Assessing Soil Quality in Areas Affected by Sulfide Mining. Application to Soils in the Iberian Pyrite Belt (SW Spain)

Abstract

Abstract:The characterization, evaluation and remediation of polluted soils is one of the present environmental challenges to be addressed in the coming years. The origin of trace elements in soils can be either geogenic or anthropogenic, but only the latter is interesting from a legal point of view. The hazard of the pollutants in the soils not only depends on their total concentration, but particularly on their availability. The mobility of the trace elements depends on their speciation, and it is also affected by several soil parameters. Mining activity is one of the most important anthropogenic causes of soil pollution. As a case study, this work is focused in the Riotinto mining area (Iberian Pyrite Belt, IPB, SW Spain). The IPB is one of the most important metallogenic provinces in the world and it has been exploited for thousands of years. The disposal of mining residues has produced important sources of contamination by trace elements and acidic waters affecting soils and rivers. In addition to these problems, the closure of mines in the Pyrite Belt at the end of the 20th Century has led to a great loss of employment, which has caused the development of an intensive agriculture of citrus fruits as a new source of income. The intensive growing of citrus fruits and the traditional subsistence agriculture have been developed surrounding the mining areas and on floodplains near to mining sites. The level of soil pollution has not been taken into account in these cases, nor has its impact on the health of the inhabitants of these areas. Therefore, it is of great interest to study the current state of the cultivated soils and the sources and types of contaminants derived from mining activity in order to program its decontamination, where appropriate, according to legislation. In order to know the present and future hazard posed by the soils chemical and mineralogical speciation has been carried out, given that the availability of a metal depends on the phase OPEN ACCESSMinerals 2011, 1 74 in which it is found. The results showed that mining activity has caused high levels of As, Cu, Pb and Zn in several cultivated soils. Moreover, Cu, Pb and Zn showed a high bioavailability. This suggests that at least other studies are necessary to preserve health in the inhabitants of this area. The methodology carried out in this work allowed to select potentially polluted areas where agricultural activities are not recommended.

Lateral and vertical variations in contaminated sediments from the Tinto River area (Huelva, SW Spain): Incidence on tracemaker activity and implications of the palaeontological approach

“…As presented by González et al (2011) in their research on soil quality in Iberian Pyrite Belt areas affected by sulfide mining, some trace elements at low concentrations are essential for plant, animal and human growth (e.g., As, Co, Cr, Cu, Fe, Mn, Mo, Se, V, and Zn), and can be considered as essential micronutrients, yet toxic above certain concentrations. Of all the trace elements found in soils, those especially toxic and available at concentrations exceeding toxic levels are Ag, As, Bi, Cd, Co, Cu, Hg, Ni, Pb, Pd, Pt, Sb, Se, Sn, Te, Tl, and Zn .…”

Potentially Toxic Elements’ Contamination of Soils Affected by Mining Activities in the Portuguese Sector of the Iberian Pyrite Belt and Optional Remediation Actions: A Review

“…General Considerations 2.1.1. Main Impacts in the IPB Mining activities are one of the most important anthropic causes of soil degradation and pollution in the world [8,[23][24][25]. Mine soils in post-mining locations have great spatial variability in their properties (e.g., pH, particle size distributions, PTEs content), largely dependent on the characteristics of the ore that was processed and on the materials which were deposited at the site [26][27][28].…”

“…This intense mining activity, developed over more than 3000 years, caused a considerable impact, modifying the landscape and leading to the contamination of soils, water and sediments [2,[5][6][7], mostly with potentially toxic trace elements (PTEs) which were associated with the polymetallic sulfides explored (Cu, Pb, Zn, Fe, As, and Sb, as well as Co and Mn [7]). Of course, in these areas, PTEs can also result from natural geochemical processes that are common in geological environments where sulfide deposits exist, for instance from the weathering of the top of the sulfide orebody forming the gossans and releasing acid rock drainage [8,9]. However, the amount released into the soil is negligible compared to that released because of the mine exploitation.…”

Effect of Land Reclamation on Soil Properties, Mineralogy and Trace-Element Distribution and Availability: The Example of Technosols Developed on the Tailing Disposal Site of an Abandoned Zn and Pb Mine

“…The danger caused by the presence of trace elements in the soil therefore, depends not only on the total concentration, but also on the availability and mobility of the elements. The mobility of trace elements depends mostly on the physical and chemical state of the element in the soil and the properties of the soil such as pH, content of SOM, redox conditions, as well as the content and type of constituents with the capacity for sorption [74,75].…”