Heavy Metal Pollution Assessment by Partial Geochemical Extraction Technique

S Estifanos

doi:10.4314/mejs.v5i1.85332

Abstract

Mn and Fe oxides are powerful absorbents of heavy metal cations in soils and stream sediments therefore considered in this environmental geochemical investigation. Steam sediment samples were collected from Au-Ag and Pb-Zn-Cu mineralized areas of the Rodalquilar old gold mine, located in the southeastern part of Spain. Total and partial chemical analyses were done, using aquaregia and hydroxylamine-hydrochloric acid solutions, respectively to examine preferential concentration of Zn, Pb and Cu in amorphous and ore mineral phases. The results show scavenging association of Pb, Zn and Cu with Mn that is shown by their concentrations in amorphous phases as detected by partial extractions,Key words: Partial and total extraction, Amorphous phase, Scavenging, Heavy metal pollutants.

Highlights

Heavy metals are not harmful to our environment because they are only present in very small amounts
The effects caused by heavy metals vary in that dissolved copper can affect lower trophic levels such as phytoplankton while lead, cadmium and mercury become accumulated through the food-chain, posing a toxic risk to species higher in the food chain, and eventually to humans
The aim of this paper is to examine the significance of selective and total extraction techniques in dissolving Mn and Fe mineral phases and assess heavy metals pollution in the mineral phases

Summary

Introduction

Heavy metals are not harmful to our environment because they are only present in very small amounts. The heavy metals threatening the ecosystem include mercury, arsenic, copper, barium, cadmium, antimony, chromium, lead and zinc. The effects caused by heavy metals vary in that dissolved copper can affect lower trophic levels such as phytoplankton while lead, cadmium and mercury become accumulated through the food-chain, posing a toxic risk to species higher in the food chain, and eventually to humans. Dissolution techniques of samples prior to chemical analysis can be classified as partial extraction and sequential (selective) multiple extraction (Fig. 1). The basic assumption of sequential extraction is that the reagents used are able to dissolve one mineral phase, selectively without solubilizing the others. Partial extraction involves dissolution of all mineral phases which requires milder reagents.

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Conclusion