Environmental Assessment

**53**

**1. Introduction**

**Chapter 4**

Herbicides Mechanisms Involved

in the Sorption Kinetic of

Experimental Conditions

*and Mauricio Escudey*

**Abstract**

*Lizethly Caceres Jensen, Angelo Neira-Albornoz* 

Ionisable and Non Ionisable

Herbicides: Impact of Physical/

Chemical Properties of Soils and

Volcanic ash-derived soils (VADS, variable-charge soils) are predominant in some regions of the world, being of great importance in the agricultural economy of several emerging countries. Their amphoteric surface charge characteristics confer physical/chemical properties different to constant surface charge-soils, showing a particular behavior in relation to the herbicide adsorption kinetics. Volcanic soils represent an environmental substrate that may become polluted over time due to intensive agronomic uses. Solute transport models have contributed to a better understanding of herbicide behavior on variable- and constant-charge soils, being also necessary to evaluate the fate of herbicides and to prevent potential contamination of water resources. The following chapter is divided into four sections: physical/chemical properties of variable and constant-charge soils, kinetic adsorption models frequently used to obtain kinetic parameters of herbicides on soils, solute transport models to describe herbicide adsorption on VADS, and impact of experimental conditions of kinetic batch studies on solute transport mechanisms.

**Keywords:** variable-charge soils, constant-charge soils, kinetic adsorption,

Nature of soils is regulated by various soil-forming factors such as parent material, climate, vegetation, and time [1]. These factors vary widely among region, and also these vary in their properties. Volcanic ash-derived soils (VADS) are predominantly found in regions of the world with geochemical characteristics dominated by active and recently extinct volcanic activity. These have great importance in the agricultural economy of several emerging and developing countries of Europe, Asia, Africa, Oceania, and America. They are abundant and widespread in

herbicides and solute transport mechanism

## **Chapter 4**
