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1.
PLoS One ; 15(9): e0239509, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32986717

RESUMO

In the past few decades, there has been a rapid growth in the concentration of nitrogenous compounds such as nitrate-nitrogen and ammonia-nitrogen in rivers, primarily due to increasing agricultural and industrial activities. These nitrogenous compounds are mainly responsible for eutrophication when present in river water, and for 'blue baby syndrome' when present in drinking water. High concentrations of these compounds in rivers may eventually lead to the closure of treatment plants. This study presents a training and a selection approach to develop an optimum artificial neural network model for predicting monthly average nitrate-N and monthly average ammonia-N. Several studies have predicted these compounds, but most of the proposed procedures do not involve testing various model architectures in order to achieve the optimum predicting model. Additionally, none of the models have been trained for hydrological conditions such as the case of Malaysia. This study presents models trained on the hydrological data from 1981 to 2017 for the Langat River in Selangor, Malaysia. The model architectures used for training are General Regression Neural Network (GRNN), Multilayer Neural Network and Radial Basis Function Neural Network (RBFNN). These models were trained for various combinations of internal parameters, input variables and model architectures. Post-training, the optimum performing model was selected based on the regression and error values and plot of predicted versus observed values. Optimum models provide promising results with a minimum overall regression value of 0.92.


Assuntos
Nitrogênio/química , Rios/química , Agricultura/métodos , Monitoramento Ambiental/métodos , Hidrologia/métodos , Malásia , Redes Neurais de Computação , Poluentes Químicos da Água/química , Qualidade da Água
2.
Nat Commun ; 11(1): 4353, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32859908

RESUMO

Continental-scale models of malaria climate suitability typically couple well-established temperature-response models with basic estimates of vector habitat availability using rainfall as a proxy. Here we show that across continental Africa, the estimated geographic range of climatic suitability for malaria transmission is more sensitive to the precipitation threshold than the thermal response curve applied. To address this problem we use downscaled daily climate predictions from seven GCMs to run a continental-scale hydrological model for a process-based representation of mosquito breeding habitat availability. A more complex pattern of malaria suitability emerges as water is routed through drainage networks and river corridors serve as year-round transmission foci. The estimated hydro-climatically suitable area for stable malaria transmission is smaller than previous models suggest and shows only a very small increase in state-of-the-art future climate scenarios. However, bigger geographical shifts are observed than with most rainfall threshold models and the pattern of that shift is very different when using a hydrological model to estimate surface water availability for vector breeding.


Assuntos
Mudança Climática , Hidrologia/métodos , Malária/transmissão , África/epidemiologia , Animais , Anopheles/fisiologia , Ecologia , Ecossistema , Mapeamento Geográfico , Geografia , Malária/epidemiologia , Mosquitos Vetores/fisiologia , Rios , Estações do Ano , Temperatura
3.
Environ Geochem Health ; 42(11): 3819-3839, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32601907

RESUMO

Monitoring the groundwater chemical composition and identifying the presence of pollutants is an integral part of any comprehensive groundwater management strategy. The present study was conducted in a part of West Tripura, northeast India, to investigate the presence and sources of trace metals in groundwater and the risk to human health due to direct ingestion of groundwater. Samples were collected from 68 locations twice a year from 2016 to 2018. Mixed Ca-Mg-HCO3, Ca-Cl and Ca-Mg-Cl were the main groundwater types. Hydrogeochemical methods showed groundwater mineralization due to (1) carbonate dissolution, (2) silicate weathering, (3) cation exchange processes and (4) anthropogenic sources. Occurrence of faecal coliforms increased in groundwater after monsoons. Nitrate and microbial contamination from wastewater infiltration were apparent. Iron, manganese, lead, cadmium and arsenic were above the drinking water limits prescribed by the Bureau of Indian Standards. Water quality index indicated 1.5% had poor, 8.7% had marginal, 16.2% had fair, 66.2% had good and 7.4% had excellent water quality. Correlation and principal component analysis reiterated the sources of major ions and trace metals identified from hydrogeochemical methods. Human exposure assessment suggests health risk due to high iron in groundwater. The presence of unsafe levels of trace metals in groundwater requires proper treatment measures before domestic use.


