Deposition of heavy metals in a Mediterranean climate area

Abstract

Deposition samples were collected and analyzed for selected heavy metals in Izmir, Turkey on different days in October 2003–June 2004. A water surface sampler was used to collect dry deposition and rainwater samples to represent the wet deposition during the rainy period of the year. Heavy metal concentrations and fluxes of both dry and wet deposition forms were determined. Dry and wet deposition samples were filtered and both filters and filtrates were analyzed for Cr, Cd, Pb, Cu, Ni and Zn. Heavy metals were determined using atomic absorption spectrometry with a graphite furnace except for zinc which was analyzed by using a flame technique. In wet deposition samples the average total heavy metal concentrations for Cr, Cd, Pb, Cu, Zn and Ni were found as 17.2 ± 8.6, 3.1 ± 1.6, 7.0 ± 4.1, 19.7 ± 25.0, 186.4 ± 225.5, 7.4 ± 2.6 μg l − 1 . These concentrations were generally higher than the values previously measured at different sites around the world. Dry and wet deposition fluxes in total (suspended + dissolved) forms indicate that both dry and wet deposition fluxes were appreciably higher in Izmir than elsewhere. Heavy metal deposition fluxes in dry and wet forms were compared to find the importance of the atmospheric cleansing mechanisms and evaluated by taking into consideration climatic conditions existing in the study area. Wet deposition rates are found to be more significant than the dry deposition rates on a daily basis. However, dry deposition is more important than wet deposition throughout the study period.