Publications
Geochemical fractionation of mercury and trace metals in river sediments of the Almadén mining district (Spain): implications for ecological risk
Sediments in the Valdeazogues River basin, part of Spain's Almadén mercury mining district, act as both sinks and potential sources for trace metals, posing persistent ecological risks despite mine closure. The study found that mercury (Hg) exhibits significant enrichment with concentrations up to 277.4 μg g⁻¹, far exceeding background levels, while manganese (Mn), zinc (Zn), and lead (Pb) also show elevated levels. Geochemical fractionation revealed that Hg, Mn, and Zn are more mobile compared to copper (Cu), nickel (Ni), and Pb, which are predominantly bound in the residual fraction. A screening-level ecological risk assessment indicated potential concern primarily for Hg, Mn, and Zn due to their higher proportions in non-residual fractions, suggesting greater bioavailability and mobility. This research underscores the need for continued monitoring and management of these sediments to mitigate long-term environmental threats.
Giovanni Antonio Scopoli's De Hydrargyro Idriensi Tentamina (1761): Mercury Mining, Mercurialism, and Preventive Reasoning in Eighteenth‐Century Occupational Medicine
Giovanni Antonio Scopoli's De Hydrargyro Idriensi Tentamina (1761) offers a groundbreaking, workplace-based account of occupational diseases among mercury miners and smelter workers in 18th-century Idrija, Slovenia. The work provides detailed clinical observations linking toxic exposure to conditions such as tremor, salivation, stomatitis, and respiratory disorders, predating modern industrial toxicology by centuries. Unlike broader nosological approaches, Scopoli's study is site-specific, combining physiological, chemical, and medical insights with preventive reasoning. This reassessment highlights its significance in the history of occupational medicine, contrasting it with later reform-oriented traditions while positioning it as a distinctive 18th-century example of pre-industrial occupational-medical inquiry.
Evaluation of sampling and sample preparation methodologies for determination of mercury concentrations and stable mercury isotopes in foliage samples
A critical evaluation of sampling and preparation methodologies for mercury (Hg) analysis in foliage reveals significant biases that can distort our understanding of Hg cycling. The study found that rinsing samples removes 24–60% of Hg, particularly particulate-bound Hg enriched in heavier isotopes, underscoring its role in internal plant Hg dynamics but not total foliar Hg content. Vertical crown stratification also significantly influences Hg concentrations, with inner canopy foliage showing up to 50% higher Hg levels due to reduced solar exposure and enhanced throughfall deposition. The research validates the comparability of drying methods for low-Hg environments while highlighting the need for consistent rinsing protocols when studying surface-bound Hg fractions. These findings emphasize the importance of methodological rigor in foliar Hg studies, urging further investigation into inter-species differences, seasonal variability, and isotopic fractionation effects.
Mercury is a Messenger
Mercury's pivotal role in early photography, particularly in the development of daguerreotype plates and silver extraction through amalgamation, is highlighted as a critical yet often overlooked element. This study traces the transatlantic trade networks involving mercury and silver, emphasizing the imperial relationships and labor histories that underpinned these processes. By focusing on visual representations of mining labor at three sites—Almadén in Spain, Pachuca in Mexico (then New Spain), and Almaden in California—the research uncovers the human cost associated with mercury extraction, including mistreatment and resistance. The findings challenge conventional narratives by presenting a more global and nuanced perspective on 'American' photography, rooted in complex labor dynamics and mineral dependencies.
The Making of Imperial Environments in Castile During the Reign of Philip II, 1556–1598
During the reign of Philip II (1556–1598), the Spanish crown intensified its control over key environmental contexts to bolster imperial ambitions, marking a transformative period in resource exploitation. This study identifies four critical sites—mercury mining at Almadén, northern coastal woodlands, the Tajo River navigation, and the Royal Stables of Córdoba—as focal points for royal intervention. Through these environments, the crown asserted unprecedented authority, leveraging natural resources to address imperial crises while reshaping human-nature relationships. The research employs a comparative analysis of crown involvement, mechanisms of royal authority, and ecological impacts, revealing how centralized control over diverse landscapes facilitated Spain's early modern expansion.
