Assessment of Heavy Metals in Indoor Settled Harmattan Dust from the University of Agriculture Makurdi, Nigeria

Abstract

Indoor settled harmattan dusts at seven sampling stations from the University of Agriculture Makurdi were collected between November, 2014 to March, 2015 (five months) using the wipe sampling methodology. Gravimetric measurement of the dust samples from all the sample locations revealed that dust loading within the institution during the period of assessment ranges from 4.475 - 6.533 g/m2. Masses of indoor settled dust were expectedly higher along high traffic, untarred roads and construction sites as well as in older buildings than others during the period of this study. AAS analysis of the dust samples shows that heavy metal concentrations (mg/kg dry weight) throughout the sampling stations during the period of investigation range from 0.2372 - 0.7152 for Cu, 293.6 - 884.9 for Fe, 4.265 - 68.55 for Mn and 4.239 - 42.53 for Zn. The concentrations of all the metals investigated were found to be lower when compared with related values in literature and were within acceptable limits during the period of this study. Pearson correlation matrix also shows positive correlation between the possible metal pairs at 95% level of confidence, indicating a similar source which may be from anthropogenic activities within and outside the area.