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Endpoint:
adsorption / desorption, other
Remarks:
adsorption
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
August 1992, August 1994, May 1996
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP compliant, non-guideline experimental investigation. Study published in scientific, peer reviewed journal.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Water samples were filtered through 0.45 µm filters to separate dissolved aluminium (in filtrate) and aluminium associated with suspended solids (on filters).
GLP compliance:
no
Type of method:
other:
Media:
other: total suspended matter
Details on sampling:
The field observations were limited to the typical fluvio-estuarine zone beginning with freshwater upstream through to marine waters at salinity of
25-30 psu. The sample collection was carried out at random tides, based on the in-situ salinity measurements. Sampling and filtration materials, including the filters, bottles, and filtration sets, were all acid cleaned followed by thorough rinse with Milli-Q water before use. Care was taken to avoid contamination. Surface water samples (0-0.5 m) were collected with 2-1 polyethylene bottles attached to the end of a 5-m glass fiber reinforced plastic pole on the bow of small boat. Deep-water samples were collected by 5-1 Niskin bottles attached to a nylon cable.
Details on test conditions:
Water samples were filtered through acid pre-cleaned 0.45 µm pore-size Satorius filters within a few hours of sampling. The filtrates were acidified to pH < 2 with HCl and kept frozen in clean polyethylene bottle within two plastic bags before analysis. Samples for dissolved (DOC) and particulate organic carbon were filtered through pre-cleaned (i.e. 450 oC overnight) Whatman GF/F filters. After filtration, the filters were rinsed with Milli-Q water, dried, and weighed again to obtain the amount of total suspended matter (TSM).
Suspended sediment concentration varied among the samplig times being lowest in autumn (flood period) and highest in spring (dry season) ranging from 10 to 1856 mg/l. Concentrations of dissolved Al varied from 0.88 to 4.06 µM depending on water status with the highest concentrations in dry season. Concentrations of particulate Al varied from 0.10 to 0.72 µM depending on water status with the highest concentrations in dry season. pH of water ranged from 6.7 to 8.2. DOC concentration ranged from 180 to 210 µM.
Computational methods:
Kd was calculated by diving the measured concentration of Al in 0.45 µm filter-retained particles (g/kg) with measured concentration of Al in filtrate (g/1).
Phase system:
suspended matter-water
Type:
log Kp
Value:
5.52 - 7.32 L/kg
Remarks on result:
other: measure at the ambient natural temperature
Validity criteria fulfilled:
not specified
Conclusions:
A significant amount of aluminium was associated with solid phase.
Executive summary:

Suspended solid-water adsorption coefficients (Kd) of aluminium were determined in a non-GLP compliant, non guideline study. The test water was sampled from the Yalujiang River that forms the boundary between China and North Korea. It is polluted by the waste drainage from both Chinese and Korean sides.Water samples were filtered through 0.45 µm filters to separate dissolved aluminium (in filtrate) and aluminium associated with suspended solids (on filters). Kd was calculated by diving the concentration of Al in 0.45 µm filter-retained particles (g/kg) with the concentration of Al in filtrate (g/1). A significant amount of aluminium was associated with solid phase giving Kds from 5.53 to 7.32 L/kg.

