Journal articles: 'Water – Sampling – Technique'

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Sunjka, Dragana, and Sanja Lazic. "Water sampling techniques for continous monitoring of pesticides in water." Pesticidi i fitomedicina 32, no. 2 (2017): 85–93. http://dx.doi.org/10.2298/pif1702085s.

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Good ecological and chemical status of water represents the most important aim of the Water Framework Directive 2000/60/EC, which implies respect of water quality standards at the level of entire river basin (2008/105/EC and 2013/39/EC). This especially refers to the control of pesticide residues in surface waters. In order to achieve the set goals, a continuous monitoring program that should provide a comprehensive and interrelated overview of water status should be implemented. However, it demands the use of appropriate analysis techniques. Until now, the procedure for sampling and quantification of residual pesticide quantities in aquatic environment was based on the use of traditional sampling techniques that imply periodical collecting of individual samples. However, this type of sampling provides only a snapshot of the situation in regard to the presence of pollutants in water. As an alternative, the technique of passive sampling of pollutants in water, including pesticides has been introduced. Different samplers are available for pesticide sampling in surface water, depending on compounds. The technique itself is based on keeping a device in water over a longer period of time which varies from several days to several weeks, depending on the kind of compound. In this manner, the average concentrations of pollutants dissolved in water during a time period (time-weighted average concentrations, TWA) are obtained, which enables monitoring of trends in areal and seasonal variations. The use of these techniques also leads to an increase in sensitivity of analytical methods, considering that pre-concentration of analytes takes place within the sorption medium. However, the use of these techniques for determination of pesticide concentrations in real water environments requires calibration studies for the estimation of sampling rates (Rs). Rs is a volume of water per time, calculated as the product of overall mass transfer coefficient and area of the receiving phase exposed to the external environment, and it is substance specific.

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Zelenchuk, A. V., V. A. Zelenchuk, and V. A. Krylenkov. "The Development of Mobile Deep-Water Sampling Technique from Polar Water Areas." Океанология 53, no. 6 (2013): 838–42. http://dx.doi.org/10.7868/s0030157413060099.

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Gunasekara, T. A. G., and C. Cunnane. "Split sampling technique for selecting a flood frequency analysis procedure." Journal of Hydrology 130, no. 1-4 (January 1992): 189–200. http://dx.doi.org/10.1016/0022-1694(92)90110-h.

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Nurmi, Pekka A., and Ilmo T. Kukkonen. "A new technique for sampling water and gas from deep drill holes." Canadian Journal of Earth Sciences 23, no. 9 (September 1, 1986): 1450–54. http://dx.doi.org/10.1139/e86-138.

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A new technique for sampling water and gas from deep (500–1500 m) drill holes is described. The principle of the technique is to raise a continuous column of water inside a thin polyamide tube with a back-pressure valve at the lower end and with shutoff valves every 50 m. The equipment is easily assembled from standard parts. Sampling can be performed by three people without mechanical apparatus. Descent to 1000 m takes 2 hours and retrieval 1 hour. The method makes it possible to obtain a practically undisturbed continuous water profile from a drill hole. Dissolved gases remaining inside the tube can be sampled at the surface. To demonstrate the efficiency of the technique, selected results from the deepest drill hole in Finland, having a vertical depth of 1100 m, are presented.

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Azcue, Jose M., and Fernando Rosa. "Effects of Sampling Technique on the Determination of Major and Trace Elements on Sediment Pore Water." Water Quality Research Journal 31, no. 4 (November 1, 1996): 709–24. http://dx.doi.org/10.2166/wqrj.1996.038.

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Abstract Pore water samples obtained by squeezing, centrifuging followed by filtration, and in situ dialysis were compared. The effects of the three methods on the measured concentrations of eight elements (Ca, Fe, K, Mg, Mn, Na, Si and Sr) were studied. Iron and Mn proved to be extremely sensitive to oxygen exposure. Immediate centrifugation followed by filtration under nitrogen yield very similar results for almost all the elements as the in situ dialysis technique. The squeezing technique was the most susceptible to handling variables such as pressure-, oxygen- and temperature-related changes. Whenever possible, we recommend the use of in situ techniques that minimize the sampling artifacts. However, the choice of the technique for sampling sediment pore water should be dictated by the objectives of the study.

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Dong, Jia, Liangchen Li, Zhiwen Jiang, Gang Zhang, and Ting Sun. "Sampling of Phenol in Water by Diffusive Gradients Using Thin Film Technique." Chemistry Letters 43, no. 7 (July 5, 2014): 1164–66. http://dx.doi.org/10.1246/cl.140231.

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Taylor, Theodore W., and Michael C. Serafini. "Screened Auger Sampling: The Technique and Two Case Studies." Groundwater Monitoring & Remediation 8, no. 3 (June 1988): 145–52. http://dx.doi.org/10.1111/j.1745-6592.1988.tb01091.x.

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Liu, Yi-Rong, Hui Wen, Teng Huang, Xiao-Xiao Lin, Yan-Bo Gai, Chang-Jin Hu, Wei-Jun Zhang, and Wei Huang. "Structural Exploration of Water, Nitrate/Water, and Oxalate/Water Clusters with Basin-Hopping Method Using a Compressed Sampling Technique." Journal of Physical Chemistry A 118, no. 2 (January 7, 2014): 508–16. http://dx.doi.org/10.1021/jp4109128.

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Anderson, David J., Thomas B. Bloem, and Jonathan V. Higgins. "Sub-Sampling Technique for the Determination of Particulate-Phase Organic Carbon in Water." Journal of Great Lakes Research 24, no. 4 (January 1998): 838–44. http://dx.doi.org/10.1016/s0380-1330(98)70865-2.

