Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 190.163
Filtrar
1.
Environ Monit Assess ; 193(5): 316, 2021 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-33931801

RESUMEN

Electrokinetic remediation technique is widely applied for the removal of heavy metal from contaminated soil, but the soil buffering capacity and fractionation of heavy metals mainly affect the cost and duration of the treatment. This study aims to treat heavy metal-contaminated sediments by electrokinetic remediation (EKR) technique by using various enhancing agents such as EDTA, [Formula: see text], HCI, [Formula: see text], acetic acid and citric acid for optimizing the cost and treatment duration. The optimum molar concentration of enhancing agent for treatment was estimated by batch experiments to maximize the dissolution of target heavy metals and reduce the dissolution of earth metals (Fe, Al and Ca) to maintain soil health. The EKR experiments were performed up to 15 days with the above enhancing agents to reduce the risk associated with heavy metals and the selection of enhancing agents based on removal efficiency was found to be in an order of EDTA > citric acid > acetic acid > [Formula: see text] > HCl [Formula: see text] [Formula: see text]. Also, a numerical model has been developed by incorporating main electrokinetic transport phenomena (electromigration and electroosmosis) and geochemical processes for the prediction of treatment duration and to scale up the EKR process. The model predicts well with experimental heavy metal removal with a MAPD of [Formula: see text] 2-18 %. The parametric study on electrode distance for full-scale EKR treatment was found in this study as [Formula: see text] 0.5 m.


Asunto(s)
Restauración y Remediación Ambiental , Metales Pesados , Contaminantes del Suelo , Monitoreo del Ambiente , Metales Pesados/análisis , Suelo , Contaminantes del Suelo/análisis
2.
Sci Total Environ ; 773: 144757, 2021 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-33940701

RESUMEN

The Clinch River watershed of the upper Tennessee River Basin of Virginia and Tennessee, USA supports one of North America's greatest concentrations of freshwater biodiversity, including 46 extant species of native freshwater mussels (Order Unionida), 20 of which are protected as federally endangered. Despite the global biological significance of the Clinch River, mussel populations are declining in some reaches, both in species richness and abundance. The aim of this study was to evaluate the exposure of adult resident mussels to a suite of inorganic and organic contaminant stressors in distinct sections of the Clinch River that encompassed a range of mussel abundance and health. To provide insight into the potential role of pollutants in the decline of mussels, including within a previously documented "zone of mussel decline", the mainstem Clinch River (8 sites) and its tributaries (4 sites) were examined over two consecutive years. We quantified and related metals and organic contaminant concentrations in mussels to their associated habitat compartments (bed sediment, suspended particulate sediment, pore water, and surface water). We found that concentrations of organic contaminants in resident mussels, particularly the suite of 42 polycyclic aromatic hydrocarbons (PAHs) analyzed, were related to PAH concentrations in all four habitat (media) compartments. Further, PAH concentrations in mussel tissue (range 37.8-978.1 ng/g dry weight in 2012 and 194.3-1073.7 ng/g dry weight in 2013) were negatively related to the spatial pattern in mussel densities (rs = -0.64, p ≤ 0.05 in 2012 and rs = -0.83, p ≤ 0.05 in 2013) within the river, and were highest in the "zone of mussel decline". In contrast, the suite of 22 metals analyzed in resident mussels were largely unrelated to the spatial pattern of variation of metals in the four habitat compartments except for Manganese (Mn; range 3630.5-23,749.2 µg/g dry weight in 2012 and 1540.4-12,605.8 µg/g dry weight in 2013) in surface water (rs = 0.58, p < 0.1) and pore water (rs = 0.76, p ≤ 0.05). This study revealed that PAHs and Mn are important pollutant stressors to mussels in the Clinch River and that they are largely being delivered through the Guest River tributary watershed. Accordingly, future conservation and management efforts would benefit by identifying, and ideally mitigating, the sources of PAHs, Mn, and other current or legacy mining-associated pollutants to the mainstem river and its tributaries.


