Heavy Metals in Atmospheric Deposition in Kandy City; Implications for Urban Water Resources

Abstract

Atmospheric deposition is a serious issue in the context of biogeochemical cycling of heavy metals (HMs) and the resulting impacts on urban water resources. In this study, dry deposition (DD) and bulk deposition (BD) samples were collected from four sites located in heavy traffic areas in Kandy, Sri Lanka. Wet deposition (WD) was determined from the difference between DD and BD. Samples were analyzed for Al, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb using inductively coupled plasma-mass spectrometry. Relatively high concentrations of Fe, Al and Zn were found in both DD and WD samples collected. In BD, percentage dissolved fraction of Ni, Cr, Cu, Cd, Al and Pb was 94, 86, 81, 78, 61, 46% respectively. Presence of high dissolved fraction of highly toxic HMs such as Cr and Pb can result in significant ecosystem health impacts due to their ready bioavailability. The presence of metals such as Al, Fe, Zn, Pb, Cr and Cd in WD was consistently more significant compared to DD. The presence of high concentrations of mobile forms of metals in WD will contribute to the pollution of urban stormwater, resulting in the degradation of urban receiving water environments and associated ecosystems.