Registration Dossier

Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Study conducted to a current guideline but currently in draft form. Since Manganese dioxide comprises of Mn4+, this form of the substance can be expected to adsorb to soil to a slightly greater extent than Mn2+, and the Kd median result is considered to be sufficiently representative at present to use in risk assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)
Deviations:
no
Remarks:
Based on draft.
GLP compliance:
not specified
Type of method:
batch equilibrium method
Media:
soil

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report):
- Molecular formula (if other than submission substance): 54MnSO4 and in selected soils MnO2 as well.
- Substance type: solid
Radiolabelling:
yes

Study design

Test temperature:
Room temperature

Batch equilibrium or other method

Analytical monitoring:
yes
Details on sampling:
- Concentrations: 143 Bq/g for acid soils (pH < 6) and 667 Bq/g for pH neutral soils (pH > 6)
- Sampling interval: two consecutive extractions
- Sample storage before analysis: 3 days and 100 days
Details on matrix:
Table 1

Nr† Location Country pH total C Organic C CaCO3 CEC Total Mn
% % % cmolc/kg mg/kg
1 Gudow Germany 3.0 5.1 5.1 0.0 5.8 20
2 Nottingham UK 3.4 5.2 5.2 0.0 6.7 37
3 Houthalen Belgium 3.4 1.9 1.9 0.0 1.9 17
4 Lommel Belgium 4.1 1.6 n.d. n.d. 1.2 20
5 Kasterlee Belgium 4.7 2.1 2.1 0.0 3.5 23
6 Zegveld Netherlands 4.7 23.3 23.3 0.0 35.3 68
7 Kövlinge Sweden 4.8 1.6 1.6 0.0 2.4 42
8 Rhydtalog UK 4.8 7.8 7.8 0.0 14.9 23
9 Wageningen Netherlands 5.0 1.5 1.5 0.0 1.9 29
10 Montpellier France 5.2 0.8 0.8 0.0 2.5 88
11 De Meern Netherlands 5.2 10.2 10.2 0.0 29.6 92
12 Zwijnaarde Belgium 5.2 1.8 1.8 n.d. 4.1 177
13 Hygum Denmark 5.4 2.3 2.3 0.0 8.6 48
14 Aluminusa Italy 5.4 0.9 0.9 0.0 22.6 49
15 Lovenjoel Belgium 5.5 3.2 n.d. n.d. 10.2 116
16 Zeveren Belgium 5.7 3.5 3.5 0.0 18.9 43
17 Plombières France 5.8 5.4 n.d. n.d. 10.1 411
18 Wilsele Belgium 6.1 2.1 n.d. n.d. 3.3 695
19 London UK 6.3 4.3 n.d. n.d. 20.3 277
20 Woburn UK 6.4 4.4 4.4 0.0 23.4 293
21 Rijswijk Uzimet Nederland 6.6 4.6 0.2 1.7 25.7 352
22 Lille Exide France 6.6 4.6 0.2 1.7 25.7 276
23 Ter Munck Belgium 6.7 0.9 0.9 n.d. 12.2 103
24 Bordeaux France 6.8 1.6 n.d. n.d. 14.4 85
25 Florival Exide Belgium 6.8 2.0 0.0 0.3 14.9 109
26 Paris France 7.2 1.4 n.d. n.d. 11.2 82
27 Rots France 7.3 2.8 1.3 13.0 14.3 2397
28 Vault de Lugny France 7.3 2.2 1.5 6.0 26.2 133
29 Souli Greece 7.4 8.3 2.6 47.4 36.3 102
30 Barcelona Spain 7.5 2.3 1.5 7.2 14.3 4150
31 Brécy France 7.5 3.6 1.5 17.6 23.5 150
32 Marknesse Netherlands 7.5 2.5 1.3 10.0 20.1 45
33 Guadalajara Spain 7.5 4.8 0.4 36.5 16.9 160
34 Nagyhörcsök Hungary 7.6 2.7 2.1 5.0 24.8 88
35 Granada Spain 8.5 n.d 0.9 24.9 7.9 20
† Numbering according to soil pH; n.d: no detectable
Details on test conditions:
Soils were collected with a metal spade from the plough layer. Stones and vegetation were cleared from the soil samples before being put in 60 litre plastic drums. Soils were stored at 4°C until drying and sieving. The time between sampling and cold storage was never more than one week. The soils were dried in a thin layer at 25°C in a plant growth cabinet with continuous illumination. After partial drying, soils were sieved through a 4 mm sieve. The sieved soil was thoroughly mixed to ensure homogeneity and further dried. Air dry, sieved soils were stored in 60 litre plastic drums.

