Derivation of critical limits of Cr, Cu, Ni, Pb and Zn in soils

Abstract

Soil contamination by potentially toxic elements (PTEs) can effect organisms because these elements can reach the food chain. The concentration of PTEs in vegetables and the daily intake can be predicted by risk assessment mathematic models. Therefore, it is necessary to understand the biogeochemical process in soil, on which management practices and public policies on soil quality are based on. The aim of this study is to evaluate the two soil-to-plant transfer models and to calculate critical concentrations for lead (Pb), copper (Cu), chromium (Cr), nickel (Ni) and zinc (Zn), taking into account results of bibliographic references from soils from humid tropical regions and temperate region. The human health risk will be assessed by using CSOIL version 2000 and Cetesb spreadsheet mathematical models considering urban and rural exposure scenarios. The datas of the pseudototal and available PTE concentrations in soil and the total absorbed by the plants will be submitted to mean comparisons. The content of PTEs in the crops will be calculated by means of non-linear soil to plant transfer relationships. The results obtained from both models will be compared for each specific scenario, identifying their major advantages and disadvantages.