Sequeira, M.D.

A decade of open-access data across 44 Portuguese river catchments proves that simple turbidity measurements can serve as a powerful, low-cost proxy for high-intensity agricultural disturbance and metal pollution. Reclassifying land-cover data revealed that intensive practices like tillage and irrigation drive significantly higher sediment transport and strongly correlated concentrations of dissolved Fe and Mn. By establishing that soil disturbance and erosion dictate catchment-wide metal fluxes, this study demonstrates how leveraging open-access turbidity data provides an accessible, cost-effective tool for large-scale environmental screening and targeted river basin management.. View more

Evaluation of a decade-long dataset across 51 catchments in mainland Portugal demonstrates that human land use, rather than broad geological background, serves as the primary driver of surface-water As levels. Multiple linear regression modelling revealed that land-use factors, particularly intensive agricultural runoff and soil disturbance from mining and construction sites, accounted for over 21% of variance in As concentrations, completely eclipsing general lithological signals. These findings prove that anthropogenic land management overrides natural background geology at the catchment scale, highlighting an urgent need to incorporate land-use controls into national water-quality strategies.. View more

During the drought that affected Portugal in the 2021/2022 hydrological year, five surface water monitoring campaigns were carried out in the Mondego River Basin. Sampling took place from March to November 2022, and the measured water quality indicators were compared to a geochemical baseline created using open data. During the drought period, surface waters tended to be more alkaline, potentially due to reduced dilution or a bicarbonate influence from groundwater. In the same period, NO2 concentrations tended to increase, almost always exceeding normal levels. At the beginning of the following hydrological year, with episodes of heavy rainfall and increased runoff, erosion, and transport of soil particles, there was a rise in turbidity, with values above normal, associated with excessive concentrations of Al, Fe, and Mn, while pH and NO2 levels returned to normal (translated). View more (in Portuguese)

Comunicações Geológicas: IF: 0.3; Q4: Environmental Science; H Index: 21

This study focuses on the impact of rural fires on water quality in the Mondego River basin in Portugal. An analysis of water quality was conducted to assess the interaction between fires, land use, geology, and precipitation. Data from a monitoring program conducted over two hydrological years were statistically analyzed and compared to a geochemical background. The results reveal substantial increases in the concentrations of Ca, K, Mg, NO3, SO4, and As in surface waters after the fires. These changes are accompanied by an increase in electrical conductivity. While some parameters returned to normal concentrations in the following months, As kept with elevated grades in some sites, which appear to reflect complex interactions between post-fire processes and geology. View more

Comunicações Geológicas: IF: 0.3; Q4: Environmental Science; H Index: 21

Surface water monitoring plays a pivotal role in identify sources of pollution, guiding sustainable practices and preserving aquatic ecosystems. This works aims at research the effectiveness of surface water monitoring in identifying land use and land cover changes and environmental pressures, assessing the impacts of land use and occupation changes, identifying drivers of surface water indicators, and formulating responses to these challenges. The Mondego River Basin located in central Portugal, characterized by diverse geology, land use, and significantly impacted by the 2017 wildfires and the 2021/2022 drought, was selected as the study area. The research hypotheses were examined through extensive monitoring and analysis, leading to practical recommendations. Systematic surface water monitoring revealed significant water quality indicators associated with environmental pressures. These included increases in water turbidity, and aluminum (Al) and iron (Fe) concentrations associated with land cover changes and increased soil erosion following the wildfires. There were also inputs of ions (e. g. NO3, SO4, Mn) associated with byproducts of combustion during the fires. Land use conversion from fire-affected areas to agricultural areas was also reflected in surface water indicators, such as increased concentrations of NO3 and arsenic (As). These indicators are particularly noticeable during periods of higher precipitation, which demonstrated the role of precipitation in the mobilization of contaminants following land use and cover changes. Long-term monitoring has proven particularly supportive in identifying the impacts of land use changes on surface water quality. By constructing geochemical baselines using historical data from the same locations, it is possible to establish a comparison threshold for currently monitored data and assess the impacts on surface water. Using data from surface water monitoring parameters as dependent variables, and precipitation data and geographical data of the catchments as independent variables, it was possible to identify that the extent of the impact from wildfires is more significant when the fires affect developed areas compared to forested areas, highlighting the resilience of ecosystems. Precipitation erosion and transport capacity are higher after land cover changes due to wildfires, even compared to the first flush following a prolonged hydrological drought. The results of this study indicate that surface water monitoring allows for the attribution of responses to issues regarding the relationship between land use and occupation changes and surface water quality. The responses operations range from measures for soil preservation following wildfires, to maintenance of surface water quality by rehabilitation of the surrounding ecosystems, and recommendations for agricultural restoration following the wildfires. Additionally, community engagement and stakeholder involvement should also contribute to improve surface water quality in these contexts. View more