Asunto(s)
Bivalvos , Contaminantes Ambientales , Contaminantes Químicos del Agua , Animales , Biodiversidad , Monitoreo del Ambiente , Agua Dulce , Tennessee , Virginia , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidad
3.
Sci Total Environ ; 773: 145351, 2021 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-33940724

RESUMEN

Cabled observatories are marine infrastructures equipped with biogeochemical and oceanographic sensors as well as High-Definition video and audio equipment, hence providing unprecedented opportunities to study marine biotic and abiotic components. Additionally, non-invasive monitoring approaches such as environmental DNA (eDNA) metabarcoding have further enhanced the ability to characterize marine life. Although the use of non-invasive tools beholds great potential for the sustainable monitoring of biodiversity and declining natural resources, such techniques are rarely used in parallel and understanding their limitations is challenging. Thus, this study combined Underwater Video (UV) with eDNA metabarcoding data to produce marine fish community profiles over a 2 months period in situ at a cabled observatory in the northeast Atlantic (SmartBay Ireland). By combining both approaches, an increased number of fish could be identified to the species level (total of 22 species), including ecologically and economically important species such as Atlantic cod, whiting, mackerel and monkfish. The eDNA approach alone successfully identified a higher number of species (59%) compared to the UV approach (18%), whereby 23% of species were detected by both methods. The parallel implementation of point collection eDNA and time series UV data not only confirmed expectations of the corroborative effect of using multiple disciplines in fish community composition, but also enabled the assessment of limitations intrinsic to each technique including the identification of false-negative detections in one sampling technology relative to the other. This work showcased the usefulness of cabled observatories as key platforms for in situ empirical assessment of both challenges and prospects of novel technologies in aid to future monitoring of marine life.


Asunto(s)
ADN Ambiental , Animales , Código de Barras del ADN Taxonómico , Monitoreo del Ambiente , Peces/genética , Irlanda
4.
Sci Total Environ ; 773: 145536, 2021 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-33940730

RESUMEN

Plastic pollution is a contaminant of global concern, as it is present even in remote ecosystems - like the Arctic. Arctic seabirds are vulnerable to ingesting plastic pollution, and these ingested particles are shed in the form of microplastics via guano. This suggests that Arctic seabird guano may act as a vector for the movement of microplastics into and around northern ecosystems. While contaminant-laden guano deposition patterns create a clear concentration gradient of chemicals around seabird colonies, this has not yet been investigated with plastic pollution. Here we tested whether a contaminant gradient of plastic pollution exists around a seabird colony that is primarily comprised of northern fulmars (Fulmarus glacialis) in the Canadian Arctic. Atmospheric deposition, surface water, and surface sediment samples were collected below the cliff-side of the colony and at increasing intervals of 1 km from the colony. Fulmars were also collected when foraging away from their colony. Microplastics and other anthropogenic microparticles were identified in all three environmental matrices as well as fulmar guano. Fibers were the most common shape in fulmar guano, atmospheric deposition and surface sediment, and fragments were the most common shape in surface water. We did not find a gradient of microplastic concentrations in environmental matrices related to distance from the colony. Combined, these results suggest that fulmars are not the primary source of microplastic around this colony. Further research is warranted to understand sources of microplastics to the areas around the colonies, including to what extent seabirds transport and concentrate microplastics in Arctic ecosystems, and whether concentrations proximate to large colonies may be species dependent.


Asunto(s)
Microplásticos , Plásticos , Animales , Regiones Árticas , Aves , Canadá , Ecosistema , Monitoreo del Ambiente
5.
Sci Total Environ ; 773: 145545, 2021 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-33940731