A preliminary assessment of mercury, methylmercury and other potentially toxic elements in largemouth bass (Micropterus salmoides) from the Almadén mining district
A preliminary assessment of mercury and methylmercury concentrations in largemouth bass (Micropterus salmoides) from the Almadén mining district reveals alarmingly high levels, with total mercury ranging between 0.47 and 7.61 mg/kg wet weight, and methylmercury constituting 79.7 to 92.1% of total mercury—among the highest ever recorded in this species. The study, conducted along a 34 km transect of the Valdeazogues River, found that mercury concentrations peak at a decommissioned open pit lake (El Entredicho) and decrease steadily downstream. While selenium levels are also elevated, the Se/Hg molar ratio and HBV Se index suggest low risk for most specimens, except for smaller, younger fish from highly contaminated sites. Other potentially toxic elements (As, Pb, Zn, Sb, Cu) showed no concerning values despite the area's history of polymetallic mining.
Dissolved gaseous mercury production and sea-air gaseous exchange in impacted coastal environments of the northern Adriatic Sea
Research reveals that dissolved gaseous mercury (DGM) production and sea-air exchange in the northern Adriatic Sea, impacted by historical Hg mining, are influenced more by water temperature and mixing conditions than DGM concentrations alone. While a highly contaminated fish farm (Val Noghera, Italy) showed substantial DGM production (126.0–711.3 pg L−1), driven by photoreduction and biotic processes, an open coastal zone (Bay of Piran, Slovenia) exhibited lower DGM levels (21.8–183.4 pg L−1). Surprisingly, Hg fluxes at both sites were comparable (VN: 7.43–41.17 ng m−2 h−1; PR: 0–81.49 ng m−2 h−1), attributed to enhanced gaseous exchange in the open coastal zone and stagnation-related limitations in the fish farm. The study, using a floating flux chamber and real-time Hg0 analyser, underscores that static saltwater conditions hinder Hg volatilisation, potentially increasing mercury availability for methylation and trophic transfer.
Evasion of Gaseous Elemental Mercury from Forest and Urban Soils Contaminated by Historical and Modern Ore Roasting Processes (Idrija, Slovenia)
A study on the Idrija mercury mining site in Slovenia reveals that despite extremely high mercury (Hg) concentrations in soils, forest cover can significantly reduce atmospheric Hg emissions. Researchers measured gaseous elemental mercury (Hg0) fluxes from both historical roasting sites and urban areas with varying Hg enrichment levels. Surprisingly, urban soils showed higher Hg0 emissions on average compared to forested historical sites, even though the latter had much higher total Hg content (up to 10,400 mg/kg). The findings suggest that shading by trees or litter can act as a natural mitigation mechanism, limiting Hg0 release into the atmosphere. The study used non-steady state flux chambers and real-time Hg0 analyzers to measure emissions, while topsoil samples were analyzed for Hg concentration and speciation.
Fluxes of settling sediment particles and associated mercury in a coastal environment contaminated by past mining (Gulf of Trieste, northern Adriatic Sea)
Historical mercury (Hg) mining at Idrija, Slovenia, continues to impact the Gulf of Trieste, with riverine inputs of suspended particles still introducing significant Hg into coastal waters. Research reveals that settling sediment particles (SSP), predominantly silt-sized, display Hg concentrations ranging from 0.61 to 6.87 µg g−1. Daily SSP fluxes vary dramatically—from as low as 7.05 ± 3.26 g m−2 day−1 under low river discharge to a peak of 92.4 ± 69.0 g m−2 day−1 during high flow events, with Hg fluxes reaching up to 245 µg m−2 day−1 in the bottom water column. These findings underscore that flood-driven river discharges are critical in transporting Hg into the Gulf, highlighting an ongoing environmental concern.
