José Miguel Nieto

Universidad de Huelva | UHU · Departamento de Ciencias de la Tierra

The treatment of acid mine drainage in sulphide mining generates large amounts of metal-rich sludge whose management suppose an environmental quandary worldwide. Although traditional practices have focused on safe disposal in landfills, more environmentally friendly solutions may be adopted. The environmental performance of these solutions can be e...

Acid mine drainage (AMD) is a worldwide pollution problem of watersheds. In addition to toxic metal(oid)s and acidity, many elements of economic interest are released into the environment, which make AMD a potential strategic secondary source of these elements such as rare earth elements (REE). Despite the importance of these metals, their origin i...

Ría of Huelva, located in southwestern Spain, is a highly metal(loid)-contaminated estuary system where sediments are exceeding action limits in an increasing order for Cd, Zn, Pb, Cu, and As. With a predicted sea level rise over the next 50 years, the estuary will be subject to flooding with brackish water or seawater. To evaluate the risk of meta...

This study evaluates for the first time the impact of a large wildfire on the hydrogeochemistry of a deeply AMD-affected river at the beginning of the wet season. To accomplish this, a high-resolution water monitoring campaign was performed within the basin coinciding with the first rainfalls after summer. Unlike similar events recorded in AMD-affe...

The efficient use of REE as tracers of weathering processes requires further data acquisition to establish robust connections between mechanisms, mineral assemblages and REE concentration patterns. Here, results are provided corresponding to rocks from four locations in the Iberian Pyrite Belt that were altered with different intensity by sulfuric...

Los ríos que drenan la Faja Pirítica Ibérica (FPI) presentan un grave problema de contaminación por aguas ácidas procedentes de minas de sulfuros abandonadas. La construcción de la presa de Alcolea, localizada en el río Odiel, se empezó en 2014 pero se paralizó en 2017, aunque actualmente hay una fuerte presión de los regantes para que se retome. D...

This study deals with the potential release of metal/loids from sulfide mine wastes upon weathering and the health risks associated with their accidental ingestion. To address this, a complete chemical and mineralogical characterization of a variety of sulfide mine wastes was performed alongside a determination of metal/loid bioaccessibility throug...

This works investigates the origin, behavior and fate of Tl in acid mine drainage (AMD) affected areas at catchment scale, following the path from rocks to the ocean. To address this issue, comprehensive data set of Tl in rocks, waters, secondary minerals, plants and other environmental compartments is presented, using the Iberian Pyrite Belt (SW S...

Schwertmannite is a common nanomineral in acid sulfate environments such as Acid Mine Drainage (AMD) and Acid Sulfate Soils (ASS). Its high surface area and positively charged surface result in a strong affinity towards toxic oxyanions such as arsenate in solution. However, natural precipitation of schwertmannite also involves the accumulation of o...

The main purpose of this study was to assess the human health risk of heavy metals in the urban-peri-urban soils from Huelva Township. The soils present high concentrations of potentially toxic elements well beyond the regional screening soil concentration. A site-specific health risk assessment of exposure (oral ingestion, oral inhalation and derm...

The Phalaborwa (Palabora) Igneous Complex (PIC), South Africa, has been mined for the last six decades for copper and phosphate, among others commodities. As a result, more than 4500 Mt. of mining wastes have been deposited in waste rock dumps (WRDs) and tailing impoundments. This study aims to investigate the potential of the PIC wastes (WRDs and...

Sulfide-mining wastes may lead to severe environmental and human health risks, especially challenging in abandoned mines without environmental regulation. This work is aimed at discussing the environmental problems associated to this type of wastes, the risks posed by metal(loid) exposure to living organisms, as well as the measures available to mi...

Acid Mine Drainage (AMD) generates a great concern worldwide due to its severe affection to water resources during hundreds and even thousands of years after the cessation of mining activity if control measures are not implemented. AMD treatment is an environmental necessity, but also constitute a tremendous opportunity for the valorization of pote...

A detailed characterization of alkaline tailing ponds and waste rock dumps from Phalaborwa Igneous Complex (PIC) South Africa, has been accomplished. The study goes beyond the environmental characterization of mining wastes, offering the first insight towards the recycling of the wastes as alkaline reagent to neutralize acid industrial wastewater....

