Journal articles: 'Surface water quantification'

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Wunderlich, Anika, Carmen Torggler, Dennis Elsässer, Christian Lück, Reinhard Niessner, and Michael Seidel. "Rapid quantification method for Legionella pneumophila in surface water." Analytical and Bioanalytical Chemistry 408, no. 9 (February 12, 2016): 2203–13. http://dx.doi.org/10.1007/s00216-016-9362-x.

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Patrick, Michael, Andrea Rösch, Birgit Beck, Tobias Doppler, and Heinz Singer. "Ultrasensitive Quantification of Pyrethroid and Organophosphate Insecticides in Surface Water." CHIMIA International Journal for Chemistry 74, no. 6 (June 24, 2020): 506. http://dx.doi.org/10.2533/chimia.2020.506.

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Berkowitz, Brian, and Erwin Zehe. "Surface water and groundwater: unifying conceptualization and quantification of the two “water worlds”." Hydrology and Earth System Sciences 24, no. 4 (April 14, 2020): 1831–58. http://dx.doi.org/10.5194/hess-24-1831-2020.

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Abstract. While both surface water and groundwater hydrological systems exhibit structural, hydraulic, and chemical heterogeneity and signatures of self-organization, modelling approaches between these two “water world” communities generally remain separate and distinct. To begin to unify these water worlds, we recognize that preferential flows, in a general sense, are a manifestation of self-organization; they hinder perfect mixing within a system, due to a more “energy-efficient” and hence faster throughput of water and matter. We develop this general notion by detailing the role of preferential flow for residence times and chemical transport, as well as for energy conversions and energy dissipation associated with flows of water and mass. Our principal focus is on the role of heterogeneity and preferential flow and transport of water and chemical species. We propose, essentially, that related conceptualizations and quantitative characterizations can be unified in terms of a theory that connects these two water worlds in a dynamic framework. We discuss key features of fluid flow and chemical transport dynamics in these two systems – surface water and groundwater – and then focus on chemical transport, merging treatment of many of these dynamics in a proposed quantitative framework. We then discuss aspects of a unified treatment of surface water and groundwater systems in terms of energy and mass flows, and close with a reflection on complementary manifestations of self-organization in spatial patterns and temporal dynamic behaviour.

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Chu, Xuefeng, Xinhua Jia, and Yang Liu. "Quantification of wetting front movement under the influence of surface topography." Soil Research 56, no. 4 (2018): 382. http://dx.doi.org/10.1071/sr17071.

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Soil surface topography affects fundamental hydrologic processes, such as infiltration and soil water percolation. Topographic variations potentially alter both the magnitude and directions of unsaturated flow. The objective of this study is to evaluate the effects of surface topography on wetting front moving patterns under different rainfall and soil conditions through combined experimental and numerical modelling studies. Specifically, laboratory-scale infiltration and unsaturated flow experiments and HYDRUS-2D modelling were conducted for different topographic surfaces, rainfall intensities, and soil types. The simulated and observed wetting front distributions were compared and evaluated. Two different stages were observed: topography-dominated two-dimensional flow and uniform one-dimensional flow. A uniformly distributed wetting front was eventually achieved although soil surfaces had dissimilar topographic characteristics. However, the timing or duration to reach such a uniform flat wetting front varied, mainly depending on surface topography, rainfall characteristics, and soil hydraulic properties. The findings from this study are important to better understand the mechanism of topography-controlled unsaturated flow, wetting front movement, and overland flow generation, and to further improve modelling of soil water flow and transport processes under such complex conditions across different scales.

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Normandin, Cassandra, Frédéric Frappart, Bertrand Lubac, Simon Bélanger, Vincent Marieu, Fabien Blarel, Arthur Robinet, and Léa Guiastrennec-Faugas. "Quantification of surface water volume changes in the Mackenzie Delta using satellite multi-mission data." Hydrology and Earth System Sciences 22, no. 2 (February 28, 2018): 1543–61. http://dx.doi.org/10.5194/hess-22-1543-2018.

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Abstract. Quantification of surface water storage in extensive floodplains and their dynamics are crucial for a better understanding of global hydrological and biogeochemical cycles. In this study, we present estimates of both surface water extent and storage combining multi-mission remotely sensed observations and their temporal evolution over more than 15 years in the Mackenzie Delta. The Mackenzie Delta is located in the northwest of Canada and is the second largest delta in the Arctic Ocean. The delta is frozen from October to May and the recurrent ice break-up provokes an increase in the river's flows. Thus, this phenomenon causes intensive floods along the delta every year, with dramatic environmental impacts. In this study, the dynamics of surface water extent and volume are analysed from 2000 to 2015 by combining multi-satellite information from MODIS multispectral images at 500 m spatial resolution and river stages derived from ERS-2 (1995–2003), ENVISAT (2002–2010) and SARAL (since 2013) altimetry data. The surface water extent (permanent water and flooded area) peaked in June with an area of 9600 km2 (±200 km2) on average, representing approximately 70 % of the delta's total surface. Altimetry-based water levels exhibit annual amplitudes ranging from 4 m in the downstream part to more than 10 m in the upstream part of the Mackenzie Delta. A high overall correlation between the satellite-derived and in situ water heights (R > 0.84) is found for the three altimetry missions. Finally, using altimetry-based water levels and MODIS-derived surface water extents, maps of interpolated water heights over the surface water extents are produced. Results indicate a high variability of the water height magnitude that can reach 10 m compared to the lowest water height in the upstream part of the delta during the flood peak in June. Furthermore, the total surface water volume is estimated and shows an annual variation of approximately 8.5 km3 during the whole study period, with a maximum of 14.4 km3 observed in 2006. The good agreement between the total surface water volume retrievals and in situ river discharges (R= 0.66) allows for validation of this innovative multi-mission approach and highlights the high potential to study the surface water extent dynamics.

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DeVries, Ben, Chengquan Huang, Megan Lang, John Jones, Wenli Huang, Irena Creed, and Mark Carroll. "Automated Quantification of Surface Water Inundation in Wetlands Using Optical Satellite Imagery." Remote Sensing 9, no. 8 (August 7, 2017): 807. http://dx.doi.org/10.3390/rs9080807.

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Dalstein, Laetitia, Kuo-Yang Chiang, and Yu-Chieh Wen. "Direct Quantification of Water Surface Charge by Phase-Sensitive Second Harmonic Spectroscopy." Journal of Physical Chemistry Letters 10, no. 17 (August 21, 2019): 5200–5205. http://dx.doi.org/10.1021/acs.jpclett.9b02156.

