scholarly journals Determination and Removal of Phosphate and Nitrate from the Ground and Surface Water at the Three Counties of Guyana

2021 ◽  
pp. 1-20
Author(s):  
Joylyn Anita Conway ◽  
Brij Bhushan Tewari
Keyword(s):  
Surface Water ◽  
Surface Waters ◽  
Natural Waters ◽  
Cost Effective ◽  
Small Scale ◽  
Transitional Metals ◽  
Sustainable Environment ◽  
Permissible Levels ◽  
The Stability

Standard analytical procedures that are based on colourimetry facilitated the determination of PO43- and NO3- in the ground and surface waters from the three (3) counties of Guyana. Phosphates and nitrates beyond their permissible levels in natural waters can pose significant threats to the aquatic environment, its inhabitants, and the health of humans and terrestrial animals. For this reason, this study aims to investigate the use of metal (nickel, cadmium, cobalt) ferrocyanides (octahedral complexes that facilitate adsorption of anions primarily on its two divalent transitional metals) as adsorbents to facilitate the removal of the aforementioned anions. Results revealed that nickel ferrocyanide is the most effective adsorbent for treating ground and surface waters that contain high levels of PO43-, while it was also the most effective adsorbent for treating surface waters that contained NO3-. Fixed volumes of water samples were treated with 50 mg, 100 mg, and 150 mg of the adsorbent. The correlation coefficient computations revealed that they were instances of both positive and negative correlations, which implied that increasing adsorbent dosage resulted in increased adsorption and other instances decreased adsorption, respectively. This occurrence went against literature, possible reasons for this are explained in detail within the discussion portion of the manuscript. Adsorption isotherms and Langmuir plots were used to facilitate adsorption studies, in various instances, the generic appearance of these isotherms was not observed, possible reasons for this occurrence are also explained in more detail within the article. Based on observations within the article, the use of cobalt ferrocyanide for treating groundwater and removing PO43- is not recommended, while cadmium ferrocyanide is not recommended to be used to facilitate the removal of NO3-, due to the possible formation of Co3(PO4)2 and Cd(NO3)2, respectively, which consequently affected the results. Technologies like those studied in this research project should be explored and studied more in-depth (particularly with regards to the stability of the adsorbents) with regards to the treating of ground and surface water supplies, to facilitate the removal of PO43- and NO3-, since the results observed, though on a small scale, can be seen to move us closer towards a green and sustainable environment, inclusive of safeguarding the health of the Worlds’ people and expanding the scope of cost-effective and simple methods that aid in the removal of anions from natural waters.

scholarly journals Fast UHPLC-MS/MS for the Simultaneous Determination of Azithromycin, Erythromycin, Fluoxetine and Sotalol in Surface Water Samples

2021 ◽  
Vol 11 (18) ◽  
pp. 8316
Author(s):  
Mira Azzi ◽  
Sylvain Ravier ◽  
Assem Elkak ◽  
Bruno Coulomb ◽  
Jean-Luc Boudenne
Keyword(s):  
Surface Water ◽  
Simultaneous Determination ◽  
Surface Waters ◽  
Water Samples ◽  
High Performance ◽  
Chemical Properties ◽  
Environmental Water ◽  
Butyl Ether ◽  
Flight Mass Spectrometry

Chromatographic development for the determination of pharmaceuticals in environmental water samples is particularly challenging when the analytes have significantly different physico-chemical properties (solubility, polarity, pKa) often requiring multiple chromatographic methods for each active component. This paper presents a method for the simultaneous determination of azithromycin, erythromycin (antibiotics), fluoxetine (anti-depressant) and sotalol (b-blocker) in surface waters by ultra-high-performance liquid chromatography coupled with ultra-high-resolution time-of-flight mass spectrometry. These pharmaceuticals—presenting a broad spectrum of polarity (0.24 ≤ log Kow ≤ 4.05)—were separated on a C-18 analytical column, after a simple filtration step for freshwater samples or after a liquid–liquid extraction with Methyl-tertio-butyl ether (MTBE) for seawater samples. The optimized separation method (in terms of nature of column and eluent, elution gradient, and of mass spectrometric parameters), enable one to reach limits of detection ranging between 2 and 7 ng L−1 and limits of quantification between 7 and 23 ng L−1 for the four targeted molecules, within a three minute run. This method was validated using samples collected from three different surface waters in Lebanon (freshwater and seawater) and analytical results were compared with those obtained in surface waters sampled in a French river, equivalent in terms of human activities. Using this method, we report the highest concentration of pharmaceuticals found in surface water (up to 377 ng L−1 and 268 ng L−1, respectively, for azithromycin and erythromycin, in the Litani river, Lebanon).