This paper tries to analyse the technical and economic performance of a full-scale passive Disperse Alkaline Substrate (DAS) treatment plant steadily operating for 28 months (840 days) to treat extremely acidic and metal rich mine waters in the Iberian Pyrite Belt (SW Spain). For the first time, an economic evaluation of this technology and its com...

This paper addresses the behaviour of several technology critical metals (TCMs), i.e., rare earth elements (REEs), Y, Sc, Ga and Tl, in the Tinto River (SW Spain), quantifying their fluxes to the Atlantic Ocean and unravelling the governing geochemical processes controlling their solubility. To accomplish this goal, a high-resolution (2–24 h) sampl...

Acid mine drainage (AMD) is a worldwide problem generated by oxidation of metal sulfides, which causes the generation of acidic and metal‐rich solutions. The strong water‐rock interaction processes observed during sulfide oxidation lead to the release of high concentrations of sulfate (up to hundreds of g/L) and pollutants such as Fe, Al, and As (f...

El papel de la metalurgia en las comunidades de la Edad del Cobre del Sureste de la península ibérica es una cuestión recurrente en la investigación arqueológica en Europa oc­cidental. A partir del análisis de isótopos de plomo y ele­mentos traza de restos arqueometalúrgicos, este artículo aborda la organización territorial de la producción meta­lú...

The Río Tinto, located in the Iberian Pyrite Belt (SW Spain), constitutes an extreme case of pollution by acid mine drainage. Mining in the area dates back to the Copper Age, although large-scale mining of massive sulfide deposits did not start until the second half of the 19th century. Due to acidic mining discharges, the Río Tinto usually maintai...

Efflorescent sulfate salts constitute a transient storage of acidity and metals during the dry season in mining areas affected by acid mine drainage, especially under semiarid climates. The main goal of this work was to study the metal partitioning among the dissolved and solid phases through the evaporative precipitation sequence of extremely meta...

Extensive extraction of technology critical elements (TCEs) from the lithosphere and their use results in a growing dispersion and remobilisation of these elements within the environmental compartments. We investigated the concentration and mobility of different TCEs (rare earth elements (REEs), Sc, Y, Ga and Tl) in acid mine drainage (AMD) outflow...

This paper presents trace element compositions and lead isotope analyses by MC-ICP-MS of 34 copper ore samples from the Internal Zone of the Betic Range, Southeast Spain. Samples were collected during a fieldwork campaign in the mines of Cerro Minado, Pinar de Bédar, Sierra Cabrera and Sierra Almagrera/Herrerías. Most samples are copper oxide miner...

Flood events may play a key role in the metal transport fluxes from rivers to oceans. This is especially relevant in semi-arid and arid climate regions, which alternate long drought periods and short but intense rainfall events, when most of the water discharge, dissolved contaminants, and suspended matter transport occurs. This study provides info...

The acidic and metal rich waters of the Odiel and Tinto rivers flow into the Huelva Estuary (SW Spain), where mixing with seawater take place. During these mixing processes intense precipitation of Fe and Al in the fluvial domain of the estuary is observed. Hence, a buffer at pH ranges between 3 and 5.5 is observed, although the spatial location of...

In May 2017, a spill from La Zarza pit lake (SW Spain) resulted in the release of approximately 270,000 m3of extremely acidic waters to the Odiel River. Around 780�103kg of Fe, 170�103kg of Al, 2.15�103kgof As and high amounts of other trace metals and metalloids were spilled. The purpose of this study is toexplain the causes, consequences and impa...

Investigation of Earth analogs and their environments is crucial for the full interpretation of geologic outcrops and processes on Mars. Phyllosilicates are important indicators of aqueous processes and their characterization is a significant piece of the geologic puzzle of Mars. They are chiefly investigated with Near-Infrared (NIR) spectroscopy f...

A large sample of human bones from a series of archaeological sites in the south‐eastern Iberian Peninsula was selected for δ¹³C and δ¹⁵N stable isotope analysis. Except for some contrast samples, the remains date from the first half of the second millennium cal BC and are ascribed to the Argar Culture, which developed during the Bronze Age in sout...

Iron-rich sediments commonly cover riverbeds affected by acid mine drainage (AMD). Initial precipitates are often dominated by schwertmannite, which has an exceptionally high capacity to sequester As and other toxic elements. This poorly crystalline Fe oxyhydroxysulfate rapidly recrystallizes to goethite; however, the influence of trace elements on...

