Resumo

DIAS, R.M.S. et al. Cadmium, Copper, Nickel and Zinc in Portuguese agricultural soils. Rev. de Ciências Agrárias [online]. 2007, vol.30, n.2, pp.358-368. ISSN 0871-018X.

Soil monitoring has been considered, by the European Commission, as an essential tool under the development of the Thematic Strategy for Soil Protection. Monitoring of European soils should allow the production of data necessary to access the pressures and threats to the soil, its state of degradation and the effectiveness of measures taken in order to protect it. According to the Working Group on Soil Monitoring, created under the development of this strategy, one of the first actions to be taken should be the establishment of a basic inventory, or baseline, for each of the seven main threats to soil identified by the Commission that could be the basis for future comparisons. In Portugal there is no national soil monitoring system and its creation is considered very important under the Thematic Strategy for Soil Protection. The present work intends to be a contribution to the above mentioned baseline, concerning the threat of soil contamination. This project aimed to access the level of Cd, Cr, Cu, Hg, Ni, Pb and Zn in 110 agricultural soils located on a 16 ? 16 km grid, throughout the Portuguese continental territory. In each location soil was sampled at four depths (0-20, 20-40, 40-60 and 60-80 cm), randomly taking 16 sub samples per composite sample. Samples were dried at 35-40ºC and sieved with a 2mm HDPE sieve. Several parameters were determined in the fine earth. In this paper we present the results concerning Cd, Cu, Ni and Zn, extracted by aqua regia (according to ISO Standard 11466) and determined by atomic absorption spectrophotometer with graphite furnace (Cd) and flame (Cu, Ni and Zn). The distribution of these elements on the surface layer (0-20cm) was (min., P50, P90 e max.): Cd (<0.02, 0.04, 0.11 and 0.23 mg kg^-1); Cu (<1.8, 21, 61 and 162 mg kg^-1); Ni (<1.9, 19, 39 and 1831 mg kg¹) e Zn (4.3, 47, 89 and 132 mg kg^-1). On the 20-40cm layer: Cd (<0.02, 0.03, 0.10 and 0.22 mg kg^-1); Cu (<1.8, 22, 51 and 133 mg kg^-1); Ni (<1.9, 21, 45 and 3069 mg kg^-1) and Zn (3.2, 46, 89 and 131 mg kg^-1).

        · resumo em Português     · texto em Português     · Português ( pdf )