Base de dados : MEDLINE
Pesquisa : J01.293.821.500.500 [Categoria DeCS]
Referências encontradas : 363 [refinar]
Mostrando: 1 .. 10   no formato [Longo]

página 1 de 37 ir para página                         

  1 / 363 MEDLINE  
              next record last record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:29202372
Autor:Telahigue F; Agoubi B; Souid F; Kharroubi A
Endereço:Higher Institute of Water Sciences and Techniques, University of Gabes University Campus, 6033 Gabes, Tunisia. Electronic address: Faten_telahigue@yahoo.fr.
Título:Groundwater chemistry and radon-222 distribution in Jerba Island, Tunisia.
Fonte:J Environ Radioact; 182:74-84, 2018 Feb.
ISSN:1879-1700
País de publicação:England
Idioma:eng
Resumo:The present study integrates hydrogeological, hydrochemical and radiogenic data of groundwater samples taken from the Plio-Quaternary unconfined aquifer of Jerba Island, southeastern Tunisia, in order to interpret the spatial variations of the groundwater quality and identify the main hydrogeochemical factors responsible for the high ion concentrations and radon-222 content in the groundwater analysed. Thirty-nine groundwater samples were collected from open wells widespread on the island. Physical parameters (EC, pH, TDS and T °) were measured, major ions (Ca , Mg , Na , K , Cl , SO , NO and HCO ) were analysed and Rn concentrations were determined using a RAD7-H O. Hydrogeochemical characterisation revealed that groundwater from the Jerba aquifer has several origins. Basically, two water types exist in the island. The first one, characterized by a low to moderate salinity with a chemical facies CaMgClSO , characterizes the central part of Jerba (a recharge area) due to carbonate and gypsum dissolution. The second water type with high salinities, dominated by NaKCl type, was observed in coastal areas and some parts having low topographic and piezometric levels. These areas seem to be affected by the seawater intrusion process. The Rn concentrations in groundwater samples in Jerba varied from 0 Bq.L to 2860 Bq.L with an average of 867 Bq.L . The highest values were registered in the western coastal wells and near the fault of Guellala. However, the central and eastern wells showed low radon levels. Compared to Rn activity in some countries with the same lithology, radon concentrations in the Jerba unconfined aquifer have higher values influenced by the structure of the aquifer and by seawater inflow enriched with Rn resulting from the decay of uranium derived from phosphogypsum deposits in the gulf of Gabes. The EC and Rn spatial variability in the study area were mapped using ARC Map 10.3 software. Hydrochemical results in addition to geological data and radon activities confirm the existence of vertical communication between the Miocene aquifer and the unconfined Plio-Quaternary aquifer through fault system and a lateral communication with the sea via seawater intrusion.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Radon-222); 0 (Water Pollutants, Radioactive); Q74S4N8N1G (Radon)


  2 / 363 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
PMID:27775681
Autor:Maran NH; Crispim BD; Iahnn SR; Araújo RP; Grisolia AB; Oliveira KM
Endereço:Faculty of Exact Sciences and Technology, Federal University of Grande Dourados, Dourados, MS 79804-970, Brazil. nayaramaran@ufgd.edu.br.
Título:Depth and Well Type Related to Groundwater Microbiological Contamination.
Fonte:Int J Environ Res Public Health; 13(10), 2016 10 21.
ISSN:1660-4601
País de publicação:Switzerland
Idioma:eng
Resumo:Use of groundwater from private wells in households has increased considerably, owing to a better cost/benefit ratio than that of water provided by local utilities for a fee. However, this water is usually untreated, which makes it a vehicle for diseases. Thus, monitoring this water is necessary to ensure its integrity and quality. We aimed to evaluate the physical, chemical, and microbiological parameters of untreated groundwater drawn from different types of wells, and the antimicrobial susceptibility profile of the bacteria isolated from this water. Wellwater samples were collected in two Brazilian cities. Although physical and chemical parameters of the water were suitable for drinking, was detected in 33% of the samples. contaminated 65% of dug wells and 10.25% of drilled wells. Many bacteria isolated were resistant to multiple antibacterial agents, including ß-lactams. Microbial contamination of this water was related to the well depth, and was more common in dug wells, making this water unfit for human consumption. Consumption of such contaminated and untreated water is a public health concern. Thus, individuals who regularly use such water must be alerted so they may either take preventive measures or connect to the water distribution system operated by local utilities.
Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
Nome de substância:0 (Drinking Water)


