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https://www.readbyqxmd.com/read/28823069/current-status-of-cattle-production-system-in-nyagatare-district-rwanda
#1
Eugene Mazimpaka, Francis Mbuza, Tukei Michael, Eugene N Gatari, E M Bukenya, Okwee-Acai James
A study was conducted to characterize the cattle production systems in Nyagatare District, Eastern Province of Rwanda using pre-tested questionnaires, interviews with key informants as well as focus group discussions in a period of 2 months. The respondents were selected by multi-stage sampling at sector and cell levels. Based on the procedure of Krejcie and Morgan (Educational and Psychological Measurement 30:607-610, 1970) to determine the overall sample size, the result indicated that the majority (98.3%) of farms were privately owned by large families of five to seven members, and most farmers (53...
August 19, 2017: Tropical Animal Health and Production
https://www.readbyqxmd.com/read/28823038/ultrastructural-morphology-and-phylogeny-of-henneguya-gilbert-n-sp-myxozoa-infecting-the-teleostean-cyphocharax-gilbert-characiformes-curimatidae-from-brazil
#2
Graça Casal, Sérgio C São Clemente, Leila Lopes, Sónia Rocha, Nilza Felizardo, Elsa Oliveira, Saleh Al-Quraishy, Carlos Azevedo
This paper describes light and ultrastructural observations and molecular analysis of a fish-infecting myxosporean, Henneguya gilbert n. sp., which was found infecting the gill epithelium of the commercially important freshwater teleost fish Cyphocharax gilbert (Curimatidae) collected in the estuarine region of Guandu River, Rio de Janeiro State, Brazil. The parasite occurs in the gills, forming whitish spherical to ellipsoidal polysporic cysts measuring up to ~ 750 μm, and displaying asynchronous development...
August 19, 2017: Parasitology Research
https://www.readbyqxmd.com/read/28823013/dynamics-of-total-microcystin-lr-concentration-in-three-subtropical-hydroelectric-generation-reservoirs-in-uruguay-south-america
#3
Mauricio González-Piana, Daniel Fabián, Andrea Piccardo, Guillermo Chalar
This study analyzed the temporal dynamics of total microcystin LR concentrations between the years of 2012 and 2015 in the Bonete, Baygorria and Palmar hydroelectric generation reservoirs in the central region of the Negro River, Uruguay. The three reservoirs showed differents total microcystin LR concentration, with no significant differences among them. Over 20 sampling dates, the three reservoirs exhibited total microcystin LR concentrations on eight occasions that corresponded to a slight to moderate human health risk according to WHO guideline values for recreational waters...
August 20, 2017: Bulletin of Environmental Contamination and Toxicology
https://www.readbyqxmd.com/read/28822574/analysis-of-individual-and-total-microcystins-in-surface-water-by-on-line-preconcentration-and-desalting-coupled-to-liquid-chromatography-tandem-mass-spectrometry
#4
Gabriel Munoz, Sung Vo Duy, Audrey Roy-Lachapelle, Barry Husk, Sébastien Sauvé
A fast and high-throughput method is proposed for the determination of total microcystins (ΣMC) in environmental surface waters. After a 1-h Lemieux-von Rudloff oxidation step to yield the 2-methyl-3-methoxy-4-phenylbutyric acid (MMPB) moiety, samples were quenched, filtered, and directly analyzed. This was achieved via solid phase extraction (SPE) coupled on-line to ultra-high performance liquid chromatography electrospray ionization triple stage quadrupole mass spectrometry. The choice of on-line SPE settings was conducted using experimental designs...
August 5, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28822345/assessment-of-oxidative-stress-and-bioaccumulation-of-the-metals-cu-fe-zn-pb-cd-in-the-polychaete-perinereis-gualpensis-from-estuaries-of-central-chile
#5
Hernán Gaete, Manuel Álvarez, Gabriela Lobos, Eulogio Soto, Carlos Jara-Gutiérrez
The estuaries of the Aconcagua and Maipo Rivers of central Chile are receptors of residues that contain metals from anthropic activities including agriculture, mining and smelters, which have different levels in the two basins. This study postulates that the exposition to metals is different in the two estuaries and that their sediments contain bioavailable chemical agents that produce oxidative stress. The aim of the study was to evaluate the effect of estuarine sediments on the polychaete Perinereis gualpensis using oxidative stress biomarkers and to determine the metal concentrations in sediments and their accumulation in P...
