Variability of edaphic conditions in metal ...

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SR 1. SR 2. SR 3. SR 4. SR 5. SR 6. SR 7. SR 8. SR 9. SR 10. SR 11. SR 12. SR 13. Cu. Co. Cd. Pb. Zn. Page 17. Gembloux agricultural University. Soil Science ...
Gembloux agricultural University Soil Science Department Edaphic conditions in contaminated sites - 1

Variability of edaphic conditions in metalcontaminated sites at multiple scales. A temperate and a tropical situations Colinet G., Leclercq J., Faucon M.P., Bock L., Mahy G., Meerts P.

Gembloux Agricultural University Université Libre de Bruxelles

COLINET et al. EUROSOIL - Vienna 2008

Gembloux agricultural University Soil Science Department Edaphic conditions in contaminated sites - 2

Zn, Pb, Cd

Steep slopes

Natura 2000

Prayon COLINET et al. EUROSOIL - Vienna 2008

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Cu, Co

Gentle slopes

Inhabited district

Lubumbashi COLINET et al. EUROSOIL - Vienna 2008

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The « Katanga syndrom »

‰Contamination ‰Acidification ‰Death of vegetation ‰Erosion COLINET et al. EUROSOIL - Vienna 2008

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Theme Soil TE content generates ecological pressure ⇒ specific flora

Conservation

Remediation COLINET et al. EUROSOIL - Vienna 2008

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Questions What range of ecological conditions? What consequences for site characterization ? remediation?

COLINET et al. EUROSOIL - Vienna 2008

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Main results

1. What range of ecological conditions?

COLINET et al. EUROSOIL - Vienna 2008

Gembloux agricultural University Soil Science Department Edaphic conditions in contaminated sites - 8

Log (Mav) = f ( log (MT) pH log(TOC) ) All

Cd Co Cu Zn

Pb Zn

Site specific relationships

COLINET et al. EUROSOIL - Vienna 2008

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2. Variability within the sites : Prayon

Differences between sites appear important because triplets (n=3) seem closer to each other than to other groups COLINET et al. EUROSOIL - Vienna 2008

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When sampling density rises, the within-site diversity appears much more important. COLINET et al. EUROSOIL - Vienna 2008

Gembloux agricultural University Soil Science Department Edaphic conditions in contaminated sites - 111

Zn in vegetation units

COLINET et al. EUROSOIL - Vienna 2008

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2. Variability within the sites : Lubumbashi

No significant difference of TE content between districts COLINET et al. EUROSOIL - Vienna 2008

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Synthetic pollution index

pHwater in Lubumbashi

COLINET et al. EUROSOIL - Vienna 2008

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The Gecamines district

Figure 1 : carte des unités des sols sur le site de GECAMINES. (Echelle approximative ?) COLINET et al. EUROSOIL - Vienna 2008

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Importance of the state of soil surface : Lubumbashi Cu content / mg kg-1 0

5000

10000

15000

20000

25000

30000

35000

40000

(C)

A

B

Covered

Bare

COLINET et al. EUROSOIL - Vienna 2008

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TE in the sediments : Lubumbashi 4,50 4,00 3,50 3,00 2,50 2,00 1,50 1,00 0,50

Cu

Co

Cd

Pb

SR 13

SR 12

SR 11

SR 10

SR 9

SR 8

SR 7

SR 6

SR 5

SR 4

SR 3

SR 2

SR 1

0,00

Zn

COLINET et al. EUROSOIL - Vienna 2008

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3. Fractionation variability : Prayon 100% 80% 60% 40% 20% 0% R

R_OM

EXC

CA

500 Red soil

R_L

B ERMn

B_OM

B_L

ORG

11,000 Black Soil

C

C_OM

Feox

C_L RES

35,000 mg kg-1 Zn Carbonated Soil COLINET et al. EUROSOIL - Vienna 2008

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3. Fractionation variability : Lubumbashi contaminated

Reference + CuSO4 100%

4.85

4.37

80%

3.41

60%

3.81

3.65

3.80

3.41

2.46 40%

20%

0%

Univ.

Univ. cont.

M1

M3 EXC

CA

ERMn

Site 1 ORG

Feox

Site 2

Site 3

Site 4

RES

Need for a typology of the contaminations… COLINET et al. EUROSOIL - Vienna 2008

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Conclusions High variability whatever the scale considered Importance of redistribution processes

Definition of differentiated management areas COLINET et al. EUROSOIL - Vienna 2008

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More research is conducted about…

(i) contaminations and physical-chemical conditions in the rhizosphere, (ii) plant tolerance for growing in multi-metallic contaminations, (iii) the ways to reduce the limitations for installation of vegetation COLINET et al. EUROSOIL - Vienna 2008

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Thank You!

COLINET et al. EUROSOIL - Vienna 2008

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Form

Abbr.

Method

Exchangeable

EXC

25 ml 1 M MgCl2, pH 7, shaking 1h

Acido-soluble

CAR

25 ml 1 M CH3COO-Na + CH3COOH, pH 5, shaking 3h

Easily reducible

ERM

25 ml 0.1 N NH2OH.HCl + 0.01 N HNO3, pH 2, shaking 30’

Organic matter

ORG

5 ml 35% (v:v) H2O2 + 3 ml 0.02 N HNO3, 2 h at 85°C 3 ml 35% (v:v) H2O2, 2 h at 85°C 10 ml 2 N NH4NO3 in 20% (v:v) HNO3, 30’

Fe and Al oxides

FOX

20 ml 1 N NH2OH.HCl + 25% (v:v) CH3COOH, 4h at 90°C

Residual forms

RES

2x (5 ml conc. HF + 1,5 ml conc. HClO4) + 10 ml 10% (v:v) HCl COLINET et al. EUROSOIL - Vienna 2008

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COLINET et al. EUROSOIL - Vienna 2008

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COLINET et al. EUROSOIL - Vienna 2008

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Identification of mobilizable-mobile relationships Relationship available / mobile soil fractions for Cd calaminary sites 40 y = 0.0654x + 2.7098

CaCl2 Cd (mg/kg)

35

2

R = 0.812

30 25 20 15 10 5 0 0

100

200

300

400

500

Acetate-EDTA Cd (mg/kg) CaCl2

r2 Zn : 0.444 ; Pb : 0.265 COLINET et al. EUROSOIL - Vienna 2008

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Red soil Prayon 100.0 90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0

Carbonated soil Prayon

0.0 EXC

100.0 90.0

CA Al

Fe

ERMn Mn

ORG Cd

FeOx Cu

Pb

RES Zn

80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 EXC

CA Al

Fe

ERMn Mn

ORG Cd

FeOx Cu

Pb

RES Zn

COLINET et al. EUROSOIL - Vienna 2008