Chemical Associations of Lead, Cadmium, Chromium, Nickel and Zinc in Household Dust of Kathmandu Metropolitan Area

Received 11 January 2013, Revised 25 June 2013, Accepted 30 June 2013 -------------------------------------------------------------------------------------------------------------------------------------------Abstract Dust samples were collected from roadside houses of seven major locations in Kathmandu metropolitan area and trace element compositions was determined by atomic absorption spectrophotometer (AAS). Results show significant concentrations of Zn, Pb, Ni, Cr and Cd in the test household dusts as compared to the undisturbed (control) area. The mean concentrations of all the studied locations were found to be 76.2 mg/kg for Zn, 40.6 mg/kg for Pb, 29.9 mg/kg for Cr, 23.9 mg/kg for Ni and 8.2 mg/kg for Cd, respectively. Increase in these trace metals in the dust can most likely be attributed to rapid urbanization, increased vehicle emissions to the atmosphere and other anthropogenic sources. Elevated Zn abundance in household dust probably originates from traffic sources. Besides, enrichment factor reveals that the household dust was most severely affected by Cd in almost all the locations. Also, correlations between metal levels in dust samples for all the metals were investigated.