RESUMEN

During 2020, the COVID-19 pandemic resulted in a widespread lockdown in many cities in China. In this study, we assessed the impact of changes in human activities on air quality during the COVID-19 pandemic by determining the relationships between air quality, traffic volume, and meteorological conditions. The megacities of Wuhan, Beijing, Shanghai, and Guangzhou were selected as the study area, and the variation trends of air pollutants for the period January-May between 2016 and 2020 were analyzed. The passenger volume of public transportation (PVPT) and the passenger volume of taxis (PVT) along with data on precipitation, temperature, relative humidity, wind speed, and boundary layer height were used to identify and quantify the driving force of the air pollution variation. The results showed that the change rates of fine particulate matter (PM2.5), NO2, and SO2 before and during the lockdown in the four megacities ranged from -49.9% to 78.2% (average: -9.4% ± 59.3%), -55.4% to -32.3% (average: -43.0% ± 9.7%), and - 21.1% to 11.9% (average: -10.9% ± 15.4%), respectively. The response of NO2 to the lockdown was the most sensitive, while the response of PM2.5 was smaller and more delayed. During the lockdown period, haze from uninterrupted industrial emissions and fireworks under the effect of air mass transport from surrounding areas and adverse climate conditions was probably the cause of abnormally high PM2.5 concentrations in Beijing. In addition, the PVT was the most significant factor for NO2, and meteorology had a greater impact on PM2.5 than NO2 and SO2. There is a need for more national-level policies for limiting firework displays and traffic emissions, as well as further studies on the formation and transmission of secondary air pollutants.


Asunto(s)
Contaminación del Aire , Contaminación del Aire/análisis , Beijing/epidemiología , China/epidemiología , Ciudades , Control de Enfermedades Transmisibles , Monitoreo del Ambiente , Humanos , Conceptos Meteorológicos , Pandemias
6.
Environ Monit Assess ; 193(6): 319, 2021 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-33942168

RESUMEN

A rational water quality assessment program directly affects a success of a national socio-economic development strategy. This study was aimed to evaluate and classify surface water quality in Dong Thap province, Vietnam, using set pair analysis (SPA) and national water quality index (WQI_VN) methods. The water quality data was collected at 58 locations in 2019 by the Department of Natural Resources and Environment of Dong Thap province. Sixteen variables including temperature (°C), pH, turbidity (NTU), dissolved oxygen (DO, mg/L), biological oxygen demand (BOD, mg/L), chemical oxygen demand (COD, mg/L), total suspended solids (TSS, mg/L), ammonia (N-NH4+, mg/L), nitrite (N-NO2-), nitrate (N-NO3-, mg/L), total nitrogen (TN, mg/L), orthophosphate (P-PO43-, mg/L), chloride (Cl-, mg/L), sulfate (SO42-, mg/L), coliform (MPN/100 mL), and Escherichia coli (MPN/100 mL) were monitored four times a year (58 water samples × 16 parameters × 4 monitoring times). The findings presented that TSS, BOD, COD, N-NH4+, N-NO2-, P-PO43-, coliform, and E. coli were the main constraints on water quality. The results of the entropy weight calculation indicated that deteriorated water quality was in the order of microbiological > nutrients > organic matters. Surface water quality was evaluated at medium (level III) and poor (level IV) by SPA and WQI_VN, respectively; however, the combination of SPA and entropy weight was considered more efficient in this classification and a positive spatial autocorrelation was also found through Moran's I. The spatial distribution of water quality based on SPA classification revealed that better water quality was found in the inner parts of the study area. Due to its ease and effectiveness, set pair analysis should be considered for inclusion in the water quality assessment program of Vietnam.


Asunto(s)
Ríos , Calidad del Agua , Grupo de Ascendencia Continental Asiática , Monitoreo del Ambiente , Escherichia coli , Humanos , Vietnam
7.
Environ Monit Assess ; 193(6): 318, 2021 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-33942175

RESUMEN

The present study was conducted to assess the response of thermotolerant wheat cultivar (Triticum aestivum L. var. WR544) to individual and combination of ambient ground level ozone (AO3) and particulate matter (PM) air pollutants with ethylene diurea (EDU) used as an ozone stress mitigator. The four treatment combinations to which wheat cultivars were exposed are T1 (AO3 + PM), T2 (EDU + PM), T3 (AO3-PM), and T4 (EDU-PM). The effect of different treatments on morphological (foliar ozone injury, leaf area, shoot height, number of leaves, and total biomass), biochemical (leaf extract pH, electrical conductivity, relative water content, total chlorophyll, ascorbic acid content), nutritional (leaf carbohydrate content and leaf protein content), and yield (biological yield, economic yield, and harvest index) attributes of the cultivar were monitored. The plants under T1 experienced 20-30% foliar ozone injury and recorded lowest economic yield (0.58 g/plant). Plants under T2 and T3 showed visible foliar ozone injury range between 0 and 5% whereas plants under T4 exhibited negligible ozone injuries. EDU-treated plants without PM deposition (T4) exhibited better morphology, leaf protein content, leaf carbohydrate content, biological and economic yield as compared to T1-, T2-, and T3-treated plants but EDU was only partially effective. Despite being a thermotolerant variety, WR544 gets adversely affected by the individual and combined exposure of AO3 and PM air pollutants. These result findings highlighted the need for more detailed study of air quality impact on the thermotolerant cultivars of other key crops to individual and combined air pollutants.


