resumo
In the Panasqueira mine area, Arbutus unedo L. (arbutus tree) grows on soils developed on waste materials and on soils impacted by mining activity. The arbutus berry brandy is considered a product with economic value. The aims of this study were to evaluate the biogeochemical impact of the mining activity on soils and arbutus trees, to assess the possible risks associated with human consumption of the fruits and the derived brandy, and to evaluate the potential of the arbutus tree in phytostabilization. Soil samples (10-15 cm deep) developed on waste materials, on schists affected by seepage water or treatment plant effluents and on colluvium-alluvium materials were characterized (fraction < 2 mm) for pH, particle size distribution, organic carbon (C-org), cation exchange capacity (CEC) and NPK by classical methodologies. Plant (A. unedo) samples (roots, leaves and twigs, and fruits) were collected at the same sites as the sampled soils, washed with tap and distilled water and dried at 40 A degrees C. The elements' concentrations in soils (total fraction-four-acid digestion and available fraction-diethylenetriaminepentaacetic acid extraction), plants (ashing followed by acid digestion) and brandy samples produced with fruits collected on contaminated and non-contaminated sites were determined by inductively coupled plasma atomic emission spectroscopy. The soils are mainly acid, silty loam, with variable values for C-org, CEC and NPK. They are contaminated with As (158-7,790 mg/kg), Cd (0.6-79 mg/kg), Cu (51-4,080 mg/kg), W (19-1,450 mg/kg) and Zn (142-12,300 mg/kg). The available fraction of the soils is quite variable between < 0.04 and 76 % of the total, depending on the element. Trace elements' concentrations, in leaves and twigs, are within the normal range for plants, except for Cd and Zn that, in some samples, are above the normal values, but without phytotoxic symptoms. Trace elements' concentrations in fruits are low. The calculated hazard quotient for all trace elements in arbutus berry was < 0.1. In the brandy, elemental concentrations are within the legal standards, except for Pb, whose higher concentrations may result from distillery equipment. According to the EC 466/2001 legislation and with a hazard quotient of < 1, the arbutus berry consumption does not constitute health risks for humans. The fruits can be used to produce local brandy. The concentration of copper in brandy is within the range established by the Portuguese legislation. Arbutus unedo can be used in the phytostabilization programs in the Panasqueira area, for it is a pioneer species and a non-accumulator of trace elements.
palavras-chave
ERICA-ANDEVALENSIS; TRACE-ELEMENTS; PHYTOREMEDIATION; TOLERANCE; EXTRACTS; TUNGSTEN; LEAVES
categoria
Environmental Sciences & Ecology; Agriculture
autores
Abreu, MM; Godinho, B; Magalhaes, MCF
nossos autores
