The Importance of Enrichment Factor (EF) and Geoaccumulation Index (Igeo) to Evaluate the Soil Contamination

Maurizio Barbieri

doi:10.4172/2381-8719.1000237

Abstract

Heavy metals are natural constituents of soils and their concentration varies depending on parental materials. In the last years, the content of heavy metal in soils has increased due to human activities as: distribution of fertilizers, pesticides, industries, waste disposal and air pollution. Due to these activities the life capacity of soils decreased; especially where the natural background is already high because of natural parental material richness in heavy metal. As a matter of fact it is very important to distinguish between the natural background values and anthropogenic inputs, and to understand that the background values change from area to area and with the scale of the area investigated. There is currently a wide variety of methods used to evaluate soil contamination. To evaluate the soil contamination rate different indexes like Enrichment Factor (EF) and geoaccumulation index (Igeo) can be applied. These indexes are used to assess the presence and intensity of anthropogenic contaminant deposition on surface soil.

Highlights

Soil is the preeminent source of most biologically active trace elements such as Lead, Cadmium, Chromium, Nickel, Silver, and Zinc that reach man through plants and animals [1]
It is estimated that the contribution of metals from anthropogenic sources in soils is higher than the contribution from natural ones [19]
Depending on their concentration in the soil, the heavy metals may determine a potential toxicity to plants and for their consumers

Summary

Introduction

Soil is the preeminent source of most biologically active trace elements such as Lead, Cadmium, Chromium, Nickel, Silver, and Zinc that reach man through plants and animals [1]. Due to the human activities most soils as of industrial, as of rural and urban environments may accumulate one or more heavy metals Many metals, such as Cu and Se, are essential elements for growth plant and for living organism, but high concentrations of these elements become toxic. The only determination of the rates of metals in the surface horizons of the soil cannot provide extensive indications about the state of contamination of soils This kind of information does not allow the distinction between natural background and anthropogenic enrichment. There are different indexes generally used to identify metal concentrations of environmental concern like: the metal enrichment factor (EF) and geoaccumulation indexes (Igeo) [23,24] These indexes identify, numerically, pollution level soils and normally they are calculated on the soil exchangeable fraction because it represents the real bio-available fraction. The highest class (Class 6) reflects at least a 100fold enrichment factor above background values

Soil dust quality Deficiency to minimal enrichment

Conclusions