Heavy Metals Contamination in Soils and Water in the Vicinity of Small Scale Gold Mines at Londoni and Sambaru, Singida Region, Tanzania

Asantael Herman

doi:10.11648/j.ijema.20150306.13

Abstract

This study was carried out to determine the concentration of heavy metals in water and soils in the vicinity of mines and processing units in small scale mining areas at Londoni and Sambaru. Heavy metals concentrations ranging from 1.7 to 53.8 mg/kg dry soil weight (dw), 8.7 to 22.24 mg/kg dw, 0.42 to 2.61mg/kg dw and 3.19 to 29.42 mg/kg dw were detected for Hg, Pb, Zn and Cu, respectively. Concentration of the same metals detected in surface and groundwater samples ranged from 0.013 to 0.17mg/L. Concentrations of mercury detected in soil samples were above Tanzanian maximum limits of mercury contamination. Sources of the metals contaminations were envisaged to be amalgamation and burning activities, improper waste rocks and tailings disposal, discharge of mine water to the surroundings and leachates from waste rocks and tailings. The study concluded that immediate adverse effect may not be feasible but continuing contamination may lead to serious human health and environmental problems.

Highlights

Mining sector plays an important role in economy and development of many countries
The concentrations for Pb and Zn in soils were within the European Mediterranean Region maximum standards of 22.8±16.1 mg/kg for Pb and 52.8±149.9 mg/kg for Zn, while that of Cu in Londoni and Sambaru sites were above the maximum allowable limits of 22.5±8.9mg/kg [15], [16], [17]
The results of this study revealed that water and soils in the studied areas around the small scale mines of Londoni and Sambaru are contaminated with heavy metals

Summary

Introduction

Mining sector plays an important role in economy and development of many countries. Significant contribution is on the employment creation and foreign currency earnings that are essential for socio-economic development [1]. Mining activities are categorized in large, medium and small scale based on capital investment, labour and technology requirements. Environmental impacts are common in each mine regardless of the scale of mine but differ from mine to mine depending on different factors including type of minerals and technology used in mining and processing the minerals of interest. The adverse environmental impacts for small scale mining are in general higher than those of other types of mining [4]. This means, the small scale mining is dirtier per unit of output than medium-sized or large and modern mining operations

Methods

Results

Conclusion