Asunto(s)
Ozono , Monitoreo del Ambiente , Ozono/toxicidad , Material Particulado/toxicidad , Compuestos de Fenilurea , Triticum
8.
Environ Monit Assess ; 193(6): 317, 2021 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-33942176

RESUMEN

Monocrotophos (MCP) is a highly toxic and broad-spectrum pesticide extensively used for agricultural and household purposes. The present study was aimed to evaluate the genotoxicity and alterations in the biochemical and physiological conditions induced by monocrotophos in a non-target organism, an estuarine bivalve, Donax incarnatus. The bivalves were exposed to three sub-lethal concentrations (6.8, 13.7, and 27.45 ppm) of MCP for a period of 72 h. DNA damage was assessed using the comet assay. Oxidative stress was analyzed using catalase, glutathione peroxidase, and superoxide dismutase. Neurotoxicity was evaluated using the acetylcholinesterase assay (AChE) and the physiological condition was assessed using the condition index (CI). A significant concentration-dependent increase of DNA damage was observed as well as a decline in the activities of the antioxidant enzymes. However, a decrease in DNA damage was observed with advancing time. A significant decrease of AChE activity and CI was observed in the bivalves exposed to MCP. Positive correlations were also observed between DNA damage and the antioxidant enzymes whereas negative correlations were observed between AChE and the antioxidant enzymes indicating MCP toxicity mediated by oxidative stress.


Asunto(s)
Bivalvos , Monocrotofos , Plaguicidas , Animales , Daño del ADN , Monitoreo del Ambiente , Monocrotofos/toxicidad , Plaguicidas/toxicidad
9.
Environ Monit Assess ; 193(6): 320, 2021 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-33942177

RESUMEN

In the present study, the transfer factors of the natural radionuclides 238U, 232Th, and 40K were estimated for several crops cultivated in farms in the suburbs of Baghdad and one farm in Al-Najaf. The transfer factor (TF) is the ratio of activity transfers from soil to plant. The specific activities of the natural radionuclides were measured with a gamma-ray spectrometer with a HPGe detector. The crops include cereals (rice and wheat), fruits (lemons and oranges), podded vegetables (vigna and okra), fruity vegetables (chili peppers and Solanum melongena), and leafy vegetables (Apium graveolens, Raphanus sativus, and Ocimum basilicum). The results showed that the highest transfer factors for 238U, 232Th, and 40K are 0.32, 0.70, and 3.44, respectively, in wheat. The average transfer factors for 238U and 232Th were founded 0.23 and 0.2 which are lower than the default unitiy value but the 1.85 were reported for 40K higher than unity.


Asunto(s)
Radio (Elemento) , Contaminantes Radiactivos del Suelo , Monitoreo del Ambiente , Radioisótopos/análisis , Radio (Elemento)/análisis , Suelo , Contaminantes Radiactivos del Suelo/análisis , Factor de Transferencia
10.
Bull Environ Contam Toxicol ; 106(5): 812-818, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33821297

RESUMEN

The aim of this work is to study precipitation chemistry in the cross-border region between Turkey and Bulgaria, situated on the south-eastern part of the Balkan Peninsula. A total of 115 wet deposition samples were collected and analysed for pH values and major ions (Na+, Mg2+, Ca2+, K+, NH4+, Cl-, NO3-, and SO42-) throughout the summer and autumn seasons of 2014. The enrichment factor analysis and non-sea salt estimates were conducted to determine the possible sources of ions in the wet deposition for the sampling period. The trajectories of the cyclones affecting the area during the study period were also analysed by separating them in different groups. The minimum, average and maximum pH values for the first group of cyclones (CG1) are 4.30, 6.04, 7.40, and 4.00, 6.14, 7.43 for the second group cyclones (CG2), respectively. The non-sea salt fractions of the K+ ion were found to be 0.94 in CG1 and 0.90 in CG2. Also, the Mg2+ ion in CG1 and CG2 is 44% and 60% of the sea salt source.