Endpoint:
adsorption / desorption, other
Remarks:
adsorption
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
2004
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP compliant, non-guideline experimental investigation. Study published in scientific, peer reviewed journal.
Reason / purpose for cross-reference:
reference to same study
Qualifier:
no guideline followed
Principles of method if other than guideline:
According to Guidance on information requirements and chemical safety assessment, Appendix R.7.13-2: Environmental risk assessment for metals and metal compounds it is possible to determine Kds for metals based on paired measured data in the solid and solution phase.
GLP compliance:
no
Type of method:
other: measured concentrations
Media:
sediment
Details on sampling:
For each study site, 11 water samples were taken. Conductivity and pH of the samples were measured immendiately. Thereafter the water samples were acidified with HNO3 (1 %). Sampling of sediment was described in Migon C and Mori C, 1999, Impact of arsenic and antimony contamination on benthic invertebrates in a minor Corsican river, Hydrobiologia 392(1999): 81-88.
Computational methods:
Kp-values were calculated by diving the concentrations of trace elements in sediment by the concentration of trace elements in water.
Phase system:
solids-water in sediment
Type:
log Kp
Value:
0.48 - 1 L/kg
Remarks on result:
other: for arsenic
Phase system:
solids-water in sediment
Type:
log Kp
Value:
0.4 - 0.85 L/kg
Remarks on result:
other: for antimony
Validity criteria fulfilled:
not specified
Conclusions:
Kp for arsenic ranged from 0.48 to 1.00 and for antimony from 0.40 to 0.85 (n = 4).
Executive summary:

According to Guidance on information requirements and chemical safety assessment, Appendix R.7.13-2: Environmental risk assessment for metals and metal compounds it is possible to determine Kps for metals based on paired measured data in the solid and solution phase. In the non-GLP compliant, non-guideline experimental investigation, concentrations of arsenic and antimony in sediment and surface water of Bravona and Presa Rivers (Corsica) were determined. Based on them Kp-values were calculated by diving the concentrations in sediment by the concentration in water. Kp for arsenic ranged from 0.48 to 1.00 and for antimony from 0.40 to 0.85 (n = 4).

Endpoint:
adsorption / desorption, other
Remarks:
adsorption/desorption
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
Not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP compliant, non-guideline experimental investigation. Study published in scientific, peer reviewed journal.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Competitive sorption and desorption of heavy metals Cd, Cu and Pb by different matrices were studied in an experimental laboratory study. The sorption/desorption potential of these heavy metals were assessed using Langmuir and Freundlich equations.
GLP compliance:
no
Type of method:
batch equilibrium method
Media:
soil
Radiolabelling:
no
Test temperature:
25°C
Details on matrix:
COLLECTION AND STORAGE
Minerals
- Kaolinite and mica were obtained from Caolinites de Vimianzo, Spain, and Vermiculite from Süd-Chimie-Spain.
- Kaolinite: 90% kaolinite, 10% mica
- Mica: 97% mica, 3% quartz
- Vermulite: >91% vermulite, <3% quartz, <3% mica, <3% calcite

Oxides
- Iron oxide (96%) was prepared with NaOH and ferric chloride. Manganese oxide (97%) was prepared with hydrogen peroxide and potassium permanganate. The formed precipitates were dried and grinded.

HOM
- Humified organic matter (HOM) was obtained from the H horizon of a Fibric Histosol. The material was air-dried, suspended in water and shaken for 2 h. Finally, the 0.1 mm sieved HOM was dried at 30°C and grinded.
- Properties: pH(H2O) 5.1, pH(KCl) 4.5, CEC(+) 12.52 cmol+/kg, organic matter 389 g/kg.
Details on test conditions:
Sorption stage was studied in a sorption solution containing metal nitrates, acetate buffer (pH 4.5) and sorbent material. After equilibrating by 24 hour shaking at 25°C, the solution was centrifuged ( 1800 x g, 10 min) and the supernatant was analysed with ICP-OES. The centrifuged solid matter was dried and resuspended in the acetate buffer, and this desorption solution was handled and analysed correnponding to the sorption solution.