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Langhoff, Jesper H., Keld R. Rasmussen, and Steen Christensen. "Quantification and regionalization of groundwater–surface water interaction along an alluvial stream." Journal of Hydrology 320, no. 3-4 (April 2006): 342–58. http://dx.doi.org/10.1016/j.jhydrol.2005.07.040.

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Mortazavi, S. S., R. Sahraei, and A. Farmany. "Sensitive nanosilver-based spectrophotometric determination of Brilliant Blue FCF in surface water samples." Water Science and Technology 67, no. 10 (May 1, 2013): 2302–6. http://dx.doi.org/10.2166/wst.2013.082.

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An accurate method was developed for the determination of Brilliant Blue FCF, a synthetic soluble colorant, in environmental samples. The method is based on the catalytic effect of silver nanoparticles (AgNPs) on the oxidation of Brilliant Blue FCF by hexacyanoferrate(III) in acetate–acetic acid medium at room temperature. Linearity of around four orders in the magnitude of concentration was generally obtained. Detection and quantification limits of the investigated dye, which was evaluated at a signal-to-noise ratio of 3 for detection limit and quantification limit, were 0.1 and 0.6–130.0 ng/mL, respectively. The recoveries of the synthetic colorant Brilliant Blue FCF in environmental matrices (surface water) ranged from 95.0 to 101.0%. Relative standard deviation of less than 3.1% was also achieved. This method has been applied successfully in the determination of water-soluble colorant Brilliant Blue FCF in surface water samples.

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Miller, K. L., S. J. Berg, J. H. Davison, E. A. Sudicky, and P. A. Forsyth. "Efficient uncertainty quantification in fully-integrated surface and subsurface hydrologic simulations." Advances in Water Resources 111 (January 2018): 381–94. http://dx.doi.org/10.1016/j.advwatres.2017.10.023.

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Bulc, T. G., A. K. Klemenčič, and J. Razinger. "Vegetated ditches for treatment of surface water with highly fluctuating water regime." Water Science and Technology 63, no. 10 (May 1, 2011): 2353–59. http://dx.doi.org/10.2166/wst.2011.588.

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Vegetated drainage ditches (VDD) as a type of constructed wetland primarily serve to remove and store excess water associated with irrigation and storm events. Current research suggests using a VDD as an additional practice in the mitigation of surface water pollution. The VDD for water treatment of the Glinscica River was constructed in 2006. The efficiency of the system was evaluated in 2008 and 2009 regarding the reduction of SS, COD, BOD5, NH4-N, NO3-N, NO2-N, TN, ON and TP. The microbiological association developed in the VDD was analyzed with a focus on the identification and quantification of the narG gene as a denitrification indicator. This paper discusses the efficiency of pollution removal and the distribution of the narG gene within the VDD. The results showed that the highly fluctuating water regime was the main reason for the even distribution and abundance of the narG gene throughout the system, regardless of oxygen saturation or the nutrient status of the wastewater. With the exception of SS, pollutant concentrations met the permitted outflow levels.

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Meng, Xue, Jian Lu, Jun Wu, Zhenhua Zhang, and Liwei Chen. "Quantification and Evaluation of Grey Water Footprint in Yantai." Water 14, no. 12 (June 12, 2022): 1893. http://dx.doi.org/10.3390/w14121893.

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Problems such as water scarcity and pollution frequently occur in coastal zones. This study investigated the grey water footprint and the sustainability and intensity of grey water footprint in Yantai between 2014 and 2019 by taking both surface water and groundwater into consideration. The research results indicated that the Yantai grey water footprint firstly increased and then decreased between 2014 and 2019. The lowest grey water footprint in 2019 was 744 million m3. The agricultural grey water footprint accounted for a large proportion of the total grey water footprint. Although the sustainability of grey water footprint fluctuates in Yantai, it maintains well. The Yantai grey footprint intensity gradually decreased to <10 m3/10,000 CNY. The economic benefit of grey water footprint and utilization efficiency of water resources have been improved yearly. The quality of the water environment in Yantai has also been improved. The research of this paper provides some useful information for water resources protection and sustainable utilization in coastal cities.

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Hamza, Ibrahim Ahmed, Lars Jurzik, Michael Wilhelm, and Klaus Überla. "Detection and quantification of human bocavirus in river water." Journal of General Virology 90, no. 11 (November 1, 2009): 2634–37. http://dx.doi.org/10.1099/vir.0.013557-0.

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Human bocavirus (HBoV) was recently discovered in children with respiratory-tract infection and has been detected frequently in faecal specimens from children with gastroenteritis. The present study addresses for the first time, to our knowledge, the prevalence of HBoV in river water. By using a newly developed real-time PCR targeting a conserved region of the NP1 gene of HBoV, virus levels in water samples were determined. Moreover, partial sequence analysis of the NP1 gene of HBoV and comparative phylogenetic analysis were performed. HBoV was detected in 40.8 % of collected water samples. The virus level ranged between 3×101 and 2×103 genome equivalents l−1. Therefore, the present study suggests that river water could play a role in the spread of HBoV. However, further work should be done to determine the actual risk of infection via surface water.

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Baig, Jameel Ahmed, Ashfaque Ali Bhutto, Siraj Uddin, Tasneem Gul Kazi, and Muhammad Irfan Khan. "Quantification of Hexavalent Chromium in Surface Water Samples by a Selective Electrochemical Method." Journal of AOAC INTERNATIONAL 101, no. 2 (March 1, 2018): 577–86. http://dx.doi.org/10.5740/jaoacint.17-0208.

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Abstract The current study aimed to develop a robust, selective, and sensitive voltammetric method for hexavalent chromium (CrVI) at a chemically modified carbon paste electrode. For the preparation of the electrode, a micropipet tip was packed with modified carbon paste mainly consisting of graphite powder and diphenylcarbazone (5 + 1, w/w). Voltammetric mode, type of electrolyte, pH, volume of electrolytes, accumulation time, accumulation potential, and stirring rate were studied in detail. The current response was linearly dependent on the concentration of CrVI from 0.20 to 2.60 µmol/L. The reproducible results were obtained for replicate analyses (n = 11) of three proposed electrodes of the same composition with RSDs of <2.0%. The LODs and LOQs were found to be 0.052 and 0.174 µmol/L, respectively. The noticeable electrode surface passivation was not observed for the detection of CrVI. The proposed methods were successfully applied for CrVI in different surface waters in Sindh, Pakistan.

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Icin, Izthak, Idan Ashur, and Abraham Ogungbile. "Rapid Detection and Quantification of Microcystins in Surface Water by an Impedimetric Biosensor." ECS Meeting Abstracts MA2021-02, no. 55 (October 19, 2021): 1597. http://dx.doi.org/10.1149/ma2021-02551597mtgabs.