  3 / 363 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:28893720
Autor:Zheng Y; Flanagan SV
Endereço:School of Environmental Science and Engineering, Southern University of Science and Technology , Shenzhen, China.
Título:The Case for Universal Screening of Private Well Water Quality in the U.S. and Testing Requirements to Achieve It: Evidence from Arsenic.
Fonte:Environ Health Perspect; 125(8):085002, 2017 Aug 03.
ISSN:1552-9924
País de publicação:United States
Idioma:eng
Resumo:BACKGROUND: The 1974 Safe Drinking Water Act (SDWA) regulates >170,000 public water systems to protect health, but not >13 million private wells. State and local government requirements for private well water testing are rare and inconsistent; the responsibility to ensure water safety remains with individual households. Over the last two decades, geogenic arsenic has emerged as a significant public health concern due to high prevalence in many rural American communities. OBJECTIVES: We build the case for universal screening of private well water quality around arsenic, the most toxic and widespread of common private water contaminants. We argue that achieving universal screening will require policy intervention, and that testing should be made easy, accessible, and in many cases free to all private well households in the United States, considering the invisible, tasteless, odorless, and thus silent nature of arsenic. DISCUSSION: Our research has identified behavioral, situational and financial barriers to households managing their own well water safety, resulting in far from universal screening despite traditional public health outreach efforts. We observe significant socioeconomic disparities in arsenic testing and treatment when private water is unregulated. Testing requirements can be a partial answer to these challenges. CONCLUSIONS: Universal screening, achieved through local testing requirements complemented by greater community engagement targeting biologically and socioeconomically vulnerable groups, would reduce population arsenic exposure greater than any promotional efforts to date. Universal screening of private well water will identify the dangers hidden in America's drinking water supply and redirect attention to ensure safe water among affected households. https://doi.org/10.1289/EHP629.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Water Pollutants, Chemical); N712M78A8G (Arsenic)


  4 / 363 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:28857032
Autor:Ribeiro TG; Gonçalves BR; da Silva MS; Novais Â; Machado E; Carriço JA; Peixe L
Endereço:1​UCIBIO-REQUIMTE, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal.
Título:Citrobacter portucalensis sp. nov., isolated from an aquatic sample.
Fonte:Int J Syst Evol Microbiol; 67(9):3513-3517, 2017 Sep.
ISSN:1466-5034
País de publicação:England
Idioma:eng
Resumo:A Gram-stain-negative strain, A60T, isolated from a water well sample in Portugal, was characterized phenotypically, genotypically and phylogenetically. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain A60T belonged to the genus Citrobacter, and recN gene phylogeny revealed one strongly supported clade encompassing strain A60T and 13 other strains from public databases, distinct from currently recognized species of the genus Citrobacter. Furthermore, multilocus sequence analysis (MLSA) based on concatenated partial fusA, leuS, pyrG and rpoB sequences confirmed the classification obtained with the recN sequence. In silico genomic comparisons, including average nucleotide identity (ANI) and the genome-to-genome distance calculator (GGDC), showed 94.6 % and 58.4 % identity to the closest relative Citrobacter freundii ATCC 8090T, respectively. The ability to metabolize different compounds further discriminated strain A60T from other species of the genus Citrobacter. The G+C content of strain A60T is 52.0 %. The results obtained support the description of a novel species within the genus Citrobacter, for which the name Citrobacter portucalensis sp. nov. is proposed, with the type strain A60T (=DSM 104542T=CECT 9236T).
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (DNA, Bacterial); 0 (RNA, Ribosomal, 16S)


