1. Soil processes and trace metals
Have some ideas about metal concentrations in soils
Get familiar with FDEP Soil Cleanup Target Levels and regulations by different countries
Background metal concentrations in Florida soils
Factors controlling metal behaviors in soils

3. Typical Eh in soils: -0.4 to 0.7
Pe=16.9 Eh = -2.1
Adding metallic iron to protect Pb corrosion??
Typical Eh in soils: -0.4 to 0.7

4. Fig. 2.1 Equilibrium redox relationships of aqueous systems.
The inscribed area is representative of most soils
pH: 4 to 9
pe: -4 to 12
Eh: -0.3 to 0.7
Sb= +110
Pb= -130
Pe = 16.9 E
Fe= -440
Lindsay (1979)

5. Possible Lead Reactions in Soils
Pb + O2 + 2H+ + 2e- --Oxidation--> PbO  + H2O
CO2 + H2O --carbonation--> H2CO3 --> H+ + HCO3-
PbO + H2CO3 --precipitation--> PbCO3  + H2O
PbCO3 --dissolution--> Pb2+ + CO32-
3Pb2+ + 2CO OH---precipitation-->Pb3(CO3)2(OH)2

7. Possible Lead Reactions in Soils
Pb + O2 + 2H+ + 2e- --Oxidation--> PbO  + H2O
CO2 + H2O --carbonation--> H2CO3 --> H+ + HCO3-
PbO + H2CO3 --precipitation--> PbCO3  + H2O
PbCO3 --dissolution--> Pb2+ + CO32-
3Pb2+ + 2CO OH---precipitation-->Pb3(CO3)2(OH)2