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1
Field, Malcolm S. "Karst Hydrology and Chemical Contamination". Journal of Environmental Systems 22, nr 1 (1.01.1992): 1–26. http://dx.doi.org/10.2190/x7mv-c93e-66gk-bfh7.
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Esselman, Peter, Shiguo Jiang, Henry Peller, David Buck i Joel Wainwright. "Landscape Drivers and Social Dynamics Shaping Microbial Contamination Risk in Three Maya Communities in Southern Belize, Central America". Water 10, nr 11 (17.11.2018): 1678. http://dx.doi.org/10.3390/w10111678.
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Land transformation can have cascading effects on hydrology, water quality, and human users of water resources, with serious implications for human health. An interdisciplinary analysis is presented, whereby remote-sensing data of changing land use and cover are related to surface hydrology and microbial contamination in domestic use areas of three indigenous Maya communities in Belize, Central America. We asked whether a departure from traditional land-use patterns toward intensified use led to consequences for hydrology and microbial contamination of drinking water, and investigated how social factors in the three study communities may act to ameliorate human health risks associated with water contamination. We showed that a departure from traditional land use to more intensive cultivation and grazing led to significantly increased surface water runoff, and intensified microbial contamination of surface water sources sometimes used for drinking. Results further suggested that groundwater contamination was widespread regardless of land cover, due to the widespread presence of pit latrines, pigs, and cows on the landscape, and that human users were consistently subject to health risks from potential pathogens as a result. Given that both surface and groundwater resources were found to be contaminated, it is important that water distribution systems (piped water from tanks; shallow and deep wells) be monitored for Escherichia coli and treated when necessary to reduce or eliminate contaminants and protect public health. Results of interviews suggested that strengthened capacity within the communities to monitor and treat centralized drinking water sources and increase water treatment at the point of use could lead to reduced risk to water consumers.
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Bennett, Gary F. "Groundwater Contamination: Vol. 1. Contamination, Sources & Hydrology; Vol. 2. Management, Containment, Risk Assessment & Legal Issues". Journal of Hazardous Materials 80, nr 1-3 (grudzień 2000): 274–75. http://dx.doi.org/10.1016/s0304-3894(00)00284-3.
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Huang, Tao, Wilfred M. Wollheim i Stephen H. Jones. "Removal of Fecal Indicator Bacteria by River Networks". Water 14, nr 4 (17.02.2022): 617. http://dx.doi.org/10.3390/w14040617.
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Fecal contamination is a significant source of water quality impairment globally. Aquatic ecosystems can provide an important ecosystem service of fecal contamination removal. Understanding the processes that regulate the removal of fecal contamination among river networks across flow conditions is critical. We applied a river network model, the Framework for Aquatic Modeling in the Earth System (FrAMES-Ecoli), to quantify removal of fecal indicator bacteria by river networks across flow conditions during summers in a series of New England watersheds of different characteristics. FrAMES-Ecoli simulates sources, transport, and riverine removal of Escherichia coli (E. coli). Aquatic E. coli removal was simulated in both the water column and the hyporheic zone, and is a function of hydraulic conditions, flow exchange rates with the hyporheic zone, and die-off in each compartment. We found that, at the river network scale during summers, removal by river networks can be high (19–99%) with variability controlled by hydrologic conditions, watershed size, and distribution of sources in the watershed. Hydrology controls much of the variability, with 68–99% of network scale inputs removed under base flow conditions and 19–85% removed during storm events. Removal by the water column alone could not explain the observed pattern in E. coli, suggesting that processes such as hyporheic removal must be considered. These results suggest that river network removal of fecal indicator bacteria should be taken into consideration in managing fecal contamination at critical downstream receiving waters.
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Squillace, Paul J., i E. M. Thurman. "Herbicide transport in rivers: importance of hydrology and geochemistry in nonpoint-source contamination". Environmental Science & Technology 26, nr 3 (marzec 1992): 538–45. http://dx.doi.org/10.1021/es00027a015.
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Ansari, Md Arzoo, U. Saravana Kumar, Jacob Noble, Naima Akhtar, M. Arslaan Akhtar i Archana Deodhar. "Isotope hydrology tools in the assessment of arsenic contamination in groundwater: An overview". Chemosphere 340 (listopad 2023): 139898. http://dx.doi.org/10.1016/j.chemosphere.2023.139898.
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Rees, W. G. "Remote sensing of oil spills on frozen ground". Polar Record 35, nr 192 (styczeń 1999): 19–24. http://dx.doi.org/10.1017/s0032247400026292.
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AbstractRemote-sensing methods, using electromagnetic radiation detected by airborne and spaceborne instruments, have the potential to revolutionise the investigation of oil contamination in high latitudes. Spaceborne monitoring, in particular, offers many advantages, including: obtaining data from relatively inaccessible areas; day and night, all-weather observations; regular monitoring opportunities; spatial resolution of 20 m or better; and areal coverage of 30,000 square kilometres or more. Calibrated, spatially registered data can be readily integrated into geographic information systems for evaluation and prediction of spill behaviour. However, very little investigation of this potential has yet been undertaken. This paper reviews the possibilities for monitoring soil characteristics, including thermal regime, the presence of contamination, and long-term consequences of spills, for topography, hydrology, and vegetation cover.
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KONDOH, Akihiko, Masaya YASUHARA i Seongwon LEE. "Special Issue: "Nitrogen contamination in environmental water - role of hydrology as an integrated science -"". Journal of Japanese Association of Hydrological Sciences 41, nr 3 (2011): 47–48. http://dx.doi.org/10.4145/jahs.41.47.
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Tyler, Scott W. "Are Arid Regions Always that Appropriate for Waste Disposal? Examples of Complexity from Yucca Mountain, Nevada". Geosciences 10, nr 1 (14.01.2020): 30. http://dx.doi.org/10.3390/geosciences10010030.
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The study of the hydrology of arid regions greatly expanded at the end of the 20th century as humans sought to reduce groundwater pollution from landfills, waste dumps and other forms of land disposal. Historically viewed as wastelands where little or no water percolated to the underlying water table, the discovery of large-scale contamination beneath arid disposal sites such as the Hanford nuclear complex in eastern Washington jumpstarted an industry in studying the hydrology of arid vadose zones and their transport behavior. These studies showed that, in spite of hyper aridity in many areas, precipitation often did infiltrate to deep water. The efforts at Yucca Mountain, Nevada to design a high-level nuclear repository stand out as one of the largest of such studies, and one that fundamentally changed our understanding of not only water flow in fractured rocks, but also of the range of our uncertainty of hydrologic processes in arid regions. In this review and commentary, we present some of the initial concepts of flow at Yucca Mountain, and the evolution in research to quantify the concepts. In light of continued stockpiling of high-level waste, and the renewed interest in opening Yucca Mountain for high-level waste, we then focus on the significant surprises and unanswered questions that remained after the end of the characterization and licensing period; questions that continue to demonstrate the challenges of a geologic repository and our uncertainty about critical processes for long-term, safe storage or disposal of some of our most toxic waste products.
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Dadfar, H., S. E. Allaire, R. De Jong, E. van Bochove, J. T. Denault, G. Thériault i F. Dechmi. "Development of a method for estimating the likelihood of crack flow in Canadian agricultural soils at the landscape scale". Canadian Journal of Soil Science 90, nr 1 (1.02.2010): 129–49. http://dx.doi.org/10.4141/cjss09066.
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Indicators of risk of water contamination by agricultural pollutants are developed in Canada to assess sustainability of agriculture. Crack flow (CF), a key pathway for sub-surface contaminant transport, is part of the transport-hydrology algorithm used in two of these risk indicators. The objective was to develop a methodology for predicting the likelihood of CF in Canadian agricultural soils at the landscape scale. The algorithm considers soil clay content, crack development followed by a runoff event based on water budget, tile drainage, and crops. More than 40% of Canadian farmlands had moderate to very high likelihood of CF, mainly in Manitoba, Ontario and Quebec, due to frequent runoffs on cracked clay soils potentially contributing to groundwater contamination. In Ontario and Quebec, farmlands with high CF likelihood correspond to regions under intensive tile drainage, which increases the risk of lateral translocation of contaminants to surface water bodies. Besides being a component of risk indicators of water contamination by phosphorus and coliforms, the CF algorithm and maps can be used to identify areas at risk of subsurface water contamination. Best management practices, adapted to reduce CF can then be targeted to these areas.Key words: Agrichemicals, contaminant transport, macropore flow, preferential flow, risk assessment, risk indicators
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Lyra, Aikaterini, Athanasios Loukas i Pantelis Sidiropoulos. "Impacts of irrigation and nitrate fertilization scenarios on groundwater resources quantity and quality of the Almyros Basin, Greece". Water Supply 21, nr 6 (2.04.2021): 2748–59. http://dx.doi.org/10.2166/ws.2021.097.