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Voigt, Christian C., Otto Von Helversen, Robert H. Michener, and Thomas H. Kunz. "Validation of a non-invasive blood-sampling technique for doubly-labelled water experiments." Journal of Experimental Zoology 296A, no. 2 (March 20, 2003): 87–97. http://dx.doi.org/10.1002/jez.a.10121.

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Miró, Manuel, Walter J. Fitz, Siegfried Swoboda, and Walter W. Wenzel. "In-situ sampling of soil pore water: evaluation of linear-type microdialysis probes and suction cups at varied moisture contents." Environmental Chemistry 7, no. 1 (2010): 123. http://dx.doi.org/10.1071/en09084.

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Environmental context. There is a need for slightly invasive techniques capable of in-situ probing of target analytes in environmental compartments. Owing to its passive sampling mode and small probe dimensions, microdialysis-based dosimetry is an appealing tool for monitoring of solute concentrations in both water bodies and pore soil waters with minimum disturbance of natural equilibrium. The development of field applications is challenging but will provide novel insights as to the speciation and bioaccessibility of environmental pollutants, e.g. trace metals, at high spatial resolution. Abstract. In-situ sampling of soil pore water is still a challenge for environmental scientists. Here, microdialysis is explored for probing metal concentrations in soil pore water at soil moisture contents ranging from 50 to 115% of the maximal water holding capacity and is compared with traditional sampling by suction cups. Metal concentrations obtained by the suction cup technique were consistently larger than those measured in the dialysate. Good agreement was obtained for Pb and Cu at soil moistures close to saturation after accounting for diffusion resistances whereas corrected Ni and Cd concentrations in the dialysates exceeded those measured by the suction cup technique. These deviations reflect inherent differences in the sampling mode and effects of soil heterogeneity at the microscale. Microdialysis offers new opportunities to probe solute concentrations at high spatial resolution and minimal disturbance of soil conditions at environmental interfaces such as the plant rhizosphere or at the transition between forest floors and the mineral soil.

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Jones, Lisa, Jenny Ronan, Brendan McHugh, and Fiona Regan. "Passive sampling of polar emerging contaminants in Irish catchments." Water Science and Technology 79, no. 2 (January 15, 2019): 218–30. http://dx.doi.org/10.2166/wst.2019.021.

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Abstract Passive sampling (PS) is a very useful approach for the monitoring of emerging contaminants in environmental matrices, showing greater sensitivity than can be achieved by current best practice – grab sampling – and is applicable to a wide variety of compounds. An EU Directive (2013/39/EC) has added substances to the existing Water Framework Directive (WFD) Priority Substance list. Investigation into PS in the monitoring of these compounds is necessary to show the potential of this technique in supporting monitoring requirements under the WFD. A catchment-based approach evaluated the occurrence of these compounds in Irish surface waters. This work deals with the challenges associated with the use of PS in a legislative context, and for routine monitoring of emerging contaminants. Looking at a number of sites across Ireland, upstream and downstream of wastewater treatment plants, the focus was on polar analytes and polar PS (POCIS). With method limits of detection (LODs) of 0.001 mg L−1 pharmaceuticals and endocrine disrupting chemicals (EDCs) were found in water and passive samples alike, whereas the polar pesticides were not often detected or were below the annual average environmental quality standard levels. The results of this study show the potential for PS as a monitoring technique for emerging and watch-list chemicals.

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Adam, C. H. "Static Electric Cone Penetration Testing in Shallow Water." Geological Society, London, Engineering Geology Special Publications 2, no. 1 (1986): 113–18. http://dx.doi.org/10.1144/gsl.1986.002.01.25.

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AbstractThis paper describes the methods available to perform static electric cone penetration tests (CPT's) in shallow waters. It refers to both the coastal environment and inland waterways up to a water depth of around 25 to 30 m.Whilst the benefits of the speed of CPT's over water are reduced, compared with testing on land, the technique is still much quicker than conventional boring and sampling methods and offers significant cost savings. One of the other main advantages is the quality and accuracy of the information obtained particularly in submerged fine grained granular soils.There are a number of techniques which can be used to perform CPT's in shallow waters. These include detached CPT rigs mounted on small jack-up barges, fixed platforms and floating barges and seabed ballast block systems. The most suitable technique depends on a number of factors including water depth, site exposure, tidal conditions and seabed soil conditions.The cone design, testing methods and interpretation of CPT data are discussed briefly. Particular reference is made to recent developments in the use of the piezocone and other sensors.

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Nur Yuliyani, Dwi, Thomas Triadi Putranto, and Nur Indah. "Study Of Spatial Effect Distribution Of Groundwater Quality On Rob Disaster In Semarang City." E3S Web of Conferences 73 (2018): 03027. http://dx.doi.org/10.1051/e3sconf/20187303027.

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Semarang City is one of the cities located in the north coast of Java, has characteristics of hilly areas and lowland areas, Semarang City is one of the coastal areas and has a high Rob potential. Subdistricts in Semarang City that are inundated by rob disasters are North Semarang Subdistrict, Ngalian, Tugu, Genuk and Pedurungan. The purpose of this research is 1) mapping of inundation in Semarang City using Geographic Information System (GIS). 2). Knowing the quality of ground water (wells) for public consumption around the coastal area of Semarang City that has been exposed to rob water. 3) Find out how many rob water levels have contaminated the Well. Widespread Distribution Population of Rob in Semarang City. Side technique in this research is Purposive Random sampling. The result of this research is the quality of well water obtained from direct measurement of field. Measurements are made using the Water Quality Checker tool. The measurement parameters include pH, DHL, TDS and Nitrate. The required data is the coastal administration map of Semarang city, and the well water quality parameters of KEPMENKES. Selection and sampling of well water by using stratified random sampling technique. The analysis includes a well water quality test in the rob area. Data collection techniques used questionnaire, observation, and documentation techniques. The measurement parameters include pH, DHL, TDS, and Nitrate. It can be seen that the worst affected District is Genuk District and the District which is still good quality is Pedurungan District.

