An investigation of heavy metal contamination in soil from a former dumpsite

Abstract

Landfills and dumpsites are potential point sources of heavy metal pollution that could threaten the surrounding soil through the release of leachate. This study's objective was to establish whether heavy metal concentrations varied by distance from the former dumpsite known as Wied il-Fulija found in Żurrieq, Malta. This objective was achieved by collecting and sampling surface and sub surface soil samples acquired at 125m intervals up to 500m in five different directions from the site. The heavy metals present within the samples were determined through a digestion and AB-DTPA extraction process, which allowed for the respective determination of total and bio-available concentrations. Samples were processed through an MP-AES and analysed for their concentration of Be, Zn, Cd, Cu, Mn, Cr, and Pb. Unsurprisingly, the available fraction was much lower than total concentration of metals. From the statistical results and observations, it does not appear that the former dumpsite contaminates the surrounding soil with heavy metals. Furthermore, concentrations do not vary significantly with soil depth. There are various reasons for these results, such as soil pH, wind forces and topography. Nevertheless, while the former dumpsite does not seem to be the cause of contamination, the area is somewhat more contaminated than neighbouring areas.