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Abstract Irrigation and nitrate fertilization scenarios were combined and simulated for crop water irrigation demands and nitrogen applications based on experiments on crop cultivation practices. Two irrigation practices (deficit irrigation and rainfed conditions) were applied to the main crop types of the Almyros Basin, a coastal basin located in Thessaly, Greece. The Almyros groundwater system suffers from progressive water balance deficit, nitrate contamination and seawater intrusion due to groundwater abstractions for agricultural irrigation to cover crop water demands in the dry season. The impacts of the irrigation and nitrate fertilization scenarios on groundwater resources quantity and quality were simulated using an Integrated Modelling System consisting of models of surface hydrology (UTHBAL), groundwater hydrology (MODFLOW), crop growth/nitrate leaching (REPIC), contaminant transport (MT3DMS), and seawater intrusion (SEAWAT), for the historical period of 1991–2018. The results of the scenarios were evaluated with the indicators of Crop Water Productivity (CWP) for crop yields and irrigation water, Partial Factor Productivity (PFP) for Nitrogen Use Efficiency, and Economic Water Productivity (EWP) for the gross profits of the irrigation water.
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Govindaraju, Rao S. "Modeling Overland Flow Contamination by Chemicals Mixed in Shallow Soil Horizons Under Variable Source Area Hydrology". Water Resources Research 32, nr 3 (marzec 1996): 753–58. http://dx.doi.org/10.1029/95wr03639.
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van Bochove, E., G. Thériault, F. Dechmi, A. N. Rousseau, R. Quilbé, M. L. Leclerc i N. Goussard. "Indicator of risk of water contamination by phosphorus from Canadian agricultural land". Water Science and Technology 53, nr 2 (1.01.2006): 303–10. http://dx.doi.org/10.2166/wst.2006.064.
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The indicator of risk of water contamination by phosphorus (IROWC_P) is designed to estimate where the risk of water P contamination by agriculture is high, and how this risk is changing over time based on the five-year period of data Census frequency. Firstly developed for the province of Quebec (2000), this paper presents an improved version of IROWC_P (intended to be released in 2008), which will be extended to all watersheds and Soil Landscape of Canada (SLC) polygons (scale 1:1, 000, 000) with more than 5% of agriculture. There are three objectives: (i) create a soil phosphorus saturation database for dominant and subdominant soil series of SLC polygons – the soil P saturation values are estimated by the ratio of soil test P to soil P sorption capacity; (ii) calculate an annual P balance considering crop residue P, manure P, and inorganic fertilizer P – agricultural and manure management practices will also be considered; and (iii) develop a transport-hydrology component including P transport estimation by runoff mechanisms (water balance factor, topographic index) and soil erosion, and the area connectivity to water (artificial drainage, soil macropores, and surface water bodies).
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Grayman, W. M., i R. M. Males. "Risk-based modeling of early warning systems for pollution accidents". Water Science and Technology 46, nr 3 (1.08.2002): 41–49. http://dx.doi.org/10.2166/wst.2002.0050.
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An early warning system is a mechanism for detecting, characterizing and providing notification of a source water contamination event (spill event) in order to mitigate the impact of contamination. Spill events are highly probabilistic occurrences with major spills, which can have very significant impacts on raw water sources of drinking water, being relatively rare. A systematic method for designing and operating early warning systems that considers the highly variable, probabilistic nature of many aspects of the system is described. The methodology accounts for the probability of spills, behavior of monitoring equipment, variable hydrology, and the probability of obtaining information about spills independent of a monitoring system. Spill Risk, a risk-based model using Monte Carlo simulation techniques has been developed and its utility has been demonstrated as part of an AWWA Research Foundation sponsored project. The model has been applied to several hypothetical river situations and to an actual section of the Ohio River. Additionally, the model has been systematically applied to a wide range of conditions in order to develop general guidance on design of early warning systems.
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Staniszewski, Ryszard, Przemysław Niedzielski, Tadeusz Sobczyński i Mariusz Sojka. "Trace Elements in Sediments of Rivers Affected by Brown Coal Mining: A Potential Environmental Hazard". Energies 15, nr 8 (13.04.2022): 2828. http://dx.doi.org/10.3390/en15082828.
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Brown coal remains an important energy source in Europe, including countries such as Germany, Poland, the Czech Republic, and Greece. Open-pit mines disturb the environment in terms of air quality, hydrology, and chemical and biological transformations in rivers receiving mine waters. In the present study, we assessed the impact of mine waters from four brown coal open-pit mines on the contamination of river sediments. Chemical analysis included the quantification of 62 elements, including heavy metals (HMs) and rare earth elements (REEs). The contamination of sediments by HMs was evaluated using the contamination factor (CF), the pollution load index (PLI), and the Nemerow multi-factor index (PI). The potential toxic effects of HMs on aquatic organisms were assessed using the potential ecological risk index (PERI). Detailed analysis of chondrite-standardized concentrations of REEs was performed to describe the effects of mine water on their pattern in sediments. Cluster analysis (CA) and principal component analysis (PCA) were employed to divide study sites into groups and to evaluate the combined effect of sediment texture and site location on HMs and REEs in sediments. The study showed that after mine water discharge, there is a decrease in HM and REE concentrations in sediments. The decrease in each element’s concentration in sites located 100 m downstream of the discharge was caused by washing out of the finest fractions of sediments by mine waters.
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Harvey, Charles F., Christopher H. Swartz, Abu Bohran M. Badruzzaman, Nicole Keon-Blute, Winston Yu, M. Ashraf Ali, Jenny Jay i in. "Groundwater arsenic contamination on the Ganges Delta: biogeochemistry, hydrology, human perturbations, and human suffering on a large scale". Comptes Rendus Geoscience 337, nr 1-2 (styczeń 2005): 285–96. http://dx.doi.org/10.1016/j.crte.2004.10.015.
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Pilloni, Giovanni, Anne Bayer, Bettina Ruth-Anneser, Lucas Fillinger, Marion Engel, Christian Griebler i Tillmann Lueders. "Dynamics of Hydrology and Anaerobic Hydrocarbon Degrader Communities in A Tar-Oil Contaminated Aquifer". Microorganisms 7, nr 2 (9.02.2019): 46. http://dx.doi.org/10.3390/microorganisms7020046.
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Aquifers are typically perceived as rather stable habitats, characterized by low biogeochemical and microbial community dynamics. Upon contamination, aquifers shift to a perturbed ecological status, in which specialized populations of contaminant degraders establish and mediate aquifer restoration. However, the ecological controls of such degrader populations, and possible feedbacks between hydraulic and microbial habitat components, remain poorly understood. Here, we provide evidence of such couplings, via 4 years of annual sampling of groundwater and sediments across a high-resolution depth-transect of a hydrocarbon plume. Specialized anaerobic degrader populations are known to be established at the reactive fringes of the plume. Here, we show that fluctuations of the groundwater table were paralleled by pronounced dynamics of biogeochemical processes, pollutant degradation, and plume microbiota. Importantly, a switching in maximal relative abundance between dominant degrader populations within the Desulfobulbaceae and Desulfosporosinus spp. was observed after hydraulic dynamics. Thus, functional redundancy amongst anaerobic hydrocarbon degraders could have been relevant in sustaining biodegradation processes after hydraulic fluctuations. These findings contribute to an improved ecological perspective of contaminant plumes as a dynamic microbial habitat, with implications for both monitoring and remediation strategies in situ.
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Berthe, T., M. Ratajczak, O. Clermont, E. Denamur i F. Petit. "Evidence for Coexistence of Distinct Escherichia coli Populations in Various Aquatic Environments and Their Survival in Estuary Water". Applied and Environmental Microbiology 79, nr 15 (31.05.2013): 4684–93. http://dx.doi.org/10.1128/aem.00698-13.
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ABSTRACTEscherichia coli, a commensal bacterium from the intestinal tracts of humans and vertebrate animals, has been used as one of two bacterial indicators of fecal contamination, along with intestinal enterococci, to monitor the microbiological quality of water. However, water environments are now recognized as a secondary habitat where some strains can survive. We investigated the survival ofE. coliisolates collected from bodies of water in France exhibiting distinct profiles of contamination, defined according to the following criteria: vicinity of the point sources of contamination, land use, hydrology, and physicochemical characteristics of the receiving water. We selected 88E. colistrains among a collection of 352 strains to carry out a microcosm experiment in filtered estuarine water for 14 days at 10°C. The relationship between the survival ofE. colistrains and genotypic and phenotypic characteristics was analyzed. This work showed that distinctE. colisurvival types, able to survive from between 7 and 14 days to less than 2 days, coexisted in the water.E. coliisolates that rapidly lost their culturability were more frequently isolated in water recently contaminated by fecal bacteria of human origin, and most were multiresistant to antibiotics and harbored several virulence factors. In contrast, persistent strains able to survive from 4 to 14 days were more often found in water with low levels of fecal bacteria, belonged mainly to the B1 phylogroup, often harbored only one virulence factor,kspEorompT, and were able to grow at 7°C.
