dissolved nitrate Articles
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Nitrate-nitrogen, Land Use/Land Cover, and Soil Drainage Associations at multiple spatial scales
Managing non–point-source pollution of water requires knowledge of land use/land cover (LULC) influences at altering watershed scales. To gain improved understanding of relationships among LULC, soil drainage, and dissolved nitrate-N dynamics within the Calapooia River Basin in western Oregon, we selected 44 watersheds ranging in size between 3 and 33 km2 for monthly synoptic sampling of surface ...
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Influence of environmental variables on saxitoxin yields by Cylindrospermopsis raciborskii in a mesotrophic subtropical reservoir
Saxitoxins are a class of toxins produced by at least two groups of evolutionarily distant organisms (cyanobacteria and dinoflagellates). While the toxicity of these toxins is relatively well characterized, to date little is known about their drivers and ecological functions, especially in lower latitude tropical and subtropical freshwater ecosystems. In the present study, we aimed to obtain ...
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Aerator retrofit enables city to meet nitrogen limits - Case Study
Problem The City of Ocala, Fla., faced tighter effluent nitrogen limits due to the presence of springs in the St. John’s River basin. The city operates an Ovivo Carrousel plant. Solution Rather than add basins, the city retrofitted the Carrousel basins with dual-impeller Excell aerators and the automated internal recycle EliminatIR gate from Ovivo USA. Result The retrofits have allowed ...
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Characterizing natural dissolved organic matter in a freshly submerged catchment (Three Gorges Dam, China) using UV absorption, fluorescence spectroscopy and PARAFAC
This study applied parallel factor analysis (PARAFAC) to fluorescence excitation–emission matrices (EEMs) of natural water samples in a freshly submerged catchment in the upper reach of Three Gorges Dam (China). Two fluorescent natural dissolved organic matter (NDOM) components (humic/fulvic-like) were uncovered and were positively correlated with selected water quality parameters, i.e. dissolved ...
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Start-up readiness of the Apache wetland.
The Apache Wetland was constructed in 1997 pursuant to a U.S. Environmental Protection Agency order to treat nitrate-contaminated groundwater within the Apache Powder Superfund Site. To date, the treatment facility is entering its fourth growing season in an effort to accumulate sufficient carbonaceous detritus of principally decayed Typha latifolia biomass. This substrate is required to maintain ...
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Redox conditions and groundwater quality issues of selected alluvial aquifers in Serbia
Redox conditions are an important regulator of aqueous biogeochemistry and knowledge about them is crucial for an understanding of the fate and occurrence of nitrates, emerging substances, and organic compounds in shallow groundwater. The aim of this paper is to determine redox categories, along with prevailing redox processes, and the differences in groundwater quality between shallow ...
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Evolution of a new surface water quality index for Karoon catchment in Iran
Water quality standards are developed worldwide by national and international agencies for pollution control decision-making. Use-based water quality classification criteria and Water Quality Indices (WQIs) also play an important role in the assessment of the suitability of water resources for various applications. The present study proposes a better overall index for water quality in Iran and ...
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A NEW MEDIUM FOR CAENORHABDITIS ELEGANS TOXICOLOGY AND NANOTOXICOLOGY STUDIES, DESIGNED TO BETTER REFLECT NATURAL SOIL SOLUTION CONDITIONS
A new toxicity test medium for C. elegans is presented. The test solution is designed so that it provides a better representation of natural soil pore water conditions than currently available test media. The medium has a composition that can readily be modified to allow for studies of the influences of a range of environmentally relevant parameters on nematode biology and toxicology. Tests ...
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Variations of nitrogen transport in the mainstream of the Yellow River, China
Three sections along the mainstream of the Yellow River were chosen as sites for monitoring the concentration variations of nitrogen species. First, the nitrogen in the water was mainly dissolved and dominated by nitrate–nitrogen. Second, the nitrogen concentrations in the middle stream were much higher than those in the upper stream, and close to those in the lower stream. Third, the nitrogen ...
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Spatio-temporal variations of water quality in Nova Ponte Reservoir, Araguari River Basin, Brazil
Multivariate techniques, like cluster analysis (CA) and principal component analysis (PCA), were used to evaluate the spatial and temporal variability of surface water quality in a large neotropical hydroelectric reservoir (Nova Ponte Reservoir). The dataset, obtained during the period of 1995–2011 from the Energy Company of Minas Gerais State (CEMIG), contains 14 parameters surveyed ...