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Ogungbile, Abraham O., Idan Ashur, Itzik Icin, Orr H. Shapiro, and Sefi Vernick. "Rapid detection and quantification of microcystins in surface water by an impedimetric immunosensor." Sensors and Actuators B: Chemical 348 (December 2021): 130687. http://dx.doi.org/10.1016/j.snb.2021.130687.

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Vione, Davide, Daniele Bagnus, Valter Maurino, and Claudio Minero. "Quantification of singlet oxygen and hydroxyl radicals upon UV irradiation of surface water." Environmental Chemistry Letters 8, no. 2 (February 26, 2009): 193–98. http://dx.doi.org/10.1007/s10311-009-0208-z.

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Gowing, Charles J. B., James M. Dinsley, Elizabeth L. Gallannaugh, Pauline L. Smedley, Andrew L. Marriott, Michael J. Bowes, Kay A. Green, and Michael J. Watts. "Method development for rapid quantification of Rn-222 in surface water and groundwater." Environmental Geochemistry and Health 42, no. 4 (June 7, 2019): 1109–15. http://dx.doi.org/10.1007/s10653-019-00335-1.

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Lamberts, Thanja, Pradipta Kumar Samanta, Andreas Köhn, and Johannes Kästner. "Quantum tunneling during interstellar surface-catalyzed formation of water: the reaction H + H2O2 → H2O + OH." Physical Chemistry Chemical Physics 18, no. 48 (2016): 33021–30. http://dx.doi.org/10.1039/c6cp06457d.

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Chiu, Shirley Wen-Yu, Ho-Wen Cheng, Zhi-Xin Chen, Huai-Hsien Wang, Ming-Yu Lai, Juen-Kai Wang, and Yuh-Lin Wang. "Quantification of biomolecules responsible for biomarkers in the surface-enhanced Raman spectra of bacteria using liquid chromatography-mass spectrometry." Physical Chemistry Chemical Physics 20, no. 12 (2018): 8032–41. http://dx.doi.org/10.1039/c7cp07103e.

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Iancu, Vasile Ion, Toma Galaon, Marcela Niculescu, and Carol Blaziu Lehr. "Neonicotinoids Detection by new LC-MS/MS Method in Romanian Surface Waters." Revista de Chimie 68, no. 8 (September 15, 2017): 1716–22. http://dx.doi.org/10.37358/rc.17.8.5751.

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Increasing and widespread use of neonicotinoid insecticides in all world, together with their highly toxicity to invertebrates and environmental persistence mean that surface waters need to be monitored for these compounds. In the 2015, neonicotinoid insecticides have been incorporated in the watch list of substances for a European Union monitoring program (495/2015/ EU). A new method using automated solid phase extraction (SPE) with polymeric cartridges (OASIS HLB) followed by LC-MS/MS provided good separation of the most common neonicotindoid compounds. The method was developed for the determination of four neonicotinoid insecticides (nitenpyram, thiamethoxam, clothianidin, acetamiprid) in surface water with low limit of quantification (0.3-0.9 ng/L, nanograms per liter). Recoveries in surface water samples fortified at 200 ng/L for each compound ranged from 71.4 to 109.9 %; relative standard deviation ranged from 4 to 9%. The method was applied to water samples from four streams in Romania, Danube River and its tributaries (Arges River, Jiu River, and Olt River). The surface water samples were found to be contaminated clothianidin (1.08-6.4 ng/L) and by thiamethoxam (1.1-3.8ng/L). The highest concentrations were recorded in Danube River in Oltenita point (6.4ng/L) and in Gura-Vaii point (5.5ng/L). The concentration of acetamiprid and nitenpyram were situated below limit of quantification in all samples.

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Subaihi, Abdu, Howbeer Muhamadali, Shaun T. Mutter, Ewan Blanch, David I. Ellis, and Royston Goodacre. "Quantitative detection of codeine in human plasma using surface-enhanced Raman scattering via adaptation of the isotopic labelling principle." Analyst 142, no. 7 (2017): 1099–105. http://dx.doi.org/10.1039/c7an00193b.

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Guerrini, Luca, Ignacio Rodriguez-Loureiro, Miguel A. Correa-Duarte, Yih Hong Lee, Xing Yi Ling, F. Javier García de Abajo, and Ramon A. Alvarez-Puebla. "Chemical speciation of heavy metals by surface-enhanced Raman scattering spectroscopy: identification and quantification of inorganic- and methyl-mercury in water." Nanoscale 6, no. 14 (2014): 8368–75. http://dx.doi.org/10.1039/c4nr01464b.

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Papciak, Dorota, Andżelika Domoń, Monika Zdeb, Agata Skwarczyńska-Wojsa, and Janusz Konkol. "Optimization of Quantitative Analysis of Biofilm Cell from Pipe Materials." Coatings 11, no. 11 (October 22, 2021): 1286. http://dx.doi.org/10.3390/coatings11111286.

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The quantitative analysis of biofilm can be used not only to assess the microbiological stability of tap water but also on its basis can assess: the degree of colonization of materials by bacterial cells, the rate of biofilm formation on the surfaces of pipes and determine their composition and number. The article presents the results of research on the development of an effective method of biofilm detachment from the surface of the galvanized steel. The number of biofilm cells was determined by methods: (1) luminometric ATP determination, (2) flow cytometry and (3) heterotrophic plate counts (HPC). The presence of the biofilm was confirmed by SEM and fractal analysis. The analysis of the obtained results showed that the most effective method of detaching the biofilm cells from the galvanized steel surface was the mechanical separation with a sterile cotton swab. The variant with the use of a sterile swab enables rapid collection of the biofilm from the surface of the ducts forming internal installations or water supply networks. Due to the simplicity and speed of obtaining results, the luminometric ATP measurement has been established as the best method for the quantification of biofilm cells. The results of this study were intended to provide reliable and useful data on the quantification of biofilm cells.

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Okoya, A. A., O. E. Akinola, O. S. Adegbaju, A. B. Akinyele, and O. S. Amuda. "Quantification and Removal of Trichloromethane in Chlorinated Water Using Coconut Shell Activated Carbon." Ghana Journal of Science 61, no. 1 (July 31, 2020): 1–14. http://dx.doi.org/10.4314/gjs.v61i1.1.