Assuntos
Água Subterrânea/análise , Metais/análise , Oligoelementos/análise , Poluentes Químicos da Água/análise , Qualidade da Água , Carbonatos/análise , Carbonatos/química , Exposição Dietética/efeitos adversos , Exposição Dietética/análise , Água Potável/análise , Monitoramento Ambiental/métodos , Fezes/microbiologia , Água Subterrânea/química , Água Subterrânea/microbiologia , Humanos , Hidrologia/métodos , Índia , Nitratos/análise , Medição de Risco/métodos , Águas Residuárias/análise , Águas Residuárias/microbiologia , Microbiologia da Água
4.
Eur J Protistol ; 74: 125693, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32305703

RESUMO

Testate amoebae are a widely-used tool for palaeohydrological reconstruction from peatlands. However, it has been observed that weak idiosomic siliceous tests (WISTs) are common in uppermost peats, but very rarely found as subfossils deeper in the peat profile. This taphonomic problem has been noted widely and it has been established that WISTs disaggregate and/or dissolve in the low pH condition of ombrotrophic peatlands. Here we investigate the effect of this taphonomic problem on water-table reconstructions from thirty European peatlands through the comparison of reconstructions based on all taxa and those with WISTs removed. In almost all cases the decomposition of WISTs does not introduce discernible bias to peatland water-table reconstructions. However, some discrepancy is apparent when large abundances of Corythion-Trinema type are present (9-12 cm deviation with 50-60% abundance of this particular taxon). We recommend that WISTs should be removed before carrying out water-table reconstructions, and that the minimum count of testate amoebae per sample should exclude WISTs to ensure the development of robust reconstructions.


Assuntos
Amoeba , Água Subterrânea , Hidrologia/métodos , Solo/parasitologia
5.
Environ Geochem Health ; 42(9): 2667-2684, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31900824

RESUMO

Groundwater quality analysis has become essentially important in the present world scenario. In recent years, advanced technologies have replaced the traditional ones which are being helpful in simplifying the complex works. In this study, multivariate statistical analysis is carried out with the help of SPSS software for 45 groundwater samples of Kanavi Halla Sub-Basin (KHSB). The quality of groundwater is determined for various parameters which were analyzed and their concentration is correlated with other parameters using correlation matrix. The PCA technique is applied on water quality parameters, from which four components are extracted with 80.28% total variance. The extracted components suggest that the sources behind the higher loadings of each factor are by geological, agricultural, rainfall, domestic wastewater and industrial activities. Results of the Kaiser-Meyer-Olkin and Bartlett's test conducted have value of 0.659 which is greater than the standard value (0.5). Based on water quality index (WQI), it was noticeably depicted that 2/3rd of the KHSB groundwater quality falls under poor to very poor condition, and hardly 26% of groundwater available is portable. Thus, this study contributes the effective use of multivariate statistics and WQI analysis for groundwater quality. It helps in understanding the hydro-geochemistry of the groundwater and also aids in minimizing the larger set of data into smaller set with effective interpretation.


Assuntos
Água Subterrânea/análise , Água Subterrânea/química , Qualidade da Água , Agricultura , Monitoramento Ambiental/métodos , Hidrologia/métodos , Hidrologia/estatística & dados numéricos , Índia , Indústrias , Análise Multivariada , Águas Residuárias
6.
Environ Geochem Health ; 42(9): 2609-2626, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31673916