Factors influencing lead, mercury and other trace element exposure in birds from metal mining areas
Birds inhabiting historical metal mining sites, such as Almadén and Sierra Madrona, continue to exhibit significant exposure to toxic metals like mercury (Hg) and lead (Pb), despite the cessation of mining activities. Feather analysis revealed that Hg contamination was prevalent in Almadén, while Pb was more pronounced in Sierra Madrona. Granivorous birds showed lower Hg levels compared to omnivorous, insectivorous, and piscivorous species, whereas Pb concentrations were higher in granivores and omnivores than in other feeding groups. The study also identified variations in 13 elements among the sites and confirmed that feather age, migratory patterns, and external deposition influence metal concentrations. These findings underscore the lingering ecological risks posed by abandoned mining sites, necessitating mitigation measures to protect local avifauna from toxic metal overexposure.
Análisis probabilístico del riesgo en la salud por exposición a metales pesados en áreas mineras contaminadas
A probabilistic risk assessment reveals significant health hazards from heavy metal exposure in two contaminated mining areas: Almadén (Spain) and Ponce Enríquez (Ecuador). In Almadén, 70% of adults face unacceptable non-carcinogenic risks due to mercury (Hg) in vegetables and fish, with dietary intake being the primary concern. Meanwhile, in Ponce Enríquez, over 95% of residents—both adults and children—experience elevated carcinogenic and non-carcinogenic risks from arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) via tap water, surface water, and sediment ingestion. Sensitivity analyses highlight Hg concentrations in local crops and As levels in water as critical factors driving risk. The study employs probabilistic methods, including bootstrap resampling and Bayesian inference, alongside deterministic assessments to identify high-risk zones, particularly in the southern region of Ponce Enríquez. Findings underscore urgent needs for water source investigations, exposure mitigation strategies, and food safety controls, especially for vulnerable populations like children.
Biomonitoring of Hg0, Hg2 and Particulate Hg in a Mining Context Using Tree Barks+
Researchers have developed a biomonitoring method using tree barks to differentiate between gaseous and particulate mercury (Hg) species in atmospheric samples, addressing a critical gap in existing Hg monitoring techniques. The study, conducted around the Almadén mining site in Spain, found that while leaves of Platanus hispanica bioaccumulated only gaseous Hg (Hg0 and Hg2+) during daylight hours, barks accumulated both total gaseous mercury (TGM) and particulate-bound mercury (PBM) day and night. By merging data from leaves and barks, the team created indicative maps delineating primary sources of TGM and PBM emissions in the urban area, offering a comprehensive approach to Hg biospeciation that complements existing monitoring systems. This method enhances risk assessment capabilities by providing detailed atmospheric Hg speciation data, which could be further validated across diverse environmental contexts.
Evaluation of the PGPR Capacity of Four Bacterial Strains and Their Mixtures, Tested on Lupinus albus var. Dorado Seedlings, for the Bioremediation of Mercury-Polluted Soils
Research demonstrates that specific Plant Growth-Promoting Rhizobacteria (PGPR) strains, particularly Pseudomonas baetica (B2) and Pseudomonas moraviensis (B1), significantly enhance the growth of Lupinus albus var. Dorado seedlings in mercury-contaminated soils, making them promising candidates for phyto-rhizoremediation strategies. The study evaluated four PGPR strains and their mixtures, isolated from naturally grown plants in Almadén's highly polluted mining district, by inoculating emerged seeds under high mercury concentrations. After 20 days, biometric measurements revealed that the treated seedlings exhibited improved growth metrics at both root and aerial levels compared to untreated controls. These findings highlight the potential of PGPR-mediated bioremediation to mitigate mercury contamination in severely affected soils like those in Almadén, offering a sustainable approach for environmental restoration.