August 16, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28822315/applications-of-radon-and-radium-isotopes-to-determine-submarine-groundwater-discharge-and-flushing-times-in-todos-os-santos-bay-brazil
#6
Vanessa Hatje, Karina Kammer Attisano, Marcelo Friederichs Landim de Souza, Barbara Mazzilli, Joselene de Oliveira, Tamires de Araújo Mora, William C Burnett
Todos os Santos Bay (BTS) is the 2nd largest bay in Brazil and an important resource for the people of the State of Bahia. We made measurements of radon and radium in selected areas of the bay to evaluate if these tracers could provide estimates of submarine groundwater discharge (SGD) and flushing times of the Paraguaçu Estuary and BTS. We found that there were a few areas along the eastern and northeastern shorelines that displayed relatively high radon and low salinities, indicating possible sites of enhanced SGD...
August 16, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28822258/photochemical-oxidation-of-dimethylsulphide-to-dimethylsulphoxide-in-estuarine-and-coastal-waters
#7
Günther Uher, J Julian Pillans, Angela D Hatton, Robert C Upstill-Goddard
Dimethylsulphide (DMS) photo-oxidation and dimethylsulphoxide (DMSO) photoproduction were estimated in 26 laboratory irradiations of coastal samples from NE England (Tyne estuary) and W Scotland (Loch Linnhe and River Nant at Taynuilt). Pseudo-first order rate constants of DMS photo-oxidation (0.038 h(-1) to 0.345 h(-1)) and DMSO photo-production (0.017 h(-1) to 0.283 h(-1)) varied by one order of magnitude and were lowest in the coastal North Sea. Estuarine samples (salinity S < 30) had a mean DMSO yield of 96 ± 16% (n = 14), consistent with 1:1 M conversion via photosensitised oxidation by singlet oxygen...
August 11, 2017: Chemosphere
https://www.readbyqxmd.com/read/28822206/prevalence-and-molecular-characterisation-of-schistosoma-haematobium-among-primary-school-children-in-kebbi-state-nigeria
#8
Shuaibu Umar, Saadatu Haruna Shinkafi, Shuaibu Abdullahi Hudu, Vasanthakumari Neela, Kumar Suresh, Syafinaz Amin Nordin, Osman Malina
Schistosomiasis is the major source of morbidity in Sub-Saharan Africa and Asia. It is estimated that 207 million people are infected, of which 97% are in Africa. The aim of this study was the determining of prevalence as well as the phylogeny of S. haematobium among school children in Argungu Emirate, Kebbi State Nigeria. A total of 325 urine samples was collected from school children between 7 to 14 years. S. heamatobium eggs was examined under dissecting microscope and DNA was extracted from urine sample and COX1 gene was amplified by nested PCR...
2017: Annals of Parasitology
https://www.readbyqxmd.com/read/28822043/industrial-pollution-and-the-management-of-river-water-quality-a-model-of-kelani-river-sri-lanka
#9
Asha Gunawardena, E M S Wijeratne, Ben White, Atakelty Hailu, Ram Pandit
Water quality of the Kelani River has become a critical issue in Sri Lanka due to the high cost of maintaining drinking water standards and the market and non-market costs of deteriorating river ecosystem services. By integrating a catchment model with a river model of water quality, we developed a method to estimate the effect of pollution sources on ambient water quality. Using integrated model simulations, we estimate (1) the relative contribution from point (industrial and domestic) and non-point sources (river catchment) to river water quality and (2) pollutant transfer coefficients for zones along the lower section of the river...
August 19, 2017: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/28821002/modeling-the-fate-and-transport-of-17%C3%AE-estradiol-in-the-south-river-watershed-in-virginia
#10
Xiaomin Zhao, Wu-Seng Lung
Hormones excreted by livestock metabolisms often enter surface water through feces and urine and can potentially cause adverse impacts to aquatic biota. This study involved a modeling analysis of 17β-estradiol (E2), a prevalent estrogen, in the South River watershed located in Augusta County, Virginia from 2013 to 2015. Cattle manure, poultry litter, biosolids, septic systems, and wastewater treatment plants (WWTPs) were considered as sources of E2 in this study. The EPA's BASINS modeling framework was configured to track the fate and transport of E2...