Of each soil, about 25 g dried soil sample was wetted to field capacity and incubated during 2 weeks in aerobic conditions. After that, carrier-free 54Mn2+ was added at about 143 Bq/g for acid soils (pH < 6) and 667 Bq/g for pH neutral soils (pH > 6) and thoroughly mixed. After 3 days and 100 days two consecutive extractions were performed with soil subsamples of 5 g:

-CaCl2 10 mM (5 g wet soil:10 mL; 2 replicates, 24 h end-over-end shaking), centrifuged at 6750 RCF and 5 mL of the liquid phase were assayed for metals, including Mn (ICP-OES, Perkin Elmer 3300 DV) and 54Mn activity (Minaxi 5,530 auto-gamma counter, decay corrected).

-NH4Ac 1.25 M (pH 4.8): 20 mL was added to each soil subsample in the centrifuge tube (combined with the CaCl2 10 mM remaining), shaken for 2 hours and centrifuged at 6750 RCF. The liquid phase was assayed for metals and 54Mn activity and Mn as described. This extraction is assumed to extract the adsorbed Mn(II) completely (Guest et al., 2002).
Five soils (3, 8, 14, 21, 29), selected to cover a range of pH values, were additionally assayed by adding 200 mg MnO2/kg. All soils were incubated moist (closed vessels, opened regularly to aerate) at room temperature. At 3 and 100 days after spiking, soils were extracted in duplicate. Extractions will also be performed after 6 months.

Selected soil properties (Table 1) were measured for the 35 uncontaminated topsoils. Results are expressed on an oven dry basis. All analyses were performed in duplicate. In the table the average values of the analysis are shown.
Total carbon (C) was measured by ignition using a Variomax CN analyser. The CaCO3 content of the soils was determined from pressure increases after addition of HCl to the soil in closed containers (including FeSO4 as a reducing agent). The organic carbon content was determined by difference between total and inorganic carbon content. The pH of the soils was measured in 0.01 M CaCl2 (1:5 soil/solution ratio) after shaking for 1 h and allowing to settle for 30 minutes before pH measurement.
The silver-thiourea method (Chhabra et al., 1975) was used to measure cation exchange capacity (CEC) at soil pH and exchangeable cations, with concentrations in extracts determined by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES, Perkin Elmer Optima 3300 DV). Total metal concentrations in soil, including Mn, were determined for all soils by boiling aqua regia extraction and analysis with ICP-OES.

Results and discussion

Adsorption coefficientopen allclose all
Type:
Kd
Value:
>= 4.5 - <= 13 564
Temp.:
25 °C
% Org. carbon:
>= 0 - <= 23.3
Remarks on result:
other: After 100 days
Type:
Kd
Value:
>= 1 - <= 20 550
Temp.:
25 °C
% Org. carbon:
>= 0 - <= 23.3
Remarks on result:
other: After 3 days
Type:
Kd
Value:
1 598
Temp.:
25 °C
% Org. carbon:
>= 0 - <= 23.3
Remarks on result:
other: Median after 3 days
Type:
Kd
Value:
1 355
Temp.:
25 °C
% Org. carbon:
>= 0 - <= 23.3
Remarks on result:
other: Median after 100 days
Type:
Kd
Value:
344
Temp.:
25 °C
% Org. carbon:
>= 0 - <= 23.3
Remarks on result:
other: Geometric mean after 3 days
Type:
Kd
Value:
580
Temp.:
25 °C
% Org. carbon:
>= 0 - <= 23.3
Remarks on result:
other: Geometric mean after 100 days

Results: Batch equilibrium or other method

Details on results (Batch equilibrium method):
See table 2
Statistics:
Standard deviation as shown in table 2.