Asunto(s)
Contaminantes Atmosféricos , Tormentas Ciclónicas , Contaminantes Atmosféricos/análisis , Bulgaria , Monitoreo del Ambiente , Estaciones del Año , Turquia
11.
PLoS One ; 16(4): e0248893, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33831024

RESUMEN

We consider a proposed system that would place sensors in a number of wastewater manholes in a community in order to detect genetic remnants of SARS-Cov-2 found in the excreted stool of infected persons. These sensors would continually monitor the manhole's wastewater, and whenever virus remnants are detected, transmit an alert signal. In a recent paper, we described two new algorithms, each sequentially opening and testing successive manholes for genetic remnants, each algorithm homing in on a neighborhood where the infected person or persons are located. This paper extends that work in six important ways: (1) we introduce the concept of in-manhole sensors, as these sensors will reduce the number of manholes requiring on-site testing; (2) we present a realistic tree network depicting the topology of the sewer pipeline network; (3) for simulations, we present a method to create random tree networks exhibiting key attributes of a given community; (4) using the simulations, we empirically demonstrate that the mean and median number of manholes to be opened in a search follows a well-known logarithmic function; (5) we develop procedures for determining the number of sensors to deploy; (6) we formulate the sensor location problem as an integer nonlinear optimization and develop heuristics to solve it. Our sensor-manhole system, to be implemented, would require at least three additional steps in R&D: (a) an accurate, inexpensive and fast SARS-Cov-2 genetic-remnants test that can be done at the manhole; (b) design, test and manufacture of the sensors; (c) in-the-field testing and fine tuning of an implemented system.


Asunto(s)
Algoritmos , Monitoreo del Ambiente , Eliminación de Residuos , Aguas del Alcantarillado/virología , Humanos
12.
Water Res ; 197: 117083, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33813168

RESUMEN

Particulate organic carbon (POC) sources, which regulate dissolved organic carbon, sediment organic carbon, and inorganic carbon via deposition, degradation, and mineralization, play an important role in lake ecosystems. Linear or Bayesian algorithms on isotope and n-alkanes have been widely used to identify the source proportion of organic carbon. However, the applicability of these methods is ambiguous because of the unilateral advantages of each model and trace factors. To test the applicability of the various methods for identifying POC sources, we analyzed dual isotopes and n-alkanes in surface water samples of Lake Taihu, and Multi-source mixing model and Bayesian mixing model were used to distinguish between endogenous and exogenous contributions. Carbon isotope presented a clear advantage in West Taihu (-21.85 ± 0.78‰) and Southwest Taih (-22.61 ± 1.35‰); nitrogen isotope also showed high values in Meiliang Bay (9.76 ± 0.92‰). The majority of the lake was dominated by short-chain n-alkanes, except for East Taihu Lake (dominated by medium-chain n-alkanes) and areas with riverine input (dominated by long-chain n-alkanes). Different principles between the Bayesian mixing model (based on the Markov Chain Monte Carlo algorithm) and the Multi-source mixing model (based on linear estimation) caused discrepancies in the estimations of source contributions. But the fraction of chemical compounds during the migration process, and the overlap of potential sources play important role in the inconsistency of results. The estimations from the different models were consistent in indicating the dominance of endogenous organic carbon in Lake Taihu (mean of 60.18 ± 20.26%), particularly in the north and western regions (West Taihu, Meiliang Bay, and Southwest Taihu). This was likely due to algal aggregation influenced by human activities and climatic factors.


