Metallic species in ambient particulate matter at rural and urban location of Delhi

In the present study 14 metallic species (six crustal and eight trace metals) were quantified in the suspended particulate matter (SPM) at a rural and urban location of Delhi, India. Particulate matter was collected on glass fiber filters for a period of one year (from September 2003 to August 2004). Rank sum test revealed that the TSP concentration at the urban site was significantly (P = 0.47) higher as compared to the rural site. Urban site showed highest SPM concentration during winter while rural site during summer. Enrichment factor (EF) and coefficient of variation (CV) were calculated to assess the variability of elemental concentration data. Trace metals viz. Pb, Cd, Cu and Zn were observed to be highly enriched at both the sites, but EF for Zn and Cu was 2-3 times higher at the urban site as compared to the rural site. Trace and crustal metal concentration displayed less variability at the urban site. In the urban area, metals were mainly found to come from construction and industrial activities in surrounding. At the rural site, re-suspended and wind-blown dust appeared to be the source of observed elemental concentration.