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Kovin, O. N. "MONITORING STUDIES OF GEOLOGICAL PROCESSES OCCURRED AT THE LAKE MEAD AREA SINCE IMPOUNDMENT IN 1935 UNTIL BEGINNING OF XXI CENTURY". Вестник Пермского университета. Геология 20, nr 4 (2021): 344–54. http://dx.doi.org/10.17072/psu.geol.20.4.344.
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Reservoirs, constructed for flood control, irrigation purposes, electric power and drinking water supply, can trigger significant changes in the geological processes on their territory and surroundings, as well as in climate, biosphere, and environ. In the article presents the results of comprehensive monitoring studies of Lake Mead reservoir on the Colorado River, Nevada, conducted on the request of Bureau of Reclamation of the U.S. Department of the Interior. Lake Mead was created after construction of the Hoover Dam that is one of the first dams on the Colorado River. Experts from geology, geophysics, oceanography, hydrology, and ecology were involved in this study. In result of the comprehensive research, headed by USGS, data on the dynamics of bottom sediments were obtained and analyzed; geodetic measurements of subsidence and earthquakes registration were performed; the main contamination sources were revealed. Furthermore, analysis of collected data allowed estimating the reservoir life up to 400 years.
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Golmohammadi, Golmar, Ramesh P. Rudra, Gary W. Parkin, Priyantha B. Kulasekera, Merrin Macrae i Pradeep K. Goel. "Assessment of Impacts of Climate Change on Tile Discharge and Nitrogen Yield Using the DRAINMOD Model". Hydrology 8, nr 1 (26.12.2020): 1. http://dx.doi.org/10.3390/hydrology8010001.
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The detrimental impacts of agricultural subsurface tile flows and their associated pollutants on water quality is a major environmental issue in the Great Lakes region and many other places globally. A strong understanding of water quality indicators along with the contribution of tile-drained agriculture to water contamination is necessary to assess and reduce a significant source of non-point source pollution. In this study, DRAINMOD, a field-scale hydrology and water quality model, was applied to assess the impact of future climatic change on depth to water table, tile flow and associated nitrate loss from an 8.66 ha agricultural field near Londesborough, in Southwestern Ontario, Canada. The closest available climate data from a weather station approximately 10 km from the field site was used by the Ontario Ministry of Natural Resources and Forestry (MNRF) to generate future predictions of daily precipitation and maximum and minimum air temperatures required to create the weather files for DRAINMOD. Of the 28 models applied by MNRF, three models (CGCM3T47-Run5, GFDLCM2.0, and MIROC3.2hires) were selected based on the frequency of the models recommended for use in Ontario with SRA1B emission scenario. Results suggested that simulated tile flows and evapotranspiration (ET) in the 2071–2100 period are expected to increase by 7% and 14% compared to 1960–1990 period. Results also suggest that under future climates, significant increases in nitrate losses (about 50%) will occur along with the elevated tile flows. This work suggests that climate change will have a significant effect on field hydrology and water quality in tile-drained agricultural regions.
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Mouri, Goro, i Taikan Oki. "Modelling the catchment-scale environmental impacts of wastewater treatment in an urban sewage system for CO2 emission assessment". Water Science and Technology 62, nr 4 (1.08.2010): 972–84. http://dx.doi.org/10.2166/wst.2010.373.
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Water shortages and water pollution are a global problem. Increases in population can have further acute effects on water cycles and on the availability of water resources. Thus, wastewater management plays an important role in mitigating negative impacts on natural ecosystems and human environments and is an important area of research. In this study, we modelled catchment-scale hydrology, including water balances, rainfall, contamination, and urban wastewater treatment. The entire water resource system of a basin, including a forest catchment and an urban city area, was evaluated synthetically from a spatial distribution perspective with respect to water quantity and quality; the Life Cycle Assessment (LCA) technique was applied to optimize wastewater treatment management with the aim of improving water quality and reducing CO2 emissions. A numerical model was developed to predict the water cycle and contamination in the catchment and city; the effect of a wastewater treatment system on the urban region was evaluated; pollution loads were evaluated quantitatively; and the effects of excluding rainwater from the treatment system during flooding and of urban rainwater control on water quality were examined. Analysis indicated that controlling the amount of rainwater inflow to a wastewater treatment plant (WWTP) in an urban area with a combined sewer system has a large impact on reducing CO2 emissions because of the load reduction on the urban sewage system.
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Won, Gayeon, Amy Gill i Jeffery T. LeJeune. "Microbial quality and bacteria pathogens in private wells used for drinking water in northeastern Ohio". Journal of Water and Health 11, nr 3 (12.06.2013): 555–62. http://dx.doi.org/10.2166/wh.2013.247.
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In agricultural intensive areas, drinking contaminated water from private wells is considered an important cause of acute gastroenteric illnesses (AGI), particularly among high-risk populations. In the summer of 2009, the microbial water quality of 180 randomly selected private wells in two northeastern Ohio counties, a region with a high concentration of dairy farms, was assessed. Forty-five percent (82/180) of water samples were contaminated with total coliforms. Generic Escherichia coli were present in 9% (16/180) of samples. Using real-time polymerase chain reaction, E. coli O157:H7 was identified in 4% (7/180) of specimens. Campylobacter spp. DNA could not be amplified from 70 of the samples tested for this organism. The frequency of generic E. coli contamination varied among townships (P < 0.001). Well structure (i.e. age and depth) or other common measures of pollution potential (depth of water, hydrology, topography, net recharge soil media) was not correlated with coliforms and E. coli contamination. Importantly, the presence of the pathogen E. coli O157:H7 was not associated with the presence of fecal indicators in the water samples: Only one of the seven E. coli O157-positive samples was also positive for generic E. coli. Appropriate risk management and communication processes are needed to reduce the potential waterborne disease outbreaks in agricultural intensive areas.
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Wilkinson, J., B. Reynolds, C. Neal, S. Hill, M. Neal i M. Harrow. "Major, minor and trace element composition of cloudwater and rainwater at Plynlimon". Hydrology and Earth System Sciences 1, nr 3 (30.09.1997): 557–69. http://dx.doi.org/10.5194/hess-1-557-1997.
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Abstract. The composition of cloudwater samples collected at Plynlimon, Mid Wales by the Institute of Hydrology is described based on one of the most comprehensive chemical records for deposition in the UK. Comparison with bulk rainwater samples for the same area demonstrates a tenfold enrichment of most elements in cloudwater. Large variations in cloudwater composition occur due to variations in marine and terrestrial/anthropogenic sources, general weather patterns, atmospheric circulation and seasonal effects. All trace metal concentrations are associated with anthropogenic contamination. The lanthanides La, Cc and Pr, and Y are highly correlated in ratios associated with lithogenic sources and fossil fuel combustion. Outliers suggest the influence of catalysts used in the petrochemical cracking process. Plantation forestry significantly enhances the annual deposition of solutes from cloudwater; between 15 and 40% of most constituents to upland forested catchments and around 50% for NO3, B and Cd come from cloud deposition. In upland moorland areas, only 10% of the annual deposited load of inorganic constituents comes from cloudwater.
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Tang, Lin, Jian Zhang, Micheal Simpson, Ami Arthur, Heather Grams, Yadong Wang i Carrie Langston. "Updates on the Radar Data Quality Control in the MRMS Quantitative Precipitation Estimation System". Journal of Atmospheric and Oceanic Technology 37, nr 9 (1.09.2020): 1521–37. http://dx.doi.org/10.1175/jtech-d-19-0165.1.
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AbstractThe Multi-Radar-Multi-Sensor (MRMS) system was transitioned into operations at the National Centers for Environmental Prediction in the fall of 2014. It provides high-quality and high-resolution severe weather and precipitation products for meteorology, hydrology, and aviation applications. Among processing modules, the radar data quality control (QC) plays a critical role in effectively identifying and removing various nonhydrometeor radar echoes for accurate quantitative precipitation estimation (QPE). Since its initial implementation in 2014, the radar QC has undergone continuous refinements and enhancements to ensure its robust performance across seasons and all regions in the continental United States and southern Canada. These updates include 1) improved melting-layer delineation, 2) clearance of wind farm contamination, 3) mitigation of corrupt data impacts due to hardware issues, 4) mitigation of sun spikes, and 5) mitigation of residual ground/lake/sea clutter due to sidelobe effects and anomalous propagation. This paper provides an overview of the MRMS radar data QC enhancements since 2014.
