Summary:
The present work is referred to geochemical study in urban soils of Athens. The major objective of this geochemical research is the determination of total concentrations of trace elements Pb, Zn, Mn, Ni and how these are differentiated in relation to depth. For this purpose, sampling took place in 10 parks and woodlands of Athens Basin. Specifically, 3 composite samples were collected from each sampling location, with each one of them containing material from different soil depth (0-5cm, 5-20 cm, 20-35cm). The total number of samples (N=30) were transferred with plastic sampling bags in laboratory. Then, followed a series of procedures (drying, degranulation, sieving, pulverization) in order to analyze soil samples with the method of pseudo-total digestion EPA 3050B. The determination of concentrations, which was the final stage of experimental procedure, was accomplished with the technique of Flame Atomic Absorption Spectroscopy (F-AAS). For the best approximation of the results (quality control), except of 30 soil samples, were analyzed 4 duplicate samples, 3 blanks and 5 Certified Reference Materials (CRM). The results that obtained (Pb: 40-610 ppm, Zn: 48-213 ppm, Mn: 267-818 ppm, Ni: 56-123 ppm), compared to previous geochemical survey data, sometimes appeared lower or higher concentrations and other times their values fluctuated at similar levels. In relation to researches of other European cities, trace elements Mn and Ni showed higher concentration values and lower Pb, Zn. Moreover, correlations were obvious between concentrations of Pb-Zn, Zn-Mn, Mn-Ni, but they weren’t high as usual, according to the origin of trace elements. Finally, no significant variabilities were detected in concentrations of trace elements, either at different depth or in each sampling area separately, with the concentration values following a specific pattern (Mn > Ni> Pb≈Zn). Parks and woodlands that were closest to the center of Athens (Zappeio, Nea Smyrni, Pedio Areos), had increased concentrations of Pb, Zn.
Keywords:
geochemical study, variability, total concentration, trace elements, depth, soil sampling, urban environment