4D dispersion of total gaseous mercury derived from a mining source: identification of criteria to assess risks related to high concentrations of atmospheric mercury
High concentrations of atmospheric mercury (Hg) pose significant inhalation risks, particularly at night, especially when wind speed and solar radiation are minimal. This study identifies critical criteria for assessing Hg-related risks by analyzing vertical and horizontal Hg dispersion over time in Almadenejos, Spain—a site impacted by decommissioned mercury mining. Using data from 2014–2015, researchers developed a model to predict Hg movement patterns, revealing that vertical transfers dominate during active mixing layers (excluding winter), while horizontal transfers prevail at night. The study emphasizes the importance of long-term monitoring, source identification, and background level determination using Lepeltier graphs to characterize Hg dispersion accurately. These findings are crucial for risk assessment under the Minamata Convention's emission reduction goals.
Enhancing the Territorial Heritage of Declining Rural Areas in Spain: Towards Integrating Top-Down and Bottom-Up Approaches
A study highlights the importance of integrating top-down institutional initiatives with bottom-up community participation to revitalize declining rural areas, using Almadén Mining Park and Molina-Alto Tajo District Geopark—both UNESCO World Heritage Sites—as case studies. The research demonstrates that collaborative governance between these approaches can minimize depopulation and territorial dislocation while leveraging synergies in local resources to ensure initiative viability and enhance visitor experiences. This dual approach, supported by rural development programs, offers a model for sustainable territorial revival.
Overview of existing information on important closed (or in closing phase) and abandoned mining waste sites and related mines in Slovenia
Slovenia's mining legacy leaves a significant environmental footprint, with closed and abandoned metal mines generating approximately 11.6 million cubic meters of waste across 33 sites, while coal mines contribute about 76.2 million cubic meters from 43 locations. The Mežica lead and zinc mine alone accounts for over half (64%) of metal mining waste, followed by the Idrija mercury mine (18%) and the Žirovski vrh uranium mine (15%). Among coal mines, Trbovlje-Hrastnik dominates with 46% of waste, while Kočevje and Kanižarica contribute 28% and 17%, respectively. This comprehensive inventory, compiled by the Geological Survey of Slovenia over two decades, maps 33 metal mines, 43 coal mines, 51 non-metallic mineral sites, and 174 waste sites, providing a critical foundation for assessing environmental impacts under EU Directive 2006/21/EC. The data, accessible via an open-access Google Earth file, highlights the need for further research into the long-term effects of mining waste on Slovenian ecosystems.
Recent and historical pollution legacy in high altitude Lake Marboré (Central Pyrenees): A record of mining and smelting since pre-Roman times in the Iberian Peninsula
A high-altitude lake in the Central Pyrenees, Lake Marboré, reveals that atmospheric metal pollution during the Roman Empire rivaled levels seen during the Industrial Period. Analysis of sediment cores showed significant increases in trace elements like lead, mercury, zinc, arsenic, and copper, particularly between 20 to 375 AD, linked to silver and lead mining and smelting in Southern Iberia. The study used statistical methods (PCA) and air mass back-trajectories to discern depositional processes and source areas of pollutants, finding that global emissions, especially from Almadén mines in central Spain, have influenced mercury levels over the last three millennia. This research underscores the long-term impact of mining on alpine ecosystems and highlights the need for sustainable management plans amid climate change and human pressure.
Including development topics in a cultural heritage management plan: Mercury heritage in Idrija
A participatory process has successfully integrated mercury heritage into the development strategy of Idrija, Slovenia, demonstrating its potential as a key driver for municipal growth while preserving authenticity. The study highlights the importance of inclusive planning that engages all stakeholders and bridges sectoral divides to ensure sustainable and harmonious development. This approach, developed through collaborative efforts, sets a precedent for balancing heritage conservation with economic progress in UNESCO World Heritage Sites.
You are here:
World Heritage Explorer > World Heritage Research > World Heritage Sites > Heritage of Mercury. Almadén and Idrija