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Hà, Dang Thi. "ASSESSMENT OF ARSENIC CONTAMINATION IN THE RED RIVER: HIGH RESOLUTION MONITORING COUPLED WITH SPATIAL ANALYSIS BY GIS". Vietnam Journal of Science and Technology 51, nr 6 (6.03.2018): 779. http://dx.doi.org/10.15625/2525-2518/51/6/11644.
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The Red River (China/Vietnam, A = 155 000 km2) is a typical humid tropics river originating from the mountainous area of Yunan Province in China. Based on two sampling campaigns covering the whole Vietnamese watershed in 40 sites at low and high water levels during 2009, the seasonal and spatial variations of As concentrations in dissolved and particulate phases were determined. The dissolved As concentrations in rainy season were relatively lower than in dry season, suggesting the dilution effect of less arsenic-contaminated water. In contract, the particulate As concentrations during low water level were clearly lower than that during high water level, demonstrating a change phenomenon in As source(s) with hydrology. In addition, in order to assess spatial distribution of the As contamination in the Red River watershed and localize geochemical anomalies, multidimensional statistical analyses combined with As maps generated by GIS tool were used. The results showed that the highest As concentrations are originated from the upstream catchment and strongly decrease from upstream to downstream. Finally, the comparison between dissolved As concentrations from the Red River watershed and the national technical regulation on surface water (QCVN 08:2008/BTNMT) indicated that the quality of water in the Vietnamese Red River watershed can be classified as poor quality in the upstream part and as mediocre quality in the downstream part.
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Ferrant, S., S. Gascoin, A. Veloso, J. Salmon-Monviola, M. Claverie, V. Rivalland, G. Dedieu i in. "Agro-hydrology and multi temporal high resolution remote sensing: toward an explicit spatial processes calibration". Hydrology and Earth System Sciences Discussions 11, nr 7 (10.07.2014): 7689–732. http://dx.doi.org/10.5194/hessd-11-7689-2014.
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Abstract. The recent and forthcoming availability of high resolution satellite image series offers new opportunities in agro-hydrological research and modeling. We investigated the perspective offered by improving the crop growth dynamic simulation using the distributed agro-hydrological model, Topography based Nitrogen transfer and Transformation (TNT2), using LAI map series derived from 105 Formosat-2 (F2) images during the period 2006–2010. The TNT2 model (Beaujouan et al., 2002), calibrated with discharge and in-stream nitrate fluxes for the period 1985-2001, was tested on the 2006–2010 dataset (climate, land use, agricultural practices, discharge and nitrate fluxes at the outlet). A priori agricultural practices obtained from an extensive field survey such as seeding date, crop cultivar, and fertilizer amount were used as input variables. Continuous values of LAI as a function of cumulative daily temperature were obtained at the crop field level by fitting a double logistic equation against discrete satellite-derived LAI. Model predictions of LAI dynamics with a priori input parameters showed an temporal shift with observed LAI profiles irregularly distributed in space (between field crops) and time (between years). By re-setting seeding date at the crop field level, we proposed an optimization method to minimize efficiently this temporal shift and better fit the crop growth against the spatial observations as well as crop production. This optimization of simulated LAI has a negligible impact on water budget at the catchment scale (1 mm yr−1 in average) but a noticeable impact on in-stream nitrogen fluxes (around 12%) which is of interest considering nitrate stream contamination issues and TNT2 model objectives. This study demonstrates the contribution of forthcoming high spatial and temporal resolution products of Sentinel-2 satellite mission in improving agro-hydrological modeling by constraining the spatial representation of crop productivity.
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Ferrant, S., S. Gascoin, A. Veloso, J. Salmon-Monviola, M. Claverie, V. Rivalland, G. Dedieu i in. "Agro-hydrology and multi-temporal high-resolution remote sensing: toward an explicit spatial processes calibration". Hydrology and Earth System Sciences 18, nr 12 (16.12.2014): 5219–37. http://dx.doi.org/10.5194/hess-18-5219-2014.
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Abstract. The growing availability of high-resolution satellite image series offers new opportunities in agro-hydrological research and modeling. We investigated the possibilities offered for improving crop-growth dynamic simulation with the distributed agro-hydrological model: topography-based nitrogen transfer and transformation (TNT2). We used a leaf area index (LAI) map series derived from 105 Formosat-2 (F2) images covering the period 2006–2010. The TNT2 model (Beaujouan et al., 2002), calibrated against discharge and in-stream nitrate fluxes for the period 1985–2001, was tested on the 2005–2010 data set (climate, land use, agricultural practices, and discharge and nitrate fluxes at the outlet). Data from the first year (2005) were used to initialize the hydrological model. A priori agricultural practices obtained from an extensive field survey, such as seeding date, crop cultivar, and amount of fertilizer, were used as input variables. Continuous values of LAI as a function of cumulative daily temperature were obtained at the crop-field level by fitting a double logistic equation against discrete satellite-derived LAI. Model predictions of LAI dynamics using the a priori input parameters displayed temporal shifts from those observed LAI profiles that are irregularly distributed in space (between field crops) and time (between years). By resetting the seeding date at the crop-field level, we have developed an optimization method designed to efficiently minimize this temporal shift and better fit the crop growth against both the spatial observations and crop production. This optimization of simulated LAI has a negligible impact on water budgets at the catchment scale (1 mm yr−1 on average) but a noticeable impact on in-stream nitrogen fluxes (around 12%), which is of interest when considering nitrate stream contamination issues and the objectives of TNT2 modeling. This study demonstrates the potential contribution of the forthcoming high spatial and temporal resolution products from the Sentinel-2 satellite mission for improving agro-hydrological modeling by constraining the spatial representation of crop productivity.
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Passone, S., D. B. Das i V. Nassehi. "Development of an effluent discharge policy for the Tay Estuary based on a finite element model". Water Science and Technology 43, nr 7 (1.04.2001): 247–55. http://dx.doi.org/10.2166/wst.2001.0432.
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The tidal hydrodynamics and effluent distribution in estuaries involve a complicated range of solute transport phenomena modelled by partial differential equations. Therefore, the quantitative estimation of the risks of water and soil contamination of coastal areas as a result of polluted estuary flows, or effects of the effluent input on the chemical loads, involves the solution of these equations. Generally, the pollutants load in an estuary is determined by the nature of land use which by altering the watershed hydrology or chemical detention/release in the river banks affect the water quality of the estuaries. The present modelling work aims to investigate the solute transport behaviour in the Tay Estuary in Scotland. Based on this study, an attempt to devise an estuary specific discharge strategy for the Tay has been made. The numerical calculations are based on using 2D Galerkin finite element discretisation of the governing equations in an Eulerian co-ordinate system. The flexibility of the formulation allows it to be extended to moving boundary situations encountered in most tidal water systems.
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Hristovski, Kiril D., Tatjana Pacemska-Atanasova, Larry W. Olson, Jasmina Markovski i Trajce Mitev. "Potential health implications of water resources depletion and sewage discharges in the Republic of Macedonia". Journal of Water and Health 14, nr 4 (10.02.2016): 682–91. http://dx.doi.org/10.2166/wh.2016.274.
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Potential health implications of deficient sanitation infrastructure and reduced surface water flows due to climate change are examined in the case study of the Republic of Macedonia. Changes in surface water flows and wastewater discharges over the period 1955–2013 were analyzed to assess potential future surface water contamination trends. Simple model predictions indicated a decline in surface water hydrology over the last half century, which caused the surface waters in Macedonia to be frequently dominated by >50% of untreated sewage discharges. The surface water quality deterioration is further supported by an increasing trend in modeled biochemical oxygen demand trends, which correspond well with the scarce and intermittent water quality data that are available. Facilitated by the climate change trends, the increasing number of severe weather events is already triggering flooding of the sewage-dominated rivers into urban and non-urban areas. If efforts to develop a comprehensive sewage collection and treatment infrastructure are not implemented, such events have the potential to increase public health risks and cause epidemics, as in the 2015 case of a tularemia outbreak.
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Chen, Yepei, Kaimin Sun, Chi Chen, Ting Bai, Taejin Park, Weile Wang, Ramakrishna R. Nemani i Ranga B. Myneni. "Generation and Evaluation of LAI and FPAR Products from Himawari-8 Advanced Himawari Imager (AHI) Data". Remote Sensing 11, nr 13 (27.06.2019): 1517. http://dx.doi.org/10.3390/rs11131517.
