Metal concentrations and distribution in the household, stairs and entryway dust of some Egyptian homes

Abstract

Household, stairs and entryway dust samples were collected from 16 houses distributed across Greater Cairo by using vacuum cleaner and sweeping methods during summer season of 2009. Lead (Pb), nickel (Ni), cadmium (Cd), aluminum (Al), iron (Fe), zinc (Zn), cobalt (Co), chromium (Cr) and copper (Cu) were measured in different dust particle sizes: <38 μm, >38–45 μm and >45–63 μm. The highest average concentrations of Pb, Ni, Cd, Co, Cu, and Cr in different particle sizes were found in entryway followed by household and stairs. Al, Fe and Zn concentrations followed the pattern of entryway > stairs > household. Pb, Ni, Cd, Zn, Co and Cr were found in significantly (p < 0.01) higher concentrations in dust of the small particle size (<38 μm), whereas Al, Fe and Cu were detected in significantly (p < 0.01) higher concentrations in dust of the large particle size (>45–63 μm). The average concentrations of the individual metals in dust of the small particle size (<38 μm) were 268, 196.4 and 254.49 μg gm−1 for Pb, 49.6, 43.5 and 46.66 μg gm−1 for Ni, 2.86, 2.15 and 2.71 μg gm−1 for Cd, 4340, 3796 and 2602 μg gm−1 for Al, 2860, 2200 and 2004 μg gm−1 for Fe, 209.25, 152.3 and 103.26 μg gm−1 for Zn, 4.1, 2.88 and 1.96 μg gm−1 for Co, 85.99, 74.06 and 83.17 μg gm−1 for Cr and 168.2, 156.5 and 122.02 μg gm−1 for Cu in entryway, stairs and household, respectively. The mean concentrations of Cu and Pb in the entryway, stairs and household dust exceeded the maximum permissible limit 100 μg gm−1 for Cu and Pb in soil. The highest concentrations of Pb, Cd, Co and Ni were found in urban areas, Al and Fe in the residential areas, and Cu, Zn and Cr in the residential near to industrial area. Significant positive correlation (p < 0.001) were found between the metal concentrations in household and entryway dust, indicating that the metals in household dust may be derived from outdoor sources in addition to dust generated within the house itself. The contribution of anthropogenic sources, especially traffic emission, to metal levels in household, entryway and stairs dust was reflected by the high values of enrichment factors for Pb, Cd, Zn and Cu and Ni and Cr in fine dust particle compared to the average crustal composition. Insignificant positive correlation coefficients were found between the concentrations of Pb and other metals in household dust. However, the correlation coefficients between the concentrations of Cd, Ni, Cr, Cu, Zn and Fe were statistically significant.