Potential use of Erica andevalensis and Erica australis in phytoremediation of sulphide mine environments: São Domingos, Portugal

摘要

The area around the São Domingos copper mine (Iberian Pyrite Belt) is subject of great environmental concern as acid minewater occurs several kilometres downstream of the mine. In addition thousands of tons of mine waste are present. Erica australisand Erica andevalensis, which are two spontaneous plant species of this area, have been studied with regard to their potential forphytostabilization.Soils and plants from São Domingos and from a reference site (Moreanes) were analysed for soil characteristics, chemicalelement content in soils (total and AB-DTPA bioavailable fraction) and in plants. Superficial and seepage water as well as wastematerial leachates were also analysed. Seepage water showed high redox potential (mean 481 mV), high conductivity (mean4337 μS cm−1) and low pH values (mean 2.6), being classified as mining water. Leachate solutions possessed mainly high levels ofFe, Al and SO42−. Soils in the mining area were highly contaminated in Pb, As and Sb. Locally also high values of Cu and Zn wereencountered and the soil available fraction of the majority of the elements showed also quite high values.E. andevalensis grows in soils with pH between 3 and 4, whereas E. australis was only found in soils with pH above 3.5. Bothspecies grow spontaneously in soils, highly contaminated with Pb, As and Sb. These plants, even in the non contaminated soils, areAl-tolerant and Mn-accumulators. In contaminated soils these species are also As-tolerant.Considering the tolerant behaviour in extreme environmental conditions, these Erica species may be of major importance forthe recovery of the sulphide mining areas, with climate conditions compatible with its breeding and growing, by physical andchemical stabilization of contaminated soils and even waste materials