August 13, 2017: Chemosphere
https://www.readbyqxmd.com/read/28820979/data-driven-analysis-of-nutrient-inputs-and-transfers-through-nested-catchments
#11
Lea Levi, Vladimir Cvetkovic, Georgia Destouni
A data-driven screening methodology is developed for estimating nutrient input and retention-delivery in catchments with measured water discharges and nutrient concentrations along the river network. The methodology is applied to the Sava River Catchment (SRC), a major transboundary catchment in southeast Europe, with seven monitoring stations along the main river, defining seven nested catchments and seven incremental subcatchments that are analysed and compared in this study. For the relatively large nested catchments (>40,000km(2)), characteristic regional values emerge for nutrient input per unit area of around 30T/yr/km(2) for dissolved inorganic nitrogen (DIN) and 2T/yr/km(2) for total phosphorus (TP)...
August 15, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28820901/using-local-ecological-knowledge-to-monitor-threatened-mekong-megafauna-in-lao-pdr
#12
Thomas N E Gray, Amphone Phommachak, Kongseng Vannachomchan, Francois Guegan
Pressures on freshwater biodiversity in Southeast Asia are accelerating yet the status and conservation needs of many of the region's threatened fish species are unclear. This impacts the ability to implement conservation activities and to understand the effects of infrastructure developments and other hydrological changes. We used Local Ecological Knowledge from fishing communities on the Mekong River in the Siphandone waterscape, Lao PDR to estimate mean and mode last capture dates of eight rare or culturally significant fish species in order to provide conservation monitoring baselines...
2017: PloS One
https://www.readbyqxmd.com/read/28820882/correlation-between-mosquito-larval-density-and-their-habitat-physicochemical-characteristics-in-mazandaran-province-northern-iran
#13
Seyed Hassan Nikookar, Mahmoud Fazeli-Dinan, Shahyad Azari-Hamidian, Seyed Nouraddin Mousavinasab, Mohsen Aarabi, Seyyed Payman Ziapour, Yahya Esfandyari, Ahmadali Enayati
Characteristics of mosquito larval habitats are important in determining whether they can survive and successfully complete their developmental stages. Therefore, data on the ecological factors affecting mosquito density and abundance especially the physicochemical properties of water of their breeding sites, can possibly be helpful in implementing larval management programs. Mosquito larvae were collected using a standard 350 ml dipper from fixed habitats including: artificial pool, river edge, creek and etc, in 30 villages of 16 counties from May-December 2014...
August 18, 2017: PLoS Neglected Tropical Diseases
https://www.readbyqxmd.com/read/28819754/development-of-the-hybrid-cells-in-series-model-to-simulate-ammonia-nutrient-pollutant-transport-along-the-umgeni-river
#14
Kayode O Olowe, Muthukrishnavellaisamy Kumarasamy
Discharge of organic waste results in high nutrient pollution of the water bodies which is a major menace to the environment. A high quantity of nutrients such as ammonia causes a reduction in the dissolved oxygen level and induces algal growth in the water bodies. Water quality models have been the tools to evaluate the rate at which streams can disperse the pollutants they receive. Many water quality models are flawed either because of their inadequacy to completely simulate the advection component of the pollutant transport, or because of the limited application of the models, due to inaccurate estimation of model parameters...
August 17, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28819745/bioassessment-of-the-effluents-discharged-from-two-export-oriented-industrial-zones-located-in-kelani-river-basin-sri-lanka-using-erythrocytic-responses-of-the-fish-nile-tilapia-oreochromis-niloticus
#15
C K Hemachandra, A Pathiratne
Complex effluents originating from diverse industrial processes in industrial zones could pose cytotoxic/genotoxic hazards to biota in the receiving ecosystems which cannot be revealed by conventional monitoring methods. This study assessed potential cytotoxicity/genotoxicity of treated effluents of two industrial zones which are discharged into Kelani river, Sri Lanka combining erythrocytic abnormality tests and comet assay of the tropical model fish, Nile tilapia. Exposure of fish to the effluents induced erythrocytic DNA damage and deformed erythrocytes with serrated membranes, vacuolations, nuclear buds and micronuclei showing cytotoxic/genotoxic hazards in all cases...