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Comina, C., M. Lasagna, D. A. De Luca, and L. Sambuelli. "Geophysical methods to support correct water sampling locations for salt dilution gauging." Hydrology and Earth System Sciences 18, no. 8 (August 26, 2014): 3195–203. http://dx.doi.org/10.5194/hess-18-3195-2014.

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Abstract. To improve water management design, particularly in irrigation areas, it is important to evaluate the baseline state of the water resources, including canal discharge. Salt dilution gauging is a traditional and well-documented technique in this respect. The complete mixing of salt used for dilution gauging is required; this condition is difficult to test or verify and, if not fulfilled, is the largest source of uncertainty in the discharge calculation. In this paper, a geophysical technique (FERT, fast electrical resistivity tomography) is proposed for imaging the distribution of the salt plume used for dilution gauging at every point along a sampling cross section. With this imaging, complete mixing can be verified. If the mixing is not complete, the image created by FERT can also provide a possible guidance for selecting water-sampling locations in the sampling cross section. A water multi-sampling system prototype aimed to potentially take into account concentration variability is also proposed and tested. The results reported in the paper show that FERT provides a three-dimensional image of the dissolved salt plume and that this can potentially help in the selection of water sampling points.

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Sharma, G. L., B. Bandyopadhyay, and A. P. Tiwari. "Spatial control of a large pressurized heavy water reactor by fast output sampling technique." IEEE Transactions on Nuclear Science 50, no. 5 (October 2003): 1740–51. http://dx.doi.org/10.1109/tns.2003.818271.

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Mathiasson, L., G. Nilvé, and B. Ulén. "A Liquid Membrane Enrichment Technique for Integrating Field Sampling in Water Applied to MCPA." International Journal of Environmental Analytical Chemistry 45, no. 2 (November 1991): 117–25. http://dx.doi.org/10.1080/03067319108026981.

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Swanson, George D. "A Minimum Variance Estimate In The Doubly Labeled Water Technique-Role Of Optimal Sampling." Medicine & Science in Sports & Exercise 41 (May 2009): 447. http://dx.doi.org/10.1249/01.mss.0000355910.50932.c2.

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Miandji, E., M. H. Sargazi Moghadam, Faramarz F. Samavati, and M. Emadi. "Real-time multi-band synthesis of ocean water with new iterative up-sampling technique." Visual Computer 25, no. 5-7 (March 26, 2009): 697–705. http://dx.doi.org/10.1007/s00371-009-0352-2.

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Zhao, Wennan, Gangfeng Ouyang, Mehran Alaee, and Janusz Pawliszyn. "On-rod standardization technique for time-weighted average water sampling with a polydimethylsiloxane rod." Journal of Chromatography A 1124, no. 1-2 (August 2006): 112–20. http://dx.doi.org/10.1016/j.chroma.2006.05.062.

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Pind, P. F., I. Angelidaki, and B. K. Ahring. "A novel in-situ sampling and VFA sensor technique for anaerobic systems." Water Science and Technology 45, no. 10 (May 1, 2002): 261–68. http://dx.doi.org/10.2166/wst.2002.0349.

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A key information for understanding and controlling the anaerobic biogas process is the concentration of Volatile Fatty Acids (VFA). However, access to this information has so far been limited to off-line measurements by manual time and labour consuming methods. We have developed a new technique that has made it possible to monitor VFA on-line in one of the most difficult media: animal slurry or manure. A novel in-situ filtration technique has made it possible to perform microfiltration inside the reactor system. This filter enables sampling from closed reactor systems without large scale pumping and filtering. Using this filtration technique together with commercially available membrane filters we have constructed a VFA sensor system that can perform automatic analysis on animal slurry at a frequency as high as every 15 minutes. The VFA sensor has been tested for a period of more than 60 days with more than 1000 samples on both a full-scale biogas plant and lab-scale reactors. The measuring range covers specific measurements of acetate, propionate, iso-/n-butyrate and iso-/n-valerate from 0.1 to 50 mM (6–3,000 mg).

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Liu, Baoling, Gang Li, Hong You, and Mingrui Sui. "Assessment of the surface water quality ranking in Mudan River using multivariate statistical techniques." Water Supply 15, no. 3 (January 29, 2015): 606–16. http://dx.doi.org/10.2166/ws.2015.015.

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The present research deals with the important issue of assessing surface water quality ranking by combining the use of two advanced multivariate statistical techniques: Kohonen's self-organizing maps (SOM) and the Hasse diagram technique (HDT). The object of the study is the Mudan River of Mudanjiang city region, China. Samples were collected on a regular monthly basis in 2007–2011 from all sampling sites along the river, involving six major water quality parameters. The grouping of water parameters and the clustering of sampling events by the use of SOM has helped in their pre-processing for application of the HDT. The HDT orders clusters according to the pre-clustered water sampling events. The water quality was ranked against norms established by the Ministry of Environmental Protection of the People's Republic of China in order to assess in detail the water quality of the whole river system. The resulting map of the spatial and temporal changes in the water quality at each sampling site was specifically described by ArcGIS.

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Comina, C., M. Lasagna, D. A. De Luca, and L. Sambuelli. "Geophysical methods to support correct water sampling locations for salt dilution gauging." Hydrology and Earth System Sciences Discussions 11, no. 5 (May 19, 2014): 5115–42. http://dx.doi.org/10.5194/hessd-11-5115-2014.

