Environmental risk evaluation of potential toxic elements in stream sediments – Monfortinho area (Central Portugal)

Os elementos potencialmente tóxicos (EPT) em sedimentos de corrente constituem uma importante ferramenta na avaliação do risco ambiental na influência de depósitos minerais. A região de Monfortinho está localizada na bacia hidrográfica do rio Erges, que faz fronteira com Espanha. Desde a época romana, que se conhecem evidências da exploração de ouro sedimentar nesta região do país, a qual tem vindo a desaparecer ao longo do tempo. Na avaliação da distribuição espacial de EPT selecionados – As, B, Ba, Cd, Cu, Fe, Ni, Pb, V e Zn - foram analisadas 217 amostras de sedimentos de corrente. Os sedimentos de corrente mostram uma elevada variabilidade na concentração dos EPT, podendo concluir-se que os valores mais elevados se relacionam com as mineralizações de Au na região de Monfortinho, bem como, com as de Sn-W que ocorrem nas proximidades. A maioria dos EPT apresenta um fator de contaminação moderado, embora para o Ba, Cr e B este seja elevado a muito elevado; o que se reflete num grau de contaminação moderado a elevado para a área de estudo. Na influência dos vários EPT, a maioria da área mostra um índice de resposta à toxicidade baixo, embora em 5% das amostras este seja moderado.Potentially toxic elements (PTE) of stream sediments are an important tool in environmental risk assessment associated with mineralized deposits. εonfortinho is in the watershed of the Erges river, a transboundary river with Spain. Since Roman period, there is evidence of sedimentary gold exploitation in this region, which has ceased over time. To define a spatial distribution of selected PTE - As, B, Ba, Cd, Cu, Fe, Ni, Pb, V and Zn - β17 samples of stream sediments were analysed. Stream sediments show a high PTE contents variability, suggesting that the highest values are related to the Au mineralization in εonfortinho, as well as the Sn-→ mineralization’s around the study area. Almost stream sediments show a moderate PTE contamination factor, although for Ba, Cr and B has a very high contamination; which is reflected in a moderate to high degree of contamination in the area. All the PTE contribution indicate a low toxic response index for the area, although for 5% of stream sediments indicate a moderate associated toxicity.Os autores agradecem ao δNEG (atual representante dos Serviços Geológicos de Portugal) pela cedência dos dados. Este trabalho foi desenvolvido no âmbito do ICT – Universidade do εinho (Braga).info:eu-repo/semantics/publishedVersio

Hydrogeochemical assessment of termal water in fractured rocks – a Portuguese case study

The thermal Fadagosa-Nisa water is located at north Alentejo (Portugal) and it is important in the economy of this region. The studied area is in a predominantly fractured granite and the water circulation is characteristic of fissured media, with a productivity of 2 L/s from a single well. Water hydrogeochemistry results revealed a mineralized water, with an electrical conductivity of 454 µS/cm and a total mineralization of 310 mg/L, neutral (pH=7.9-8.0) and a temperature of 19ºC. The thermal water has a dominant hydrogeochemical sodium-bicarbonate facies, with a fluoride (F-=9.6 mg/L) and hydrogen sulphide content (HS=15.2 mg/L), and moderate amounts of silica (SiO2=34.0 mg/L). The low nitrate (NO3-=0.1 mg/L) and sulphate (SO42-=1.6-5.2 mg/L) contents support the low vulnerability associated to the groundwater catchment. No significant seasonal changes have been found in the Fadagosa-Nisa thermal groundwater composition, suggesting a hydrogeochemical stability to the area. The regular hydrogeochemical results is in accordance to the low vulnerability obtained by the application of DRASTIC index in the Fadagosa-Nisa area.Institute of Earth Sciences (ICT), under contracts UID/GEO/04683/2013 with FCT (the Portuguese Science and Technology Foundation)info:eu-repo/semantics/publishedVersio

Impact of Sewage Effluent Discharges prediction using QUAL2Kw in a sensitive protected area – Portugal

