Estudio de metales pesados en suelos bajo cultivos hortícolas de la provincia de Castellón.
Heavy metals can be transferred from soils to other ecosystem parts, and affect ecosystems and human health through the web chain. Since several years, this environmental issue concerns scientists. In this context, heavy metal concentrations were studied in agricultural soils devoted to vegetable crops in the province of Castellón (East Spain), where an intensive agriculture takes place. Furthermore, heavy metals bioavailability and their influence on vegetable crops are studied, as starting point for developing adequate strategies to prevent soil contamination. Soil properties, total and extractable heavy metal contents in soils (USEPA 3051A method and EDTA 0,05M extraction) and heavy metal contents in crops (leaf and inflorescence crops) were determined to carry out this study.
Total concentrations (mg/kg) of heavy metals (0,328 for Cd, 7,7 for Co, 33,3 for Cr, 36,6 for Cu, 16.915 for Fe, 385 for Mn, 19,3 for Ni, 55,8 for Pb and 78,5 for Zn) reflect normal levels for agriculture soils. However, high levels have been found in some samples, where probably contaminated associated to inadequate practices are acting. Two groups of heavy metals were obtained by multivariate analysis, which may indicate source of the heavy metals. Furthermore, mean percentages of extractable fraction relative to total content reflect that Cd, Cu, Pb and Zn are more bioavailability. This can be due to their human-induced origin.
The comparison of heavy metal contents between the two crop types and soils, which were grouped by crop types, shows that heavy metal contents (Cd, Co, Cr, Cu, Fe, Mn, Ni and Pb) were higher in leaf crops than in inflorescence crops, except for Zn. The higher contents of heavy metals in leaf crops seem to be due to metabolic processes as these crops are accumulators.
Finally, total concentrations were considered to establish background and reference values for agricultural soils with vegetable crops in Castellón. These values were derived by applying several statistic approaches, and one of them were selected as a proposal of reference values. This proposal will allow assessing contaminated processes by heavy metals and, following Spanish Royal Decree 9/2005, to declare a soil as contaminated.
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Advisor:Sánchez Díaz, Juan; Recatalá Boix, Luís
School:Universitat de València
Source Type:Master's Thesis
Date of Publication:11/16/2005