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Abstract. To improve water management design, particularly in irrigation areas, it is important to evaluate the baseline state of the water resources, including canal discharge. Discharge measurements, using salt dilution gauging, are a traditional and well-documented technique. The complete mixing of salt used for dilution gauging is required for reliable measurements; this condition is difficult to test or verify and, if not fulfilled, is the largest source of uncertainty in the discharge calculation. In this paper, a geophysical technique (FERT, Fast Electrical Resistivity Tomography) is proposed for imaging the distribution of the salt plume used for dilution gauging at every point along a sampling cross-section. In this way, it is possible to check whether complete mixing has occurred. If the mixing is not complete, the image created by FERT can also provide guidance for selecting water-sampling locations in the sampling cross-section. A water multi-sampling system prototype for the simultaneous sampling of canal water at different points within the cross-section, aimed to potentially take into account concentration variability, is also proposed and tested. Preliminary results of a single test with salt dilution gauging and FERT in a real case are reported. The results show that imaging the passage of the salt plume is possible by means of geophysical controls and that this can potentially help in the selection of water sampling points.

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Ting, Josephine Ong Ning, and S. K. Yee. "Review on water quality monitoring technologies." Indonesian Journal of Electrical Engineering and Computer Science 18, no. 3 (June 1, 2020): 1416. http://dx.doi.org/10.11591/ijeecs.v18.i3.pp1416-1423.

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<span>Water quality monitoring is always the prior element to ensure the drinking water is safe to be consumed. A lot of researches have been carried out over the past decades to design and develop a robust and cost-effective water monitoring system. The conventional water monitoring techniques were based on laboratory instruments which is time-consuming and laborious. Furthermore, it is not suitable when the water sampling point is far from the commercial laboratory centres. These limitations were then been solved by the developments of portable testing kits and microwave technique. The microwave techniques such as spectroscopy techniques and microwave sensor approach have improved the water quality monitoring experience which is convenient without sacrificing the measurement accuracy and sensitivity. Its portability enables the on-site measurement at rural areas and thus reduce the transportation and manpower cost. This paper intends to review the water contaminant detection techniques which include standardized drinking water parameter testing and microwave-based in terms of physical, chemical and microbiological parameters. Furthermore, this review also emphasizes the current trend of the water quality testing method in microwave technique. At the end of this paper, a significant advantages and drawbacks of the techniques are summarized, and recommendations are provided for future development in the water quality monitoring.</span>

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Laureau, Axel, Vincent Lamirand, Dimitri Rochman, and Andreas Pautz. "Uncertainty propagation based on correlated sampling technique for nuclear data applications." EPJ Nuclear Sciences & Technologies 6 (2020): 8. http://dx.doi.org/10.1051/epjn/2020003.

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A correlated sampling technique has been implemented to estimate the impact of cross section modifications on the neutron transport and in Monte Carlo simulations in one single calculation. This implementation has been coupled to a Total Monte Carlo approach which consists in propagating nuclear data uncertainties with random cross section files. The TMC-CS (Total Monte Carlo with Correlated Sampling) approach offers an interesting speed-up of the associated computation time. This methodology is detailed in this paper, together with two application cases to validate and illustrate the gain provided by this technique: the highly enriched uranium/iron metal core reflected by a stainless-steel reflector HMI-001 benchmark, and the PETALE experimental programme in the CROCUS zero-power light water reactor.

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Trifu, M. C., and V. Daradici. "New monitoring technique for rapid investigation of nitrates pollution in aquatic systems." Proceedings of the International Association of Hydrological Sciences 364 (September 16, 2014): 481–85. http://dx.doi.org/10.5194/piahs-364-481-2014.

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Abstract. In situ measurement with a portable multi-parameter sonde was used in the framework of the Cleanwater project – LIFE09 ENV/RO/000612, for a rapid investigation of nitrates pollution in Barlad River basin, in rivers and domestic wells, in addition to laboratory measurements. Water samples were analysed in an accredited laboratory for water monitoring, such as the Vaslui Water Management System from Barlad basin. Sampling campaigns were performed monthly in the period April–November 2011. In order to find the main factors that influence the measurements, the behaviour of equipment was analysed in rivers, for different water sampling points along the river and the cross-sections, taking into account the water level, the turbulence, the vegetation and the obstacles along the river. Results proved the multiparameter sonde as a useful device for rapidly monitoring spatial distributions or temporal trends of nitrates or chlorophyll a, and detecting sudden changes in surface and groundwater quality.

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Ekhwan Toriman, Mohd, Hassan Mohammed Ali Alssgeer, Muhammad Barzani Gasim, Khairul Amri Kamarudin, Mabroka Mohamed Daw, and Laila Omaer Mohammed Alabyad. "Impacts of Land-Use Changes on Water Quality by an Application of GIS Analysis: a Case Study of Nerus River, Terengganu, Malaysia." International Journal of Engineering & Technology 7, no. 3.14 (July 25, 2018): 155. http://dx.doi.org/10.14419/ijet.v7i3.14.16877.

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The impact of land use change on water quality of Nerus River Kuala Terengganu is an event that needs to be taken seriously in this study. The objectives of the study area are to carried out 13 parameters water quality samplings and analysis of Nerus River as well as to classify water quality concentration based on NWQS and WQI classifications; to interpret 2000 and 2013 land use/land cover maps of Nerus River Basin and to evaluate water quality data by statistical technique such as similarities and dissimilarities between sampling stations to determine pollution sources. Methods that were used in study area GIS will use to classify land cover/land use changes in the catchment between 2000 and 2013 land use maps. Water quality analysis and monitoring were done based on three sampling stations during both dry and wet seasons, involving analysis 13 water quality parameters. Water quality classification is using the National Water Quality Standard (NWQS) and the Water Quality Index (WQI). Statistical analysis such as similarities and dissimilarities between sampling stations was applied. Results of the study show that the river was classified as class II (slightly polluted), III (moderately polluted) in accordance with previous studies.

