High-resolution temporal monitoring of rare earth elements in acidic drainages from an abandoned sulphide mine (iberian pyrite belt, Spain).

Rare earth elements (REE) are strategic elements due to their economic importance. However, the studies dedicated to the distribution and behaviour of REE in aquatic systems have been scarce until a few decades ago. This work studies the seasonal variations of REE concentrations in acid mine drainage (AMD) affected water courses and the factors controlling their mobility under different hydrological conditions. To address this issue, a high-resolution sampling was performed for two years in selected sampling sites. REE concentrations were very high (median values of 2.7-3.4 mg/L, maximum of 7.0 mg/L). These values are several orders of magnitude higher than those found in natural waters, highlighting the importance of AMD processes on the release of REE to the hydrosphere. No good correlations were found between pH and REE concentration, while REE correlated positively (r Spearman coefficient of 0.78-0.94) with EC and negatively (r -0.88 to -0.90) with discharge in AMD-affected streams. A conservative behaviour of REE was observed due to the strongly acidic conditions observed in the study area. The waters also showed an enrichment in MREEs over LREEs and HREEs (mean values of GdN/LaN>1.8 and YbN/GdN < 0.7), typical of AMD waters. An asymmetry in the content of LREE and HREE was observed in AMD samples studied, which could be explained by the preferential dissolution of LREE or HREE-enriched minerals within each waste heaps. Multivariate analysis suggests the influence of Mn-rich minerals existent in the study area as a potential source of LREE.

Stream-pit lake interactions in an abandoned mining area affected by acid drainage (Iberian Pyrite Belt).

Opencast mining of sulfide ore deposits may lead to the formation of anthropogenic acidic lakes with highly polluted waters. In these systems, it is crucial to understand the hydrological connections between surface and groundwater and their contribution to the pollutant load delivered to the downgradient streams. This study characterizes the interactions between surface and groundwater in an acidic pit lake using different geochemical tracers (i.e., REE and other trace metals). The San Telmo pit lake, located in one of the most pollutant sources of the Iberian Pyrite Belt (IPB), can be considered as a flow-through pit lake except during dry periods, when it behaves as a terminal lake due to lower inputs by surface waters and higher outputs by evaporation. Results based on geochemical tracers indicate that the main inputs to the pit lake come from surface waters, with minor groundwater inputs rich in As, Cr, Cu, Fe and Pb. The contaminant load released from the mining area is very high (e.g., median values of 520 kg/day of Fe and 38 kg/day of Zn), causing the degradation of the fluvial network downstream. Most of released pollutants come from waste dumps located at the W of the mining zone (~50-70% of Al, Cd, Mg, Mn, Ni, SO4 and Zn and > 70% for Cu, Cr, Fe and, V), while the contribution of the water coming out the pit lake and other dumps is much lower. Thus, remediation efforts to improve the area and fluvial courses downstream must focus on the W waste dumps.

Temporal evolution of acid mine drainage (AMD) leachates from the abandoned tharsis mine (Iberian Pyrite Belt, Spain).

Acid mine drainage (AMD) due to the mining of sulfide deposits is one of the most important causes of water pollution worldwide. Remediation measures, especially in historical abandoned mines, require a deep knowledge of the geochemical characteristics of AMD effluents and metal fluxes, considering their high spatial and temporal evolution, and the existence of point and diffuse sources with a different response to rainfall events. This study investigates the temporal variations and hydrogeochemical processes affecting the composition of main AMD sources from the Tharsis mines (SW Spain), one of most important historical metal mining districts in the world. To address this, a fortnightly-monthly sampling was performed during two years in the main AMD sources and streams within the mine site covering different hydrological conditions. A seasonal pattern was observed linked to hydrological variations; higher pollutant concentrations were observed during the dry season (maximum values of 4,6 g/L of Al, 11,8 g/L of Fe, and 67 g/L of sulfate) and lower ones were observed during the rainy periods. Stream samples exhibited a negative correlation between electrical conductivity (EC) and flow, while positive values were observed in AMD sources, where groundwater fluxes were predominant. High flow also seems to be the main driver of Pb fluxes from AMD sources, as the concentration of Pb in waters increased notably during these events. The precipitation of secondary Fe minerals may limit the mobility of As and V, being retained in the proximity of mine sites. The concentration of Zn in waters seems to be controlled by the original grade in the metal deposit from which the waste is generated, together with the age of these wastes. The pollutant load delivered by the Tharsis mines to the surrounding water courses is very high; e.g., mean of 733 ton/yr of Al or 2757 ton/yr of Fe, deteriorating the streams and reservoirs downstream.

Seasonal variability of extremely metal rich acid mine drainages from the Tharsis mines (SW Spain).

