaCO3) and organic material. The CaCO3 analyses were determined (grain sizes < 63μ) using a method of Talme and Almén, 1975 which measures the amount of CO2 developing during the reaction between
CaCO3 and HCl. The content of organic material was measured by determining the weight loss after burning a sample at 550°C. That method is referred to as loss on ignition (LOI).

PROPERTIES
- Carbonate as CaCO3: 25% dw (Site A), 0.6 % dw (Site C), 0.3 % dw (Site D), 0.3 % dw (Site F), 5.3 % dw (Site G)
Key result
Type:
Kd
Value:
280 L/kg
Matrix:
soil
Remarks on result:
other: Geometric mean of 7 Swedish sites
Key result
Type:
Kd
Value:
370 L/kg
Matrix:
soil
Remarks on result:
other: Geometric mean of Canadian soils
Validity criteria fulfilled:
not applicable
Conclusions:
A Kd value for soil of 280 L/kg (7 Swedish sites) and 370 L/kg (Canadian soil) was determined for lithium.
Executive summary:

Kd values were measured at 7 different sites in Forsmark and Simpevarp. At each site 10 samples were drawn from a depth of 30 cm. Each peat sample had a size of 200 g. Bulk densities, grain size distribution as well as calcite and organic material were measured/determined. The following kind of soils were included in the measurement; clayey silty till, peat, sandy till and clay gyttja. A Kd value for soil of 280 L/kg was determined for lithium in the Swedish coastal area. A literature Kd value of 370 L/kg was given for Canadian soil. The Kd data set in Canada consists of over 200 soils.

Endpoint:
adsorption / desorption, other
Remarks:
field method
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
Principles of method if other than guideline:
This report summarized Kd data for regolith and marine sediments based on concentrations of 69 indigenous stable elements measured from samples collected at the Forsmark site. The samples included 50 regolith samples from agricultural land and wetlands, 8 samples of till collected at different depths, and two marine sediment samples.
GLP compliance:
not specified
Remarks:
GLP was not indicated in the published data.
Type of method:
other: field method
Media:
sediment
Radiolabelling:
no
Analytical monitoring:
no
Details on matrix:
COLLECTION AND STORAGE
- Geographic location: bay Kallrigafjärden, Sweden
- Collection procedures: three sediment cores were taken using 60‑cm‑long metal-free polycarbonate tubes. Only cores providing intact sediment of at least 35‑40 cm in length were accepted. The samples
were collected by a diver. The sampler, sediment slicer, and tubes were washed in detergent and rinsed before use between the corings. The sediment cores were sliced and two layers, the surface layer 0‑5 cm and a layer below the redox-front (or at approximately 25–35 cm depth if a redox front was not detected) were retained for analysis.
- Sampling depth (cm): 0-5 cm, 20-25 cm
- Storage conditions: Each sample of a sediment layer was transferred to a separate, labelled, gas impermeable plastic bag and entrapped headspace air was removed by squeezing the bag. The plastic bags were then placed in labelled HDPE bottles filled with argon gas, two samples in each bottle, and chilled. The argon in the bottles was topped up periodically as new sample bags were placed in the bottles for transport.
Computational methods:
- Adsorption and desorption coefficients (Kd):
The basic computation of Kd is the concentration retained on the regolith solids (Cs, mg/kg dry regolith or Bq/kg dry regolith) divided by the concentration in the contacting pore water (Cw, mg/m³ or Bq/m³), giving Kd in units of m³/kg dry soil. For elements with relatively low Kd values, where the Kd is in the same order of magnitude as the soil moisture content (expressed in the same units of m³/kg dry sediment), then it is important to account for the amount of pore water dried onto the soil solids when the solids are prepared for chemical analysis. For elements with high Kd, this correction has little effect, but is still valid. Thus, the full equation was:
Kd = Cs/Cw – MC
where MC is the soil moisture content of the soil when dried for analysis in the same units as Kd (volume per mass dry soil).

Once Kd was computed for every (detectable) element in every sample, the log10 of the values were computed, and all statistical analyses were of log‑transformed data. Statistical analyses used log‑transformed Kd and included Pearson correlations and analysis of variance (ANOVA).
Key result
Type:
Kd
Value:
520 L/kg
Matrix:
marine sediment
Remarks on result:
other: % organic carbon was not indicated
Validity criteria fulfilled:
not applicable
Conclusions:
A Kd value for sediment of 520 L/kg was determined for lithium.
Executive summary:

Kd value for sediment was measured in marine sediment sampled in the bay Kallrigafjärden at the coast of Forsmark. Three sediment cores were taken using 60‑cm‑long metal-free polycarbonate tubes. Only cores providing intact sediment of at least 35‑40 cm in length were accepted. The samples were collected by a diver. The sampler, sediment slicer, and tubes were washed in detergent and rinsed before use between the corings. The sediment cores were sliced and two layers, the surface layer 0‑5 cm and a layer below the redox-front (or at approximately 25–35 cm depth if a redox front was not detected) were retained for analysis. Pore water was filtered (0.45 µm) and acidified (HNO3) before spectroscopic analysis. Solid material was digested using a microwave based method with a nitric/hydrochloric/hydrofluoric acid mixture in a closed teflon vessel. The basic computation of Kd is the concentration retained on the regolith solids (Cs, mg/kg dry regolith or Bq/kg dry regolith) divided by the concentration in the contacting pore water (Cw, mg/m³ or Bq/m³), giving Kd in units of m³/kg dry soil. A Kd value of 520 L/kg was determined for lithium in the marine sediment.

