Effect of Soil Organic Matter in Contaminant Retention

Abstract

The purpose of this paper is to present a few general considerations about the role played by soil organic matter in the study of the mobility of contaminants, such as heavy metals. Information was reviewed about the quality of soil organic matter as an important factor related to accumulation and release of heavy metals. The first part of the article talks about the accumulation and release of heavy metals. The second part refers to pH and the part third to the presence of organic complexing agents. In the case of lead A, high pH levels in Pb can precipitate as hydroxide, phosphate and carbonate. At low pH levels, this element dissolves very slowly. In the case of cadmium, it increases as pH increases. However, the organic matter’s composition and the soil’s mineral phase have a significant influence on their speciation. Nickel, which is found in organic forms, mostly as easily soluble chelates in the soil’s surface, is strongly absorbed by organic matter. Copper, soil minerals such as Fe-Mn oxides, carbonates, phosphates and some clay silicates have a high tendency to bind Cu in soil, in a non-diffusible and very stable way. Chromium (as Cr +3) predominates in most soils as insoluble oxide and hydroxide