Droughts have become a critical high-impact hydro-meteorological disaster and are projected to become more extreme in the near future. The Iberian Peninsula is unarguably considered a pronounced hot spot for drought. Worrisome projections for drought risk come to emphasize the urgency of building drought-resilient societies, through integrated risk management processes that bring together all societal spheres, including lay citizens. However, citizens remain disengaged from climate risk and adaptation processes. Therefore, it is critical to understand how societies respond to climate-related hazardous processes, such as drought, and to determine the predictors of citizens' engagement in disaster risk management. To respond to this research need, this study sought to explore citizens' preferences for drought management policies and to ascertain the psychosocial predictors of citizens' willingness to take action towards drought and support for drought risk management. A cross-sectional study was implemented, in which 401 Portuguese participants enrolled in a survey questionnaire measuring predictor variables of citizens' willing-ness to take action and support for drought risk management. A robust set of statistical analysis was implemented, mainly based on structural equation modelling. Results demonstrate that citizens tend to prefer low-cost measures and policies that due not imply personal heightened burden, at a financial and behavioral level. Moreover, personal experience with drought, risk perception, perceived urgency and emotional states play a critical role in citizens’ engagement and sup-port for disaster risk management. Findings are discussed in light of their theoretical and practical implications, particularly for risk communication and for risk management policymaking. View more

International Journal of Disaster Risk Reduction: IF: 5.6; Q1: Geology; H Index: 115

Five monitoring campaigns across the Mondego basin during the severe 2021/2022 drought revealed how climate extremes alter surface water chemistry. Reduced flow made waters increasingly alkaline as bicarbonate-rich groundwater dominated inputs, driving a steady buildup of NO2. When heavy rains finally broke the drought, NO2 levels normalized, but intense runoff immediately triggered severe turbidity spikes and washed elevated concentrations of metals, including Al, As, Fe and Mn, across all monitored watercourses.. View more (in Portuguese)

Statistical regression models built from two years of surface water monitoring across ten Mondego river basin watercourses isolated the primary drivers of post-fire water contamination. While precipitation introduced Al and NO3 alongside turbidity spikes, geological formations dictated background As and Ca concentrations, and local agricultural practices controlled general electrical conductivity. Crucially, the extent of fire-affected artificial areas emerged as the single most impactful variable across models, driving major surges in As, NO3 and SO4 into the water supply. View more

As water is facing increasing pressures from population and economic growth and climate change, it becomes imperative to promote the protection, restoration and management of this resource and its watersheds. Since water quality depends on multiple factors both natural and anthropic, it is not easy to establish their influences. After the October 2017 fires that affected almost 30% of the Mondego hydrographic basin in Central Portugal, 10 catchments were selected for periodic physical-chemical monitoring. These monitoring campaigns started one month after the fires and lasted for two hydrological years, measuring the electric conductivity (EC), pH, dissolved oxygen (DO), turbidity (Turb), alkalinity (Alk), major and minor ions, and trace elements. The obtained data were then statistically analysed alongside the geomorphological characteristics of each catchment coupled with features of land-use and occupation. From the results, it was possible to establish that fire-affected artificial areas, through the atmospheric deposition and surface runoff of combustion products, had the most impact on surface water quality, increasing As, K−, Ca2+, Mg2+, NO3−, SO42− and Sr, and consequently increasing electrical conductivity. Agricultural land-use seems to play a major influence in raising the water’s EC, Cl, K− and Na2+. Regarding natural factors such as catchment geology, it was found that the extent of igneous exposures influences As, and the carbonate sedimentary units are a source of Ca2+ and HCO32− concentrations and impose an increase in alkalinity. Rainfall seems, in the short term, to increase the water concentration in Al and NO3−, while also raising turbidity due to sediments dragged by surface runoff. While, in the long-term, rainfall reduces the concentrations of elements in surface water and approximates the water’s pH to rainfall features. View more

