Modeling of metal binding in tropical Fluvisols and Acrisols treated with biosolids and wastewater.
There is growing concern about the accumulation of metals in tropical agricultural soils. In this study, experimental results from batch studies were used to test whether multi-surface geochemical models could describe metal binding in selected Vietnamese soils. The multi-surface models considered metal binding to iron hydroxides (using the diffuse layer model), organic matter (Stockholm Humic model and NICA-Donnan model), and phyllosilicate clay (Gaines-Thomas equation) as well as complexation to dissolved organic and inorganic ligands in the solution phase. We found that for total dissolved Cd, Cu and Zn the two multi-surface models being tested provided very good model fits for all soils, as evidenced by low root-mean square errors between model predictions and observations. These results suggest that organic matter is an important sorbent for many metals in these soils. However, poor fits were obtained for Cr(III), Mn and Pb for all soils. The study also suggests that the pH is the main factor that controls the solubility of metals in tropical Fluvisols and Acrisols subjected to application of biosolids and wastewater, and that advanced multi-surface models can be used to simulate the binding and release of many trace metals.
Khai
Nguyen Manh
NM
Department of Soil Sciences, Swedish University of Agricultural Sciences (SLU), P.O. Box 7014, SE-750 07 Uppsala, Sweden. Nguyen.Manh.Khai@mv.slu.se
Oborn
Ingrid
I
Hillier
Steve
S
Gustafsson
Jon Petter
JP
D000327:Adsorption; D002104:Cadmium / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D004784:Environmental Monitoring; D006863:Hydrogen-Ion Concentration; D019216:Metals, Heavy / Q000737:chemistry*; D008962:Models, Theoretical; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis; D014872:Water Movements; D015032:Zinc / Q000737:chemistry
D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium; D003300:Copper; D015032:Zinc