Micromorphological and Chemical Approaches to Understand Changes in Ecological Functions of Metal-Impacted Soils under Various Land Uses

J A Acosta,S Martinez-Martinez,A Faz,J M Van Mourik,J M Arocena

doi:10.1155/2011/521329

Abstract

We investigated the changes in faunal activities as measures of the ecological functions of soils impacted by potentially toxic metals (PTMs) under urban, industrial, agricultural, and natural uses. Concentrations and distributions of Zn, Cd, Pb, Cu, Mn, and Fe were estimated by sequential chemical extractions, while relicts and present faunal activities were studied by micromorphological analyses. Urban and natural lands were contaminated with Pb, Cd, and Zn. Microarthropods and fungi are observed to be active in the litter decomposition in natural, agricultural and urban lands which indicates that total concentration of PTMs in soils is not a good indicator to evaluate the limitations of PTMs to fauna activity. Metals immobilization on carbonates and Fe/Mn oxides, and fertilizations reduced the negative effects of metals on faunal activity. Micromorphological analyses showed the impacts of metal on soil ecological functions in industrial site, where the surface soils are devoid of any evidence of faunal activity; likely due to high proportion of Pb and Zn in organic components. Therefore, the impacts of metals in soil fauna activities, hence ecological functions of soils, are best evaluated by the knowledge of metal partitioning on solid phases in combination with observations of fauna activities using micromorphological techniques.

Highlights

The major anthropogenic sources of potentially toxic metals (PTMs) in soil are urbanization [1, 2], industrialization [3, 4] and agricultural practices [5, 6]
We investigated the changes in faunal activities as measures of the ecological functions of soils impacted by potentially toxic metals (PTMs) under urban, industrial, agricultural, and natural uses
Urban and natural profiles are contaminated with Pb, Cd, and Zn, where the likely main sources are emissions from intense vehicular traffic, abrasion of tires and brakes in urban sites, and deposition of particles with PTMs transported by the wind for natural land use

Summary

Introduction

The major anthropogenic sources of potentially toxic metals (PTMs) in soil are urbanization [1, 2], industrialization [3, 4] and agricultural practices [5, 6]. Atmospheric deposition of particulate matter contributes to the diffuse pollution of surface soils [7]. Atmospheric depositions from industrial plants impact any soils regardless of land use [8, 9]. Spillage of various liquids and industrial wastes are the principal sources of PTMs accumulation in surface and subsurface soils around industrial areas. Metals reach the soil from applications of liquid and solid manure or inorganic fertilizers [10, 11].

Methods

Results

Conclusion