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Leaf area index (LAI) and fraction of photosynthetically active radiation (FPAR) absorbed by vegetation are two of the essential biophysical variables used in most global models of climate, hydrology, biogeochemistry, and ecology. Most LAI/FPAR products are retrieved from non-geostationary satellite observations. Long revisit times and cloud/cloud shadow contamination lead to temporal and spatial gaps in such LAI/FPAR products. For more effective use in monitoring of vegetation phenology, climate change impacts, disaster trend etc., in a timely manner, it is critical to generate LAI/FPAR with less cloud/cloud shadow contamination and at higher temporal resolution—something that is feasible with geostationary satellite data. In this paper, we estimate the geostationary Himawari-8 Advanced Himawari Imager (AHI) LAI/FPAR fields by training artificial neural networks (ANNs) with Himawari-8 normalized difference vegetation index (NDVI) and moderate resolution imaging spectroradiometer (MODIS) LAI/FPAR products for each biome type. Daily cycles of the estimated AHI LAI/FPAR products indicate that these are stable at 10-min frequency during the day. Comprehensive evaluations were carried out for the different biome types at different spatial and temporal scales by utilizing the MODIS LAI/FPAR products and the available field measurements. These suggest that the generated Himawari-8 AHI LAI/FPAR fields were spatially and temporally consistent with the benchmark MODIS LAI/FPAR products. We also evaluated the AHI LAI/FPAR products for their potential to accurately monitor the vegetation phenology—the results show that AHI LAI/FPAR products closely match the phenological development captured by the MODIS products.
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Odeloui, Diane, Bertil Nlend, Frédéric Huneau, Hélène Celle, Emilie Garel, Abdoukarim Alassane, Moussa Boukari i Gédéon Sambienou. "Insight into Groundwater Resources along the Coast of Benin (West Africa) through Geochemistry and Isotope Hydrology; Recommendations for Improved Management". Water 14, nr 14 (7.07.2022): 2154. http://dx.doi.org/10.3390/w14142154.
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Along the West-African coast, groundwater is under several threats coming from both human activities and climate change. However, hydrogeological studies have so far been conducted in a piecemeal way, city by city. In this paper, a regional study was conducted along the Beninese coast, combining hydrogeochemistry and water stable isotopes. Monthly rainfall samples were analyzed in terms of chemistry and isotopes as well as groundwater from Holocene (upper aquifer) and Mio-Plio-Pleistocene (lower aquifer). This allowed to determine the recharge timing of aquifers (April to October, excluding August). Rainwater then infiltrates the soil with a slight evaporation. The upper aquifer, more heterogeneous, is displaying many different water types while the lower aquifer shows mainly a Na-Cl water type. While the upper aquifer shows many signs of contamination from human activities and saltwater intrusion from lakes and lagoons, the deeper aquifer is more influenced by a geogenic signature. These results are then interpreted regarding the demographic trends and climate change scenario. In the long-term, the groundwater level of the lower aquifer is expected to decrease as the rate of abstraction increases and recharge rate decreases. It is therefore recommended to develop adapted and urgent protection measures of the water resource to ensure sustainable and healthy groundwater exploitation.
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Bubb, J. M., T. P. Williams i J. N. Lester. "The Behaviour of Mercury within a Contaminated Tidal River System". Water Science and Technology 28, nr 8-9 (1.10.1993): 329–38. http://dx.doi.org/10.2166/wst.1993.0631.
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The historical emission of mercury from a municipal sewage treatment works, which discharges to a lowland river, has resulted in a 17 km contamination plume, the nature of which is strongly dependent upon river bed morphology. Significant variations occur in the spatial distribution of mercury concentrations over very short distances as dictated by sediment type, channel morphology, hydrology and sedimentation rates. The major sedimentalogical process is one of net deposition of paniculate matter rather than downstream transportation, which has buried contaminated sediment beneath a cleaner overlay. The behaviour of methylmercury within the sediment system is not dependent solely upon total mercury concentrations but instead is governed by a complex interplay between sediment redox potential, temperature, sulphur chemistry and the nature of bacterial communities. Detectable levels of methylmercury were confined to the uppermost 40 cm of sediment with peak loadings occurring 4-8 cm from the sediment/water interface. Methylmercury concentrations vary seasonally with minimum loadings in the autumn and highest concentrations in the summer. The distribution of methylmercury within the sediment compartment closely mirrors that of the mercury tolerant bacteria but in-situ and laboratory based experiments have also linked seasonal variations in methylmercury levels to changes in temperature.
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Al Ali, Saja, Fabrice Rodriguez, Céline Bonhomme i Ghassan Chebbo. "Accounting for the Spatio-Temporal Variability of Pollutant Processes in Stormwater TSS Modeling Based on Stochastic Approaches". Water 10, nr 12 (3.12.2018): 1773. http://dx.doi.org/10.3390/w10121773.
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Stormwater quality modeling remains one of the most challenging issues in urban hydrology today. The processes involved in contaminant generation and transport are very complex, with many associated uncertainties, including uncertainty arising from process variability. In this study, the spatio-temporal variability of build-up/wash-off processes in a heterogeneous urban catchment within the Parisian region is assessed based on three stochastic modeling approaches integrated into the physically based distributed hydrological model, the Urban Runoff Branching Structure (URBS) model. Results demonstrate that accounting for process variability at the scale of a hydrological element is important for analyzing the contamination recorded at the catchment outlet. The intra-event dynamics of total suspended solids (TSS) were most accurately selected for the stochastic exponential SWMM model, as this model succeeded not only in simulating the general trend of TSS concentrations fluctuations but also in replicating multiple peaks observed in pollutographs. The advantage of this approach is that it captures the stochastic nature of the processes with minimal prior knowledge and without extensive calibration, though further enhancement is necessary for it to become a useful tool to support decision making.
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Jayasinghe, Amadini, Scott Elliott, Georgina A. Gibson i Douglas Vandemark. "The Role of Phytoplankton Biomacromolecules in Controlling Ocean Surface Roughness". Atmosphere 13, nr 12 (14.12.2022): 2101. http://dx.doi.org/10.3390/atmos13122101.
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Satellite altimetric data routinely map sea surface topography by measuring the ocean return signal. One source of altimeter measurement contamination occurs when the radar ocean backscatter becomes unusually large, a situation termed a Sigma-0 bloom. Past research suggests Sigma-0 blooms are associated with weak wind and natural surface slick conditions where capillary waves at the air–sea interface are suppressed. To date, no explicit connection between these conditions and Sigma-0 bloom presence has been provided. Using a series of simplified equations, our reduced model determines capillary wave heights from estimates of planktonic carbon concentrations and regional wind speed. Our results suggest that the radar signal reflection increases as capillary wave height decreases. This relationship depends on surfactant concentration, surfactant composition, and wind speed. Model sensitivity analysis indicates that the interface reflectivity depends on biological activity and wind speed. Our proposed simplified model provides a method to identify potential Sigma-0 bloom regions. We conclude that because of the demonstrated impact of biological surfactants on ocean roughness, it is necessary to consider the biological activity, i.e., phytoplankton bloom events, when interpreting signals from radar altimetry and when developing ocean hydrology models.
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Franzluebbers, Alan J., John A. Stuedemann i Dorcas H. Franklin. "Water infiltration and surface-soil structural properties as influenced by animal traffic in the Southern Piedmont USA". Renewable Agriculture and Food Systems 27, nr 4 (26.08.2011): 256–65. http://dx.doi.org/10.1017/s1742170511000378.
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AbstractSurface-soil structural condition in perennial pastures is expected to be modified by how forage is (a) harvested through haying or grazing and (b) stimulated through source of nutrients applied, as well as by compactive forces, e.g., grazing cattle or hay harvest machinery. Changes in surface-soil condition can affect hydrologic processes that have important implications for plant growth, greenhouse gas emissions and off-site water quality. We determined the effects of harvest management and nutrient source on the rate of ponded water infiltration and penetration resistance in a bermudagrass [Cynodon dactylon (L.) Pers.]/tall fescue (Lolium arundinaceum Schreb. S.J. Darbyshire) pasture on a Typic Kanhapludult in Georgia. During a period when soil was wet (61% water-filled pore space), the rate of water infiltration was 2.8 ± 1.5 times greater when forage was left unharvested as when hayed or grazed (mean ± standard deviation among nine nutrient source × harvest management comparisons). During a subsequent period, when soil was dry (28% water-filled pore space), the rate of water infiltration followed the same treatment pattern, but was not statistically different among harvest-management practices (1.5 ± 0.4 times greater between unharvested and other systems). Penetration resistance of the surface at 10 cm depth followed the order: unharvested (62 J) < hayed (100 J) < low grazing pressure (119 J) < high grazing pressure (137 J). Water infiltration during the wet period was negatively related (P ⩽ 0.01) to soil-water content (r = − 0.57), penetration resistance at 0–10 cm depth (r = − 0.50) and bulk density at 3–6 cm depth (r = − 0.53), but was positively related to surface residue C (r = 0.47) and soil organic C concentration at 12–20 cm depth (r = 0.42). These results suggest that complex soil physical (i.e., aggregation, penetration resistance and infiltration) and biological (i.e., plant growth, surface residues and soil organic matter) interactions occur in pastures. We conclude that well-managed grazing systems with excellent ground cover should have adequate hydrologic condition to promote pasture productivity and limit environmental contamination from runoff. Further work is needed to understand the linkages between field- and watershed-scale hydrology in perennial pastures and their implications on water quality.