Earth analogs are indispensable to investigate mineral assemblages on Mars because they enable detailed analysis of spectroscopic data from Mars and aid environmental interpretation. Samples from four sites in the Iberian Pyrite Belt (El Villar, Calañas, Quebrantahuesos, and Tharsis) were investigated using mineralogical, chemical, and spectroscopi...

The concentration of meteoric 10Be in estuarine sediment samples has been measured by Spanish Accelerator for Radionuclides Analysis (SARA) at CNA and subsequently used to assess the denudation rate in Guadiana river basin together with the sediment budget method, on both sides of the frontier between Spain and Portugal. The two methods yielded coi...

Carbon-capture and storage is considered to be a potential mitigation option for climate change. However, accidental leaks of CO2 can occur, resulting in changes in ocean chemistry such as acidification and metal mobilization. Laboratory experiments were performed to provide data on the effects of CO2-related acidification on the chemical fractiona...

Patient-based study explored the impact of chronic metal exposure on gallstones. • Gallstones from geologically contrasting areas were analyzed for chemical content. • The study group exhibited enrichment in sulfide-associated metal(loid)s. • Pigment stones in the study group were enriched in Fe, Cu, Zn, Sr, As, Ag, Sb and Pb. This study aims to ex...

Highly acidic phosphogypsum wastes with elevated potential for contaminant leaching are stack-piled near coastal areas worldwide, threatening the adjacent environment. Huge phosphogypsum stacks were disposed directly on the marshes of the Estuary of Huelva (SW Spain) without any impermeable barrier to prevent leaching and thus, contributing to the...

This research reports the effects of pH increase on contaminant mobility in phosphogypsum leachates by seawater mixing, as occurs with dumpings on marine environments. Acid leachates from a phosphogypsum stack located in the Estuary of Huelva (Spain) were mixed with seawater to achieve gradually pH 7. Concentrations of Al, Fe, Cr, Pb and U in mixed...

Sulfate reduction and its associated contaminant immobilization in marsh soils supporting a phosphogypsum stack was examined by pore-water and solid analysis, selective extractions, microscopy and sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy. The negative impact of this stack on estuarine environments is a concerning prob...

Cyanide heap leach operations developed in Tharsis (SW Spain) from 1982 to 2001 left the legacy of a huge amount of cyanidation wastes deposited over a total area of 47 ha without any type of isolation. The main goals of this work are to study the release of metals and metalloids under rainfall occurrence and the potential impact on the aquatic lif...

The current work reports on the preliminary results of a toxicity test using screening experiments to check the efficiency of an innovative passive treatment plant designed for acid mine drainage purification. Bioassays took place with water samples before and after the treatment system and in the river, once treated water is discharged. Due to the...

Iron-rich sediments cover the riverbeds affected by acid mine drainage (AMD) resulting from sulfide mineral oxidation. Precipitates are mainly composed of schwertmannite, which is a poorly-crystalline Fe-oxyhydroxysulfate that recrystallizes over a short-time period to goethite. Schwertmannite precipitation has a strong capacity for removal of some...

Basaluminite is a nanocrystalline aluminum oxyhydrosulfate of important environmental implications. It is present in areas affected by acid mine drainage and acid sulfate soils, where potential toxic elements present in solution, such as Cu and As, can be retained by co-precipitation or adsorption onto it. Basaluminite has been described as a nanom...

Basaluminite is a poorly crystalline aluminum hydroxysulfate that precipitates in waters affected by acid mine drainage (AMD) and in acid sulfate soils (ASS). Its ability to sequester potentially toxic elements, such as Cu and As, makes it an important component of these systems, with strong environmental implications. Although it was initially des...

This paper investigates the mobility and fluxes of REE, Y and Sc under weathering conditions from an anomalously metal-rich phosphogypsum stack in SW Spain. The interactions of the phosphogypsum stack with rainfall and organic matter-rich solutions, simulating the weathering processes observed due to its location on salt-marshes, were simulated by...

The Huelva Province located in the southwest of Spain has a long history of mining, industry and agriculture. These anthropogenic activities have a potential environmental impact, with the dispersion of chemical elements in soils and water, and a potential negative effect on the food production and human health. In this study, the concentration of...