The Tharsis mine is presently abandoned, but the past intense exploitation has left large dumps and other sulphide-rich mining wastes in the area generating acid mine drainages (AMD). The main goal of this work is to study the effect of hydrogeochemical processes, hydrological regime and the waste typology on the physicochemical parameters and dissolved concentrations of pollutants in a deeply AMD-affected zone. Extreme leachates are produced in the area, reaching even negative pH and concentrations of up to 2.2 g/L of As and 194 g/L of Fe. The results of the comparison of ore grades of sulphide deposits with dissolved concentrations in waters shows that Pb is the least mobile element in dissolution probably due to the precipitation of Pb secondary minerals and/or its coprecipitation on Fe oxyhydroxysulphates. Arsenic, Cr, and V are also coprecipitated with Fe minerals. Seasonal patterns in metal contents were identified: elements coming from the host rocks, such as Al, Mn and Ni, show their maximum values in the dry period, when dilution with freshwater is lower and the interaction of water-rock processes and evaporation is higher. On the other hand, As, Cr, Fe, Pb and V show minimum concentrations in the dry period due to intense Fe oxyhydroxysulphate precipitation. In this sense, large sulphide rich waste heaps would be a temporal sink of these elements (i.e. Pb, As, Cr and V) in the dry period, and a significant source upon intense rainfalls.

Mitochondrial DAMPs induce endotoxin tolerance in human monocytes: an observation in patients with myocardial infarction.

Monocyte exposure to mitochondrial Danger Associated Molecular Patterns (DAMPs), including mitochondrial DNA (mtDNA), induces a transient state in which these cells are refractory to further endotoxin stimulation. In this context, IRAK-M up-regulation and impaired p65 activity were observed. This phenomenon, termed endotoxin tolerance (ET), is characterized by decreased production of cytokines in response to the pro-inflammatory stimulus. We also show that monocytes isolated from patients with myocardial infarction (MI) exhibited high levels of circulating mtDNA, which correlated with ET status. Moreover, a significant incidence of infection was observed in those patients with a strong tolerant phenotype. The present data extend our current understanding of the implications of endotoxin tolerance. Furthermore, our data suggest that the levels of mitochondrial antigens in plasma, such as plasma mtDNA, should be useful as a marker of increased risk of susceptibility to nosocomial infections in MI and in other pathologies involving tissue damage.

Habilidades intelectuales de niños indígenas de las etnias Tenek y Nahúa que viven en condiciones de pobreza y desnutrición / Intellectual abilities of indigenous children in tenek and nahua ethnic groups living in poverty and malnutrition

Las poblaciones indígenas en México son las más vulnerables, debido a que viven en condiciones de pobreza extrema y menor cumplimiento de sus derechos fundamentales. Se ha demostrado que los niños son el grupo que recibe mayor impacto sobre el desarrollo psicológico y físico. El presente trabajo tiene como objetivo describir la relación entre el nivel socioeconómico (NSE), habilidades intelectuales evaluadas con la Batería Woodcock-Muñoz y desnutrición en niños indígenas Tenek y Nahúa que viven en condiciones alta marginación. Los resultados muestran diferencias significativas entre los niños y niñas de nivel NSE bajo, NSE muy bajo y el rendimiento en las pruebas cognitivas que evalúan habilidad intelectual, inteligencia cristalizada e inteligencia visual. Respecto de los indicadores de desnutrición se observó una diferencia estadísticamente significativa para desnutrición aguda entre el NSE bajo y NSE muy bajo. Los efectos del nivel socioeconómico sobre las habilidades intelectuales y el estado nutricional han sido demostrados ampliamente, pero pocos estudios se han realizado con indígenas. Los hallazgos con estas poblaciones son un llamado urgente para las políticas públicas, considerando que el decremento en puntuaciones de habilidades intelectuales, y la desnutrición, en mediano y largo plazo representan graves costos en la calidad de vida, economía y desarrollo humano...

Indigenous populations in Mexico are the most vulnerable in the country, due to the extreme poverty conditions in which they develop and the lessened observance of their fundamental rights. There is proof that children is the group that receives a higher impact on psychological and physical development. The objective of the present work is to describe the relation among the socioeconomic level (NSE), intellectual Abilities evaluated with the Woodcock Muñoz Battery and malnutrition in Tenek and Nahua indigenous children that live under high marginalization conditions. Findings show significant differences among males and females with low NSE, very low NSE and lower performance in the cognitive tests that assess intellectual skills, crystallized intelligence and visual intelligence. In regards to the malnutrition indicators, a statistically significant difference was observed for acute malnutrition between the low NSE and the very low NSE. The effects of the socioeconomic level on intellectual skills and the nutritional condition have been widely demonstrated, but few studies have been performed with indigenous. The findings with these populations are an urgent call for public policy, considering that the decrease in the intellectual Abilities scores, and malnutrition, in the mid and long term represents severe costs to the quality of life, economy and human development...