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Pennino, M. J., S. S. Kaushal, P. M. Mayer, R. M. Utz i C. A. Cooper. "Stream restoration and sanitary infrastructure alter sources and fluxes of water, carbon, and nutrients in urban watersheds". Hydrology and Earth System Sciences Discussions 12, nr 12 (16.12.2015): 13149–96. http://dx.doi.org/10.5194/hessd-12-13149-2015.
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Abstract. An improved understanding of sources and timing of water and nutrient fluxes associated with urban stream restoration is critical for guiding effective watershed management. We investigated how sources, fluxes, and flowpaths of water, carbon (C), nitrogen (N), and phosphorus (P) shift in response to differences in stream restoration and sanitary infrastructure. We compared a restored stream with 3 unrestored streams draining urban development and stormwater management over a 3 year period. We found that there was significantly decreased peak discharge in response to precipitation events following stream restoration. Similarly, we found that the restored stream showed significantly lower monthly peak runoff (9.4 ± 1.0 mm d−1) compared with two urban unrestored streams (ranging from 44.9 ± 4.5 to 55.4 ± 5.8 mm d−1) draining higher impervious surface cover. Peak runoff in the restored stream was more similar to a less developed stream draining extensive stormwater management (13.2 ± 1.9 mm d−1). Interestingly, the restored stream exported most carbon, nitrogen, and phosphorus loads at relatively lower streamflow than the 2 more urban streams, which exported most of their loads at higher and less frequent streamflow. Annual exports of total carbon (6.6 ± 0.5 kg ha−1 yr−1), total nitrogen (4.5 ± 0.3 kg ha−1 yr−1), and total phosphorus (161 ± 15 g ha−1 yr−1) were significantly lower in the restored stream compared to both urban unrestored streams (p < 0.05) and similar to the stream draining stormwater management. Although stream restoration appeared to potentially influence hydrology to some degree, nitrate isotope data suggested that 55 ± 1 % of the nitrate in the restored stream was derived from leaky sanitary sewers (during baseflow), similar to the unrestored streams. Longitudinal synoptic surveys of water and nitrate isotopes along all 4 watersheds suggested the importance of urban groundwater contamination from leaky piped infrastructure. Urban groundwater contamination was also suggested by additional tracer measurements including fluoride (added to drinking water) and iodide (contained in dietary salt). Our results suggest that integrating stream restoration with restoration of aging sanitary infrastructure can be critical to more effectively minimize watershed nutrient export. Given that both stream restoration and sanitary pipe repairs both involve extensive channel manipulation, they can be considered simultaneously in management strategies. In addition, ground water can be a major source of nutrient fluxes in urban watersheds, which has been less considered compared with upland sources and storm drains. Goundwater sources, fluxes, and flowpath should also be targeted in efforts to improve stream restoration strategies and prioritize hydrologic "hot spots" along watersheds where stream restoration is most likely to succeed.
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B.K. Ratha, S. R. Barick. "Hydrological Analysis and Assessment about the impact of Limestone Mining on water Pollution in Hial Area , Bolangir district, Odisha, India". International Journal of Scientific Research and Management (IJSRM) 5, nr 8 (6.08.2017): 6613–17. http://dx.doi.org/10.18535/ijsrm/v5i8.06.
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80 percent area of Odisha are underlain by hard rock .Therefore Ground water resource is very scarce inmost part of the state. Bolangir district is known as drought prone area .Our study area comes under drought prone zone. Most people depend on ground water for agricultural and drinking purpose. Water is a scarcere source there. A number of Lime Stone mines are being operated in the study area adds to further scarcity as contamination may render a part of available resource as unsuitable for use . Lithology controls the water chemistry of the area . There is a direct relationship between the rock type and water composition of the area. Rock type is the main factor which is responsible for controlling water quality mechanism of the study area. While Lime Stone affects the water pollution , simultaneously host rock in the area and variation of the rock type is also notable factor in its hydrology. Therefore it is essential to make a detailed hydrological study of the area under observation in order to assess the impact of Lime Stone Mining on water pollution .For quality evaluation during pre monsoon period and post monsoon period from 2010 to 2015 water samples were collected from the study area and were analysed in Laboratory .
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Severini, Edoardo, Marco Bartoli, Monica Pinardi i Fulvio Celico. "Reactive Silica Traces Manure Spreading in Alluvial Aquifers Affected by Nitrate Contamination: A Case Study in a High Plain of Northern Italy". Water 12, nr 9 (9.09.2020): 2511. http://dx.doi.org/10.3390/w12092511.
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In the northern sector of the Po River Plain (Italy), widespread intensive agriculture and animal farming are supported by large amounts of water from Alpine lakes and their emissaries. Flood irrigation and excess fertilization with manure affect both the hydrology and the chemical quality of surface and groundwater, resulting in diffuse nitrogen pollution. However, studies analyzing the mechanisms linking agricultural practices with vertical and horizontal nitrogen paths are scarce in this area. We investigated groundwater quality and quantity in an unconfined, coarse-grained alluvial aquifer adjacent to the Mincio River (a tributary of the Po River), where steep summer gradients of nitrate (NO3−) concentrations are reported. The effects of manure on solutes’ vertical transport during precipitation events in fertilized and in control soils were simulated under laboratory conditions. The results show high SiO2 and NO3− leaching in fertilized soils. Similarly, field data are characterized by high SiO2 and NO3− concentrations, with a comparable spatial distribution but a different temporal evolution, suggesting their common origin but different processes affecting their concentrations in the study area. Our results show that SiO2 can be used as a conservative tracer of manure spreading, as it does not undergo biogeochemical processes that significantly alter its concentrations. On the contrary, nitrate displays large short-term variations related to aquifer recharge (i.e., flood irrigation and precipitation). In fact, aquifer recharge may promote immediate solubilization and stimulate nitrification, resulting in high NO3− concentrations up to 95.9 mg/L, exceeding the Water Framework Directive (WFD) thresholds. When recharge ends, anoxic conditions likely establish in the saturated zone, favoring denitrification and resulting in a steep decrease in NO3− concentrations.
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Van Rooy, Dirk. "An Evaluation of the Importance of Transmissivity, Head and Concentration Data for Contaminant Transport Modelling". Hydrology Research 18, nr 3 (1.06.1987): 121–50. http://dx.doi.org/10.2166/nh.1987.0010.
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The 3 basic data types of contaminant hydrology are examined by stochastic modelling of a groundwater contamination case. The stochastic transport model, which is of the Monte Carlo type, uses a numerical flow and transport model, and views transmissivity as a random autocorrelated field. A large set of transmissivity realisations is generated using the turning bands technique. Conditioning is done with regard to transmissivity, head and concentration observations. The unconditional approach assumes, explicitly, a stationary stochastic process of logtransmissivity. This is implicitly turned into a non-stationary process by the conditioning procedures. These use simple and universal kriging, and utilize the kriging uncertainties to determine subsets of realisations that are in agreement with the observations at a predefined confidence level. The approach followed allows quantification of the uncertainties of predicted head and concentration through space and time. Conditioning on head observations leaves large transport uncertainties. Conditioning on the transmissivity data has a more prominent effect. The single, most effective data type is the concentration data. Smallest transport uncertainties occur when all the data are simultaneously taken into account. The conditioning effect depends on the number and spatial configuration of the data. A trade-off between the stochastic and deterministic transport approach is suggested. In modelling terms this corresponds to a trade-off between advection and dispersion.
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Liu, Wen, Liankai Zhang, Pengyu Liu, Xiaoqun Qin, Xiaojing Shan i Xin Yao. "FDOM Conversion in Karst Watersheds Expressed by Three-Dimensional Fluorescence Spectroscopy". Water 10, nr 10 (11.10.2018): 1427. http://dx.doi.org/10.3390/w10101427.
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A karst system, formed by the dissolution of carbonate rocks, is usually susceptible to contamination. Little is known about the composition of natural dissolved organic matter (DOM) in groundwater systems, especially in karstic groundwater. To reveal the characteristics of DOM in a karst aquifer, the Yufuhe River Basin, a typical karst watershed in northern China, was selected. DOM fluorescence (FDOM) was measured with the excitation-emission matrices (EEMs) spectroscopy technique. Parallel factor analysis (PARAFAC) was used to analyze the karst hydrogeological factors that affect FDOM biogeochemical behavior. Three fluorescent components, i.e., tyrosine-like, tryptophan-like, and ultraviolet fulvic acid were found. Their fluorescence properties were closely related to human activity and subterranean hydrology. Fluorescence properties suggested that FDOM in the Yufuhe River karst aquifer was predominant from anthropogenic activity. In addition, due to the effect of karstic heterogeneous hydrological conditions, FDOM showed obvious differentiation in the recharge, flow path, and discharge systems. The FDOM fluorescence intensity (FI) was weak in surface water and groundwater at the upper reaches (recharge area). In the middle of the flow path area, the percentage of tyrosine-like and tryptophan-like substances degraded and fulvic acid rose gradually. However, after infiltrating into the lower reaches (discharge area) of the deep karst aquifer system, the fulvic acid matter was consumed and protein-like matter accumulated.