International Journal of Environmental Research and Public Health: IF: 4.8; Q1: Public Health, Environmental and Occupational Health; H Index: 256

Long-term surface water monitoring following the devastating October 2017 wildfires in Central Portugal revealed immediate hydrochemical spikes compared to a 30-year historical baseline. The combustion of organic matter and severe soil erosion drove sharp initial increases in turbidity, NO3, SO4, and metals and metalloids, such as Al and As across the Mondego River Basin. While most watercourses recovered to normal baseline levels by the second hydrological year, agricultural sub-basins showed persistent elevation of NO3 and As, demonstrating how wildfire disturbances intersect with and amplify ongoing agricultural pollution.. View more (in Portuguese)

In October 2017, the Mondego hydrological basin was devastated by multiple wildfires. To understand the impacts that these had on surface water quality, monthly monitoring campaigns were implemented in the affected catchments. The campaigns oversaw the water’s physical characteristics and major, minor and trace constituents. Analysis of major changes was performed, as well as comparisons with geochemical backgrounds, determined using publicly available data collected prior to the fires. The backgrounds allowed us to verify which water parameters were most influenced by the fires. Wildfires were responsible for increasing turbidity on all watercourses, and electrical conductivity increased in watercourses with flatter, granitoid/sedimentary-dominated watersheds. Cl−, NO3−, and SO42− surpassed background values in most monitored basins. Changes in Al, Fe, Mn, As, Ba, and Zn concentrations were observed in all watercourses after the wildfires and decreases after intense rainfall. Background values were particularly exceeded for Al in all monitoring points and As in basins with extensive agricultural areas. Burnt plant material and organic matter partially account for the increases in Cl−, NO3−, SO42−, Al, As, Fe, and Mn content. High Al, Fe and Zn with low water conductivity suggests that these elements were associated with sediment loads after the removal of vegetation. View more

Water: IF: 3.6; Q1: Water Science and Technology; H Index: 145

Following the major wildfires that affected the Central region of Portugal in 2017, a watercourse monitoring campaign was initiated in November 2017 to determine changes in water proprieties in a post-fire scenario, and establish the persistence of these effects. In the Mondego River basin, 10 points, from 6 watercourses, were chosen based on the size of the watershed and the percentage of burnt area. Monthly water monitorization featured in situ parameters and major ions analysis. A higher electrical conductivity was found in water in November 2017, before the first runoffs. Major ions have, in generally, decreased from December to January. However, the Cavalos brook showed an increase in NO3 concentration, and the downstream of Mondego River showing increase in Ca, HCO3 and NO3. View more

Comunicações Geológicas: IF: 1.0; Q4: Environmental Science; H Index: 21

The wildfires of 2017 were responsible for vegetation clearance in a wide area of central Portugal, leaving the weathering profiles more exposed to erosive action. In the present research, suspended loads from a set of catchment areas affected by these fires with diverse geological and orographic features were periodically sampled to evaluate spatial and seasonal variability in sediment production. Bulk mineralogy reflected the geology of the source areas, but displayed high variability even for a single sampling site, which can be partially linked to the grain-size control on sediment composition. Clay mineralogy provided a better picture of the denudation at catchment scale. The predominance of detrital illite with low I5/I10 (ratio of the intensities at 5 Å (002) and 10 Å (001)) indicated very shallow weathering profiles. Chlorite was usually the second most common mineral, more common in metasedimentary-derived sediments, whilst kaolinite was detected only in less steep catchment areas with a predominance of granitic basement rocks or where previous-cycle depositional units are also present. Year-long shifts in clay assemblages were attributed to different spatial patterns of denudation. A depletion of kaolinite occurred in sampling sites mainly sourced by granitoids. An opposite trend was observed where areas with Meso-Cenozoic deposits, less affected by the wildfires than those with basement units, occupy significant proportions of the drainage basins. This trend was ascribed to the wearing out of the weathering profiles covering the basement. Regolith denudation was also testified by a progressive decrease in I5/I10. Shifts in clay mineralogy linked with progressive surface denudation were found to be limited in areas with shallow soils, but may complicate any paleoenvironmental reconstructions based on sediment composition when more evolved weathering profiles have been eroded. View more

