José Molina-Ruiz

Impact of acid mine drainages on surficial waters of an abandoned mining site

Weathering of sulphide minerals produces a great variety of efflorescences of soluble sulphate salts. These minerals play an important role for environmental pollution, since they can be either a sink or a source for acidity and trace elements. This paper aims to characterise surface waters affected by mining activities in the Sierra Minera of Cartagena-La Union (SE, Spain). Water samples were analysed for trace metals (Zn, Cd, Pb, Cu, As and Fe), major ions (Na+, K+, Ca2+ and Mg2+) and anions (F−, Cl−, NO3−, CO32−, SO42−) concentrations and were submitted to an “evaporation-precipitation” experiment that consisted in identifying the salts resulting from the evaporation of the water aliquots sampled onsite. Mineralogy of the salts was studied using X-ray diffraction and compared with the results of calculations using VISUAL MINTEQ. The study area is heavily polluted as a result of historical mining and processing activities that has produced large amount of wastes characterised by a high trace elements content, acidic pH and containing minerals resulting from the supergene alteration of the raw materials. The mineralogical study of the efflorescences obtained from waters shows that magnesium, zinc, iron and aluminium sulphates predominate in the acid mine drainage precipitates. Minerals of the hexahydrite group have been quantified together with minerals of the rozenite group, alunogen and other phases such as coquimbite and copiapite. Calcium sulphates correspond exclusively to gypsum. In a semiarid climate, such as that of the study area, these minerals contribute to understand the response of the system to episodic rainfall events. MINTEQ model could be used for the analysis of waters affected by mining activities but simulation of evaporation gives more realistic results considering that MINTEQ does not consider soluble hydrated salts.

Spatial distribution and sources of trace elements in sediments affected by old mining activities

The distribution of trace elements throughout mining areas is an important issue because abandoned tailings could be a major source of environmental pollution. In order to analyze the spatial variation of trace elements in a zone where mining activities took place and to identify pollution sources in the study area, a three-step study was carried out at a regional, at a local, and a detailed scale. In addition, a conceptual model of trace elements dispersion was established and confirmed by a geographic information system. The results obtained allowed to establish points affected by primary, secondary, and tertiary contamination, according to their proximity to contamination sources and as a function of attenuation processes which could take place in the studied area.

Assessment of the Acoustic Impact of Wind Farm Projects: Methodology and Case

Wind energy is a clean renewable and its benefits are considered greater than the disadvantages. However, even though wind farms represent environmentally friendly projects, they frequently generate public resistance. Wind turbines are socially controversial because of their visual and acoustic impacts. The aim of this work was to design a methodology for the preliminary evaluation of potential acoustic impact of wind farms. Three steps have been proposed: identification, characterization and assessment of the acoustic impact during the construction, operation and decommissioning phase. Obtained results in the studied area suggested that at a maximum power, at 500 meters of wind turbines, noise level is lower than the reference level established in the legislation. In summary, proposed methodology could help to determine and to evaluate the best location for new wind farm projects. Proposed methodology could help to determine and to evaluate the best location for new wind farm projects. Moreover, this method could be used as a consulting tool for public organizations and private institutions, being quick, concise and clear. Obtained results for the studied wind farm project suggested that almost all the area showed noise levels lower than established background noise level.

Geogenic Distribution of Arsenic (As) and Antimony (Sb) in Soils of the Murcia Region in Spain

The objective of this study was to determine the As and Sb contents in soils from the Murcia Region of Spain and the possible relationship between the mineralogical composition, soil properties, and As and Sb concentrations. In this study, 490 samples were selected from areas with different characteristics in order to study As and Sb variability. Results show that As and Sb concentrations are positively correlated with the phyllosilicate and quartz content but negatively correlated with the calcite content. The generic reference level (GRL) for these elements was determined according to the Spanish legislation. Established GRL values vary according to the established mineralogical groups, suggesting that GRL has to be determined considering the lithological characteristics of the study area.