Plants growing in abandoned mines of Portugal are useful for biogeochemical exploration of arsenic, antimony, tungsten and mine reclamation

Abstract

Several plants across taxonomic hierarchy have evolved heavy metal tolerance strategies and detoxification mechanisms that enable them to survive, grow and reproduce in metal contaminated and polluted sites. Plants growing on the abandoned Portuguese mines, highly contaminated with arsenic (As), antimony (Sb) and tungsten (W), have been studied for their biogeochemical prospecting and mine stabilization potential. The results of soil analysis show relevant anomalies of As, Sb and W. We have observed that the plant species accumulating tungsten are Digitalis purpurea, Chamaespartium tridentatum, Cistus ladanifer, Pinus pinaster, Erica umbellata, and Quercus ilex subsp. ballota. Accumulators of antimony are D. purpurea, E. umbellata, Calluna vulgaris and C. ladanifer. Accumulations of arsenic are found in the old needles of P. pinaster, Calluna vulgaris and C. tridentatum and leaves of C. ladanifer, E. umbellate and Q. ilex subsp. ballota. These are the key stone species allowing biogeochemical delineation of areas of anomalous soil composition. D

Arsenic in soil and vegetation of a contaminated area

“…The current technologies for the remediation of metal/ metalloid-contaminated soils are expensive, time consuming, and can create risks to workers, or produce secondary waste (Wenzel et al 1999;Lombi et al 2000;Pratas et al 2005). Recently, phytoremediation has been proposed as a cost-effective, promising and environment friendly alternative (McGrath et al 1993;Baker 1995).…”

Temporal variation in the arsenic and metal accumulation in the maritime pine tree grown on contaminated soils

“…Meanwhile, this accumulation generally does not change linearly with time, and varies either seasonally or with the age of the sampled organs (Kuang et al 2007;Pratas et al 2004Pratas et al , 2005. In the first case of variation, the solution to characterizing the variation of the accumulation of compounds lies in the orientation of the sampling campaign for a certain period of time, and in the second case of variation the introduction of the factor ''age of the material collected'' reveals the need for detailed studies.…”

“…In addition, although not as numerous, there have also been studies of tree leaves as bioaccumulators in rural and background areas (e.g., Chiarenzelli et al 2001;Coşkun 2006). Besides the potential use for biogeochemical prospecting and environmental biomonitoring, those metal-tolerant perennials plants with high biomass and bioproductivity can also be useful in phytostabilization and mine restoration (Hooper and Vitousek 1997;Pratas et al 2005).…”

“…Pinus pinaster needles have been reported to accumulate aluminum (Al), arsenic (As), cadmium (Cd), copper (Cu), chromium (Cr), iron (Fe), Hg, manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn). Pratas et al (2004Pratas et al ( , 2005 studied the needles and stems of Pinus pinaster as the indicators for delineating areas of anomalous soil composition in the biogeochemical prospecting of As, antimony (Sb) and tungsten (W).…”

Tolerance and accumulation of heavy metals and As in different species of Cistus L.

“…Los resultados mostraron que la concentración media de As más alta registrada fue para C. psilosepalus y C. monspeliensis con un valor de 39 mg kg -1 . Sin embargo, en el estudio realizado por Pratas et al (2005) mostró que el As se acumuló en las hojas de C. ladanifer con una concentración máxima de 2,77 mg kg -1 . En conclusión, los resultados indicaron que C. laurifolius, C. monspeliensis, C. psilosepalus y C. salviifolius podrían ser utilizadas para la recuperación de suelos mineros que presenten moderadas concentraciones de metales pesados.…”