Plant community tolerant to trace elements growing on the degraded soils of São Domingos mine in the south east of Portugal: environmental implications

Abstract

The selection of trace element tolerant species is a key factor to the success of remediation of degraded mine soils. Mining activities generate a large amount of waste rocks and tailings, which get deposited at the surface. The degraded soils, the waste rocks and tailings are often very unstable and will become sources of pollution. The direct effects will be the loss of cultivated land, forest or grazing land, and the overall loss of production. The indirect effects will include air and water pollution and siltation of rivers. These will eventually lead to the loss of biodiversity, amenity and economic wealth. Restoration of a vegetation cover can fulfil the objectives of stabilization, pollution control, visual improvement and removal of threats to human beings. Thus, remediation of mine spoils/tailings and biogeochemical prospecting would rely on the appropriate selection of plant species. Plant community responds differently on their ability to uptake or exclude a variety of metals. In this work, plant species were sampled from all populations established in an abandoned copper mine of São Domingos, SE Portugal. Plants belonging to 24 species, 16 genera and 13 families were collected from the degraded copper mine of São Domingos. Plant samples were analysed for total Ag, As, Cu, Ni, Pb, and Zn. The highest concentrations of metals in soils dry matter were 11217.5 mg Pb kg(-1), 1829 mg Cu kg(-1), 1291 mg As kg(-1), 713.7 mg Zn kg(-1), 84.6 mg Cr kg(-1), 54.3 mg Co kg(-1), 52.9 mg Ni kg(-1) and 16.6 mg Ag kg(-1). With respect to plants, the higher concentrations of Pb and As were recorded in the semi-aquatic species Juncus conglomeratus with 84.8 and 23.5 mg kg(-1) dry weight (DW), Juncus efusus with 22.4 and 8.5 mg kg(-1) DW, and Scirpus holoschoenus with 51.7 and 8.0 mg kg(-1) DW, respectively. Thymus mastichina also showed high content of As in the aboveground parts, 13.6 mg kg(-1) DW. Overall, the results indicate accumulation of various metals by different plant species, with some of these metals being partitioned to the shoots. Environmental implications of these observations are discussed.

Copper tolerance and genetic diversity of Porcellionides sexfasciatus (ISOPODA) in a highly contaminated mine habitat

“…Natural vegetation in the study area is dominated by Quercus ilex and Eucalyptus spp. trees and by Lavandula stoechas and Genista hirsuta shrubs [16]. Three sampling sites were defined in the mine area: one contaminated site, Santana de Cambas (37837 0 56 00 N, 7831 0 06 00 W), and two references, Tronco (37840 0 55 00 N, 7830 0 54 00 W) and Corte do Pinto (37842 0 10 00 N, 7827 0 31 00 W; Fig.…”

“…This method does not require previous DNA sequence information and so is adequate when few genetic data are available, such as for the terrestrial isopod P. sexfasciatus. Metal tolerance at the study area has already been found in plants [16] and aquatic invertebrates [4]; however, until now, no metal-tolerance studies have been performed with soil invertebrates.…”

Metal Accumulation in 5 Native Plants Growing on Abandoned Cu-Tailings Ponds

“…The success of any phytoremediation technique depends upon the identification of suitable species that hyperaccumulate trace elements and produce large amount of biomass using established crop production and management practices [3,8,9]. Thus collecting plant species on contaminated sites prior to evaluation of plant metal concentration can be used to get information about specific plant behavior in this environment, which may be effective for selecting potential plants to be used in mine remediation and also to complete data about metal dispersion, with reference to their mobility to biomass [12,14]. There are many evidences that plants grown on metal enriched soil can accumulate high amount of heavy metals in their tissues such as Silene armeria [12], Typha latifolia [29], Festuca sp.…”

Avaliação Ecotoxicológica Do Resíduo De Mineração De Carvão

“…Para l. corniculatus, a germinação de sementes foi influenciada somente no PVA (Figura 2). A toxicidade não depende somente de concentrações específicas; a forma química do metal, a presença de outros produtos químicos que possam agravar ou melhorar a toxicidade do metal, o teor de nutrientes e o pH, que prevalece no solo contaminado, interferirão o modo de como as plantas respondem ao metal (Freitas et al, 2004). O baixo valor de pH pode ter comprometido a germinação em razão da presença de metais como Al 3+ e Mn 2+ (Moses et al, 1987).…”

“…É essencial escolher plantas tolerantes aos metais específicos, bem como tolerância à seca e falta de nutrientes frequentes em áreas de mineração. Também, o plantio de diferentes espécies de gramíneas, como a. sativa; leguminosas, como l. corniculatus; e a rotação com espécies nativas serão capazes de restaurar a fertilidade do solo e acelerar a sucessão ecológica (Freitas et al, 2004).…”