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Modeling effects of nitrate from non-point sources on groundwater quality in an agricultural watershed in Prince Edward Island, Canada | Modélisation des effets des apports nitratés diffus sur la qualité des eaux souterraines dans un bassin agricole de l’île du Prince Edouard, Canada Modelación de los efectos del nitrato de fuentes no puntuales en la calidad de las aguas subterráneas en una cuenca agrícola en Isla Prince Edward, Canadá 模拟非点源硝酸盐对加拿大爱德华王子岛某农业流域地下水水质的影响 Modelação da influência do nitrato de fontes não pontuais na qualidade da água subterrânea numa bacia hidrográfica de uso agrícola em Prince Edward Island, Canadá Texte intégral
2009
Jiang, Yefang | Somers, George
Intensification of potato farming has contaminated groundwater with nitrate in many cases in Prince Edward Island, Canada, which raises concerns for drinking water quality and associated ecosystem protection. Numerical models were developed to simulate nitrate-N transport in groundwater and enhance understanding of the impacts of farming on water quality in the Wilmot River watershed. Nitrate is assumed non-reactive based on δ¹⁵N and δ¹⁸O in nitrate and geochemical information. The source functions were reconstructed from tile drain measurements, N budget and historical land-use information. The transport model was calibrated to long-term nitrate-N observations in the Wilmot River and verified against nitrate-N measurements in two rivers from watersheds with similar physical conditions. Simulations show groundwater flow is stratified and vertical flux decreases exponentially with depth. While it would take several years to reduce the nitrate-N in the shallow portion of the aquifer, it would take several decades or even longer to restore water quality in the deeper portions of the aquifer. Elevated nitrate-N concentrations in base flow are positively correlated with potato cropping intensity and significant reductions in nitrate-N loading are required if the nitrate level of surface water is to recover to the standard in the Canadian Water Quality Guidelines.
Afficher plus [+] Moins [-]Groundwater monitoring in Denmark: characteristics, perspectives and comparison with other countries | Suivi des eaux souterraines au Danemark : caractéristiques, perspectives et comparaison avec d’autres pays Monitoreo de aguas subterráneas en Dinamarca: características, perspectivas y comparación con otros países 丹麦的地下水监测——特征、展望以及与其它国家的对比 Monitorização da água subterrânea na Dinamarca: características, perspectivas e comparação com outros países Grundvandsovervågning i Danmark – karakteristika, perspektiver og sammenligning med andre lande Grundwasser-Monitoring in Dänemark: Eigenschaften, Perspektiven und Vergleich mit anderen Ländern مراقبة المياه الجوفية في الدنمارك-الخواص ,الافاق,والمقارنة مع الدول ألأخرى Grondwater monitoring in Denemarken: Kenmerken, perspectieven en vergelijking met andere landen Grundvattenövervakning i Danmark - karaktäristik, perspektiv och jämförelse med andra länder Texte intégral
2009
Jørgensen, LisbethFlindt | Stockmarr, Jens
More than 99% of water use in Denmark is based on groundwater. Denmark has had a comprehensive national groundwater-monitoring programme since 1988 based on 74 well catchment areas and six small agricultural catchments with more than 1,500 screens at different depths for regular, mostly annual, water quality sampling. In addition, water samples from 10,000 abstraction wells are analysed every 3–5 years. The water is analysed for main components, inorganic trace elements, organic micro pollutants, and pesticides and their metabolites. A unique feature is the 20-year time-series data of inorganic pollutants. Groundwater modelling supports traditional monitoring to improve the conceptual geological understanding and to assess the quantitative status and the interaction between groundwater and surface water. The programme has been continuously adjusted to incorporate new knowledge from research programmes and meet new policy demands, currently the European Union Water Framework Directive, particularly with respect to an increased focus on quantitative aspects and on the groundwater/surface water interaction. The strengths and weaknesses of the Danish programme are assessed and compared with other national groundwater-monitoring programmes. Issues discussed include: strategic considerations for monitoring design, the link between research and monitoring, and adoption of responses to climate changes.
Afficher plus [+] Moins [-]Influence of hydrostratigraphy and structural setting on the arsenic occurrence in groundwater of the Cimino-Vico volcanic area (central Italy) | Influence des paramètres hydrostatiques et structuraux sur la présence d’arsenic dans les eaux souterraines dans la région volcanique de Cimino-Vico (Italie centrale) Influencia del esquema hidroestratigráfico y estructural sobre la existencia de arsénico en las aguas subterráneas del área volcánica de Cimino – Vico (Italia central) 水文地层和构造对Cimino-Vico火山岩地区 (意大利中部) 地下水中砷分布的影响 Influenza dell’assetto idrostratigrafico e strutturale sulla presenza dell’arsenico nelle acque sotterranee dell’area vulcanica del Cimino-Vico (Italia centrale) Influência da hidrostratigrafia e do enquadramento estrutural na ocorrência de arsénio nas água subterrâneas da zona vulcânica de Cimino-Vico (Itália central) Texte intégral
2009
Angelone, Massimo | Cremisini, Carlo | Piscopo, Vincenzo | Proposito, Marco | Spaziani, Fabio
Arsenic occurrence in groundwater near the Cimino-Vico volcanoes (central Italy) was analysed considering the hydrostratigraphy and structural setting and the shallow and deep flows interacting within the Quaternary volcanics. Groundwater is the local source of drinking water. As documented in the past, arsenic in the groundwater has become a problem, and the European maximum allowable contaminant level was recently lowered to 10 μg/L. Chemical analyses of groundwater were conducted, sampled over an area of about 900 km², from 65 wells and springs representative of the volcanic aquifer and thermal waters. Considering the type of aquifer, the nature of the aquifer formation and its substratum, the hydrochemical data highlight that the arsenic content of the groundwater is mainly connected with the hydrothermal processes in the volcanic area. Thermal waters (54–60°C) fed from deep-rising fluids show higher arsenic concentrations (176–371 μg/L). Cold waters sampled from the volcanic aquifer are characterized by a wide variability in their arsenic concentration (1.6–195 μg/L), and about 62% exceed the limit of 10 μg/L. Where the shallow volcanic aquifer is open to deep-rising thermal fluids, relatively high arsenic concentrations (20–100 μg/L) are found. This occurs close to areas of the more recent volcano-tectonic structures.
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