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Commercially, available activated carbon (CAC) and coconut shell activated carbon (CSAC) were used in the adsorption of Trichloromethane (TCM) from disinfected water using the optimum conditions (concentration, dosage, pH and time) obtained. Concentrations of TCM were determined using GC-MS. Physicochemical parameters of CSAC were investigated. The CSAC gave percentage carbon yield (86.72±1.41), surface area 1200 m2/g and CHNS/O Elemental Analyzer gave elemental Carbon of 60.08% as the highest of the elements in the char. A pore structure dispersed on the CSAC surface was observed. Best conditions for CSAC were: 1.4 × 104μg/l TCM, 5.0 pH, 0.8 g absorbent within 30 minutes. The data fitted Freundlich than Langmuir model (R2 of 0.9977 and 0.9232, respectively). Percentage removal of TCM for CAC and CSAC was 98.3±1.55 and 96.7±1.27, respectively for the water sample. Results indicated that CSAC was efficient for removal of TCM present in water and could be used as alternative for CAC in water treatment.

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Primus, A., and S. Azman. "Quantification and Characterisation of Microplastics in Fish and Surface Water at Melayu River, Johor." IOP Conference Series: Materials Science and Engineering 1229, no. 1 (February 1, 2022): 012014. http://dx.doi.org/10.1088/1757-899x/1229/1/012014.

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Abstract Microplastics are plastic particles (< 5 mm) found in the environment that can be ingested by animals and transferred up in the trophic level. The study was conducted through sample collection, digestion of gastrointestinal (GI) tracts of fish, density separation using NaCl, filtration, microscopy, and ATR-FTIR Spectroscopy. The amount of ingested microplastics by Melayu River fish samples was: Gray Eel-Catfish (3.92 ± 4.17 particles/individual) > Sagor Catfish (2.00 ± 1.41 particles/individual) > Spotted Sicklefish (2.00 ± 0.00 particles/individual). The trend of microplastics by month in water samples was Mar-20 (2.89 ± 1.36 particles/L) > Feb-20 (1.33 ± 1.00 particle/L) and Jan-20 (1.00 ± 0.87 particle/L). Microplastics were mostly in the class size 0 µm – 0.50 µm. In the fish samples, fibres were found to be dominant. In water samples, films were dominant. Ingestion of microplastics by colour was ranked as blue > black > red > yellow in fish samples whereas microplastics’ colour in water samples was ranked as blue > red > black > translucent > green. Therefore, it is concluded that the abundance of blue microplastics in fish samples was due to the common blue plastics used by the locals. The identified microplastics were of polyethylene terephthalate (PET) and polyethene (PE) origins.

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Bataiero, M. O., R. S. Araujo, A. C. Nardocci, M. H. Matté, M. I. Z. Sato, M. S. Lauretto, and M. T. P. Razzolini. "Quantification of Giardia and Cryptosporidium in surface water: a risk assessment and molecular characterization." Water Supply 19, no. 6 (April 4, 2019): 1823–30. http://dx.doi.org/10.2166/ws.2019.059.

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Abstract This study aimed to estimate the annual probability of Giardia and Cryptosporidium infection for a population supplied by contaminated drinking water sources. Parasites were quantified by the USEPA Method 1623.1/2012. Annual risk was estimated using the quantitative microbial risk assessment (QMRA) approach. Genotyping was performed using specific primers based on the 18S rRNA gene for Cryptosporidium and gdh gene for Giardia. Giardia was detected in 83.3% of the samples (<0.1 to 8.6 cysts/L) and Cryptosporidium in 37.5% (<0.1 to 2 oocysts/L). In general, annual risk values for Giardia were 1 log higher when compared with those obtained for Cryptosporidium. Giardia intestinalis A and B were present as well as C. hominis and C. parvum. The lack of protection measures for the water supply catchment point put the population's health at risk. The results provide data to support decision-makers to take actions to improve environmental quality resulting in a positive impact on consumers' health.

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Xin, Pei, Shen S. J. Wang, Chengji Shen, Zeyu Zhang, Chunhui Lu, and Ling Li. "Predictability and Quantification of Complex Groundwater Table Dynamics Driven by Irregular Surface Water Fluctuations." Water Resources Research 54, no. 3 (March 2018): 2436–51. http://dx.doi.org/10.1002/2017wr021761.

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Oguma, Hidetoshi, Eri Seitoku, Mami Mutoh, Saori Yoshizawa, Ko Nakanishi, Yosuke Bando, Yuko Era, et al. "Size- and Morphology-Controlled Preparation of Surface-Modified Water-Dispersible Fullerene Nanoparticles for Bioapplications." Journal of Nanoscience and Nanotechnology 20, no. 5 (May 1, 2020): 2668–74. http://dx.doi.org/10.1166/jnn.2020.17473.

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In this study, we investigated water-dispersible surface modification for size- and shape-controlled fullerene nanoparticles (C60P) based on a condensation reaction with di-amino alkane. This modification provided for water dispersibility of C60P and the capability for secondary modification as well. The resultant C60P particles have several useful physical properties: water-dispersibility for ease of injection; fluorescence for detection and quantification; and a characteristic morphology to assist identification. These properties will widely extend the applications of these particles, especially into the biological fields of bioimaging and drug delivery.

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Diedrich, H., R. Preusker, R. Lindstrot, and J. Fischer. "Quantification of uncertainties of water vapour column retrievals using future instruments." Atmospheric Measurement Techniques Discussions 5, no. 5 (September 6, 2012): 6323–55. http://dx.doi.org/10.5194/amtd-5-6323-2012.

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Abstract. This study presents a quantification of uncertainties of water vapour retrievals based on near infrared measurements of upcoming instruments. The concepts of three scheduled spectrometer were taken into account: OLCI (Ocean and Land Color Instrument) on Sentinel-3, METimage on MetOp (Meteorological Operational Satellite) and FCI (Flexible Combined Imager) on MTG (Meteosat Third Generation). Optimal estimation theory was used to estimate the error of an hypothetical total water vapour column retrieval for 27 different atmospheric cases. The errors range from 100% in very dry cases to 2% in humid cases with a very high surface albedo. Generally the absolute uncertainties increase with higher water vapour column content due to H2O-saturation and decrease with a brighter surface albedo. Uncertainties increase with higher aerosol optical thickness, apart from very dark cases. Overall the METimage channel setting enables the most accurate retrievals. The retrieval using the MTG-FCI buildup has the highest uncertainties apart from very bright cases. A retrieval using two absorption channels increases the accuracy, in some cases by one order of magnitude, in comparison to a retrieval using just one absorption channel. On the other hand, a retrieval using three absorption channels has no significant advantage over a two-absorption channel retrieval. Furthermore, the optimal position of the absorption channels was determined using the concept of the "information content". For a single channel retrieval a channel at 900 or 915 nm has the highest mean information contents over all cases. The second absorption channel is ideally weakly correlated with the first one, thus positioned at 935 nm, in a region with stronger water vapour absorption.

