Status of Ecosystem Services in Abandoned Mining Areas in the Iberian Peninsula: Management Proposal.

An abandoned sphalerite mining area in the southwest (SW) of the Iberian Peninsula was studied to evaluate the impact that the presence of metal(loid)s has on soil and ecosystem health. Five zones were delimited: sludge, dump, scrubland, riparian zone, and dehesa. Critical total levels of lead (Pb), zinc (Zn), thallium (Tl), and chromium (Cr), well above the limit indicative of toxicity problems, were found in the areas close to the sources of contamination. Pb-Zn concentrations were very high in the riparian zone, reaching values of 5875 mg/kg Pb and 4570 mg/kg Zn. The whole area is classifiable as extremely contaminated with Tl, with concentrations above 370 mg/kg in the scrubland. Cr accumulation mainly occurred in areas away from the dump, with levels up to 240 mg/kg in the dehesa. In the study area, several plants were found growing luxuriantly despite the contamination. The measured metal(loid)s content is the cause of a significant decrease in ecosystem services, resulting in unsafe soils for food and water production, so the implementation of a decontamination program is advisable. The plant species Retama sphaerocarpa, present in the sludge, scrubland, riparian zone, and dehesa, is postulated as suitable for use in phytoremediation.

Threats of metal mining on ecosystem services. Conservation proposals.

We have studied, in a protected area with intense hunting activity, the consequences of the abandonment of facilities and tailings of a metal mine. The area studied has the peculiarity of having a steep slope and containing a water reservoir for irrigation and human consumption. Soil, sludge, vegetation, and water samples were analyzed, in which many metal(loid)s exceeded the generic reference levels (NGR) established for the health of the ecosystem. The concentration of Tl in the soils ranged between 300 and 700 mg kg-1, because of continuous diffuse pollution, produced both by the alteration of sphalerite and the combustion products of a coal-fired power plant near the study area. Soil concentrations of Pb (250-1500 mg kg-1) and Zn (350-700 mg kg-1) from the tailings indicate extreme contamination in the areas adjacent to them and in the reservoir. The contamination affects the water quality of the stream running through the study area, with 64 µg L-1 of Tl and 9.1 µg L-1 of Zn having been detected in the reservoir water. To ensure protection of human and ecosystem health, the following is proposed: (i) soil stabilization for erosion control and reduction of diffuse pollution, (ii) monitoring of soils for agricultural use and water quality, and (iii) study the impact of contamination on wildlife, both hunting and non-game species. Given their capacity to accumulate heavy metals it is proposed to use Cistus ladanifer, Lavandula stoechas and Retama sphaerocarpa as phytoremedial species. The novelty of this research lies in two considerations. First, a proposal for the analysis of environmental compartments as an interconnected and interdependent network in terms of impacts and their repercussions on the ES. Secondly, the application of the model DPSIR, which assumes that anthropogenic activities have an impact on the environment.

Lead content in soils and native plants near an abandoned mine in a protected area of south-western Spain: an approach to determining the environmental risk to wildlife and livestock.

A study of the impact of an abandoned lead (Pb) mine ("Las Musas"), located in SW Spain, on the contamination of the surface soil and pastures in its vicinity revealed the presence of widely distributed, high levels of Pb contamination. The total Pb concentrations in soils sampled at distances from 3 to 998 m from the mine ranged between 129 and 1053 mg/kg, when it has been reported that non-polluted soils have concentrations of 29-40 mg/kg. These exceed the maximum tolerable levels in agricultural soils for the protection of environmental and human health as established in international and regional regulations. While the concentrations of potentially bioavailable Pb in the soils also surpassed the regulatory levels, the effective bioavailable fractions were low. The Pb concentrations measured in native plants ranged from 1.70 to 129 mg/kg dry weight, with Cynosurus echinatus, Philadelphus coronarius, and Fraxinus angustifolia being the species that bioaccumulated the greatest concentrations of this metal. Estimation of the environmental risk to wildlife and livestock grazing in the studied area showed no potential toxicity for these animals.