Computational methods:
Langmuir and Freundlich models by least squares.
Type:
Kd
Remarks:
Pb
Value:
1 176.6 L/kg
pH:
4.5
Matrix:
Mn oxide
% Org. carbon:
0
Type:
Kd
Remarks:
Cu
Value:
147.24 L/kg
pH:
4.5
Matrix:
Mn oxide
% Org. carbon:
0
Type:
Kd
Remarks:
Cd
Value:
7.59 L/kg
pH:
4.5
Matrix:
Mn oxide
% Org. carbon:
0
Type:
Kd
Remarks:
Pb
Value:
15.44 L/kg
pH:
4.5
Matrix:
Fe oxide
% Org. carbon:
0
Type:
Kd
Remarks:
Cu
pH:
4.5
Matrix:
Fe oxide
% Org. carbon:
0
Remarks on result:
other: no sorption detected
Type:
Kd
Remarks:
Cd
Value:
1.74 L/kg
pH:
4.5
Matrix:
Fe oxide
% Org. carbon:
0
Type:
Kd
Remarks:
Pb
Value:
574.27 L/kg
pH:
4.5
Matrix:
HOM
% Org. carbon:
38.9
Type:
Kd
Remarks:
Cu
Value:
189.15 L/kg
pH:
4.5
Matrix:
HOM
% Org. carbon:
38.9
Type:
Kd
Remarks:
Cd
Value:
14.37 L/kg
pH:
4.5
Matrix:
HOM
% Org. carbon:
38.9
Type:
Kd
Remarks:
Pb
Value:
117.91 L/kg
pH:
4.5
Matrix:
Vermiculite
% Org. carbon:
0
Remarks on result:
other: Information on organic carbon content not available.
Type:
Kd
Remarks:
Cu
Value:
3 457.28 L/kg
pH:
4.5
Matrix:
Vermiculite
% Org. carbon:
0
Remarks on result:
other: Information on organic carbon content not available.
Type:
Kd
Remarks:
Cu
Value:
89.5 L/kg
pH:
4.5
Matrix:
Vermiculite
% Org. carbon:
0
Remarks on result:
other: Information on organic carbon content not available.
Type:
Kd
Remarks:
Pb
Value:
0.56 L/kg
pH:
4.5
Matrix:
Mica
% Org. carbon:
0
Remarks on result:
other: Information on organic carbon content not available.
Type:
Kd
Remarks:
Cu
pH:
4.5
Matrix:
Mica
% Org. carbon:
0
Remarks on result:
other: No sorption detected. Information on organic carbon content not available.
Type:
Kd
Remarks:
Cd
Value:
0.31 L/kg
pH:
4.5
Matrix:
Mica
% Org. carbon:
0
Remarks on result:
other: Information on organic carbon content not available.
Type:
Kd
Remarks:
Pb
Value:
2.68 L/kg
pH:
4.5
Matrix:
Kaolinite
% Org. carbon:
0
Remarks on result:
other: Information on organic carbon content not available.
Type:
Kd
Remarks:
Cu
pH:
4.5
Matrix:
Kaolinite
% Org. carbon:
0
Remarks on result:
other: No sorption detected. Information on organic carbon content not available.
Type:
Kd
Remarks:
Cd
Value:
1.39 L/kg
pH:
4.5
Matrix:
Kaolinite
% Org. carbon:
0
Remarks on result:
other: Information on organic carbon content not available.
Adsorption and desorption constants:
See Table 1 for Kd values.
Details on results (Batch equilibrium method):
See Table 1.

Selectivity sequences:

Sorption
Kaolinite: Pb>Cd>Cu
Mica: Pb>Cd>Cu
Vermiculite: Cu>Pb>Cd
HOM: Pb>Cu>Cd
Fe oxide: Pb>Cd>Cu
Mn oxide: Pb>Cu>Cd

Retention
Kaolinite: Pb>Cd>Cu
Mica: Cu=Cd=Pb
Vermiculite: Cu>Cd>Pb
HOM: Pb>Cu>Cd
Fe oxide: Pb>Cd>Cu
Mn oxide: Pb>Cu>Cd


Table 1. Distribution coefficients kd100 (L/kg) for sorption and desorption.