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Magana, Adiel. "Modifying Surber sampling technique increases capture of freshwater crabs in African upland streams." Inland Waters 2, no. 1 (February 1, 2012): 11–15. http://dx.doi.org/10.5268/iw-2.1.436.

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Gwo, J. P., L. E. Toran, M. D. Morris, and G. V. Wilson. "Subsurface Stormflow Modeling with Sensitivity Analysis Using a Latin-Hypercube Sampling Technique." Ground Water 34, no. 5 (September 1996): 811–18. http://dx.doi.org/10.1111/j.1745-6584.1996.tb02075.x.

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Kinner, Nancy E., James P. Malley, Jonathan A. Clement, Peter A. Quern, Gretchen S. Schell, and Carol E. Lessard. "Effects of sampling technique, storage, cocktails, sources of variation, and extraction on the liquid scintillation technique for radon in water." Environmental Science & Technology 25, no. 6 (June 1991): 1165–71. http://dx.doi.org/10.1021/es00018a023.

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Boyd, Claude E., Edgar Hernandez, John C. Williams, and Robert P. Romaire. "Effects of Sampling Technique on Precision Estimates for Water Quality Variables in Fish Culture Ponds." Journal of Applied Aquaculture 4, no. 1 (July 1994): 1–18. http://dx.doi.org/10.1300/j028v04n01_01.

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Goran, M. I., E. T. Poehlman, and E. Danforth. "Experimental reliability of the doubly labeled water technique." American Journal of Physiology-Endocrinology and Metabolism 266, no. 3 (March 1, 1994): E510—E515. http://dx.doi.org/10.1152/ajpendo.1994.266.3.e510.

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The experimental reliability of measuring CO2 production rates (rCO2) with the doubly labeled water (DLW) technique was assessed in five young healthy men (23 (DLW) technique was assessed in five young healthy men (23 +/- 4 yr; 66.1 +/- 4.6 kg). To minimize the confounding effects of fluctuations in physical activity and eating patterns on variation in energy expenditure, the subjects lived under sedentary living conditions by confinement to their own room at a Clinical Research Center and were maintained on a fixed and known level of energy intake. rCO2 was determined in duplicate over two identical 9-day study periods after separate loading doses of deuterium and oxygen-18. Turnover rates were determined from multipoint sampling to reduce error from analytical uncertainty. Dilution spaces were determined by both the intercept and plateau methods. The average experimental variation for rCO2 estimates was approximately +/- 8.5% and was not significantly different among three published calculation models that differ in their assumptions regarding the relationship between the dilution spaces of deuterium and oxygen-18. The experimental reliability of +/- 8.5% exceeds theoretical values generated from calculations based on propagation of error from analytical uncertainty. Between subjects, the experimental variation ranged from 1 to 21%, and the half-width of the 95% confidence interval for the precision of rCO2 estimates was high (+/- 12 mol/day) relative to the mean reported value of approximately 16 mol/day.(ABSTRACT TRUNCATED AT 250 WORDS)

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Putra, Arief Yandra, and Putri Ade Rahma Yulia. "Kajian Kualitas Air Tanah Ditinjau dari Parameter pH, Nilai COD dan BOD pada Desa Teluk Nilap Kecamatan Kubu Babussalam Rokan Hilir Provinsi Riau." Jurnal Riset Kimia 10, no. 2 (September 30, 2019): 103–9. http://dx.doi.org/10.25077/jrk.v10i2.337.

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Based on a preliminary study that has been carried out, Teluk Nilap Village, Kubu Babussalam District, Rokan Hilir was affected by the disposal of waste from oil company. The waste partly seeps into the residents' water sources which are used for domestic activities. It was because the location of the water sources close to the location of the waste oil disposal. The sampling technique in this study used the observation point technique (pumping test). Sampling refers to the point of waste oil flow (upstream, middle, downstream) and dug well water taken randomly (random sampling). The results showed pH values ranged from 2.8 to 6.6; BOD values range from 0.42 to 141.1 mg / L; COD values range from 20 to 291 mg / L. Ground water quality at some point in Teluk Nilap Village exceeded quality standard limits allowed and included in heavy pollution category.

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Speakman, J. R., and P. A. Racey. "Measurement of CO2 production by the doubly labeled water technique." Journal of Applied Physiology 61, no. 3 (September 1, 1986): 1200–1202. http://dx.doi.org/10.1152/jappl.1986.61.3.1200.

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Recent applications of the doubly labeled water technique to the study of human metabolism have employed multiple sampling of body water over protracted periods, rather than the more traditional method of taking only an initial and final sample for isotopic analysis. In addition fractional turnovers of the body pools have been estimated by fitting curves to the sequential log-converted isotope enrichment against time. By manipulation of data collected in the field in a study of metabolism of vespertilionid bats, it is shown the curve-fitting technique results in an accurate estimate of CO2 production only when the rate of CO2 production is constant. Biologically realistic nonsteady-state conditions result in errors in estimates of CO2 production of up to 30%. In conditions where CO2 production is known to be temporally variable, the more traditional two-sample method may provide a more accurate estimate of CO2 production.

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Rödelsperger, M., U. Rohmann, and F. Frimmel. "A Stationary Packer System for Layerwise Groundwater Sampling in Monitoring Wells – Technique and Results." Water Science and Technology 23, no. 1-3 (January 1, 1991): 545–53. http://dx.doi.org/10.2166/wst.1991.0454.

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A sampling device was designed as a stationary equipment for deep monitoring wells in order to obtain representative groundwater samples from different layers of the aquifer. The device consists of several packer units which can be combined at variable distances, allowing adaption to the local conditions of the aquifer and of the well. The pumps are situated below the groundwater table. Each of the drawing tubes ends between two packers at the concerning depth. Experimental results demonstrate the importance of the application of a stationary packer system instead of a mobile doublepacker in deep aquifers of inhomogeneous structure. Examples of concentration profiles obtained from layerwise groundwater sampling are given and a technique for selective groundwater discharge is described.