Appl. Clay Sci.: IF: 5.2; Q1: Soil Science; H Index: 182

In October of 2017 a series of rural fires affected Portugal’s Central Region, leading to the destruction of 40–60% of the forest area in some districts. A monitoring program was initiated in 5 catchments of the Mondego drainage basin, in order to understand the temporal evolution of the water’s physical and chemical characteristics in a post-fire scenario. This monitoring program was implemented in catchments with sizes between 20 km2 and 160 km2 in areas 60%–99% burnt. For each catchment a gauging point was selected near the mouth of the river. These 5 gauging points were assessed monthly, starting one month after the fire, in November 2017, and ending in June 2018. In each campaign stream water was sampled for laboratory analysis and in-situ physical-chemical proprieties were measured. Major ions in water samples were determined through ion chromatography (IC) and molecular absorption spectroscopy, and inductively coupled plasma optical emission spectrometry (ICP-OES). Trace elements were evaluated through ICP-OES and inductively coupled plasma mass spectrometry. Total organic carbon and dissolved organic carbon were evaluated through the oxidation method and polycyclic aromatic hydrocarbons were determined by high-performance liquid chromatography. The data collected was crossed with the catchment’s morphometric, geological and land use data, including characteristics of the burnt area. Results showed that these fires affected the surface waters in the studied catchments, producing an increase in turbidity, and in the concentrations of Al, Fe, Mn and possibly NO3 and As. View more

Ecol. Indicators: IF: 8.5; Q1: Ecology; H Index: 222

Post-fire monitoring following the catastrophic 2017 wildfires in Central Portugal revealed severe degradation of surface water quality across the Mondego River basin. Analysis across six affected watercourses showed elevated turbidity from sediment and ash, alongside some spikes in Al, Fe, Si, and surface-runoff-transported As. Multiple watercourses exceeded legal safety thresholds for public consumption, with pH drops and unsafe heavy metal levels detected in the Mondego River and Ribeira de Cavalos, underscoring the urgent need for rapid catchment management to safeguard drinking water.. View more (in Portuguese)

Individuals play a crucial role in combating climate change, but high levels of acknowledgment and engagement are needed to lead to changes toward more sustainable behaviours. In this aspect, media plays an important role in shaping individuals' awareness about climate change. This study aims to analyse Iberian media coverage about climate change to further discuss its influence on the public's engagement with the subject. A total of 449 news were collected from Iberian newspapers. Their characteristics were analysed through quantitative content analysis. Data shows important journalistic bias toward a national framing, mainly focusing on drought and its impact on agriculture. The debate is focused on technological and political discourses. The gaps found on the Iberian media coverage may contribute to public's low levels of acknowledgement and engagement, not enhancing the possibility of change in individuals' behaviours for more sustainable actions. View more

Sci. Total Envi.: IF: 8.7; Q1: Env. Chemistry; H Index: 439

Analysis of Portuguese online media coverage from 2017 to 2018 reveals a significant gap in public climate literacy. Evaluating 217 news articles across major outlets like Diário de Notícias and Público demonstrated that media coverage predominantly focuses on immediate, present-day disasters, specifically droughts and forest fires, while treating climate change as a passive process. By overemphasizing short-term political responses rather than actionable adaptation strategies or underlying scientific processes, news reporting inadvertently reinforces public passivity, highlighting a vital opportunity to redesign environmental communication to foster active community resilience.

