Seasonal Variations and Sources of Heavy Metals in Free Fall Dust in an Industrial City of Western India

This study investigates seasonal variations in average concentrations of metals in free fall dust samples (350) collected at various sampling sites situated in five different zones of an industrial city Kota, India. Average concentrations of heavy metals (Cu, Cd, Zn and Pb) were higher in winter and lower in summer and reverse trend was observed for crustal metals (Fe, Ca and Mg). Overall, the order of average concentrations of heavy metals were Zn >Pb> Cu > Cd in both seasons.Seasonal differences in metal concentrationswere due to differences in wind direction, wind strength, temperature, relative humidity and anthropogenic activities at sampling sites. Enrichment factor and positive correlation between anthropogenic metal species such as Cu and Cd; Cu and Zn; Cu and Pb; Cd and Zn; Cd and Pb; Zn and Pb in both seasons indicate that their origin source iscommon i.e. coal combustion at thermal power station.