Asunto(s)
Carbono , Sedimentos Geológicos , Alcanos , Teorema de Bayes , Carbono/análisis , Isótopos de Carbono/análisis , China , Ecosistema , Monitoreo del Ambiente , Humanos , Lagos
13.
Water Res ; 197: 117076, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33819662

RESUMEN

Stormwater runoff pollution has become a key environmental issue in urban areas. Reliable estimation of stormwater pollutant discharge is important for implementing robust water quality management strategies. Even though significant attempts have been undertaken to develop water quality models, deterministic approaches have proven inappropriate as they do not address the variability in stormwater quality. Due to the random nature of rainfall characteristics and the differences in catchment characteristics, it is difficult to generate the runoff pollutographs to a desired level of certainty. Bayesian hierarchical modelling is an effective tool for developing complex models with a large number of sources of variability. A Bayesian model does not look for a single value of the model parameters, but rather determines a distribution of the model parameters from which all inference is drawn. This study introduces a Bayesian hierarchical linear regression model to describe a catchment specific runoff pollutograph incorporating the associated uncertainties in the model parameters. The model incorporates catchment and rainfall characteristics including the effective impervious area, time of concentration, rain duration, average rainfall intensity and the antecedent dry period as the contributors to random effects.


Asunto(s)
Movimientos del Agua , Contaminantes Químicos del Agua , Teorema de Bayes , Ciudades , Monitoreo del Ambiente , Lluvia , Contaminantes Químicos del Agua/análisis
14.
Water Res ; 197: 117089, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33836295

RESUMEN

Groundwater resources are under increasing threats from contamination and overuse, posing direct threats to human and environmental health. The purpose of this study is to better understand drivers of, and relationships between, well and aquifer characteristics, sampling frequencies, and microbiological contamination indicators (specifically E. coli) as a precursor for improving knowledge and tools to assess aquifer vulnerability and well contamination within Ontario, Canada. A dataset with 795, 023 microbiological testing observations over an eight-year period (2010 to 2017) from 253,136 unique wells across Ontario was employed. Variables in this dataset include date and location of test, test results (E. coli concentration), well characteristics (well depth, location), and hydrogeological characteristics (bottom of well stratigraphy, specific capacity). Association rule analysis, univariate and bivariate analyses, regression analyses, and variable discretization techniques were utilized to identify relationships between E. coli concentration and the other variables in the dataset. These relationships can be used to identify drivers of contamination, their relative importance, and therefore potential public health risks associated with the use of private wells in Ontario. Key findings are that: i) bedrock wells completed in sedimentary or igneous rock are more susceptible to contamination events; ii) while shallow wells pose a greater risk to consumers, deep wells are also subject to contamination events and pose a potentially unanticipated risk to health of well users; and, iii) well testing practices are influenced by results of previous tests. Further, while there is a general correlation between months with the greatest testing frequencies and concentrations of E. coli occurring in samples, an offset in this timing is observed in recent years. Testing remains highest in July while peaks in adverse results occur up to three months later. The realization of these trends prompts a need to further explore the bases for such occurrences.


Asunto(s)
Agua Potable , Agua Subterránea , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Escherichia coli , Humanos , Aprendizaje Automático , Ontario , Contaminantes Químicos del Agua/análisis , Abastecimiento de Agua , Pozos de Agua
15.
Environ Monit Assess ; 193(5): 306, 2021 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-33905038

RESUMEN

The El Moghra area is located in northwestern Egypt in the Western Desert. It is classified as the first priority of the national project to reclaim 1.50 million feddan of Egypt's desert lands. Groundwater quality assessment of the El Moghra aquifer is essential because irrigation water requirements in the El Moghra area depend solely on groundwater. A geochemistry analysis was conducted for 230,000 feddans from forty-six groundwater samples collected during the drilling process of deep wells in year 2018 and 2019. Our study's main objective is to determine whether the groundwater in the El Moghra aquifer is suitable for irrigation use. ArcGIS was used to prepare the geospatial distribution maps of major elements. Hydrochemical characteristics and groundwater types were identified from descriptive analyses of groundwater samples. Multivariate statistical analysis was run using SPSS; correlation coefficients were first determined; then, a correlation matrix was generated. Principal component analysis was performed and a covariance matrix with varimax rotation was produced. Results revealed the alkalinity and the high salinity of groundwater in the project study area. Most of the samples had a total hardness greater than 300 mg/l. Sodium chloride (Na-Cl) is the dominant type for groundwater samples. The mechanism controlling groundwater chemistry depends on rock weathering. Principal component analysis results showed that two eigenvectors among ten have a 72.86% contribution to the cumulative variance. The higher TDS values (14,008 mg/l) confirm the ions release when the upward groundwater flow from the lower Nubian Sandstone aquifer system to the upper quaternary aquifer occurs. Additionally, the geospatial maps of ion distribution showed that the frequent release of minerals happens in the northwestern part of the project study area: the eastern Qattara Depression. A perfect correlation between sodium and chloride distributions was obtained, and it is identical to the electrical conductivity distribution as well. Our study recommends very salt-tolerant crops as canola, barley, quinoa, and jojoba to be planted in the project area. Drought-tolerant crops as Barbary fig and Jatropha are also recommended. Applying irrigation water frequently with short intervals between irrigations to avoid soil drying and surface clusters' formation, as well as enhance leeching of salts away from the root systems, is essential.


Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Egipto , Monitoreo del Ambiente , Sistemas de Información Geográfica , Salinidad , Contaminantes Químicos del Agua/análisis , Calidad del Agua
16.
Water Sci Technol ; 83(8): 2012-2024, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33905369

RESUMEN

The distribution and ecological risks of 11 phenolic compounds were studied in Weihe River, Northwest China. The concentrations of phenolic compounds were determined by ultra-high performance liquid chromatography (UPLC). The total concentration of 11 phenolic compounds (∑PC11) ranged from 0.06 to 14.12 µg/L with an average of 5.22 µg/L in water, from 0.92 to 34,885 µg/g with an average of 4,446 µg/g in suspended particulate matter (SPM), and from 3.54 to 34.09 µg/g with an average of 11.09 µg/g in sediment. For individual phenolic compound, the mean concentration of pentachlorophenol was the highest in water (2.65 µg/L) and in SPM (3,865 µg/g), while in sediment the mean concentration of 2,4,6-trichlorophenol was the highest (3.05 µg/g). The total concentration of 5 chlorophenols (∑CP5) was significantly higher than that of 6 non-chlorophenols (∑NCP6) in all three studied compartments. The phenolic compounds in Weihe River were at moderate levels in water and at high levels in sediment. The ecological risk assessment results indicated that phenolic compounds exhibited a high ecological risk in Weihe River water. In most sites, the distribution coefficient (Kd) (SPM) was much higher than Kd (sediment), which probably suggested fresh phenolic compounds input in Weihe River.


Asunto(s)
Ríos , Contaminantes Químicos del Agua , China , Monitoreo del Ambiente , Sedimentos Geológicos , Material Particulado/análisis , Agua/análisis , Contaminantes Químicos del Agua/análisis
17.
Medicina (B Aires) ; 81(2): 166-172, 2021.
Artículo en Español | MEDLINE | ID: mdl-33906134

RESUMEN

Hydatidosis - caused by the parasite Echinococcus granulosus - is a zoonosis endemic to the province of Santa Cruz, associated with areas of livestock production. Once infected, man may remain asymptomatic for a prolonged period but the disease has an important impact on public health owing to the complexity and costs of its treatment. This study aimed at assessing the prevalence of environmental E. granulosus infection in rural and peri-urban areas of the town of Los Antiguos, through the detection of antigens in scattered canine feces, and to identify risk factors for transmission. From May-2016 to April-2017, 38 peri-urban and rural farms, defined as "epidemiological units", were visited; 144 samples of canine feces were analyzed with the copro-ELISA technique. Rural settlers were enrolled in an epidemiological survey on cultural patterns related to hydatidosis. An environmental contamination index of 17.3% was found and 44.7% of the epidemiological units were positive. Risk practices were found, such as domiciliary slaughter (34.2%), canine feeding with raw viscera (52.6%), and lack of dog deworming (86.8%). In turn, about half of the surveyed population ignored the modes of transmission of the infection and the measures to prevent it. This work shows a high infection index in the area and establishes a baseline for future comparisons. It also reinforces the need to implement education, prevention, and control activities at the local level - according to national program guidelines - in order to reduce the prevalence of environmental contamination of the disease.