  5 / 363 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:28728142
Autor:MacDonald Gibson J; Pieper KJ
Endereço:Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Título:Strategies to Improve Private-Well Water Quality: A North Carolina Perspective.
Fonte:Environ Health Perspect; 125(7):076001, 2017 07 07.
ISSN:1552-9924
País de publicação:United States
Idioma:eng
Resumo:BACKGROUND: Evidence suggests that the 44.5 million U.S. residents drawing their drinking water from private wells face higher risks of waterborne contaminant exposure than those served by regulated community water supplies. Among U.S. states, North Carolina (N.C.) has the second-largest population relying on private wells, making it a useful microcosm to study challenges to maintaining private-well water quality. OBJECTIVES: This paper summarizes recommendations from a two-day summit to identify options to improve drinking-water quality for N.C. residents served by private wells. METHODS: The Research Triangle Environmental Health Collaborative invited 111 participants with knowledge of private-well water challenges to attend the Summit. Participants worked in small groups that focused on specific aspects and reconvened in plenary sessions to formulate consensus recommendations. DISCUSSION: Summit participants highlighted four main barriers to ensuring safe water for residents currently relying on private wells: (1) a database of private well locations is unavailable; (2) racial disparities have perpetuated reliance on private wells in some urbanized areas; (3) many private-well users lack information or resources to monitor and maintain their wells; and (4) private-well support programs are fragmented and lack sufficient resources. The Summit produced 10 consensus recommendations for ways to overcome these barriers. CONCLUSIONS: The Summit recommendations, if undertaken, could improve the health of North Carolinians facing elevated risks of exposure to waterborne contaminants because of their reliance on inadequately monitored and maintained private wells. Because many of the challenges in N.C. are common nationwide, these recommendations could serve as models for other states. https://doi.org/10.1289/EHP890.
Tipo de publicação: JOURNAL ARTICLE; REVIEW
Nome de substância:0 (Water Pollutants, Chemical)


  6 / 363 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:28645723
Autor:Woodman ND; Rees-White TC; Beaven RP; Stringfellow AM; Barker JA
Endereço:Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1B, UK.. Electronic address: n.d.woodman@soton.ac.uk.
Título:Doublet tracer tests to determine the contaminant flushing properties of a municipal solid waste landfill.
Fonte:J Contam Hydrol; 203:38-50, 2017 Aug.
ISSN:1873-6009
País de publicação:Netherlands
Idioma:eng
Resumo:This paper describes a programme of research investigating horizontal fluid flow and solute transport through saturated municipal solid waste (MSW) landfill. The purpose is to inform engineering strategies for future contaminant flushing. Solute transport between injection/abstraction well pairs (doublets) is investigated using three tracers over five separate tests at well separations between 5m and 20m. Two inorganic tracers (lithium and bromide) were used, plus the fluorescent dye tracer, rhodamine-WT. There was no evidence for persistent preferential horizons or pathways at the inter-well scale. The time for tracer movement to the abstraction wells varied with well spacing as predicted for a homogeneous isotropic continuum. The time for tracer movement to remote observation wells was also as expected. Mobile porosity was estimated as ~0.02 (~4% of total porosity). Good fits to the tracer breakthrough data were achieved using a dual-porosity model, with immobile regions characterised by block diffusion timescales in the range of about one to ten years. This implies that diffusional exchanges are likely to be very significant for engineering of whole-site contaminant flushing and possibly rate-limiting.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Bromides); 0 (Solid Waste); 0 (Water Pollutants, Chemical); 9FN79X2M3F (Lithium)