RESUMO

Karst groundwater, an important water source, is often highly influenced by human impacts, causing environmental damage and threats to human health. However, studies on the anthropogenic influences on the hydrogeochemical evolution of karst groundwater are relatively rare. To assess hydrogeochemical formation and evolution, we focused on a typical karst groundwater system (Jinan, China) which is composed of cold groundwater (av. temperature 13-17 °C), springs and geothermal water (av. temperature > 30 °C) and is significantly affected by human activities. The study was performed by means of water samples collecting and analyzing and isotope analysis (2H, 18O and 14C). The statistical analysis and inverse models were also applied to further understand geochemical processes and anthropogenic influences. The 2H, 18O and 14C results indicate that the cold karst groundwater is easily influenced and contaminated by the local environment, while geothermal water is relatively old with a slow rate of recharge. The hydrochemical types of cold karst groundwater are mainly HCO3-Ca and HCO3·SO4-Ca, while geothermal water hydrochemical types are SO4-Ca·Na and SO4-Ca. Groundwater Ca2+, Mg2+, HCO3- and SO42- are mainly controlled by carbonate equilibrium, gypsum dissolution and dedolomitization. Groundwater Na+, K+ and Cl- are mainly derived from halite dissolution, and in geothermal water, they are also affected by incongruent dissolution of albite and K-feldspar. Anthropogenic nitrogen produces ammonium resulting in nitrification and reduction in CO2(g) consumption and HCO3- release from carbonate dissolution. Principal component analysis and inverse models also indicate that nitrification and denitrification have significantly affected water-rock interactions. Our study suggests that karst groundwater quality is dominated by water-rock interactions and elucidates the influence of anthropogenic nitrogen. We believe that this paper will be a good reference point to study anthropogenic influences on the groundwater environment and to protect karst groundwater globally.


Assuntos
Água Subterrânea/análise , Água Subterrânea/química , Radioisótopos de Carbono/análise , Carbonatos/análise , China , Cloretos/análise , Monitoramento Ambiental/métodos , Humanos , Hidrologia/métodos , Hidrologia/estatística & dados numéricos , Modelos Teóricos , Nascentes Naturais , Isótopos de Oxigênio/análise , Potássio/análise , Análise de Componente Principal , Sódio/análise , Temperatura , Poluentes Químicos da Água/análise , Qualidade da Água
7.
Chemosphere ; 239: 124741, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31518921

RESUMO

In many parts of the world, wastewater irrigation has become a common practice because of freshwater scarcity and to increase resource reuse efficiency. Wastewater irrigation has positive impacts on livelihoods and at the same time, it has adverse impacts related to environmental pollution. Hydrochemical processes and groundwater behaviour need to be analyzed for a thorough understanding of the geochemical evolution in the wastewater irrigated systems. The current study focuses on a micro-watershed in the peri-urban Hyderabad of India, where farmers practice intensive wastewater irrigation. To evaluate the major factors that control groundwater geochemical processes, we analyzed the chemical composition of the wastewater used for irrigation and groundwater samples on a monthly basis for one hydrological year. The groundwater samples were collected in three settings of the watershed: wastewater irrigated area, groundwater irrigated area and upstream peri-urban area. The collected groundwater and wastewater samples were analyzed for major anions, cations and nutrients. We systematically investigated the anthropogenic influences and hydrogeochemical processes such as cation exchange, precipitation and dissolution of minerals using saturated indices, and freshwater-wastewater mixtures at the aquifer interface. Saturation indices of halite, gypsum and fluorite are exhibiting mineral dissolution and calcite and dolomite display mineral precipitation. Overall, the results suggest that the groundwater geochemistry of the watershed is largely controlled by long-term wastewater irrigation, local rainfall patterns and water-rock interactions. The study results can provide the basis for local decision-makers to develop sustainable groundwater management strategies and to control the aquifer pollution influenced by wastewater irrigation.


Assuntos
Irrigação Agrícola/métodos , Água Subterrânea/química , Águas Residuárias , Ânions/análise , Carbonato de Cálcio/química , Sulfato de Cálcio/química , Cátions/análise , Meio Ambiente , Monitoramento Ambiental/métodos , Água Doce/química , Água Subterrânea/análise , Hidrologia/métodos , Índia , Magnésio/química , Salinidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Qualidade da Água
8.
Environ Geochem Health ; 42(2): 693-707, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31446575