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Assessment of groundwater quality in the Seraidi region (north-east of Algeria) using NSF-WQI
Scarcity of water, pollution load, political issues and rising population have drawn great attention for proper management of water resources such as groundwater in the 21st century. The evaluation of groundwater quality is a critical element in the assessment of water resources. The quality/potability of water that is consumed defines the baseline of protection against many diseases and ...
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Case study – benzene contamination pilot study - retail gasoline site, Northglenn, Colorado
Introduction LTE was contracted by Shell Oil Products US (Shell) to conduct a pilot test program at a petroleum hydrocarbon impacted retail facility north of Denver, Colorado. The goals of the pilot program were to: 1) Determine the viability of using a carbon-based injectate (RPI’s BOS 200®) to remove hydrocarbons from soil and groundwater, 2) Assess transient hydraulic conditions ...
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Quality assessment of roof-harvested rainwater in the West Bank, Palestinian Authority
Rain harvesting is becoming more common in the Palestinian Territories as a result of drinking water scarcity. Although it might pose serious human health risk, this water is being consumed without treatment in many areas of the West Bank. The present study evaluates the physicochemical and microbial quality of harvested rainwater that is used as potable water in the West Bank. Samples from ...
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Water quality and antifungal susceptibility of opportunistic yeast pathogens from rivers
Yeasts from water sources have been associated with diseases ranging from superficial mucosal infections to life threatening diseases. The aim of this study was to determine the water quality as well as diversity and antifungal susceptibility of yeasts from two rivers. Yeast levels and physico-chemical parameter data were analyzed by principal component analysis to determine correlations ...
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Assessing selenium contamination in the irrigated stream–aquifer system of the Arkansas river, Colorado
Received for publication December 4, 2008. Prudent interventions for reducing selenium (Se) in groundwater and streams within an irrigated river valley must be guided by a sound understanding of current field conditions. An emerging picture of the nature of Se contamination within the Lower Arkansas River Valley in Colorado is provided by data from a large number of groundwater and surface water ...
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Design and management of rainwater harvesting systems to control water quality for potable purposes in Cu Khe, Vietnam
There are debates about whether rainwater is suitable as drinking water. A serious shortcoming of the debate is that there are differences in the design and management of rainwater harvesting (RWH) systems. This study is based on the performance of two RWH systems that are used for drinking purposes at a kindergarten and a primary school in Cu Khe, Vietnam. Each system comprised a painted ...
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The use of shallow high resolution seismic reflection data to determine drilling locations at the Apache powder superfund site.
INTRODUCTION Groundwater contamination at the Apache Powder Superfund Site in Cochise County, Arizona includes dissolved nitrate-N and perchlorate. Past studies have determined that these contaminants migrate laterally from a perched zone underlying Apache Nitrogen Products, Inc. operating areas into the shallow aquifer of the San Pedro River alluvium (shallow aquifer). The base of both the ...
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Water quality monitoring with hydrolab MS5
Background The Škocjan caves are a unique natural phenomenon located in south western Slovenia and are preserved as the Škocjan Caves Park under UNESCO protection. One of the most famous network of underground caves in the world, they were formed by the flow of the Reka River as it bored tunnels through the region’s limestone geology. The river first disappears underground just outside the ...
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Concurrent bioremediation of perchlorate and 1,1,1-trichloroethane in an emulsified oil barrier
Abstract A detailed field pilot test was conducted to evaluate the use of edible oil emulsions for enhanced in situ biodegradation of perchlorate and chlorinated solvents in groundwater. Edible oil substrate (EOS®) was injected into a line of ten direct push injection wells over a 2-day period to form a 15-m-long biologically active permeable reactive barrier (bio-barrier). Field monitoring ...
By Redox Tech
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TEP and biofilm fouling on membranes
Summary Biological fouling on membranes is a major problem in desalination and water purification plants. Oceanographers and limnologists have found that most marine and fresh waters are full of microscopic Transparent Exopolymer Particles, otherwise known as TEP. In this article, aquatic microbiologist Tom Berman and Filtration Specialist Marina Holenberg (Amiad Filtration Systems, Amiad, ...
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