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A., Adjagodo, Agassounon Djikpo Tchibozo M., Kelomè N.C., Vissin E.W., and Agbossou E. "Pollution Physique Et Bactériologique De L’eau Du Fleuve Dans La Basse Vallée De L’ouémé Pendant Les Périodes De Basses Et Hautes Eaux Au Bénin." European Scientific Journal, ESJ 13, no. 33 (November 30, 2017): 167. http://dx.doi.org/10.19044/esj.2017.v13n33p167.

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The objective of this study is to assess the water river quality of the Lower Valley of Ouémé in Benin. Two river water sampling campaigns were carried out during low and high water. At each sampling campaign, eleven (11) sampling sites were selected and at each site four samples were taken, making a total of 44 water samples. Hydrogen potential, dissolved oxygen, suspended matter and turbidity were measured in situ. Fecal contamination germs such as total coliforms, thermotolerant coliforms, Escherichia coli and fecal enterococci were counted by the membrane filtration technique. The results of the physical analyzes reveal that the pH measured in the water samples conformed to the WHO standard except turbidity. The results of the bacteriological analyzes in 100 mL of water sample of the river reveal average bacterial loads in periods of low and high waters which vary respectively from 2.57.10 2 ± 451 CFU and 3.35.102 ± 459 CFU for total coliforms; 1.42.102 ± 315 CFU and 1.55.102 ± 251 for thermotolerant coliforms; 0,79.102 ± 216 CFU and 1.55.102 ± 251 for E. coli. The Enterococci are absent in the waters during these two periods. The high burden of these germs counted in the high water period may be due runoff phenomenon and unhygienic behavior observable in the study area.

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Smolley, Mark, and Janet C. Kappmeyer. "Cone Penetrometer Tests and HydroPunch® Sampling: A Screening Technique for Plume Definition." Groundwater Monitoring & Remediation 11, no. 2 (May 1991): 101–6. http://dx.doi.org/10.1111/j.1745-6592.1991.tb00371.x.

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Vilaginès, Ph, B. Sarrette, and R. Vilaginès. "Viral Multicloning Procedure and Replicates Technique." Water Science and Technology 21, no. 3 (March 1, 1989): 85–92. http://dx.doi.org/10.2166/wst.1989.0083.

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The identification of virus particles is usually a lengthy process requiring extensive technical assistance. Studies of virus migration through agar media used for plaque assays demonstrated that it was possible to repetitively sample virus particles from a plaque with a pin and transfer them by pricking into an agar film pre-overlaid on a cell monolayer. Moreover, when antibodies were incorporated in the pre-overlay, it was possible to serotype the transferred virus with a 24 h response for poliovirus. This simple technique allows very fast sampling and identification of viral populations isolated from environmental sources, opening up a new direction for epidemiological studies. From a practical point of view, an implement was designed for the simultaneous transfer of several plaques in order to obtain replicas.

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Sharma, G. L., B. Bandyopadhyay, and A. P. Tiwari. "Fault-tolerant spatial control of a large pressurised heavy water reactor by fast output sampling technique." IEE Proceedings - Control Theory and Applications 151, no. 1 (January 1, 2004): 117–24. http://dx.doi.org/10.1049/ip-cta:20040016.

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Speakman, J. R., P. A. Racey, and A. M. Burnett. "Metabolic and behavioural consequences of the procedures of the doubly labelled water technique on white (MF1) mice." Journal of Experimental Biology 157, no. 1 (May 1, 1991): 123–32. http://dx.doi.org/10.1242/jeb.157.1.123.

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The effects of the doubly labelled water technique (intraperitoneal injection, temporary food deprivation and blood sampling) on the energy expenditure, food intake and behaviour of 18 white (MF1) mice was investigated. There were no significant differences in mean energy expenditure or food intake between experimental and control animals, on which the techniques were not performed, over the first 24 h after manipulation. These data indicate that there are no direct metabolic consequences associated with the procedures. During the 100 min immediately after blood sampling, the behaviour of experimental animals involved significantly more grooming, mostly at the site of the blood sample wound, more feeding and more general activity, at the expense of resting, when compared with controls. Twenty hours later the behavioural differences were less marked, but still statistically significantly different, and reversed: experimental animals spent more time resting and less in general activity or feeding. The effects of the technique on the behaviour of white mice had trivial consequences for their daily energy expenditure. This may reflect the restricted behavioural repertoire of these captive animals within respirometry chambers. The effect on wild animals may be more profound and requires investigation.

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Şimşek, Arife, Şule Sancak, and Gülfem Bakan. "Monitoring of Heavy Metal Pollution in Water and Sediments at the Mid-Black Sea Region by Using Passive Sampling Method Diffusive Gradients in Thin Films." Turkish Journal of Agriculture - Food Science and Technology 9, no. 6 (July 3, 2021): 1076–86. http://dx.doi.org/10.24925/turjaf.v9i6.1076-1086.4217.