RESUMO

The objective of this study is geochronological investigation of sedimentological and inorganic composition, in the Danube Djerdap Lake sediments in order to obtain reliable information about former pollution. Eleven samples were taken from the 135-cm-deep sediment core drilled at the Orlova location. Since the core represents sediments deposited during 1972-2016, the sedimentation rate of ~ 3 cm year-1 was estimated. Grain size, mineralogical and geochemical composition was determined. Sediments are sandy silts and clayey silts, and only the deepest and shallowest layers contain > 30% of sand-size fraction. The highest concentrations of minor elements are found in the oldest sediment (1972-1977) as a consequence of the high flux of the material from variable sources. During the sedimentation period (1975-1990), the concentrations of analyzed elements are generally decreasing until the beginning of 1990s. After this period, there are two distinct decreases and two distinct increases in concentrations of elements. The fluctuations in minor element concentrations are a consequence of both natural and anthropogenic sources. Granitic rocks situated south are source of minerals that carry minor elements. Enrichment Factor, Geoaccumulation Index, Contamination Factor and Pollution Load Index indicate that concentrations of certain minor elements at specific depositional periods have anthropogenic source.


Assuntos
Sedimentos Geológicos/química , Lagos/química , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Sedimentos Geológicos/análise , Hidrologia/métodos , Lagos/análise , Metais/análise , Minerais/análise , Sérvia
9.
Environ Geochem Health ; 42(3): 933-953, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31494783

RESUMO

Water resource assessment is crucial for human well-being and ecosystem health. Assessments considering both blue and green water are of great significance, as green water plays a critical but often ignored role in the terrestrial ecosystem, especially in arid and semi-arid regions. Many approaches have been developed for green and blue water valuation; however, few approaches consider the interrelationship between green and blue water. This study proposed a new framework for green and blue water assessment by considering the interactions between green and blue water and the connections between human and natural ecosystems in an arid endorheic river basin where hydrological cycling is dramatically altered by human activities. The results show that even though green water is the dominant water resource, blue water is also critical. Most of the blue water is redirected back into the soil through physical and human-induced processes to meet the water demand of the ecosystem. The blue and green water regimes are found to be totally different in different ecosystems due to the temporal and spatial variability in water supply and consumption. We also found that humans are using an increasing proportion of water, resulting in decreasing water availability. Extensive water use by humans reduces the water availability for the natural ecosystem. Approximately 38.6% of the vegetation-covered area, which is dominated by farmland and forest, may face a moderate or high risk of increased conflict and tension over freshwater. This study provides crucial information to better understand the interactions between green and blue water and the relations between humans and nature by explicitly assessing water resources. It also provides crucial information for water management strategies that aim to balance humankind and nature.


Assuntos
Água Doce , Hidrologia/métodos , Recursos Hídricos , China , Conservação dos Recursos Hídricos/métodos , Clima Desértico , Ecossistema , Água Subterrânea , Humanos , Reciclagem , Rios , Solo/química , Abastecimento de Água
10.
PLoS One ; 14(11): e0224558, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31770381

RESUMO

Torrential and long-lasting rainfall often causes long-duration floods in flat and lowland areas in data-scarce Nyaungdon Area of Myanmar, imposing large threats to local people and their livelihoods. As historical hydrological observations and surveys on the impact of floods are very limited, flood hazard assessment and mapping are still lacked in this region, making it hard to design and implement effective flood protection measures. This study mainly focuses on evaluating the predicative capability of a 2D coupled hydrology-inundation model, namely the Rainfall-Runoff-Inundation (RRI) model, using ground observations and satellite remote sensing, and applying the RRI model to produce a flood hazard map for hazard assessment in Nyaungdon Area. Topography, land cover, and precipitation are used to drive the RRI model to simulate the spatial extent of flooding. Satellite images from Moderate Resolution Imaging Spectroradiometer (MODIS) and the Phased Array type L-band Synthetic Aperture Radar-2 onboard Advanced Land Observing Satellite-2 (ALOS-2 ALOS-2/PALSAR-2) are used to validate the modeled potential inundation areas. Model validation through comparisons with the streamflow observations and satellite inundation images shows that the RRI model can realistically capture the flow processes (R2 ≥ 0.87; NSE ≥ 0.60) and associated inundated areas (success index ≥ 0.66) of the historical extreme events. The resultant flood hazard map clearly highlights the areas with high levels of risks and provides a valuable tool for the design and implementation of future flood control and mitigation measures.