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Tseng, Kuo-Hsin, Chung-Yen Kuo, Min-Hui Lo, C. K. Shum, Md Mizanur Rahman, Yuanyuan Jia, Ting-Yi Yang, and Po-Hung Shih. "Using MODIS/Terra and Landsat imageries to improve surface water quantification in Sylhet, Bangladesh." Terrestrial, Atmospheric and Oceanic Sciences 30, no. 1 (2019): 111–26. http://dx.doi.org/10.3319/tao.2018.11.15.04.

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Araújo e Nógrega, Jaldair, Lucilene Santos Rosa, Higor Nara Rigon, Rosemeire Aparecida Nunes Oliveira, Carlos Fabiano Capato, Evaristo Alexandre Falcão, Anderson Lima Caires, and Eriton Rodrigo Botero. "Quantification of chrysene and benzo(a)pyrene in surface water samples by fluorescence measurement." Brazilian Journal of Development 6, no. 1 (2020): 3092–104. http://dx.doi.org/10.34117/bjdv6n1-224.

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Singh, Gulshan, Poornima Vajpayee, Neetika Rani, Anurag Jyoti, Kailash Chand Gupta, and Rishi Shanker. "Bio-capture of S. Typhimurium from surface water by aptamer for culture-free quantification." Ecotoxicology and Environmental Safety 78 (April 2012): 320–26. http://dx.doi.org/10.1016/j.ecoenv.2011.11.039.

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Rodrigues, Alexandrina, António Brito, Peter Janknecht, Maria Fernanda Proença, and Regina Nogueira. "Quantification of humic acids in surface water: effects of divalent cations, pH, and filtration." J. Environ. Monit. 11, no. 2 (2009): 377–82. http://dx.doi.org/10.1039/b811942b.

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Nadav, Itamar, Jorge Tarchitzky, Anat Lowengart-Aycicegi, and Yona Chen. "Soil surface water repellency induced by treated wastewater irrigation: physico-chemical characterization and quantification." Irrigation Science 31, no. 1 (June 12, 2011): 49–58. http://dx.doi.org/10.1007/s00271-011-0291-3.

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Swana, Umhle U., Usisipho Feleni, Tshepo J. Malefetse, Bhekie B. Mamba, Peter Schmitz, and Thabo T. I. Nkambule. "The status and quantification of de facto water reuse in South Africa – a review." Water Practice and Technology 15, no. 2 (March 19, 2020): 225–47. http://dx.doi.org/10.2166/wpt.2020.021.

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Abstract The practice of discharging insufficiently treated wastewater to surface water used for potable use (de facto reuse) is common globally. Although de facto reuse provides a sustainable supply of water, it also affects the environment and human health negatively because the inadequately treated effluents contain contaminants of emerging concern (CECs). Therefore, there is a need to determine the extent of de facto reuse in water bodies of South Africa (SA) and thus assess the potential environmental and health risks associated with the reuse of insufficiently treated wastewater in the country. This review summarizes the status of de facto reuse in SA and its negative impact on human health and the environment. Furthermore, the review provides background information on water reuse and as well as the current treatment technologies available in the country for potable water reuse. The use of a geographic information system (GIS) model in combination with caffeine (a wastewater tracer that is abundant in SA surface water systems) for the quantification of de facto reuse is also cited. Such methods, it is envisaged, will enable water management authorities to make well informed decisions regarding water quality issues in SA.

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Gruber, G., S. Winkler, and A. Pressl. "Quantification of pollution loads from CSOs into surface water bodies by means of online techniques." Water Science and Technology 50, no. 11 (December 1, 2004): 73–80. http://dx.doi.org/10.2166/wst.2004.0673.

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Based on novel technologies, a modular online monitoring station suitable for continuous application in sewer networks, wastewater treatment plants and receiving water bodies has been designed. The monitoring station serves as the backbone of a water quality pilot network. As one part of this network a sewer monitoring station has been installed at a combined sewer overflow in Graz to quantify pollution concentrations and loads in the combined sewer and into the receiving water and is operated since October 2002. The design and equipment of the measurement station and first operating experiences and results are given in this paper.

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Zhu, Wei, Che-Jen Lin, Xun Wang, Jonas Sommar, Xuewu Fu, and Xinbin Feng. "Global observations and modeling of atmosphere–surface exchange of elemental mercury: a critical review." Atmospheric Chemistry and Physics 16, no. 7 (April 11, 2016): 4451–80. http://dx.doi.org/10.5194/acp-16-4451-2016.

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Abstract. Reliable quantification of air–surface fluxes of elemental Hg vapor (Hg0) is crucial for understanding mercury (Hg) global biogeochemical cycles. There have been extensive measurements and modeling efforts devoted to estimating the exchange fluxes between the atmosphere and various surfaces (e.g., soil, canopies, water, snow, etc.) in the past three decades. However, large uncertainties remain due to the complexity of Hg0 bidirectional exchange, limitations of flux quantification techniques and challenges in model parameterization. In this study, we provide a critical review on the state of science in the atmosphere–surface exchange of Hg0. Specifically, the advancement of flux quantification techniques, mechanisms in driving the air–surface Hg exchange and modeling efforts are presented. Due to the semi-volatile nature of Hg0 and redox transformation of Hg in environmental media, Hg deposition and evasion are influenced by multiple environmental variables including seasonality, vegetative coverage and its life cycle, temperature, light, moisture, atmospheric turbulence and the presence of reactants (e.g., O3, radicals, etc.). However, the effects of these processes on flux have not been fundamentally and quantitatively determined, which limits the accuracy of flux modeling. We compile an up-to-date global observational flux database and discuss the implication of flux data on the global Hg budget. Mean Hg0 fluxes obtained by micrometeorological measurements do not appear to be significantly greater than the fluxes measured by dynamic flux chamber methods over unpolluted surfaces (p = 0.16, one-tailed, Mann–Whitney U test). The spatiotemporal coverage of existing Hg0 flux measurements is highly heterogeneous with large data gaps existing in multiple continents (Africa, South Asia, Middle East, South America and Australia). The magnitude of the evasion flux is strongly enhanced by human activities, particularly at contaminated sites. Hg0 flux observations in East Asia are comparatively larger in magnitude than the rest of the world, suggesting substantial re-emission of previously deposited mercury from anthropogenic sources. The Hg0 exchange over pristine surfaces (e.g., background soil and water) and vegetation needs better constraints for global analyses of the atmospheric Hg budget. The existing knowledge gap and the associated research needs for future measurements and modeling efforts for the air–surface exchange of Hg0 are discussed.