August 17, 2017: Bulletin of Environmental Contamination and Toxicology
https://www.readbyqxmd.com/read/28819258/groundwater-nitrate-response-to-sustainable-nitrogen-management
#16
Birgitte Hansen, Lærke Thorling, Jörg Schullehner, Mette Termansen, Tommy Dalgaard
Throughout the world, nitrogen (N) losses from intensive agricultural production may end up as undesirably high concentrations of nitrate in groundwater with a long-term impact on groundwater quality. This has human and environmental health consequences, due to the use of groundwater as a drinking water resource, and causes eutrophication of groundwater-dependent ecosystems such as wetlands, rivers and near-coastal areas. At national scale, the measured nitrate concentrations and trends in Danish oxic groundwater in the last 70 years correlate well with the annual agricultural N surpluses...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28819112/tracing-nitrate-sources-with-dual-isotopes-and-long-term-monitoring-of-nitrogen-species-in-the-yellow-river-china
#17
Fu-Jun Yue, Si-Liang Li, Cong-Qiang Liu, Zhi-Qi Zhao, Hu Ding
A heavy load of nitrogenous compounds reflects nutrient loss and influences water quality in large rivers. Nitrogenous concentrations and dual isotopes of nitrate were measured to ascertain the spatial and temporal distributions of nitrate transformation in the Yellow River, the second-longest river in China. Assessment of the long-term record indicates that [NO3(-)-N] has increased by two-fold over the past three decades. Weekly observation of ammonium over a twelve-year period revealed high concentrations and suggests impairment of water quality, particularly since 2011...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28818328/deep-eutectic-solvent-based-ultrasound-assisted-dispersive-liquid-liquid-microextraction-coupled-with-high-performance-liquid-chromatography-for-the-determination-of-ultraviolet-filters-in-water-samples
#18
Huazi Wang, Lu Hu, Xinya Liu, Shujun Yin, Runhua Lu, Sanbing Zhang, Wenfeng Zhou, Haixiang Gao
In the present study, a simple and rapid sample preparation method designated ultrasound-assisted dispersive liquid-liquid microextraction based on a deep eutectic solvent (DES) followed by high-performance liquid chromatography with ultraviolet (UV) detection (HPLC-UVD) was developed for the extraction and determination of UV filters from water samples. The model analytes were 2,4-dihydroxybenzophenone (BP-1), benzophenone (BP) and 2-hydroxy-4-methoxybenzophenone (BP-3). The hydrophobic DES was prepared by mixing trioctylmethylammonium chloride (TAC) and decanoic acid (DecA)...
July 22, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28817268/natural-organic-matter-concentration-impacts-the-interaction-of-functionalized-diamond-nanoparticles-with-model-and-actual-bacterial-membranes
#19
Arielle C Mensch, Rodrigo Tapia Hernandez, Joshua E Kuether, Marco D Torelli, Z Vivian Feng, Robert J Hamers, Joel A Pedersen
Changes to nanoparticle surface charge, colloidal stability, and hydrodynamic properties induced by interaction with natural organic matter (NOM) warrant consideration in assessing the potential for these materials to adversely impact organisms in the environment. Here we show that acquisition of a coating, or "corona", of NOM alters the hydrodynamic and electrokinetic properties of diamond nanoparticles (DNPs) functionalized with the polycation poly(allylamine HCl) in a manner that depends on the NOM-to-DNP concentration ratio...
August 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28817260/current-use-flame-retardants-in-the-water-of-lake-michigan-tributaries
#20
Jiehong Guo, Kevin Romanak, Stephen Westenbroek, Ronald A Hites, Marta Venier
In this study, we measured the concentrations of 65 flame retardants in water samples from five Lake Michigan tributaries. These flame retardants included organophosphate esters (OPEs), brominated flame retardants (BFRs), and Dechlorane-related compounds. A total of 59 samples, including both the particulate and the dissolved phases, were collected from the Grand, Kalamazoo, Saint Joseph, and Lower Fox rivers and from the Indiana Harbor and Ship Canal (IHSC) in 2015. OPEs were the most abundant among the targeted compounds with geometric mean concentrations ranging from 20 to 54 ng/L; OPE concentrations were comparable among the five tributaries...
August 17, 2017: Environmental Science & Technology
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