Following the major wildfires that affected the Central region of Portugal in 2017, an environmental monitoring campaign was initiated in November of 2017. Among other environmental issues, the program aims to understand the shifts in sediment production. Mineralogical data obtained so far indicate a progressive decrease in kaolinite and increase in feldspar contents in most sampling sites. These trends point to a strong erosion in the areas affected by the wildfires during the high rainfall events of late 2017 and early 2018.

Devastating 2017 wildfires in Portugal's Central Region exposed vulnerable soils, triggering immediate hydrochemical shifts across the Mondego River basin. Post-fire monitoring revealed an initial spike in electric conductivity from immediate ash deposition, followed by sharp drops in pH and major ions (Cl, Na, Ca, and SO4) as heavy rains drove highly mineralized runoff into local watercourses. These rapid shifts in water chemistry, accompanied by altered hydrochemical facies, underline the severe impact of post-fire erosion and highlight the urgent necessity for long-term watershed monitoring to safeguard drinking water and aquatic ecosystems.. View more

Centuries of cartography in central Portugal once grouped all granitic rocks into a single massive intrusion. Tracking national map revisions from the 19th century to today reveals how advanced K-Ar, Rb-Sr, and U-Pb radiometric dating shifted recognized magmatic origins back to the Neoproterozoic. Redefining these complex tectonic boundaries near Coimbra and Nisa exposes a critical gap between state-of-the-art laboratory data and outdated 1:500,000 national geological maps.

Evolution of Portuguese geological mapping from 1876 to 2010 reveals a dramatic shift in understanding the ancient granites between Coimbra and Nisa. Early field-based maps classified these complex formations as Variscan or Hercynian, but modern radiometrical dating methods, such as U-Pb zircon isotopic analysis, pushed their origins back to the late Neoproterozoic, over 540 million years ago. Tracking this cartographic transformation highlights how emerging analytical techniques continuously reshape knowledge of continental collision zones, while exposing key geological units like the Arega and Beco gneisses that still lack modern geochemical data.

The 15th-century Patio de Escuelas Menores in Salamanca, Spain, faces severe structural risks driven by a chaotic mix of construction materials, ranging from delicate sandstones to modern concrete. Structural analysis of the external wall, entrance arch, and ancient fountain revealed deep fractures linked to past seismic activity, accelerating erosion, and four distinct lichen species degrading 16th-century bas-reliefs. Pinpointing these physical-chemical vulnerabilities provides the critical foundation needed to execute immediate safety interventions and prevent irreversible collapse.. View more

The old Escádia Grande gold mine, located in the Góis region, was exploited during the roman occupation in the Iberian Peninsula, and again between 1939 and 1952, having been abandoned ever since. The area is predominantly constituted by the “Complexo Xisto Grauvaquico” (CXG), consisting of phyllites and metagraywackes, with intrusions of stockwork type veins that where explored. The mine has four entrances to the galleries that are sealed, with drains at the bottom that pour mining drainage, as well as two tailing occupying a total area of 25,000 m2, which are a mixed of the sterile material and the discarded materials from the process of ore treatment. The presented study describes and evaluates the environmental changes that have been generated by the mining activity and its abandonment in terms of water, stream sediments and soils. The waters that travel through the mining area show a contamination that extends up to 1.5 km South, with high levels of As, Cu, Pb and SO4, associated with a decrease in pH and an increase in electrical conductivity. Due to the low pH values, and high concentrations of arsenic and nickel, the water becomes unfit for human consumption, being, however, acceptable for irrigation. The stream sediments are under the direct influence of the mine, presenting high geoaccumulation indexes of Ag, As, Au, Fe, Pb, Sb and Zn, being the highest preoccupation the water line that crosses the mining area, with high geoaccumulation of arsenic, antimony, silver and gold, occurring smaller contaminations of lead, iron and zinc. The mining area and mineralized veins area present, generally, acid soils with low electric conductivity. The Southern tailings causes, in the surrounding soils, an increase in concentrations of As, Au, Cu, Mn, Ni, Pb, Sb and Zn, being the main focus of soil contamination. The Northern tailings causes an increase of Cu and Ni concentrations in the nearby soils. While the mineralized veins increase the concentrations of Ag, Au and Sb. View more (in Portuguese)