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Diedrich, H., R. Preusker, R. Lindstrot, and J. Fischer. "Quantification of uncertainties of water vapour column retrievals using future instruments." Atmospheric Measurement Techniques 6, no. 2 (February 14, 2013): 359–70. http://dx.doi.org/10.5194/amt-6-359-2013.

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Abstract. This study presents a quantification of uncertainties of total column water vapour retrievals based on simulated near-infrared measurements of upcoming instruments. The concepts of three scheduled spectrometers were taken into account: OLCI (Ocean and Land Color Instrument) on Sentinel-3, METimage on an EPS-SG (EUMETSAT Polar System – Second Generation) satellite and FCI (Flexible Combined Imager) on MTG (Meteosat Third Generation). Optimal estimation theory was used to estimate the error of a hypothetical total water vapour column retrieval for 27 different atmospheric cases. The errors range from 100% in very dry cases to 2% in humid cases with a very high surface albedo. Generally, the absolute uncertainties increase with higher water vapour column content due to H2O-saturation and decrease with a brighter surface albedo. Uncertainties increase with higher aerosol optical thickness, apart from very dark cases. Overall, the METimage channel setting enables the most accurate retrievals. The retrieval using the MTG-FCI build-up has the highest uncertainties apart from very bright cases. On the one hand, a retrieval using two absorption channels increases the accuracy, in some cases by one order of magnitude, in comparison to a retrieval using just one absorption channel. On the other hand, a retrieval using three absorption channels has no significant advantage over a two-absorption channel retrieval. Furthermore, the optimal position of the absorption channels was determined using the concept of the "information content". For a single channel retrieval, a channel at 900 or 915 nm has the highest mean information content over all cases. The second absorption channel is ideally weakly correlated with the first one, and therefore positioned at 935 nm, in a region with stronger water vapour absorption.

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Piayda, Arndt, Maren Dubbert, Rolf Siegwolf, Matthias Cuntz, and Christiane Werner. "Quantification of dynamic soil–vegetation feedbacks following an isotopically labelled precipitation pulse." Biogeosciences 14, no. 9 (May 5, 2017): 2293–306. http://dx.doi.org/10.5194/bg-14-2293-2017.

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Abstract. The presence of vegetation alters hydrological cycles of ecosystems. Complex plant–soil interactions govern the fate of precipitation input and water transitions through ecosystem compartments. Disentangling these interactions is a major challenge in the field of ecohydrology and a pivotal foundation for understanding the carbon cycle of semi-arid ecosystems. Stable water isotopes can be used in this context as tracer to quantify water movement through soil–vegetation–atmosphere interfaces. The aim of this study is to disentangle vegetation effects on soil water infiltration and distribution as well as dynamics of soil evaporation and grassland water use in a Mediterranean cork oak woodland during dry conditions. An irrigation experiment using δ18O labelled water was carried out in order to quantify distinct effects of tree and herbaceous vegetation on the infiltration and distribution of event water in the soil profile. Dynamic responses of soil and herbaceous vegetation fluxes to precipitation regarding event water use, water uptake depth plasticity, and contribution to ecosystem soil evaporation and transpiration were quantified. Total water loss to the atmosphere from bare soil was as high as from vegetated soil, utilizing large amounts of unproductive evaporation for transpiration, but infiltration rates decreased. No adjustments of main root water uptake depth to changes in water availability could be observed during the experiment. This forces understorey plants to compete with adjacent trees for water in deeper soil layers at the onset of summer. Thus, understorey plants are subjected to chronic water deficits faster, leading to premature senescence at the onset of drought. Despite this water competition, the presence of cork oak trees fosters infiltration and reduces evapotranspirative water losses from the understorey and the soil, both due to altered microclimatic conditions under crown shading. This study highlights complex soil–plant–atmosphere and inter-species interactions controlling rain pulse transitions through a typical Mediterranean savannah ecosystem, disentangled by the use of stable water isotopes.

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Lane-Smith, Derek, and Michael Schubert. "Absolute Measurement of Thoron in Surface Waters." Water 12, no. 11 (November 3, 2020): 3083. http://dx.doi.org/10.3390/w12113083.

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Thoron (radon-220, 220Rn, half-life 55.6 s) is a useful aqueous tracer suitable for applications such as locating and measuring groundwater discharge in surface waters (including the coastal ocean) and detecting radium-224 (224Ra) bearing scale inside water pipes. Generally, such applications require only relative thoron measurements in the water. However, if a thoron-in-water quantification in absolute numbers is desired the knowledge of the thoron sensitivity of the measurement system is obligatory. Absolute readings would, e.g., give a measure of the 224Ra activity in the sediment, supporting the thoron, or of the quantity of 224Ra in the pipe scale. Since there is no standardised source of thoron-in-water (such as a NIST standard), there is no way to calibrate a thoron-in-water measurement system, in the usual sense. Up until now, therefore, it has not been possible to make absolute measurements of thoron in water. This paper presents a novel method of assessing the sensitivity of a mobile thoron-in-water measurement system. The paper analyses such systems and describes a straightforward experimental approach to obtain all setup-specific values of critical parameters that will allow a reasonably precise determination of the system thoron sensitivity. The method is simple enough that a thoron sensitivity calibration can be performed on site with no additional equipment.

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Van Hoi, Bui, Cam-Tu Vu, Lan-Anh Phung-Thi, Thao Thi Nguyen, Phuong Thanh Nguyen, Huong Mai, Phuong-Thu Le, et al. "Determination of Pharmaceutical Residues by UPLC-MS/MS Method: Validation and Application on Surface Water and Hospital Wastewater." Journal of Analytical Methods in Chemistry 2021 (January 8, 2021): 1–12. http://dx.doi.org/10.1155/2021/6628285.

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In this study, an analytical method for the simultaneous determination of 7 major pharmaceutical residues in Vietnam, namely, carbamazepine, ciprofloxacin, ofloxacin, ketoprofen, paracetamol, sulfamethoxazole, and trimethoprim, in surface water and hospital wastewater has been developed. The method includes enrichment and clean-up steps by solid phase extraction using mix-mode cation exchange, followed by identification and quantification using an ultrahigh-performance liquid chromatography and tandem mass spectrometry and employing electrospray ionization (UPLC-ESI-MS/MS). Seven target compounds were separated on the reversed phase column and detected in multiple reaction monitoring (MRM) mode within 6 minutes. The present study also optimized the operating parameters of the mass spectrometer to achieve the highest analytical signals for all target compounds. All characteristic parameters of the analytical method were investigated, including linearity range, limit of detection, limit of quantification, precision, and accuracy. The important parameter in UPLC-ESI-MS/MS, matrix effect, was assessed and implemented via preextraction and postextraction spiking experiments. The overall recoveries of all target compounds were in the ranges from 55% to 109% and 56 % to 115% for surface water and hospital wastewater, respectively. Detection limits for surface water and hospital wastewater were 0.005–0.015 µg L−1 and 0.014–0.123 µg L−1, respectively. The sensitivity of the developed method was allowed for determination of target compounds at trace level in environmental water samples. The in-house validation of the developed method was performed by spiking experiment in both the surface water and hospital wastewater matrix. The method was then applied to analyze several surface water and hospital wastewater samples taken from West Lake and some hospitals in Vietnam, where the level of these pharmaceutical product residues was still missed. Sulfamethoxazole was present at a high detection frequency in both surface water (33% of analyzed samples) and hospital wastewater (81% of analyzed samples) samples.