The quality of water, under the influence of the wastewater treatment plant's discharges, makes the simulation of the water parameters a key issue, broadly when considering intermittent rivers. In the case of study, the Pracana reservoir works as an example of the characterization, monitoring, and control of the impact of several, wastewater treatment plant's discharges, directly contributing to water quality. Proença-a-Nova's wastewater treatment plant contributes directly to the Pracana reservoir (Central Portugal), which is a protected field. Twelve georeferenced water samples were gathered, between the sewage discharge and downstream to the Pracana reservoir, at almost equal distances. Sampling campaigns were taken during three different periods: rainy winter (January), intermediate conditions (March) and dry season (June). The following chemical parameters were analyzed: Biochemical Oxygen Demand (BOD5), Dissolved Oxygen (DO), Dry Residue, Ptotal, Ntotal, pH, Temperature, and Microbiological Parameters. DO, BOD5 and Microbiological Parameters served as indicators, for environmental pollution evaluation. A coupled hydrodynamic and water dispersion model, QUAL2kw, was used for water's quality simulation. The results lead to conclude that the water quality is acceptable for multiple purposes, except for human consumption, mainly due to moderate to high values of BOD5.Águas do Centro Enterprise and by the Institute of Earth Sciences (ICT), under contracts UID/GEO/04683/2013 with FCT (the Portuguese Science and Technology Foundation

Effects of wastewater treatment plant’s discharges on a freshwater ecosystem—a case study on the Ramalhoso River (Portugal)

Sewage discharges constitute severe stress in freshwater ecosystems. The Ramalhoso River belongs to the Tagus river watershed and was chosen for a pilot study on the impact of wastewaters discharges in a freshwater ecosystem and its ability for self-depuration. Twelve water samples were collected along the river and were georeferenced. The first point is located upstream of the first discharge point, the second one corresponding to the discharge flow, and all the other samples located downstream of secondary inflows at approximately equal distances. Three sampling campaigns were conducted during the rainy winter (January), the intermediate conditions (March), and the dry season (June). The following chemical parameters were analyzed: Biochemical Oxygen Demand (5), Dissolved Oxygen concentration (DO), Ptotal, Ntotal, pH, temperature, total suspended solids (TSS), microbiological parameters (MP), and flow determination. Dissolved oxygen (DO), biochemical oxygen demand, for 5 days (BOD5), and the total suspended solids were used as indicators of environmental pollution. A coupled hydrodynamic and water dispersion model simulated different pollution scenarios using the QUAL2kw software to construct a water quality model. The simulation results are consistent with field observations and demonstrate that the model has been correctly calibrated, allowing feasibility studies of different treatment schemes and the development of specific monitoring activities.Águas do Centro Enterprise and by the Institute of Earth Sciences (ICT), under contracts UID/GEO/04683/2013 with FCT (Portuguese Science and Technology Foundation

Groundwater vulnerability assessment in the Naturtejo UNESCO glogal Geopark, Portugal

Nowadays, groundwater vulnerability assessment has become a useful tool for groundwater contamination prevention. Groundwater vulnerability maps provide useful data to protect groundwater resources and work as a tool for the improvement of changes in agricultural patterns and land use applications. The study area of this research survey is the Naturtejo UNESCO Global Geopark, located in central inland Portugal and corresponding to a mainly rural territory where intensive agricultural practices showed a rising tendency in the last decades. The most used method of vulnerability evaluation is the DRASTIC index. In this survey, a modified DRASTIC method, DRASTICAI, is introduced. A new attribute designated as Anthropogenic Influence is introduced. Map algebra in a GIS environment allowed the computation of two maps by overlaying the needed attributes. The Vila-Velha-de Rodão and Idanha-a-Nova municipalities show moderate to high vulnerability and, therefore, in need of monitoring, since intensive agricultural practices are the main economic activity. The algebraic subtraction of DRASTIC and DRASTICAI maps revealed a considerable increase in the risk of contamination, over the surveyed area, namely in Idanha-a-Nova where it is observed risk increase up to 45 points, changing from moderately vulnerable to highly vulnerable and, therefore, stressing the importance of anthropogenic activities