Polluted by acid mine drainage (AMD), the Agrio River is the major input of pollutants to the Odiel River. To study the behaviour of dissolved elements, water collected directly from the Agrio stream was subjected to infrared light to total evaporation. The physicochemical parameters, monitored daily, showed electrical conductivity increased from 1...

Lanthanide series have been used as a record of the water–rock interaction and work as a tool for identifying impacts of acid mine drainage (lixiviate residue derived from sulphide oxidation). The application of North-American Shale Composite-normalized rare earth elements patterns to these minority elements allows determining the origin of the con...

Huelva Estuary is a transition zone where REE-rich acidic waters interact with saline-alkaline seawater. This mixing process influences the geochemical and mineralogical characteristics of particulate and dissolved fractions. The Tinto River has > 11,000 μg L− 1 dissolved REE (pH = 1.66), whereas seawater only reaches 8.75 · 10− 2 μg L− 1 dissolved...

Fluxes of acidity and contaminants from acid mine drainage (AMD) sources to the receiving surface water bodies were studied in a mining-impacted watershed (Meca River, SW Spain) using a novel methodology based on the joint application of EMMA and MIX codes. The application of EMMA and elemental ratios allowed delimiting the end-members responsible...

The Betic Ophiolites consist of numerous tectonic slices, metric to kilometric in size, of eclogitized mafic and ultramafic rocks associated to oceanic metasediments, deriving from the Betic oceanic domain. The outcrop of these ophiolites is aligned along 250 km in the Mulhacen Complex of the Nevado-Filabride Domain, located at the center-eastern z...

Phosphogypsum is the main waste generated by the phosphate fertilizer industry. Despite the high level of pollutants found in phosphogypsum and the proximity of stacks to cities, there are no specific regulations for the management of this waste. This study addresses this issue by applying to phosphogypsum, from a fertilizer plant in Huelva (SW Spa...

The Odiel River Basin (SW Spain) drains the central part of the Iberian Pyrite Belt (IPB), a world-class example of sulfide mining district and concomitantly of acid mine drainage (AMD) pollution. The severe AMD pollution and the incipient state of remediation strategies implemented in this region, coupled with the proximity of the deadline for com...

This paper explores the possibility of using wastes (i.e. solid phosphogypsum (PG), process waters and edge outflows) generated by a fertilizer plant in SW Spain as a source of elements of economic interest, estimating the available metal reserves and discussing the technological and economic pros and cons of this potential source of raw materials....

This study assesses the environmental impact and the potential valorization of metal-sludge waste generated by the active neutralization of extremely metal-polluted acid mine drainage (AMD). To this end, two regulated leaching tests (EN 12457-2 and 1311 USEPA TCLP), a standardized sequential extraction protocol (BCR sequential extraction) and singl...

Resumen: El presente trabajo muestra los resultados preliminares de un ensayo de toxicidad mediante experimentos en laboratorio con el pez Gambusia holbrooki para comprobar la eficiencia de una innovadora planta de tratamiento pasivo diseñado para la depuración de drenajes ácidos de minas. Los bioensayos se llevaron a cabo con muestras de agua ante...

El concepto y la percepción de la metalurgia prehistórica, de su desarrollo cronológico, tecnológico y social, ha sido modificado desde la evaluación y análisis de la actividad metalúrgica en el asentamiento de Cabezo Juré. En este trabajo se presentan los resultados de la definición de los procesos tecnológicos asociados a la producción de instrum...

In this work the first metallurgical stages of the Southwest of the Iberian Peninsula are evaluated from a new theoretical and methodological approach: The technological processes used in the manufacture of metallurgical ceramics. From this way it aims to analyse the degree of interaction between the pottery and metallurgical activity, and how the...

Introducción Para mantener los actuales niveles de producción agrícola en el mundo es básica la obtención de fertilizantes fosfatados. Éstos son elaborados a partir de ácido fos-fórico, el cual se obtiene por la digestión de rocas fosfóricas con ácido sulfúrico. Este proceso conlleva la generación de un sub-producto residual: el fosfoyeso. Por cada...

Iron-rich sediments commonly cover riverbeds that have been affected by acid drainage associated with sulfidemineral oxidation. Freshly-formed precipitates correspond to poorly-crystalline oxyhydroxysulfates that recrystallize over time. This study examined the distribution and mineral association of trace elements (e.g., As, Cu, Zn) in modern and...