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Kayastha, Sadhana Pradhanang. "Heavy metals Fractionation in Bagmati River Sediments, Nepal". Journal of Hydrology and Meteorology 9, nr 1 (30.08.2016): 119–28. http://dx.doi.org/10.3126/jhm.v9i1.15587.
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The aim of this work was speciation of heavy metals on the level of the geochemical background; in bottom sediments of the Bagmati River in Kathmandu valley. The distribution and accumulation of heavy metals in the sediments of the Bagmati River were investigated. Sediment samples from six locations were collected and characterized for metals content (cadmium, lead, copper and zinc). The determination of extractable heavy metals such as, Cd, Pb, Cu and Zn, in the sediment samples was carried out by atomic absorption spectrometry. The study has been conducted using five steps sequential extraction procedure described by tessier. Apart from total concentration, the distribution of the above metals into five fractions: exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to organic matter, and residual, was studied by means of an analytical procedure involving sequential chemical extraction. The result obtained showed total metal concentration to be in the range of Cd 0.89-2.29 mg/kg; Pb 57.58-221mg/kg; Cu 52.2 -198.17 mg/kg and 78.23-362.90 mg/kg in all the areas studied. The fractionated toxic metals like Cd, and Pb were observed to be in the range of 15-36%, and 11- 29%, respectively, in mobile or bio-available fractions of sediments. This potentially mobile fraction could pose a serious threat, with respect to contamination of waterways and aquatic environment.Journal of Hydrology and Meteorology, Vol. 9(1) 2015, p.119-128
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Wang, Hongyan, Gaili Wang i Liping Liu. "Climatological Beam Propagation Conditions for China’s Weather Radar Network". Journal of Applied Meteorology and Climatology 57, nr 1 (styczeń 2018): 3–14. http://dx.doi.org/10.1175/jamc-d-17-0097.1.
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AbstractThe vertical refractivity gradient (VRG) is critical to weather radar beam propagation. The most common method of calculating beam paths uses the 4/3 Earth radius model, which corresponds to standard refraction conditions. In the present work, to better document propagation conditions for radar electromagnetic waves, which is essential for hydrology and numerical weather forecast models to more fully benefit from observations taken from the new-generation weather radar network in China, VRG spatial and temporal variations in the first kilometers above the surface are explored using 6-yr sounding observations. Under the effects of both regional climatic and topographic conditions, VRG values for most of the radars are generally smaller than those of the standard conditions for much of the year. There are similar or slightly larger values at only a few radar sites. Smaller VRG values are more frequent and widespread, especially during rainy seasons when weather radar observations are important. In such conditions, beam heights estimated using standard atmospheric refraction are overestimated relative to actual heights for most of the radars. Underestimates are much less common and of much shorter duration. However, height deviations are acceptable for being well within the uncertainty of radar echo height owing to the ~1° beamwidth. In coastal areas and the middle and lower reaches of the Yangtze River, radar observations should be applied with much more caution because of the greater risk of beam blockage and clutter contamination.
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Cattan, Philippe, Jean-Baptiste Charlier, Florence Clostre, Philippe Letourmy, Luc Arnaud, Julie Gresser i Magalie Jannoyer. "A conceptual model of organochlorine fate from a combined analysis of spatial and mid- to long-term trends of surface and ground water contamination in tropical areas (FWI)". Hydrology and Earth System Sciences 23, nr 2 (7.02.2019): 691–709. http://dx.doi.org/10.5194/hess-23-691-2019.
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Abstract. In this study, we investigated the management of long-term environmental pollution by organic pollutants such as organochlorine pesticides. We set out to identify conditions that are conducive to reducing pollution levels for these persistent molecules and then propose a conceptual model of organochlorine fate in water. Our approach looked at spatio-temporal changes in pollutant contents in surface water (SW) and groundwater (GW) on a large scale, in order to decipher the respective roles of soil, geology, hydrology and past treatment practices. The case of chlordecone (CLD) on the island of Martinique (1100 km2) was selected given the sampling campaigns carried out since 2007 over more than 150 sites. CLD, its metabolite chlordecone-5b-hydro (5bCLD) and the metabolite-to-parent-compound ratio were compared. As regards the spatial variability of water contamination, our results showed that banana cropping areas explained the location of contaminated SW and GW, whereas the combination of soil and geology factors explained the main spatial variability in the 5bCLD∕CLD ratio. For temporal variability, these conditions defined a high diversity of situations in terms of the duration of pollution, highlighting two groups: water draining old geological formations and ferralsols or vertisols vs. recent geology and andosols. A conceptual leaching model provided some key information to help interpret downward trends in CLD and 5bCLD observed in water. Lastly, a conceptual model of organochlorine fate is proposed to explain the diversity of the 5bCLD∕CLD ratio in water. Our conclusions highlight the combined role of soil and groundwater residence time for differentiating between conditions that are more conducive, or not, to the disappearance of CLD from the environment. This paper presents a model that provides an overall perception of organochlorine pesticide fate in the environment.
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Tan, Weiwei, Chunzhu Wei, Yang Lu i Desheng Xue. "Reconstruction of All-Weather Daytime and Nighttime MODIS Aqua-Terra Land Surface Temperature Products Using an XGBoost Approach". Remote Sensing 13, nr 22 (22.11.2021): 4723. http://dx.doi.org/10.3390/rs13224723.
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Generating spatiotemporally continuous land surface temperature (LST) data is in great demand for hydrology, meteorology, ecology, environmental studies, etc. However, the thermal infrared (TIR)-based LST measurements are prone to cloud contamination with missing pixels. To repair the missing pixels, a new XGBoost-based linking approach for reconstructing daytime and nighttime Moderate Resolution Imaging Spectroradiometer (MODIS) LST measurements was introduced. The instantaneous solar radiation and two soil-related predictors from China Data Assimilation System (CLDAS) 0.0625°/1-h data were selected as the linking variables to depict the relationship with instantaneous MODIS LST data. Other land surface properties, including two vegetation indices, the water index, the surface albedo, and topographic parameters, were also used as the predictor variables. The XGBoost method was used to fit an LST linking model by the training datasets from clear-sky pixels and was then applied to the MODIS Aqua-Terra LSTs during summer time (June to August) in 2017 and 2018 across China. The recovered LST data was further rectified with the Savitzky–Golay (SG) filtering method. The results showed the distribution of the reconstructed LSTs present a reasonable pattern for different land-cover types and topography. The evaluation results using in situ longwave radiation measurements showed the RMSE varies from 3.91 K to 5.53 K for the cloud-free pixels and from 4.42 K to 4.97 K for the cloud-covered pixels. In addition, the reconstructed LST products correlated well with CLDAS LST data with similar LST spatial patterns. The variable importance analysis revealed that the two soil-related predictors and the elevation variable are key parameters due to their great contribution to the XGBoost model performance.
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Liddle, Elisabeth S., Sarah M. Mager i Etienne Nel. "Water quality awareness and barriers to safe water provisioning in informal communities: A case study from Ndola, Zambia". Bulletin of Geography. Socio-economic Series 26, nr 26 (1.12.2014): 167–81. http://dx.doi.org/10.2478/bog-2014-0052.
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Abstract Local water providers in developing nations typically view shallow hand-dug wells as traditional and backward sources of water supply. It has long been assumed that the urban poor do not have the ability to develop these in a way that allows them to be classified as ‘improved’ in terms of the Millennium Development Goal for water, believing that users do not understand the factors that constitute safe water and the threats to these sources. Our assessment of the level of environmental knowledge held by local water-users in Ndola in Zambia demonstrates a coherent understanding of the safety of their water sources, the quality of these, the threats to them, and the fundamentals of how their local hydrology works, all of which is contrary to the perspective of key informants who are involved in water supply. Despite their environmental awareness, the majority of users did not generally protect their wells from contamination nor treat their water. The apparent paradox between awareness of risks to water and implementing protection of that water source is a function of the complex suite of socially manifested attitudes, habits and behaviours when it comes to water protection and treatment, which is exacerbated by vulnerable community and family structures and entrenched poverty. For meaningful outcomes in improved access to safe water to be realised providers need to increase their engagement with the informal communities, moving deeper into community-based participatory planning and recognise the societal and cultural factors that are entrained into these communities water supply practices. A key part of this involves the need for providers to move away from simple knowledge-based education to the more holistic form of skill-based health education.