Does Platform Migration Compromise Content Moderation? {Evidence} from {r/The\_Donald} and {r/Incels}

When toxic online communities on mainstream platforms face moderation measures, such as bans, they may migrate to other platforms with laxer policies or set up their own dedicated website. Previous work suggests that, within mainstream platforms, community-level moderation is effective in mitigating the harm caused by the moderated communities. It is, however, unclear whether these results also hold when considering the broader Web ecosystem. Do toxic communities continue to grow in terms of user base and activity on their new platforms? Do their members become more toxic and ideologically radicalized? In this paper, we report the results of a large-scale observational study of how problematic online communities progress following community-level moderation measures. We analyze data from r/The_Donald} and r/Incels, two communities that were banned from Reddit and subsequently migrated to their own standalone websites. Our results suggest that, in both cases, moderation measures significantly decreased posting activity on the new platform, reducing the number of posts, active users, and newcomers. In spite of that, users in one of the studied communities (r/The_Donald) showed increases in signals associated with toxicity and radicalization, which justifies concerns that the reduction in activity may come at the expense of a more toxic and radical community. Overall, our results paint a nuanced portrait of the consequences of community-level moderation and can inform their design and deployment

Sensitive areas under radium/uranium mine drainage - the Picoto mine case study, central Portugal

A zona mineira de Picoto está localizada próximo de Vilar Seco (Viseu, Centro de Portugal). Ocorre numa área de declive suave, altitude variando entre 360-380 m, incluída na bacia do rio Cagavaio, com drenagem dominante NE-SW. A mineralização ocorre em veios de quartzo, que intersectam o granito Varisco, porfiróide de duas micas. Os filões de quartzo preenchem falhas N37°-45°E e N50°-70°E, localmente brechificadas. Estes filões contêm meta-torbernite e uranófano, e alguns minerais portadores de U, como clorite e hidróxidos de Fe e Mn. A exploração ocorreu em duas fases, entre 1917 e 1953. Após cessada a exploração, permaneceram as escombreiras resultantes da exploração e a área nunca foi reabilitada. Neste momento, está ocupada por culturas locais, principalmente vinhas e produtos agrícolas. Vinte amostras de águas superficiais e subterrâneas foram colhidas entre 2008 e 2009. Em geral, as águas apresentam valores de pH entre 4.7 a 6.3 e são pouco mineralizadas (CE = 44-190 μS/cm; TDS = 49-137 mg/L). Contudo, algumas águas estão contaminadas em NO2, Fe, Mn, Cu, As e U, e não devem ser utilizadas para consumo humano nem em atividades agrícolas. A contaminação da água está associada principalmente à antiga mina de rádio/urânio e atividades humanas desenvolvidas.The Picoto mine area is located at Vilar Seco village (Viseu, central Portugal), in a soft slope area with altitudes ranging from 360 to 380 m, included in the Cagavaio river catchment, with a dominant NE-SW drainage. The mineralization occurs mainly in quartz veins, which intersect a Variscan porphyritic two-mica granite. The quartz veins fill N37°-45°E and N50°-70°E faults, locally brecciated. The quartz veins contain meta-torbernite and uranophane, and some U-bearing minerals, such as chlorite and Fe- and Mn-hydroxides. The exploitation was carried out in two stages, between 1917 and 1953. Since closure, the area contains mine rejected materials and has never been restored. Therefore, a local cultivated area, mainly for vines and domestic consumption agricultural products, is now deployed. A total of twenty surface and groundwater samples were collected between 2008 and 2009. In general, the waters yield pH values ranging from 4,4 to 6,3 and are poorly mineralized (EC=44-190 µS/cm; TDS= 49-137 mg/L). However, some waters are contaminated with NO₂, Fe, Mn, Cu, As and U and must not be used neither for human consumption nor in agricultural activities. The water contamination is mainly associated with the old radium/uranium mine and subsequent human activities developed in the area.Este trabalho teve suporte financeiro através do ICT e do projeto UID/GEO/04035/2013.info:eu-repo/semantics/publishedVersio