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Van Hoi, Bui, Cam-Tu Vu, Lan-Anh Phung-Thi, Thao Thi Nguyen, Phuong Thanh Nguyen, Huong Mai, Phuong-Thu Le, et al. "Determination of Pharmaceutical Residues by UPLC-MS/MS Method: Validation and Application on Surface Water and Hospital Wastewater." Journal of Analytical Methods in Chemistry 2021 (January 8, 2021): 1–12. http://dx.doi.org/10.1155/2021/6628285.

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In this study, an analytical method for the simultaneous determination of 7 major pharmaceutical residues in Vietnam, namely, carbamazepine, ciprofloxacin, ofloxacin, ketoprofen, paracetamol, sulfamethoxazole, and trimethoprim, in surface water and hospital wastewater has been developed. The method includes enrichment and clean-up steps by solid phase extraction using mix-mode cation exchange, followed by identification and quantification using an ultrahigh-performance liquid chromatography and tandem mass spectrometry and employing electrospray ionization (UPLC-ESI-MS/MS). Seven target compounds were separated on the reversed phase column and detected in multiple reaction monitoring (MRM) mode within 6 minutes. The present study also optimized the operating parameters of the mass spectrometer to achieve the highest analytical signals for all target compounds. All characteristic parameters of the analytical method were investigated, including linearity range, limit of detection, limit of quantification, precision, and accuracy. The important parameter in UPLC-ESI-MS/MS, matrix effect, was assessed and implemented via preextraction and postextraction spiking experiments. The overall recoveries of all target compounds were in the ranges from 55% to 109% and 56 % to 115% for surface water and hospital wastewater, respectively. Detection limits for surface water and hospital wastewater were 0.005–0.015 µg L−1 and 0.014–0.123 µg L−1, respectively. The sensitivity of the developed method was allowed for determination of target compounds at trace level in environmental water samples. The in-house validation of the developed method was performed by spiking experiment in both the surface water and hospital wastewater matrix. The method was then applied to analyze several surface water and hospital wastewater samples taken from West Lake and some hospitals in Vietnam, where the level of these pharmaceutical product residues was still missed. Sulfamethoxazole was present at a high detection frequency in both surface water (33% of analyzed samples) and hospital wastewater (81% of analyzed samples) samples.

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Iancu, Vasile-Ion, Niculescu Marcela, Diana Puiu, Toma Galaon, Jana Petre, and Luoana Florentina Pascu. "Determination of Hypoglycemic Agents in Surface Water Samples Using SPE-LC-MS/MS Method." Revista de Chimie 71, no. 7 (August 4, 2020): 337–46. http://dx.doi.org/10.37358/rc.20.7.8252.

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Antidiabetic compounds are a class of emerging contaminants in environment, for which there are no regulations in the world environmental legislation. These compounds are among the most widely used drugs in the world due to the large number of patients with diabetic conditions. The presence of these pollutants in the environment is insufficiently studied, so efficient analytical methods are needed to allow their detection at trace levels (ng/L). For the simultaneously quantification of the five antidiabetics (glyburide, metformin, glipizide, gliclazide, glimepiride) and one bio-degradation product (guanyl urea) in surface water samples a SPE-LC-MS/MS (solid phase extraction -liquid chromatography coupled with mass spectrometry detection) method was validated using real river water samples. The compounds were separated on C18 LC column in 9 minutes at 300C using a gradient of mobile phase of 0.1% formic acid and acetonitrile. Good performance parameters were obtained using the method: low limits of quantification (LOQs 0.1-2.4 ng/L), precision (repeatability 3.5-7.2% and reproducibility 6.5-12.7%) and determination coefficients (higher than 0.99). The most contaminated river was represented by Ialomita, which had a total concentration of antidiabetics of 112.1 ng/L in the downstream point, followed by the Siret and Dambovita rivers, which had a total concentration of antidiabetics of 66.3 ng/L and 57.3 ng/L, respectively, also in the downstream points.

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Mayr, Stefan, Igor Klein, Martin Rutzinger, and Claudia Kuenzer. "Systematic Water Fraction Estimation for a Global and Daily Surface Water Time-Series." Remote Sensing 13, no. 14 (July 7, 2021): 2675. http://dx.doi.org/10.3390/rs13142675.

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Fresh water is a vital natural resource. Earth observation time-series are well suited to monitor corresponding surface dynamics. The DLR-DFD Global WaterPack (GWP) provides daily information on globally distributed inland surface water based on MODIS (Moderate Resolution Imaging Spectroradiometer) images at 250 m spatial resolution. Operating on this spatiotemporal level comes with the drawback of moderate spatial resolution; only coarse pixel-based surface water quantification is possible. To enhance the quantitative capabilities of this dataset, we systematically access subpixel information on fractional water coverage. For this, a linear mixture model is employed, using classification probability and pure pixel reference information. Classification probability is derived from relative datapoint (pixel) locations in feature space. Pure water and non-water reference pixels are located by combining spatial and temporal information inherent to the time-series. Subsequently, the model is evaluated for different input sets to determine the optimal configuration for global processing and pixel coverage types. The performance of resulting water fraction estimates is evaluated on the pixel level in 32 regions of interest across the globe, by comparison to higher resolution reference data (Sentinel-2, Landsat 8). Results show that water fraction information is able to improve the product’s performance regarding mixed water/non-water pixels by an average of 11.6% (RMSE). With a Nash-Sutcliffe efficiency of 0.61, the model shows good overall performance. The approach enables the systematic provision of water fraction estimates on a global and daily scale, using only the reflectance and temporal information contained in the input time-series.

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Vannoy, Kathryn J., Inyoung Lee, Koji Sode, and Jeffrey E. Dick. "Electrochemical quantification of accelerated FADGDH rates in aqueous nanodroplets." Proceedings of the National Academy of Sciences 118, no. 25 (June 14, 2021): e2025726118. http://dx.doi.org/10.1073/pnas.2025726118.