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Boreux, Maxime P., Scott F. Lamoureux i Brian F. Cumming. "Use of water isotopes and chemistry to infer the type and degree of exchange between groundwater and lakes in an esker complex of northeastern Ontario, Canada". Hydrology and Earth System Sciences 25, nr 12 (13.12.2021): 6309–32. http://dx.doi.org/10.5194/hess-25-6309-2021.
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Abstract. While interactions between groundwater and lake-water influence water chemistry, water balance, aquatic organisms, biochemical cycles and contamination levels, they remain a poorly studied component of lake hydrology. Identifying the controls of groundwater and lake-water interactions at the landscape level and classifying lakes into categories based on their degree of interaction with the groundwater can provide insights into a lake's sensitivity and vulnerability to environmental stressors. Such information can also provide baseline conditions for comparison to future changes that are important for water management and conservation. To this end, water chemistry and water isotopic composition were investigated in a set of 50 boreal lakes located at different elevations in an esker system near Timmins, Ontario. Analyses focused on stable isotopic ratios of hydrogen and oxygen and specific conductance as indicators of the position of a lake with respect to the influence of groundwater. Both isotopic composition and specific conductance distinguished higher-elevation groundwater-recharge lakes from lower-elevation groundwater-discharge lakes. Groundwater-recharge lakes were high-elevation lakes characterized by enriched isotopic values and low values of specific conductance. In contrast, groundwater-discharge lakes were isotopically depleted and had higher values of specific conductance and occurred at lower elevations. An intermediate group of lakes was also defined (termed seepage lakes) and had intermediate isotopic and water-chemistry characteristics compared to recharge and discharge lakes. Differences in water geochemistry between field campaigns revealed that upland groundwater-recharge lakes showed evidence of evaporative drawdown, indicating sensitivity to short-term changes in climate, whereas the lower-elevation groundwater-discharge lakes showed little variation between seasonal samples and consequently would likely be affected only by hydroclimatological changes of greater duration and magnitude.
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Boada-Robayo, Laura, Danna Lesley Cruz-Reyes, Carlos Cifuentes-González, William Rojas-Carabali, Ángela Paola Vargas-Largo i Alejandra de-la-Torre. "Exploring the association between precipitation and population cases of ocular toxoplasmosis in Colombia". PLOS Neglected Tropical Diseases 16, nr 10 (5.10.2022): e0010742. http://dx.doi.org/10.1371/journal.pntd.0010742.
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Background Previous studies suggest a relationship between precipitation and ocular toxoplasmosis (OT) reactivation and congenital toxoplasmosis infection. We aimed to investigate the relationship between precipitation and the frequency of new OT cases in Colombia from 2015 to 2019. Methodology This retrospective cohort study analyzed data obtained from a claims-based database created by the Colombian Ministry of Health and national registries of precipitation of the Institute of Hydrology, Meteorology, and Environmental Studies. We estimated the daily number of OT cases, interpolating data from the average number of annual cases from 2015 to 2019. Then, we compared exposures (mean daily precipitation) in the case period in which the events (interpolated OT new cases) occurred by a quasi-Poisson regression, combined with a distributed lag non-linear model to estimate the non-linear and lag–response curve. Principal findings In the 5-year analysis, there were 1,741 new OT cases. Most of the cases occurred in 2019, followed by 2015 and 2018. New OT cases among departments were significantly different (P< 0.01). The cumulative exposure-response curve was decreasing for most departments. Nevertheless, in Chocó, Bogotá, Cesar, Cauca, and Guajira, when a certain amount of precipitation accumulates, the relative risk (RR) increases, which was contrary to the pattern observed in the other regions. The response curves to the one-day lag showed that precipitation influences the RR; however, the trends vary by department. Finally, an increasing trend in the number of cases was directly proportional to precipitation in Guajira, Atlántico, Norte de Santander, Santander, Caquetá and Quindío (r = 0.84; P< 0.05). Conclusions Precipitation influenced the RR for new OT cases. However, varying trends among geographical regions (departments) lead us to hypothesize that other sociodemographic, behavioral, and environmental variables, such as wind and water contamination, could influence the RR.
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Pérez-Iglesias, Juan Manuel, Nadia Carla Bach, Patricia Laura Colombetti, Pablo Acuña, Jorge Esteban Colman-Lerner, Silvia Patricia González, Julie Celine Brodeur i Cesar Américo Almeida. "Biomonitoring of Alterations in Fish That Inhabit Anthropic Aquatic Environments in a Basin from Semi-Arid Regions". Toxics 11, nr 1 (12.01.2023): 73. http://dx.doi.org/10.3390/toxics11010073.
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Industrial, agricultural, and urban areas can be sources of pollution and a cause of habitat fragmentation. The Conlara River located in the northeast of San Luis Province suffers different environmental pressures along its course from urban to agro-industrial areas. The present study aims to assess the water quality of the Conlara basin by evaluating how metals and pesticide contamination as well as physicochemical parameters relate to physiological stress in Jenynsia multidentata. Samplings were carried out in four sites characterized by a growing gradient of anthropic impact from the springs to the final sections of the river, starting with tourism passing through urban areas and ending with large agricultural areas (from S1 to S4) during both the dry and wet seasons. A total of 27 parameters were determined (11 physicochemical, 9 heavy metals, and 7 pesticides) in surface waters. Biomarkers (CAT, TBARS, ChE, and MN) showed significant physiological and cytological alterations in J. multidentata depending on the hydrology season. The combination of physicochemical parameters, metals, and pesticide levels allowed typification and differentiation of the sites. Some metal (Cr, Mn, Pb, and Zn) and pesticide (α-BHC, chlorpyrifos, permethrin and cypermethrin, and endosulfan α) levels recorded exceeded the recommended Argentinian legislation values. A principal component analysis (PCA) allowed detection of differences between both seasons and across sites. Furthermore, the differences in distances showed by PCA between the sites were due to differences in the presence of physicochemical parameters, metals, and pesticides correlated with several biomarkers’ responses depending on type of environmental stressor. Water quality evaluation along the Conlara River shows deterioration and different types of environmental stressors, identifying zones, and specific sources of pollution. Furthermore, the biomarkers suggest that the native species could be sensitive to anthropogenic environmental pressures.
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Abd-Elaty, Ismail, Lorenzo Pugliese, Martina Zelenakova, Peter Mesaros i Abdelaziz El Shinawi. "Simulation-Based Solutions Reducing Soil and Groundwater Contamination from Fertilizers in Arid and Semi-Arid Regions: Case Study the Eastern Nile Delta, Egypt". International Journal of Environmental Research and Public Health 17, nr 24 (15.12.2020): 9373. http://dx.doi.org/10.3390/ijerph17249373.
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Intensive agriculture requires increasing application of fertilizers in order to sustain food production. Improper use of these substances in combination with increasing seawater intrusion results in long-term and nonpoint soil and groundwater contamination. In this work, a 3-D groundwater and solute transport numerical model was created to simulate the effect of excessive fertilizers application along the Bahr El Baqar drain system, in the eastern Nile Delta, Egypt. The geotechnical properties of the soils, hydrologic parameters, and unconfined compressive strength were determined at different sites and used as input parameters for the model. Model results showed that silty clay soils are able to contain the contaminations and preserve the groundwater quality. Nevertheless, sandy soils primarily located at the beginning of the Bahr El Baqar drain allow leakage of fertilizers to the groundwater. Thus, fertilizer application should be properly managed in the top sandy layers to protect the groundwater and soil, as increasing aquifer by excess irrigation water increased the groundwater contamination in confined layers due to the high value of cumulative salt for the current situation while the unconfined zone decreased groundwater and soil contamination. A mass transport 3-D multi-species (MT3D) model was set to identify the optimal measure to tackle soil and groundwater contamination along the Bahr El-Baqar drain system. A potential increase of the abstraction rates in the study area has a positive impact in reducing the transfer of fertilizer contamination to groundwater while it has a negative impact for soil contamination. The scenario analysis further indicated that the installation of a drainage network decreases the groundwater and soil contamination. Both solutions are potentially effective for protection against nonpoint contamination along the Bahr El Baqar drain system. However, a more sustainable management approach of fertilizer application is needed to adequately protect the receptors located further downstream in the Nile Delta.
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Hubbard, Laura E., Steffanie H. Keefe, Dana W. Kolpin, Larry B. Barber, Joseph W. Duris, Kasey J. Hutchinson i Paul M. Bradley. "Understanding the hydrologic impacts of wastewater treatment plant discharge to shallow groundwater: before and after plant shutdown". Environmental Science: Water Research & Technology 2, nr 5 (2016): 864–74. http://dx.doi.org/10.1039/c6ew00128a.
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WWTP cessation is a rare environmental event with far-ranging hydrologic effects. Results have implications for shallow-groundwater recharge and WWTP-derived contamination kilometers downstream from the outfall.