Assuntos
Monitoramento Ambiental/métodos , Inundações/prevenção & controle , Hidrologia/métodos , Avaliação de Risco e Mitigação , Imagens de Satélites , Monitoramento Ambiental/estatística & dados numéricos , Inundações/estatística & dados numéricos , Modelos Estatísticos , Mianmar , Chuva , Medição de Risco/métodos , Medição de Risco/estatística & dados numéricos , Rios
11.
Artigo em Inglês | MEDLINE | ID: mdl-31703350

RESUMO

The stationarity of observed hydrological series has been broken or destroyed in many areas worldwide due to changing environments, causing hydrologic designs under stationarity assumption to be questioned and placing designed projects under threat. This paper proposed a data expansion approach-namely, the cross-reconstruction (CR) method-for frequency analysis for a step-changed runoff series combined with the empirical mode decomposition (EMD) method. The purpose is to expand the small data on each step to meet the requirements of data capacity for frequency analysis and to provide more reliable statistics within a stepped runoff series. Taking runoff records at three gauges in western China as examples, the results showed that the cross-reconstruction method has the advantage of data expansion of the small sample runoff data, and the expanded runoff data at steps can meet the data capacity requirements for frequency analysis. In addition, the comparison of the expanded and measured data at steps indicated that the expanded data can demonstrate the statistics closer to the potential data population, rather than just reflecting the measured data. Therefore, it is considered that the CR method ought to be available in frequency analysis for step-changed records, can be used as a tool to construct the hydrological probability distribution under different levels of changing environments (at different steps) through data expansion, and can further assist policy-making in water resources management in the future.


Assuntos
Hidrologia/métodos , Movimentos da Água , Recursos Hídricos , China
12.
Sensors (Basel) ; 19(22)2019 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-31717509

RESUMO

The Athabasca River watershed plays a dominant role in both the economy and the environment in Alberta, Canada. Natural and anthropogenic factors rapidly changed the landscape of the watershed in recent decades. The dynamic of such changes in the landscape characteristics of the watershed calls for a comprehensive and up-to-date land-use and land-cover (LULC) map, which could serve different user-groups and purposes. The aim of the study herein was to delineate a 2016 LULC map of the Athabasca River watershed using Landsat-8 Operational Land Imager (OLI) images, Moderate Resolution Imaging Spectroradiometer (MODIS)-derived enhanced vegetation index (EVI) images, and other ancillary data. In order to achieve this, firstly, a preliminary LULC map was developed through applying the iterative self-organizing data analysis (ISODATA) clustering technique on 24 scenes of Landsat-8 OLI. Secondly, a Terra MODIS-derived 250-m 16-day composite of 30 EVI images over the growing season was employed to enhance the vegetation classes. Thirdly, several geospatial ancillary datasets were used in the post-classification improvement processes to generate a final 2016 LULC map of the study area, exhibiting 14 LULC classes. Fourthly, an accuracy assessment was carried out to ensure the reliability of the generated final LULC classes. The results, with an overall accuracy and Cohen's kappa of 74.95% and 68.34%, respectively, showed that coniferous forest (47.30%), deciduous forest (16.76%), mixed forest (6.65%), agriculture (6.37%), water (6.10%), and developed land (3.78%) were the major LULC classes of the watershed. Fifthly, to support the data needs of scientists across various disciplines, data fusion techniques into the LULC map were performed using the Alberta merged wetland inventory 2017 data. The results generated two useful maps applicable for hydro-ecological applications. Such maps depicted two specific categories including different types of burned (approximately 6%) and wetland (approximately 30%) classes. In fact, these maps could serve as important decision support tools for policy-makers and local regulatory authorities in the sustainable management of the Athabasca River watershed.


