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The geochemical characterization of the mine deposits and soils in metal mining areas is essential in order to develop an effective mine reclamation strategy. The determination of total potentially toxic element (PTE) content, together with the application of chemical extraction procedures, can give insight into the behavior of contaminants after the application of different mine reclamation solutions, as well as identify the areas where urgent action is needed. This work presents a practical application to the evaluation of the pollution potential of trace elements in soils affected by mining activities, to be used in metallic mine reclamation. The PTE behavior was assessed by single extractions in order to simulate four environmental conditions: PTE mobility under rainfall conditions, acid mine drainage, reducing conditions, and plant uptake. The spatial distribution of contaminants in the study area was evaluated by determination of PTE total content in soil samples. Trace elements with high natural mobility, such as Zn, appeared concentrated at water and sediment discharge areas, while As, Pb, and Cu contents were higher near the mine wastes. The results obtained after the extractions suggested that the highest PTE content was extracted in the complexing–reducing medium, due to the dissolution of secondary sulfates and Fe3+ oxyhydroxides and the subsequent release of PTEs associated with those mineral phases. Reclamation strategies applied in the study area should promote efficient water drainage, infiltration, and subsuperficial water circulation in order to maintain oxidant conditions in the soil. The methodology applied in this study may constitute a valuable tool to define the geochemical constraints in metal mining areas, as well as help to develop appropriate mine reclamation solutions.

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<p> “Rambla”are temporary watercourses, which are characteristic of mediterranean and semi-arid climates, with low rainfall and sporadic torrential rain. A few times a year, when the rainfall exceeds 80 mm in less than an hour, they are capable of evacuating high flows of water mixed with particulate material of different granulometries to the sea.</p><p>The Sierra Minera of Cartagena (Murcia, Spain) has two marine slopes, one of short distance and steep slope towards the Mediterranean Sea, and another of a greater extent that affects the Mar Menor, a specially protected saltwater lagoon.</p><p>The processes that can take place in the course of the ramblas that begin in the Sierra Minera, when water is present, are those of transport of particulate and soluble material, processes of dissolution, hydrolysis, redox, complexation, carbonation and precipitation among others. When the rainy season ends and the Surface water disappears, the sediments that have been left in the riverbed are subject to other secondary processes that lead to the formation of very particular mineralogical species, efflorescence of hydrated sulphates, carbonates and oxydroxides. This is due to the pore water which can remain for a long period of time in the sediments of the rambla bed. Depending on the degree of influence of the current mining sediments in the rambla, the water it transports can have an acid pH (3.5-5.5), being qualified as acid mine drainage.</p><p>The Rambla del Beal is one of the various watercourses that cross the Sierra and flow into the Mar Menor next to a wetland that is an Special Protection Area (SPA), which makes the study more interesting. Like other ramblas in the area, during different periods, it carried the waste from the mineral floatation plants to the sea, as if it were a natural pipe, so along its route there are abundant terraces formed by this waste. This is in addition to the materials dumped and the materials eroded from the ponds and dumps that are in its receiving basin.</p><p>A selective sampling has been carried out along the riverbed to its mouth, analysing the content of potential toxic elements (PTEs), granulometry, general characteristics and mineralogy.</p><p>The bioavailability and mobility of the different PTEs (As, Pb, Zn, Cd and Fe) and their relationship with the mineralogy have also been studied.</p><p>The results show that only in the central part of the rambla can sediments not affected by primary pollution be found (they are secondary pollution), and that the Rambla del Beal itself can be considered a focus or primary source of pollution by PTEs.</p><p> </p>