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Determining the potential bioavailability of heavy metals, evaluating according to adapted regulations is essential to efficiently conserve our coastal and estuarine waters. In this study, it is aimed to determine the industrial pollution and various other pollution sources that the Black Sea Basin is exposed to by using DGT (Diffusive Gradients in Thin Films) method and grab (manuel) sampling method in water and sediment and to evaluate the existing pollution according to quality standards. In Samsun, seasonal samples were collected from five different sampling stations, namely Akkiraz Stream, Hıdırellez Stream, Organized Industrial Zone (OIZ) Channel, Şabanoğlu Stream and Selyeri Stream, which are selected from Tekkeköy region where industry is intensively active. In order to determine the heavy metal content in both water and sediment samples, the DGT method was chosen for passive sampling and the grab sampling method was used for active sampling, and the efficiency of the methods was evaluated. According to the results of the study, the heavy metal concentration in grab sampling for water samples in descending order Al> Fe> Zn> Pb> Ni> Cu; In the samples taken with DGT, they are listed as Al> Fe> Zn> Cu> Ni> Pb. There were significant relationships between the total metal concentrations of sediment (Csed) and water (Csu) in grab sampling and metal concentrations sediment (Csed-DGT) and water (Csu-DGT) measured by DGT. It was found that the sensitivity and performance of sampling with DGT was 2-10 times higher compared to grab sampling. The high resolution in situ DGT technique for the assessment and management of the potential release risk of heavy metals at the water-sediment interface is a complementary method that contributes to the standard grab sampling method.

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Kraleva, Elka, Vencislav Karamfilov, and Georgi Hibaum. "Determination of PAH in the Black Sea Water by GC/MS Following Preconcentration with Solid-Phase Extraction." Ecological Chemistry and Engineering S 19, no. 3 (January 1, 2012): 393–403. http://dx.doi.org/10.2478/v10216-011-0029-4.

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Determination of PAH in the Black Sea Water by GC/MS Following Preconcentration with Solid-Phase Extraction Determination of PAHs in marine coastal waters has to be carried out with great care to avoid serious losses occurring during the sampling and storage stage. This is due to the hydrophobic properties of PAHs, and their tendency to be adsorbed to surfaces they are in contact with, including suspended particulate matter. The best technique to separate PAHs is gas chromatography with mass spectrometer. Because of low concentration levels to be quantified in water samples, an enrichment step is needed before chromatographic analysis. For PAHs, several preconcentration techniques have been used, but the most concentration technique is solid-phase extraction (SPE). The main objective of this work is to adapt and implement a relatively simple and rapid method for gas chromatographic determination of individual PAHs in samples of coastal and running waters. The present work analyses the yield and precision of extraction of PAHs by solid phase extraction with using different sorbents for SPE (Bond Elut: C18 and Plexa SPE discs), the two most common methods used for aqueous samples.

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Dorrell, Jordan, and Livia B. Pártay. "Thermodynamics and the potential energy landscape: case study of small water clusters." Physical Chemistry Chemical Physics 21, no. 14 (2019): 7305–12. http://dx.doi.org/10.1039/c9cp00474b.

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We investigated the structure and the thermodynamic properties of small water clusters with the nested sampling computational technique, using two different water models, the coarse-grained mW (up to 25 molecules) and the flexible version of TIP3P (up to 16 molecules).

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Jiang, Kaiyun, and Ralph Kaye. "Comparison study on portable wind tunnel system and isolation chamber for determination of VOCs from areal sources." Water Science and Technology 34, no. 3-4 (August 1, 1996): 583–89. http://dx.doi.org/10.2166/wst.1996.0479.

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Many environmental monitoring programmes require the determination of volatile organic compounds (VOCs) emitted from large areal sources including liquid surfaces. A study was carried out to compare existing sampling techniques. Both the isolation chamber method (static technique) and the wind tunnel method (dynamic technique) were examined. A review of the mechanisms suggested that static techniques would not be appropriate for determining emissions from liquid surfaces which result from gas phase controlled volatilisation processes. A portable wind tunnel developed at the University of New South Wales and an isolation chamber built to USEPA specification were used in an experimental study of emissions from aqueous liquid surfaces. An acetone solution was chosen to represent gas phase controlled volatilisation processes. Toluene and methyl ethyl ketone in aqueous solution were chosen, respectively to investigate (1) liquid phase controlled volatilisation processes, and (2) combined gas and liquid phase controlled volatilisation processes. It was found that the use of the isolation chamber method resulted in different degrees of underestimation of the emission rates for the above three compounds. The wind tunnel method is suitable for sampling all VOC emissions from areal sources.

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Ahmad, U. K., Z. Ujang, Z. Yusop, and T. L. Fong. "Fluorescence technique for the characterization of natural organic matter in river water." Water Science and Technology 46, no. 9 (November 1, 2002): 117–25. http://dx.doi.org/10.2166/wst.2002.0219.

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The complex nature of natural organic matter (NOM), and the impact of this matter on drinking water quality have necessitated the characterization studies of NOM. A fluorescence technique for the characterization of NOM in Malaysian river water is reported. Water samples from several river sampling sites were collected and concentrated using a low-pressure reverse osmosis (LPROM). Solid phase extraction (SPE) using C18 extraction cartridges were used to fractionate the water samples into humic and non-humic fractions. To differentiate and classify various types of humic substances, fluorescence was applied in emission, excitation and in synchronous-scan modes. A synchronous spectral profile was found to be able to differentiate humic and fulvic acids better than the emission or excitation spectra. Synchronous excitation spectra showed different spectral patterns for the water samples due to different origin. All water samples showed the presence of both fulvic and humic acids.

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Choubert, J. M., D. Granger, C. Bourdon, and A. Héduit. "Biochemical acidogenic potential in domestic wastewaters: effect of sampling and storage to characterize daily average composite samples." Water Science and Technology 63, no. 7 (April 1, 2011): 1396–404. http://dx.doi.org/10.2166/wst.2011.314.

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To estimate the expectable enhanced biological phosphorus removal value of a wastewater, the concentration of volatile fatty acids (VFAs) and the biochemical acidogenic potential (BAP) are generally determined on grab samples of wastewater, as these variables are prone to rapid change after sampling. However, such sampling technique do not take into account the variations of these parameters during the day. This work has evaluated the changes of VFAs and BAP occurring during sampling and storage in an automatic sampler over 24 h. The consequences of waterfall oxygen input during sampling, and changes during storage (fermentation and sulfatereducing process) were studied. The results for two wastewaters showed that the sampling technique used for daily flow proportional composite samples provided a correct estimation of VFAs, and underestimated BAP by up to 25%. For hourly-average composite samples of wastewaters, significant modifications of the concentrations of these two parameters were recorded around the daily average values.

