Heavy metals in indoor settled dusts in Toronto, Canada

Total concentrations of nine potentially toxic heavy metals (Ba, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn) in indoor settled dusts from houses, offices, classrooms, and laboratories in Greater Toronto Area, Canada were determined. Mercury concentrations were determined using cold vapor atomic fluorescence spectroscopy (CVAFS), whereas the concentrations of eight other metals were determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES). The results showed that the highest level of heavy metals was in the laboratory dusts. Metal concentrations (except those for Mn and Zn) in household, office, and classroom dusts were comparable. Cd, Cr, Cu, Ni, and Zn concentrations in the laboratory dusts and Cu and Zn concentrations in household, office, and classroom dusts exceeded the Canadian Soil Guideline. Metal concentrations in the indoor dusts found in this study were, in general, consistent with those reported in literature. Among the metals studied, Cd, Cu, Hg, Pb, and Zn showed the greatest enrichment in the indoor environments relative to their crustal abundances.