Do Platform Migrations Compromise Content Moderation? Evidence from r/The_Donald and r/Incels

When toxic online communities on mainstream platforms face moderation measures, such as bans, they may migrate to other platforms with laxer policies or set up their own dedicated websites. Previous work suggests that within mainstream platforms, community-level moderation is effective in mitigating the harm caused by the moderated communities. It is, however, unclear whether these results also hold when considering the broader Web ecosystem. Do toxic communities continue to grow in terms of their user base and activity on the new platforms? Do their members become more toxic and ideologically radicalized? In this paper, we report the results of a large-scale observational study of how problematic online communities progress following community-level moderation measures. We analyze data from r/The_Donald and r/Incels, two communities that were banned from Reddit and subsequently migrated to their own standalone websites. Our results suggest that, in both cases, moderation measures significantly decreased posting activity on the new platform, reducing the number of posts, active users, and newcomers. In spite of that, users in one of the studied communities (r/The_Donald) showed increases in signals associated with toxicity and radicalization, which justifies concerns that the reduction in activity may come at the expense of a more toxic and radical community. Overall, our results paint a nuanced portrait of the consequences of community-level moderation and can inform their design and deployment

The Evolution of the {Manosphere} Across the {Web}

In this paper, we present a large-scale characterization of the Manosphere, a conglomerate of Web-based misogynist movements roughly focused on "men's issues," which has seen significant growth over the past years. We do so by gathering and analyzing 28.8M posts from 6 forums and 51 subreddits. Overall, we paint a comprehensive picture of the evolution of the Manosphere on the Web, showing the links between its different communities over the years. We find that milder and older communities, such as Pick Up Artists and Men's Rights Activists, are giving way to more extremist ones like Incels and Men Going Their Own Way, with a substantial migration of active users. Moreover, our analysis suggests that these newer communities are more toxic and misogynistic than the former

Spatial environmental risk evaluation of potential toxic elements in stream sediments

Potential toxic elements (PTE), in stream sediments, were used as contamination indicators for the definition of high-/low-grade spatial clusters in the Monfortinho area (Central Portugal). A set of 271 stream sediment samples was used for spatial modelling and further definition of rings of enrichment-high and low rings. A three-step multivariate statistical and geostatistical approach was used: (1) principal components analysis for PTE's association evaluation and dimensionality reduction; (2) ordinary kriging as an unbiased interpolator for content inference and construction of a continuous representation of the considered attributes, at any arbitrary spatial location; (3) G clustering algorithm for the definition of high and low significance clusters. A moderate contamination in stream sediments is observed for almost all the considered PTE and a very high contamination for Ba, Cr and B. High contamination clusters are observed for Fe, Ni, Ba, Cu, B, Zn, V-northwest and southeast clusters-and for Cr-north and southwest clusters. The contamination degree index varies from moderate to high, which is mainly associated with the old mineralizations. The high computed rings often overlap the areas of abandoned Ba-Zn mineralization, as well as the sedimentary gold concentrations, along the Erges River banks. Tin and Cd spatial distribution may be related to former cassiterite exploitations in the survey area. Chromium is possibly connected with the schists. The definition of clusters with a PTE spatial enrichment will allow for the identification of contamination activities and therefore, the definition of adequate monitoring and mitigation actions.Our thanks are due to Prof. M.R. Machado Leite for the use of data on stream sediments from Instituto Geolo´gico e Mineiro, S. Mamede de Infesta (Portugal). This work is co-funded by the European Union through the European Regional Development Fund, based on COMPETE 2020 (Programa Operacional da Competitividade e Internacionalizac¸a˜o), project ICT (UID/GEO/04683/2013) with reference POCI-01-0145-FEDER-007690 and national funds provided by Fundac¸a˜o para a Cieˆncia e Tecnologia.info:eu-repo/semantics/publishedVersio