  7 / 363 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:28482868
Autor:Tyler MD; Richards DB; Reske-Nielsen C; Saghafi O; Morse EA; Carey R; Jacquet GA
Endereço:Boston Medical Center, Boston, USA. mdtyler4@gmail.com.
Título:The epidemiology of drowning in low- and middle-income countries: a systematic review.
Fonte:BMC Public Health; 17(1):413, 2017 May 08.
ISSN:1471-2458
País de publicação:England
Idioma:eng
Resumo:BACKGROUND: According to the World Health Organization, drowning is the 3rd leading cause of unintentional injury-related deaths worldwide, accounting for 370,000 annual deaths and 7% of all injury-related deaths. Low- and middle-income countries are the most affected, accounting for 91% of unintentional drowning deaths. METHODS: The authors performed a systematic review of literature indexed in EMBASE, PubMed, Web of Science, Cochrane Library, and Traumatology journals formerly indexed in PubMed in January 2014 and again in September 2016. Abstracts were limited to human studies in English, conducted in low- and middle-income countries, and containing quantitative data on drowning epidemiology. RESULTS: A total of 62 articles met inclusion criteria. The majority of articles originate from Asia (56%) and Africa (26%). Risk factors for drowning included young age (<17-20 years old), male gender (75% vs. 25% female), rural environment (84% vs. 16% urban), occurring in the daytime (95% vs. 5% night time), lack of adult supervision (76% vs. 18% supervised), and limited swimming ability (86% vs. 10% with swimming ability). There was almost equal risk of drowning in a small body of water versus a large body of water (42% ponds, ditches, streams, wells; 46% lakes, rivers, sea, ocean). CONCLUSION: Drowning is a significant cause of injury-related deaths, especially in LMICs. Young males who are unsupervised in rural areas and have limited formal swimming instruction are at greatest risk of drowning in small bodies of water around their homes. Preventative strategies include covering wells and cisterns, fencing off ditches and small ponds, establishing community daycares, providing formal swimming lessons, and increasing awareness of the risks of drowning.
Tipo de publicação: JOURNAL ARTICLE; REVIEW


  8 / 363 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:28335539
Autor:Abia AL; Schaefer L; Ubomba-Jaswa E; Le Roux W
Endereço:Departments of Biotechnology, Vaal University of Technology, Private Bag X021, Andries Potgieter Blvd, Vanderbijlpark 1911, South Africa. lutherkinga@yahoo.fr.
Título:Abundance of Pathogenic Escherichia coli Virulence-Associated Genes in Well and Borehole Water Used for Domestic Purposes in a Peri-Urban Community of South Africa.
Fonte:Int J Environ Res Public Health; 14(3), 2017 Mar 20.
ISSN:1660-4601
País de publicação:Switzerland
Idioma:eng
Resumo:In the absence of pipe-borne water, many people in Africa, especially in rural communities, depend on alternative water sources such as wells, boreholes and rivers for household and personal hygiene. Poor maintenance and nearby pit latrines, however, lead to microbial pollution of these sources. We evaluated the abundance of and the prevalence of pathogenic virulence genes in water from wells, boreholes and a river in a South African peri-urban community. Monthly samples were collected between August 2015 and November 2016. In all, 144 water samples were analysed for using the Colilert 18 system. Virulence genes ( , , , , , , , ) were investigated using real-time polymerase chain reaction. Mean counts ranged between 0 and 443.1 Most Probable Number (MPN)/100 mL of water sample. Overall, 99.3% of samples were positive for at least one virulence gene studied, with being the most detected gene (81/140; 57.6%) and the gene the least detected gene (8/140; 5.7%). Both intestinal and extraintestinal pathogenic genes were detected. The detection of virulence genes in these water sources suggests the presence of potentially pathogenic strains and is a public health concern.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Escherichia coli Proteins); 0 (Genetic Markers); 0 (Virulence Factors)