Any other information on results incl. tables

Table 2

Manganese Kdvalues (mean and standard deviation of 2 replicates) obtained for a collection of 35 European soils.

Soil nr

Soil name

pH (CaCl2)

Kd(L/kg)

Factor change 3-100 days

 

 

 

3 days

 

100 days

 

 

 

 

 

mean

SD

mean

SD

 

1

Gudow

3.12

1.4

0.8

25.9

12.5

18.5

2

Nottingham

3.70

3.8

0.9

8.5

0.1

2.2

3

Houthalen

3.54

1.0

0.1

33.1

7.1

31.5

4

Lommel

3.84

1.1

0.3

4.5

0.4

4.2

5

Kasterlee

4.25

13.5

1.6

96.4

7.6

7.1

6

Zegveld

4.23

29.5

9.3

60.2

15.2

2.0

7

Kövlinge I

5.02

4.6

0.5

84.7

0.9

18.3

8

Rhydtalog

4.55

15.6

4

69.4

10

4.4

9

Wageningen

5.63

34.0

9

1944

140

57.2

10

Montpellier

5.59

698

40

237

26

0.3

11

De Meern

5.80

346

28

6441

1012

18.6

12

Zwijnaarde

5.59

8

1

163

48

20.9

13

Hygum

5.23

1800

1501

907

20

0.5

14

Aluminusa

5.39

1931

304

3045

21

1.6

15

Lovenjoel

5.10

1788

362

32

0.1

0.02

16

Zeveren

5.49

18

5

50

14

2.8

17

Plombières

5.52

14

4

468

27

32.8

18

Wilsele

5.73

2570

526

1840

1286

0.7

19

London

5.79

3052

736

4891

629

1.6

20

Woburn

5.86

88

10

1997

32

22.6

21

RijswijkUzimet

5.36

15

1

20

2

1.3

22

LilleExide

7.13

1598

781

2506

792

1.6

23

Ter Munck

7.40

10519

3992

1615

1809

0.2

24

Bordeaux 

6.47

20550

11373

1433

258

0.1

25

Florival Exide

6.66

3591

363

1046

536

0.3

26

Paris

7.08

4331

2451

1355

121

0.3

27

Rots

7.24

8755

5308

4045

220

0.5

28

Vault de Lugny

7.36

13584

2562

7836

188

0.6

29

Souli

7.38

1497

711

1261

529

0.8

30

Barcelona

7.31

19180

8256

3957

207

0.2

31

Brécy

7.34

14176

8256

12417

408

0.9

32

Marknesse

7.26

1810

297

3728

1714

2.1

33

Guadalajara

7.55

11595

11907

6854

715

0.6

34

Nagyhörcsök

7.36

17512

10615

13564

14172

0.8

35

Granada

7.49

3454

663

2294

1655

0.7

 

 

 

 

 

 

 

 

Average

 

 

4131

 

2467

 

 

Median

 

 

1598

 

1355

 

 

Geomean

 

 

344

 

580

 

 

 

 

 

 

 

 

 

 

Applicant's summary and conclusion

Conclusions:
Sorption strength increases with pH. However, in several soils, residual 54Mn in solution was below values expected for sorption, suggesting oxidation. A median Kd of 1355 was obtained across all 35 soils (pH 3.0-8.5). Since Manganese dioxide comprises of Mn4+, this form of the substance can be expected to adsorb to soil to a slightly greater extent than Mn 2+, and the Kd median result is considered to be sufficiently representative at present to use in risk assessment.