Assuntos
Ecologia/métodos , Hidrologia/métodos , Rios , Imagens de Satélites
13.
Artigo em Inglês | MEDLINE | ID: mdl-31683789

RESUMO

A digital elevation model (DEM) is a digital model or 3D representation of a terrain's surface. There are many methods to create DEM such as LiDAR, stereo photogrammetry and topographic maps. DEMs are very important for many applications such as extracting terrain parameters for geomorphology and modeling water flow for hydrology or mass movement. A number of websites are available to provide DEM such as SRTM, GTOPO30 and ASTER GDEM but their accuracy differs from one to another and also selecting a small DEM size (high resolution) gives accurate information, but the analysis takes long time. This paper aims to analyze the impact of using different available DEMs on watershed geomorphological properties on order to provide guidelines for users to select the most suitable DEM that obtain an accurate analysis in less time. Three programs; watershed modeling systems: WMS, Global Mapper and Google Earth were used in this study. Three case studies were studied to check the accuracy of these models and select the most accurate one for application. Satellite images downloaded from Google Earth were used as a guide reference for the comparison due to their accuracy and high resolution. The results indicated that the SRTM model was more accurate (95%) for all case studies according to our comparison between its delineation and satellite images. ASTER GDEM is the second most accurate model with an accuracy of 87%, the GTOPO30's accuracy is 80%.


Assuntos
Conservação dos Recursos Naturais/métodos , Confiabilidade dos Dados , Monitoramento Ambiental/métodos , Hidrologia/métodos , Topografia de Moiré , Imagens de Satélites , Egito , Modelos Teóricos
14.
Proc Natl Acad Sci U S A ; 116(39): 19563-19570, 2019 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-31488710

RESUMO

Changes in the amount, intensity, and timing of precipitation are increasing hydrologic variability in many regions, but we have little understanding of how these changes are affecting freshwater species. Stream-breeding amphibians-a diverse group in North America-may be particularly sensitive to hydrologic variability during aquatic larval and metamorphic stages. Here, we tested the prediction that hydrologic variability in streams decreases survival through metamorphosis in the salamander Gyrinophilus porphyriticus, reducing recruitment to the adult stage. Using a 20-y dataset from Merrill Brook, a stream in northern New Hampshire, we show that abundance of G. porphyriticus adults has declined by ∼50% since 1999, but there has been no trend in larval abundance. We then tested whether hydrologic variability during summers influences survival through metamorphosis, using capture-mark-recapture data from Merrill Brook (1999 to 2004) and from 4 streams in the Hubbard Brook Experimental Forest (2012 to 2014), also in New Hampshire. At both sites, survival through metamorphosis declined with increasing variability of stream discharge. These results suggest that hydrologic variability reduces the demographic resilience and adaptive capacity of G. porphyriticus populations by decreasing recruitment of breeding adults. They also provide insight on how increasing hydrologic variability is affecting freshwater species, and on the broader effects of environmental variability on species with vulnerable metamorphic stages.


Assuntos
Metamorfose Biológica/fisiologia , Urodelos/crescimento & desenvolvimento , Animais , Demografia , Ecossistema , Água Doce , Hidrodinâmica , Hidrologia/métodos , Larva , América do Norte , Dinâmica Populacional , Rios , Estações do Ano
15.
Sci Rep ; 9(1): 13506, 2019 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-31534180

RESUMO

Stream microbes that occur in the Mediterranean Basin have been shown to possess heightened sensitivity to intensified water stress attributed to climate change. Here, we investigate the effects of long-term drought (150 days), storms and rewetting (7 days) on the diversity and composition of archaea, bacteria and fungi inhabiting intermittent streambed sediment (surface and hyporheic) and buried leaves. Hydrological alterations modified the archaeal community composition more than the bacterial community composition, whereas fungi were the least affected. Throughout the experiment, archaeal communities colonizing sediments showed greater phylogenetic distances compared to those of bacteria and fungi, suggesting considerable adaptation to severe hydrological disturbances. The increase in the class abundances, such as those of Thermoplasmata within archaea and of Actinobacteria and Bacilli within bacteria, revealed signs of transitioning to a drought-favoured and soil-like community composition. Strikingly, we found that in comparison to the drying phase, water return (as sporadic storms and rewetting) led to larger shifts in the surface microbial community composition and diversity. In addition, microhabitat characteristics, such as the greater capacity of the hyporheic zone to maintain/conserve moisture, tended to modulate the ability of certain microbes (e.g., bacteria) to cope with severe hydrological disturbances.