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Gardner, Peter, and Andrew Deamer. "An evaluation of methods for assessing the removal efficiency of a grit separation device." Water Science and Technology 33, no. 9 (April 1, 1996): 269–75. http://dx.doi.org/10.2166/wst.1996.0228.

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The paper considers the many problems which can beset any attempt to verify or measure the performance of a grit removal device, including contractual ambiguities, the difficulties of assessing any flow dependency, sampling difficulties, uncertainty about analytical techniques and efficiency definitions. The different definitions of efficiency are discussed and it is concluded that the ‘partial penetration’ would be the most applicable to the situation. The usefulness is discussed of attempting to separate grits which do not damage machinery and improve the handleability of the primary sludge. In the measurement of efficiency only two process streams need be sampled. Different protocols are considered which specify which streams should be sampled, and the advantages and disadvantages of each are set out. Solid stream sampling of recovered grit and primary sludges over a lengthy period is rejected as an unwieldy technique which may be impracticable on certain sites. The analysis of sludges for a small quantity of grit is problematic and subject to error, but this is also true of settled liquid stream samples. Rather it is concluded that supplementary grit addition coupled with liquid effluent stream sampling would give an efficiency subject to little error. The results of recent significant work carried out in the testing of a Grit KingR Separator, both in-situ and under controlled conditions, using different methods are presented in this paper. The recommended technique is described together with the sampling methods and further work required to verify/validate the procedure.

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Samson, Paul N., Haim Fligelman, and Carol Braester. "NEW PRESSURE ANALYSIS TECHNIQUE USING REPEAT FORMATION TESTER DATA." APPEA Journal 25, no. 1 (1985): 275. http://dx.doi.org/10.1071/aj84024.

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Current practice is to derive permeability from the pretest of wireline formation testers by the conventional Horner plot method. The major drawback of this type of analysis is the reliability of the flow time and flow rate estimates.A new technique to derive permeability from pressure response during the sampling period has been developed. The new method is based on the principle that at the end of the sampling period the volume of the fluid in the chamber is equal to the nominal volume of the sample chamber.The suggested method applies the approximation of the continuous pressure decline by a series of pressure steps as applied for water influx calculations.In its present form the technique has limitations due to flow regime shapes, number of phases present and the degree of formation damage.Research is underway to find acceptable solutions for the stated limitations.

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M. Zolkipli, H., H. Juahir, G. Adiana, N. Zainuddin, A. Ismail, A. B. H. M. Maliki, N. I. Hussain, M. K. A. Kamarudin, M. E. Toriman, and M. Mokhtar. "Spatial Assessment and the Most Significant Parameters for Drinking Water Quality Using Chemometric Technique: A Case Study at Malaysia Water Treatment Plants." International Journal of Engineering & Technology 7, no. 3.14 (July 25, 2018): 115. http://dx.doi.org/10.14419/ijet.v7i3.14.16871.

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The objectives of this study are to determine the most significant spatial variation of drinking water pollutant and to identify the most significant parameters in each group of physico- chemical parameters (PCPs), Inorganic parameters (IOPs), heavy metals and organic parameters (HMOPs) and pesticides parameters (PPs). The Discriminant Analysis (DA) and One- Way Analysis of variance (ANOVA) showed spatial variation on four station categories and the variance of four group parameter in water drinking quality while principle component analysis (PCA) was carried out to identify the most significant of each water quality parameters base on given group. DA and ANOVA successfully reduced the physico and inorganic pollutants concentration with significant value 98.63% and 96.90%. PCA revealed six most significant drinking water quality parameters for PCPs, nine significant parameters for IOPs, fourteen parameters on HMOPs and four significant of PPs with the p value less than 0.05 (p < 0.05). Therefore, this study proves that chemometric method is the alternative way to explain the characteristic of the drinking water quality and could reduce several parameters and sampling points in the future sampling strategy.

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Roy, Biplab, and Ajay Kumar Manna. "The Status of Surface Water in West Tripura District, India: An Approach by Using Water Quality Index and Multivariate Statistical Technique." Asian Journal of Water, Environment and Pollution 18, no. 2 (April 29, 2021): 27–36. http://dx.doi.org/10.3233/ajw210016.

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The present investigation provides a better interpretation of surface water (rivers, ponds, bills, lakes, etc.) quality utilising entropy weighted water quality index (EWWQI) and different multivariate statistical techniques. Eleven physicochemical parameters including alkalinity, dissolved oxygen (DO), pH, total dissolved solids (TDS), electrical conductivity (EC), calcium (Ca), turbidity, magnesium (Mg), total hardness (TH), chloride (Cl-), and iron (Fe) were analysed and monitored at 23 sampling sites (in December 2018) of West Tripura district. Experimental outcomes of turbidity followed by Fe contamination exceeded recommended WHO standard limit. The maximum values of Fe and turbidity were estimated as 8.745 mg/L and 797.7 NTU, respectively. WQI values confirmed that most of the monitoring locations had poor water quality except three reported areas (S7, S14, and S15) but without Fe and turbidity, estimated WQI confirmed drinkable water condition for entire samples. Multivariate statistical approaches like correlation analysis, principal component analysis (PCA) and cluster analysis (CA) were applied to explore water quality. PCA outcomes recognised three principal factors explaining almost 85% of the total variance. CA investigated three major clusters of 23 sampling sites namely less polluted, highly polluted and moderately polluted zone. Confirming all above, the surface water at the monitoring locations is a major concern which may lead to serious health issues in local people.

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Journal articles on the topic 'Water – Sampling – Technique'

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