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(15-34) Heavy metals in soils as an indicator of environment anthropogenitation. Alonso-Martirena, Juan Ignacio*,1, Iņigo, Victoria1, Andrades, Marisol1, Marin, Alvaro1, 1 Departamento de Agricultura y Alimentacion.CCT. Universidad de La Rioja., Logroņo, Spain ABSTRACT- The region of La Rioja (in the NW of Spain) produces a large amount of fruits for the national and international market. This fact has prompted the farmers to intensify their practices, thus increasing the concentration and distribution of heavy metals. In this work, we have studied the influence of the road traffic and the farming practices on the lead, cadmium, copper, zinc and manganese content in the soils and the leafs, together with the indicative role played by the pollution of the barks of the threes. The sampled soils came from plots located on both sides of two roads with a different intensity of traffic and were taken at 1, 10 and 80 m. 48 soil samples were analysed, as well as 36 samples of leafs and barks. The use of agrochemical products and farming machinery has homogenized the heavy metals content in the plots at 10 and 80 m in the soil, the foils and the barks, thus neutralizing the potential effect of the road traffic. The use of cupper and zinc sulphates on the soil, a very widespread practice in the area, has given rise to a high concentration of Cu and Zn at this points, both in the soil and in the leafs. The barks, as a pollution indicator, show an even higher concentration, given their cumulative nature. The statistical study provides several positive and significant correlations among the total and extracted Ni, Cu, Zn and Cd values. The correlations also reveal that the most available forms in the soil solution are: for Cu, the changing forms linked to the clay minerals; for Zn, those associated with the organic material; and for Ni, the ones related to the carbonates. The quality of the soils is acceptable (Directive 86/278/EEC), although it would be advisable to rationalize the treatments rich in Cu and Zn. No influence of the road traffic is observed. Key words: heavy metals , soils, road traffic, fertilizers |