Assuntos
Hidrologia/métodos , Microbiota/fisiologia , Adaptação Biológica/genética , Archaea/classificação , Bactérias/classificação , Mudança Climática , Secas , Fungos/classificação , Sedimentos Geológicos/microbiologia , Filogenia , Rios/microbiologia
16.
Mar Pollut Bull ; 149: 110554, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31542596

RESUMO

Although numerous steady-state effluent plume dilution models are in use, their application in tidal environments remains a challenge. Three-dimensional dynamic circulation models are also inadequate, often due to the lack of required resolution and simplifying assumptions. To overcome these limitations, we present FVCOM-plume-an outfall plume dilution and transport model that operates within the Finite Volume Coastal Ocean Model (FVCOM) framework. It provides simultaneous inclusion of near-field dilution and far-field plume transport processes. The near-field is based on UM3 model using Lagrangian Control Volume approach to compute buoyant plume trajectory and dilution from multiport diffusers. The far-field uses neutrally buoyant particles with point masses and the random walk method to solve unsteady advection-diffusion processes. A density kernel approach is used to compute concentrations at point locations and analyze far-field plume characteristics. The results demonstrate the ability of FVCOM-plume to simultaneously capture near-field and far-field effluent plume dynamics in tidal environments.


Assuntos
Hidrologia/métodos , Modelos Teóricos , Águas Residuárias , Difusão , Hidrodinâmica
17.
Environ Monit Assess ; 191(9): 548, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31392422

RESUMO

Global warming portends an accelerated water cycle as increased evaporation feeds atmospheric moisture and precipitation. To monitor effects on surface water levels, we describe a low-cost hydrologic observatory suitable for small to medium size lakes. The observatory comprises sensor platforms that were built in-house to compile continuous, sub-daily water budgets. The variables measured directly are lake stage (S), evaporation (E), and precipitation (P). A net inflow term (Qnet) is estimated as a residual in the continuity equation: ∆S = P - E + Qnet. We describe how to build in-lake stilling wells and floating evaporation pans using readily available materials. We assess their performance in laboratory tests and field trials. A 3-month deployment on a small Wisconsin lake (18 ha, 10 m deep) confirms that continuous estimates of ∆S, E, P, and Qnet can be made with good precision and accuracy at hourly time scales. During that deployment, daily estimates of E from the floating evaporation pans were comparable with estimates made using the more data-intensive Bowen ratio energy balance method and a mass transfer model. Since small lakes are numerically dominant and widely distributed across the globe, a network of hydrologic observatories would enable the calibration and validation of climate models and consumptive use policies at local and regional scales. And since the observatories are inexpensive and relatively simple to maintain, citizen scientists could facilitate the expansion of spatial coverage with minimal training.


Assuntos
Monitoramento Ambiental/métodos , Hidrologia/métodos , Lagos/análise , Clima , Aquecimento Global , Ciclo Hidrológico , Wisconsin
18.
Mar Pollut Bull ; 146: 711-717, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426213

RESUMO

Narragansett Bay is an urban estuary that historically has been impacted by long-term discharge of sanitary wastewater (WW) effluents. High-density water sampling was conducted in Narragansett Bay, RI, USA, in an effort to understand the distribution and behavior of sucralose, an artificial sweetener that has shown utility as a sanitary wastewater tracer. Water samples were collected at sixty-seven sites and analyzed for sucralose, whose performance was compared to other tracers present in wastewater effluents. Concentrations of sucralose were much higher than the other tracers measured, carbamazepine and caffeine, ranging from 18 to 3180 ng/L and corresponded well with salinity (r2 = 0.88), demonstrating conservative behavior throughout the Bay. Mapped interpolation data using an empirical bayesian kriging model clearly show the spatial trends of WW and how estuarine processes influence dilution and dispersion throughout the Bay. These findings provide further evidence of the efficacy of sucralose as a wastewater tracer in large urban estuaries where continuous high-volume discharge of WW occur.


