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Dan Vasile Stumbea, University (Romania)
Laviniu Apostoae, University (Romania)
Ovidiu Gabriel Iancu, University (Romania)
Nicolae Buzgar, University (Romania)
Ionut Ciprian Popa, University (Romania)
Cristian Secu, University (Romania)
Liliana Apostoae, University (Romania)
Marcel Raileanu, University (Romania)
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The identification of the potentially noxious content of heavy metals in the urban and periurban soils from Romania is imposed by the necessity to globally estimate the impact of the anthropic activity on the environment. Until now, in Ia°i municipality the studies of this type had a selective character, being focused on the soils within or confining the industrial plants areas. A number of about 1000 soil samples from urban and adjacent areas of Ia°i municipality form 31 alignments were examined, in order to assess their quality in terms of concentration and source of heavy metals. For this reason, the types of soil, the contents of Zn, Cu, Mn, Pb, Cd and the pH were determined. The studies were carried out on soil types, whose destination is mainly agricultural, and secondary rural or urban inhabited, belonging to chernozems (31,5%), fluvisols (14%), anthrosols (11%), regosols (9%), phaeozems (7%), entic anthrosols (3%), luvic phaeozems (3%), erodosols (3%) and soil complexes (18,5%) soil classes.
Topsoil samples were collected on a grid of 500 m, from a depth of 0-25 cm, with a 25 cm long hand sampler. The samples weighting between 1.5 and 2.5 kg were dried and sieved to < 1 mm fraction and then randomized and analyzed by Atomic Absorption Spectroscopy (AAS) and by X-Ray Fluorescence Spectroscopy (XRF). The pH was determined by using a Corning M-555 pH/Ion Meter. The study of the distribution of chemical elements has emphasized local and/or regional anomalies in relation with the normal content values in the soils and exceeding the alert thresholds for elements Zn, Cu, Pb, Cd. Thus, the contents of the heavy metals in the studied soils varies in the areas : Zn - 27,9 ppm and 1620,3 ppm; Cu - 11,6 ppm and 792,6 ppm; Mn - 50,0 ppm and 1669 ppm; Pb - 4,5 ppm and 326,3 ppm; Cd - 0,001 ppm and 8,15 ppm. The soil pH varies between 4,068 and 10,074. The integrated pollution index (IPI) for the studied heavy metals oscillates between 0,999 - Mn from the anthrosols and 2,997 - Zn from the luvic phaeozems. Our analysis did not show strong correlation between the parental material of the soil and the high contents in heavy metals, these being concentrated by the anthropic activity, especially by the coal combustion, plastic industry, steel smelters, refractory bricks factories, traffic, waste disposal and incineration, fertilizers, insecticide and geogenic dust.
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