Estimation of the environmental pollution level be monitoring the heavy metal content of the deposited airborne dust

Complete text of publication follows. The heavy metal content of 10 dust samples collected from 4 different areas of Campia Turzii city (Cluj County, Romania) was quantified by flame atomic spectrometry, using in the methane-air premixed flame. The heavy metals (Zn Cu, Cd, Pb, Fe, Ni, Mn and Co) have been determined by atomic absorption spectrometry. For extra information, the alkaline- and earth metal content (Na, Li, K, Rb, Mg, Ca and Sr) was determined too, by atomic emission spectrometry. The sampling, the sample treatment and the wet acid digestion were carried out using the standard method for soil, sludge and dust sample analysis. The heavy metal quantity varies between large limits, ranging from tenth to tens of mg/g of sample, depending on the element considered. The lowest quantity, in average of 0.01 mg/g, was found for Cd, considered as natural level. The highest metal concentrations were determined for Fe (22.3 - 72.1 mg/g), fact which suggests a serious pollution of the site, being of industrial and traffic origin. The cluster analysis (for 15 variables, 10 cases, Euclidian distances and the total linkage between the variables considered) reveals that the samples are grouped in three separate clusters, based on their origin. The metals are grouped in three main clusters too; the elements, which allow the classification of samples, are those in trace level (in ascending order of linkage distance): Co, Ni, Cd, Li, Sr and Cu.