Metal ions bound to colloids from database to field systems

Nowadays, environmental problems related to soil pollution with heavy metals are numerous, therefore, it is important to understand metal behavior in aquatic sediments and soils and to appreciate their transfer. The fate of the metals in the environment is closely related to their interactions with the major reactive compartments （organic matter, iron and manganese oxides, clays）. The objective of this work is to develop an approach based on the combination of several models to study metal ion speciation in different environmental systems. Models used to describe the interactions of metals with the main reactive phases in the soil are CD-MUSIC （amorphous and crystallized iron oxides）, NICA-Donnan （organic matter and manganese oxides）, and cationic ion exchange model （clays）. Firstly, this work implies the definition of generic parameters to describe the interactions of the studied metals with iron and manganese oxides, a part of this information is missing in the literature. Then, after the validation of the approach by comparison with analytical results, this multi-surface model is applied to test sites corresponding to a soil and to two riverine environments. These new models give good predictions of the behavior of major and trace metal ions even in heterogeneous system characteristics of the natural environment. The measured free metal concentrations in the solution are in agreement with those obtained from model calculations.

Metal ions bound to colloids from database to field systems