Assuntos
Monitoramento Ambiental/métodos , Sacarose/análogos & derivados , Águas Residuárias/análise , Poluentes Químicos da Água/análise , Teorema de Bayes , Baías , Cafeína/análise , Estuários , Hidrologia/métodos , Rhode Island , Salinidade , Sacarose/análise , Edulcorantes/análise
19.
Isotopes Environ Health Stud ; 55(5): 438-458, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31437024

RESUMO

Changes in groundwater evolutionary processes due to aquifer overexploitation show a world-wide increase and have been of growing concern in recent years. The study aimed to improve the knowledge of groundwater evolutionary processes by means of stable water isotopes and hydrochemistry in a representative lake basin, Ordos energy base. Groundwater, precipitation, and lake water collected during four campaigns were analysed by stable isotopes and chemical compositions. Results showed that temperature effect predominated the isotope fractionation in precipitation, while evaporation and inadequate groundwater recharge were the key factors explaining high salinity and isotopic enrichment in lake water. Additionally, the Kuisheng Lake was a preferential area of groundwater recharge, while the Subei Lake received less sources from underlying aquifer due to the combined effects of low permeable zone and upstream groundwater captured by the production wells. The homogeneous isotope signatures of groundwater may be ascribed to the closely vertical hydraulic connectivity between the unconfined and the confined aquifers. Isotopically enriched groundwater pumping from well field probably promoted isotopic depletion in groundwater depression cone. These findings not only provide the conceptual framework for the inland basin, but also have important implications for sustainable groundwater management in other groundwater discharge basins with arid climate.


Assuntos
Deutério/análise , Água Subterrânea/química , Lagos/química , Isótopos de Oxigênio/análise , China , Monitoramento Ambiental/métodos , Água Subterrânea/análise , Hidrologia/métodos , Lagos/análise , Chuva , Salinidade , Movimentos da Água
20.
Environ Sci Pollut Res Int ; 26(26): 26706-26720, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31297708

RESUMO

Since decades, surface water bodies have been exposed to pesticides from agriculture. In many places, retention systems are regarded as an important mitigation strategy to lower pesticide pollution. Hence, the processes governing the transport of pesticides in and through a retention system have to be understood to achieve sufficient pesticide attenuation. In this study, the temporal dynamics of metazachlor and its transformation products metazachlor-oxalic acid (OA) and -sulphonic acid (ESA) were observed in an agricultural retention pond and hydrologic tracers helped to understand system-inherent processes. Pesticide measurements were carried out for 80 days after their application during transient flow conditions. During a short-term (3 days) experiment, the tracers bromide, uranine and sulphorhodamine B were used to determine hydraulic conditions, residence times and sorption potential. A long-term experiment with sodium naphthionate (2 months) and isotopes (12 months) provided information about inputs via interflow and surface-groundwater interactions. During transient conditions, high concentration pulses of up to 35 µg L-1 metazachlor, 14.7 µg L-1 OA and 22.5 µg L-1 ESA were quantified that enduringly raised solute concentrations in the pond. Mean residence time in the system accounted for approximately 4 h showing first tracer breakthrough after 5 min and last tracer concentrations 72 h after injection. While input via interflow was confirmed, no evidence for surface-groundwater interaction was found. Different tracers illustrated potentials for sorption and photolytic degradation inside the system. This study shows that high-resolution sampling is essential to obtain robust results about retention efficiency and that hydrological tracers may be used to determine the governing processes.


Assuntos
Acetamidas/análise , Herbicidas/análise , Hidrologia/métodos , Poluentes Químicos da Água/análise , Acetamidas/química , Agricultura , Biodegradação Ambiental , Brometos/análise , Fluoresceína/análise , Alemanha , Água Subterrânea , Herbicidas/química , Ácido Oxálico/química , Tanques , Rodaminas/análise , Ácidos Sulfônicos/química , Poluentes Químicos da Água/química , Poluição Química da Água/prevenção & controle
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