Atmospheric trace metal concentrations in Suspended Particulate Matter (SPM) of a rural residential area in southern Nigeria

Abstract

Trace metals are one of the most toxic constituents of atmospheric particulates. The baseline  concentrations of Pb, Cd, Zn and Cr in airborne particulates collected at a rural community in southern  Nigeria have been evaluated. The particulate samples from where the metals were characterized and  quantified, were collected between December 2007 and March 2008, using a Gravimetric technique a  portable SKC 506673 High volume Gravimetric sampler. The air particulate samples were collected from  the kitchens, living rooms and outdoor environment of five households in the community. The  quantification of the trace metals was done using Atomic Absorption spectrometry method, employing HNO based wet digestion. High baseline  concentration of SPMwere obtained with an outdoor range of  240.74 555.55 μgm , living room range of 546.30 955.56 μgm and kitchen range of 425.92 1444.00 μgm . However, relatively low concentrations of the trace metals were measured in the samples with Zn and Cr being the most abundant. The outdoor and kitchen Zn concentration ranged from < 0.0001 0.0603 μgm and 0.0185 0.1171 μgm respectively, while the Cr levels were < 0.0001 0.0252 μgm (outdoor) and < 0.0001 0.0204 μgm (kitchen). The correlation matrix analysis showed a strong positive correlation  between the kitchen, living room and outdoor sites, suggesting identical sources of the trace metals. Principal component analysis (PCA) identified two fundamental sources of the metals, whichwas further confirmed by the hierarchical cluster analysis.

Keywords: Heavy Metals, Suspended Particulate Matter,Rural Area