Asunto(s)
Enfermedades de los Perros , Equinococosis , Echinococcus granulosus , Animales , Enfermedades de los Perros/epidemiología , Enfermedades de los Perros/prevención & control , Perros , Equinococosis/epidemiología , Equinococosis/prevención & control , Heces , Humanos , Población Rural
19.
Environ Monit Assess ; 193(5): 283, 2021 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-33871678

RESUMEN

Landfall of the Amphan (very severe cyclonic storm) occurred at 1730 hrs Indian Standard Time (IST) on May 20, 2020, near the West Bengal (W.B.) coast of India. High wind speed, storm surge, and torrential rainfall-induced flooding caused devastation in W.B. The present study aims to analyse the impacts of Amphan cyclone on land use/land cover (LULC) such as built-up area, cropland, brick-kiln industries and vegetation cover of nine districts of W.B. namely, Barddhaman, Nadia, North 24 Parganas, South 24 Parganas, Purba Medinipur, Paschim Medinipur, Haora, and Kolkata. Flood extent has been mapped using Sentinel-1A and B interferometric wide swath (IW) ground range detected (GRD) VV polarisation images dated May 22, 2020. The total actual flooded area covers 488 km2 of the study area. For the pre-cyclone period, LULC classification and normalised difference vegetation index (NDVI) have been done using Sentinel-2B multispectral instrument (MSI) images dated May 14, 2020. Post-cyclone NDVI has been computed using Sentinel-2B MSI images dated June 3, 2020. Flood-affected cropland covers a large chunk (88.2%) of the total actual flooded area. Mean NDVI values of non-flooded and flooded cropland and vegetation cover have been reduced between May 14, 2020, and June 3, 2020. District, block and pixel-wise changes in pre- and post-cyclone NDVI values have also been analysed. This study helps planners and policy makers to understand the district-wise flooding behavior, severity of damage to cropland and vegetation cover and to plan restriction on high-value land use in flooded low-lying areas.


Asunto(s)
Tormentas Ciclónicas , Monitoreo del Ambiente , India
20.
Environ Monit Assess ; 193(5): 284, 2021 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-33876293

RESUMEN

Approximately 1 billion tons of phosphogypsum (PG), a by-product of the fertilizer industry, are currently stacked in Florida. PG emits radon gas, which is a risk factor for lung cancer and can also increase particulate matter (PM) associated non-cancer mortality in exposed individuals. We measured concentrations of atmospheric radon and particulate matter near PG stacks and their short-term variations at different distances to estimate exposures in nearby communities. Specifically, we measured atmospheric levels of radon, and mass concentrations of PM1, PM2.5, and PM10, and number concentrations of PM0.3, PM0.5, PM1, PM2.5, PM5, and PM10 near three large PG stacks in Florida. Atmospheric radon was collected at distances of 2.5, 5.0, and 7.5 miles downwind from three large PG stacks using charcoal-based kits and measured by liquid scintillation counting. A professional radon monitor was used to take 24-h-average radon reading at 5.0 miles from each stack for comparison purposes. The median (IQR) radon levels were 0.325 (0.150, 0.675), 0.150 (0.150, 0.650), and 0.500 (0.150, 0.700) pCi/L at 2.5, 5, and 7.5 miles, respectively. The median (IQR) PM2.5 levels were 5 (4, 6), 5 (3, 7), and 5 (2, 9) µg/m3 at 2.5, 5, and 7.5 miles, respectively. Non-parametric Kruskal-Wallis test could not detect any association between radon or PM levels and distances (2.5-7 miles) from PG stacks. With scintillation counting, median radon levels detected were above the US Environmental Protection Agency (EPA) recommended standard in some of the sites; however, much higher levels were detected through the more advanced digital monitor. PM2.5 levels were below the US-EPA 24-h average national ambient air quality standard in the study area. We conclude that ambient radon levels near PG stacks could exceed US EPA recommended outdoor standards and do not vary within a short distance from the sources, implying similar exposures in nearby communities.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Radón , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Sulfato de Calcio , Exposición a Riesgos Ambientales/análisis , Monitoreo del Ambiente , Florida , Humanos , Material Particulado/análisis , Fósforo , Radón/análisis
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...