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Enzymes are molecules that catalyze reactions critical to life. These catalysts are often studied in bulk water, where the influence of water volume on reactivity is neglected. Here, we demonstrate rate enhancement of up to two orders of magnitude for enzymes trapped in submicrometer water nanodroplets suspended in 1,2-dichloroethane. When single nanodroplets irreversibly adsorb onto an ultramicroelectrode surface, enzymatic activity is apparent in the amperometric current-time trace if the ultramicroelectrode generates the enzyme cofactor. Nanodroplet volume is easily accessible by integrating the current-time response and using Faraday’s Law. The single nanodroplet technique allows us to plot the enzyme’s activity as a function of nanodroplet size, revealing a strong inverse relationship. Finite element simulations confirm our experimental results and offer insights into parameters influencing single nanodroplet enzymology. These results provide a framework to profoundly influence the understanding of chemical reactivity at the nanoscale.

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Lakshmi, Venkat, Seungbum Hong, Eric E. Small, and Fei Chen. "The influence of the land surface on hydrometeorology and ecology: new advances from modeling and satellite remote sensing." Hydrology Research 42, no. 2-3 (April 1, 2011): 95–112. http://dx.doi.org/10.2166/nh.2011.071.

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The importance of land surface processes has long been recognized in hydrometeorology and ecology for they play a key role in climate and weather modeling. However, their quantification has been challenging due to the complex nature of the land surface amongst other reasons. One of the difficult parts in the quantification is the effect of vegetation that are related to land surface processes such as soil moisture variation and to atmospheric conditions such as radiation. This study addresses various relational investigations among vegetation properties such as Normalized Difference Vegetation Index (NDVI), Leaf Area Index (LAI), surface temperature (TSK), and vegetation water content (VegWC) derived from satellite sensors such as Moderate Resolution Imaging Spectroradiometer (MODIS) and EOS Advanced Microwave Scanning Radiometer (AMSR-E). The study provides general information about a physiological behavior of vegetation for various environmental conditions. Second, using a coupled mesoscale/land surface model, we examine the effects of vegetation and its relationship with soil moisture on the simulated land–atmospheric interactions through the model sensitivity tests. The Weather Research and Forecasting (WRF) model was selected for this study, and the Noah land surface model (Noah LSM) implemented in the WRF model was used for the model coupled system. This coupled model was tested through two parameterization methods for vegetation fraction using MODIS data and through model initialization of soil moisture from High Resolution Land Data Assimilation System (HRLDAS). Finally, this study evaluates the model improvements for each simulation method.

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Goedecke, C., I. Fettig, C. Piechotta, R. Philipp, and S. U. Geissen. "A novel GC-MS method for the determination and quantification of metformin in surface water." Analytical Methods 9, no. 10 (2017): 1580–84. http://dx.doi.org/10.1039/c6ay02606k.

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Srinivasan, Siddarth, Shreerang S. Chhatre, Jesus O. Guardado, Kyoo-Chul Park, Andrew R. Parker, Michael F. Rubner, Gareth H. McKinley, and Robert E. Cohen. "Quantification of feather structure, wettability and resistance to liquid penetration." Journal of The Royal Society Interface 11, no. 96 (July 6, 2014): 20140287. http://dx.doi.org/10.1098/rsif.2014.0287.

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Birds in the cormorant (Phalacrocoracidae) family dive tens of metres into water to prey on fish while entraining a thin layer of air (a plastron film) within the microstructures of their feathers. In addition, many species within the family spread their wings for long periods of time upon emerging from water. To investigate whether wetting and wing-spreading are related to feather structure, microscopy and photographic studies have previously been used to extract structural parameters for barbs and barbules. In this work, we describe a systematic methodology to characterize the quasi-hierarchical topography of bird feathers that is based on contact angle measurements using a set of polar and non-polar probing liquids. Contact angle measurements on dip-coated feathers of six aquatic bird species (including three from the Phalacrocoracidae family) are used to extract two distinguishing structural parameters, a dimensionless spacing ratio of the barbule ( D *) and a characteristic length scale corresponding to the spacing of defect sites. The dimensionless spacing parameter can be used in conjunction with a model for the surface topography to enable us to predict a priori the apparent contact angles of water droplets on feathers as well as the water breakthrough pressure required for the disruption of the plastron on the feather barbules. The predicted values of breakthrough depths in water (1–4 m) are towards the lower end of typical diving depths for the aquatic bird species examined here, and therefore a representative feather is expected to be fully wetted in a typical deep dive. However, thermodynamic surface energy analysis based on a simple one-dimensional cylindrical model of the feathers using parameters extracted from the goniometric analysis reveals that for water droplets on feathers of all six species under consideration, the non-wetting ‘Cassie–Baxter’ composite state represents the global energy minimum of the system. By contrast, for other wetting liquids, such as alkanes and common oils, the global energy minimum corresponds to a fully wetted or Wenzel state. For diving birds, individual feathers therefore spontaneously dewet once the bird emerges out of water, and the ‘wing-spreading’ posture might assist in overcoming kinetic barriers associated with pinning of liquid droplets that retard the rate of drying of the wet plumage of diving birds.

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Salvador, Daniel, Célia Neto, Maria João Benoliel, and Maria Filomena Caeiro. "Assessment of the Presence of Hepatitis E Virus in Surface Water and Drinking Water in Portugal." Microorganisms 8, no. 5 (May 19, 2020): 761. http://dx.doi.org/10.3390/microorganisms8050761.

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Hepatitis E virus (HEV) is a non-enveloped single-stranded positive-sense RNA virus, belonging to the Hepeviridae family, resistant to environmental conditions, and transmitted by the consumption of contaminated water. This virus is responsible for both sporadic and epidemic outbreaks, leading to thousands of infections per year in several countries, and is thus considered an emerging disease in Europe and Asia. This study refers to a survey in Portugal during 2019, targeting the detection and eventual quantification of enteric viruses in samples from surface and drinking water. Samples positive for HEV RNA were recurrently found by reverse transcription quantitative PCR (RT-qPCR), in both types of matrix. The infectivity of these samples was evaluated in cultured Vero E6 cells and RNA from putative viruses produced in cultures evidencing cytopathic effects and was subjected to RT-qPCR targeting HEV genomic RNA. Our results evidenced the existence of samples positive either for HEV RNA (77.8% in surface water and 66.7% in drinking water) or for infectious HEV (23.0% in surface water and 27.7% in drinking water). These results highlight the need for effective virological control of water for human consumption and activities.

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Journal articles on the topic 'Surface water quantification'

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