 Metal   

 Kaolinite   

 Mica   

 Vermiculite   

 HOM   

 Fe oxide   

 Mn oxide   

 Sorption

 Retention

  Sorption

  Retention

  Sorption

  Retention

  Sorption

  Retention

  Sorption

  Retention

  Sorption

  Retention

Cd

 1.39

 12.99

 0.31

  nd

 89.5

 143.38

 14.37

 25.24

 1.74

 33.18

 7.59

 114.86

 Cu

 nd

 nd

 nd

  nd

 3457.28

 3258.42

 189.15

 462.16

  nd

  nd

 147.24

 4539.11

 Pb

 2.68

 18.38

 0.56

  nd

 117.91

 61.56

 232.96

 574.27

 15.44

 98.12

 1176.6

 12203.03

The entry "nd" indicates that no sorption or retention was detected.

Validity criteria fulfilled:
not specified
Conclusions:
Highest Kd values were found for the following metals: copper and zinc in vermiculite, and lead in HOM, Fe and Mn oxides. Copper was found to sorb also in HOM and Mn oxide at some extent, but it retained least in kaolinite. Cadmium and lead were retained in Fe oxide.
Executive summary:

Competitive sorption and desorption of heavy metals Cd, Cu and Pb were studied in sorption solution containing metal nitrates, acetate buffer (pH 4.5) and sorbent material humified organic matter, Fe and Mn oxides, kaolinite, vermiculite and mica in a non-GLP non-guideline study. After equilibrating by 24 hour shaking at 25°C, the solution was centrifuged (1800 x g, 10 min) and the supernatant was analysed with ICP-OES. The centrifuged solid matter was dried and resuspended in the acetate buffer, and this desorption solution was handled and analysed correnponding to the sorption solution. The sorption/desorption potential of these heavy metals were assessed using Langmuir and Freundlich equations. Competitive metals present caused, that sorbents generally failed to comply with the isotherms. Exemptions were vermiculite and HOM, from which metals desorpted most. Highest Kd values were found for the following metals: copper in vermiculite, and lead in HOM, Fe and Mn oxides. Copper was found to sorb also in HOM and Mn oxide at some extent, but it retained least in kaolinite. Cadmium and lead were retained in Fe oxide. Sorption affinity of the metals in certain matrix is a clincher in sorption in the presence of competitors.

Description of key information

Kd values were obtained from three non-GLP, non-guideline experimental investigation published in scientific, peer reviewed journals. In the first investigation sorption and retention of metals (Cu, Cd and Pb) on different materials was determined based on Langmuir and Freundlich isotherms. In the second investigation, sorption of aluminium to suspended solids was determined based on the field samples. Paired measured data on concentrations of As and Sb in solid and solution phase was obtained from the third investigation and was used for calculating Kd values (according to Guidance on information requirements and chemical safety assessment, Appendix R.7.13-2: Environmental risk assessment for metals and metal compounds). Highest Kp values were found for aluminium in suspended solids. Sorption affinity of the metals in certain matrix is a clincher in sorption in the presence of competitors. The Kd values for Cd, Cu and Pb are presented in table 1 below. Kp values for Al, As and Sb were 1.72E6, 4.48 and 5.64, respectively. The key value for chemical safety assessment was the weigthed average of all the critical elements.

Key value for chemical safety assessment

Other adsorption coefficients

Type:
log Kp (solids-water in sediment)
Value in L/kg:
1 690 000

Additional information

Table 1. Distribution coefficients kd100 (L/kg) for sorption and desorption.

 Metal   

 Kaolinite   

 Mica   

 Vermiculite   

 HOM   

 Fe oxide   

 Mn oxide   

 Sorption

 Retention

  Sorption

  Retention

  Sorption

  Retention

  Sorption

  Retention

  Sorption

  Retention

  Sorption

  Retention

Cd

 1.39

 12.99

 0.31

  nd

 89.5

 143.38

 14.37

 25.24

 1.74

 33.18

 7.59

 114.86

 Cu

 nd

 nd

 nd

  nd

 3457.28

 3258.42

 189.15

 462.16

  nd

  nd

 147.24

 4539.11

 Pb

 2.68

 18.38

 0.56

  nd

 117.91

 61.56

 232.96

 574.27

 15.44

 98.12

 1176.6

 12203.03

The entry "nd" indicates that no sorption or retention was detected.