  9 / 363 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:28262572
Autor:Reimus PW; Arnold BW
Endereço:Los Alamos National Laboratory, Los Alamos, NM, United States. Electronic address: preimus@lanl.gov.
Título:Evaluation of multiple tracer methods to estimate low groundwater flow velocities.
Fonte:J Contam Hydrol; 199:1-13, 2017 Apr.
ISSN:1873-6009
País de publicação:Netherlands
Idioma:eng
Resumo:Four different tracer methods were used to estimate groundwater flow velocity at a multiple-well site in the saturated alluvium south of Yucca Mountain, Nevada: (1) two single-well tracer tests with different rest or "shut-in" periods, (2) a cross-hole tracer test with an extended flow interruption, (3) a comparison of two tracer decay curves in an injection borehole with and without pumping of a downgradient well, and (4) a natural-gradient tracer test. Such tracer methods are potentially very useful for estimating groundwater velocities when hydraulic gradients are flat (and hence uncertain) and also when water level and hydraulic conductivity data are sparse, both of which were the case at this test location. The purpose of the study was to evaluate the first three methods for their ability to provide reasonable estimates of relatively low groundwater flow velocities in such low-hydraulic-gradient environments. The natural-gradient method is generally considered to be the most robust and direct method, so it was used to provide a "ground truth" velocity estimate. However, this method usually requires several wells, so it is often not practical in systems with large depths to groundwater and correspondingly high well installation costs. The fact that a successful natural gradient test was conducted at the test location offered a unique opportunity to compare the flow velocity estimates obtained by the more easily deployed and lower risk methods with the ground-truth natural-gradient method. The groundwater flow velocity estimates from the four methods agreed very well with each other, suggesting that the first three methods all provided reasonably good estimates of groundwater flow velocity at the site. The advantages and disadvantages of the different methods, as well as some of the uncertainties associated with them are discussed.
Tipo de publicação: JOURNAL ARTICLE


  10 / 363 MEDLINE  
              first record previous record
seleciona
para imprimir
Fotocópia
Texto completo
PMID:28220696
Autor:Patterson LA; Konschnik KE; Wiseman H; Fargione J; Maloney KO; Kiesecker J; Nicot JP; Baruch-Mordo S; Entrekin S; Trainor A; Saiers JE
Endereço:Nicholas Institute for Environmental Policy Solutions, Duke University , 2111 Campus Drive, Durham North Carolina 27708, United States.
Título:Unconventional Oil and Gas Spills: Risks, Mitigation Priorities, and State Reporting Requirements.
Fonte:Environ Sci Technol; 51(5):2563-2573, 2017 Mar 07.
ISSN:1520-5851
País de publicação:United States
Idioma:eng
Resumo:Rapid growth in unconventional oil and gas (UOG) has produced jobs, revenue, and energy, but also concerns over spills and environmental risks. We assessed spill data from 2005 to 2014 at 31 481 UOG wells in Colorado, New Mexico, North Dakota, and Pennsylvania. We found 2-16% of wells reported a spill each year. Median spill volumes ranged from 0.5 m in Pennsylvania to 4.9 m in New Mexico; the largest spills exceeded 100 m . Seventy-five to 94% of spills occurred within the first three years of well life when wells were drilled, completed, and had their largest production volumes. Across all four states, 50% of spills were related to storage and moving fluids via flowlines. Reporting rates varied by state, affecting spill rates and requiring extensive time and effort getting data into a usable format. Enhanced and standardized regulatory requirements for reporting spills could improve the accuracy and speed of analyses to identify and prevent spill risks and mitigate potential environmental damage. Transparency for data sharing and analysis will be increasingly important as UOG development expands. We designed an interactive spills data visualization tool ( http://snappartnership.net/groups/hydraulic-fracturing/webapp/spills.html ) to illustrate the value of having standardized, public data.
Tipo de publicação: JOURNAL ARTICLE



página 1 de 37 ir para página                         
   


Refinar a pesquisa
  Base de dados : MEDLINE Formulário avançado   

    Pesquisar no campo  
1  
2
3
 
           



Search engine: iAH v2.6 powered by WWWISIS

BIREME/OPAS/OMS - Centro Latino-Americano e do Caribe de Informação em Ciências da Saúde