Description of key information

Aquatic compartment

- Partition coefficient in marine water sediment: Kpsed = 520 L/kg (log Kd(sed/w) = 2.72)

- Partition coefficient in marine water suspended matter (estimated from sediment): Kpsed = 780 L/kg (log Kd(sed/w) = 2.89)

Terrestrial compartment
- Partitioning coefficient: Kd value soil: 370 L/kg(log Kp (pm/w) = 2.57)

Key value for chemical safety assessment

Other adsorption coefficients

Type:
log Kp (solids-water in soil)
Value in L/kg:
2.57

Other adsorption coefficients

Type:
log Kp (solids-water in sediment)
Value in L/kg:
2.72

Other adsorption coefficients

Type:
log Kp (solids-water in suspended matter)
Value in L/kg:
2.89

Additional information

According to Annex XI, Section 2 of Regulation (EC) No 1907/2006 (REACH) testing for a specific endpoint may be omitted if it is technically not possible to conduct the study as a consequence of the properties of the substance itself. A study to investigate the adsorption / desorption characteristics of lithium nitrate has not been conducted. The justifications for not providing these data are as follows:

- A screening study according to OECD Guideline 121 is not technically possible as the test method is not validated for inorganic substances.

- A batch equilibrium study according to OECD Guideline 106 was deemed to be not applicable to lithium nitrate for the following reasons:

Firstly, both lithium and carbonate are natural constituents of soils and as such analysis of the test material may not be possible due to interference from the soil extracts that may leach into the aqueous media during the test. This would prevent quantification of the test material.

In addition, the mobility of the test item would be dependent on the anion exchange capacity of the soils as the main component of the test material is an anion. This absorption relationship would not be anticipated to correlate with the organic carbon content of the soils and is considered to be beyond the scope of the OECD 106 method.

Metals such as sodium, potassium, calcium and lithium are expected to behave similarly in the environment, with ions in the aqueous environment remaining in solution. Lithium is a naturally occurring element, “found in small amounts in nearly all igneous rocks and in the waters of many mineral springs” (Lide 2009) and the adsorption/desorption of lithium in the environment is not expected to be scientifically relevant. This is supported by a peer-reviewed database (Webwiser, 2019) where it is stated that in general lithium compounds are not expected to adsorb strongly to soils or sediments. Aral and Vecchio-Sadus (2008) also conclude that lithium appears to be only poorly adsorbed onto river sediments. The available partitioning coefficients from read-across substances further support the above assumptions.

Two field studies are available where partition coefficients for lithium were determined in selected soils and sediments. Sheppard et al (2009) took soil samples from 7 different sites in Forsmark and Simpevarp in Sweden. At each site 10 samples were drawn from a depth of 30 cm. Each peat sample had a size of 200 g. Bulk densities, grain size distribution as well as calcite and organic material were measured/determined. The following kinds of soil were included in the measurement; clayey silty till, peat, sandy till and clay gyttja. A Kd value for soil of 280 L/kg was determined for lithium in the Swedish coastal area. A literature Kd value of 370 L/kg was given for Canadian soil. This Kd data set in Canada was based on measured values of over 200 soils.

Sheppard et al. (2011) take marine sediment samples in the bay Kallrigafjärden at the coast of Forsmark, Sweden. Three sediment cores were taken using 60cmlong metal-free polycarbonate tubes. Only cores providing intact sediment of at least 3540 cm in length were accepted. The samples were collected by a diver. The sampler, sediment slicer, and tubes were washed in detergent and rinsed before use between the corings. The sediment cores were sliced and two layers, the surface layer 05 cm and a layer below the redox-front (or at approximately 25–35 cm depth if a redox front was not detected) were retained for analysis. Pore water was filtered (0.45 µm) and acidified (HNO3) before spectroscopic analysis. Solid material was digested using a microwave based method with a nitric/hydrochloric/hydrofluoric acid mixture in a closed Teflon vessel. The basic computation of Kd is the concentration retained on the regolith solids (Cs, mg/kg dry regolith or Bq/kg dry regolith) divided by the concentration in the contacting pore water (Cw, mg/m³ or Bq/m³), giving Kd in units of m³/kg dry soil. A Kd value of 520 L/kg was determined for lithium in the marine sediment.

No partition data was found regarding the suspended matter. The suspended material, if more organic, will have a lower particle density (mass per unit volume), and may, because it has remained suspended, be of smaller particle size. Thus it will have a higher specific surface area (surface area when hydrated per unit mass when dry). This will tend to result in higher Kd values. Thus it was decided to estimate the suspended matter value considering the sediment Kd of 520 L/kg. As a worst case consumption a 50 % higher value was estimated and considered for risk assessment. Thus, a Kd value for suspended matter of 780 L/kg was determined.

From the field experiments and the literature the adsorption of lithium can be regarded as neglible.

References

Lide DR (editor) (2009) CRC Handbook of Chemistry and Physics (89th edition);CRC Press, Taylor and Francis Group

Aral, H. and Vecchio-Sadus, A. (2008) Toxicity of lithium to humans and the environment—A literature review; Ecotoxicology and Environmental Safety 70; 349– 356

https://webwiser.nlm.nih.gov/knownSubstanceSearch.do ; Webwiser, US NLM, 2012, cited 2019-10-31