scholarly journals Properties, processes and regimes of soil solutions and surface waters

2020 ◽  
Vol 175 ◽  
pp. 12022
Author(s):  
Guriyat Podvolotskaya ◽  
Sergey Belopukhov ◽  
Vitaly Savich ◽  
Andrey Sorokin ◽  
Nikolay Tyutrin
Keyword(s):  
Biological Activity ◽  
Surface Water ◽  
Surface Waters ◽  
Pair Correlation ◽  
Rate Of Change ◽  
Water Soluble ◽  
Soil Solutions ◽  
Different Depths ◽  
Different Soils

Soil solutions and the surface waters are characterized by properties, processes and regimes. Soil solutions of different soils and their surface water have different biological activity and change the activity of dissolved stimulants and inhibitors. The object of the study are soil solutions of the main types of soils obtained in the model experiments with the ratio of soils: water equal to 1:1 and 1: 2, soil solutions and surface water in the flooding of soils with water for 1 week – 3 months. The research method consisted in the assessment of pH, Eh, activity of K, NO3, NH4, Ca, Mg by conventional methods, assessment of concentrations of water-soluble compounds extracted from soils by ionite membranes, in the assessment of biological activity of solutions using biotests. The following is suggested for additional evaluation: the using of cation and anion membranes, determination of interrelation between the properties of waters, equation of pair correlation and multiply regression. The informative value of the gradient of surface water concentrations at different distances from the floor of the reservoir, at different depths of the overwatered soils is shown. The mobility of Ca, Mg, Fe, Mn in soils and the content of their water-soluble forms depends on both pH and Eh, whose influence on the content of water-soluble forms of the considered cations shows the effects of synergy and antagonism. The rate of change in the composition of soil solutions during soil flooding depends on a combination of soil properties, temperature, and duration of flooding. Soil solutions of different soils and their surface waters have differentrates.

Enantioselective determination of ibuprofen residues by chiral liquid chromatography: a systematic study of enantiomeric transformation in surface water and sediments

2016 ◽  
Vol 13 (4) ◽  
pp. 656 ◽  
Author(s):  
María Eugenia León-González ◽  
Noelia Rosales-Conrado
Keyword(s):  
Liquid Chromatography ◽  
Surface Water ◽  
Surface Waters ◽  
Solid Phase ◽  
Multivariate Techniques ◽  
Enantioselective Separation ◽  
Environmental Matrices ◽  
Ibuprofen Enantiomers ◽  
Shed Light

Environmental context Ibuprofen, a common anti-inflammatory drug and one of many pharmaceuticals sold as a mixture of enantiomers, has recently been found in river and surface waters. There are, however, few analytical methods able to separate and accurately measure ibuprofen enantiomers in environmental matrices. This study reports a method for quantifying ibuprofen enantiomers in sediments and surface water, and applies it to shed light on the degradation and fate of the enantiomers in aquatic systems. Abstract The enantioselective composition of ibuprofen in sediments in contact with surface water was evaluated over 168h in the presence and absence of light. Multivariate techniques applied for the evaluation of enantiomeric fraction (EF) and recoveries of enantiomers in water and sediments show differences in the EF and composition of each enantiomer. In sediments, differences in the EF are a result of the presence or absence of light, whereas in water it is attributable to degradation of the two enantiomers with time. To achieve enantioselective separation of ibuprofen in surface water and sediments, a clean-up and preconcentration procedure using solid phase extraction combined with a direct chiral liquid chromatography–ultraviolet method was developed. Quantitation limits of the proposed method were between 0.12 and 0.15µgg–1 for each enantiomer in sediments, and between 2.4 and 3.0µgL–1 in surface water. Intra- and inter-day precisions were between 5.1 and 8.9%. Multivariate techniques can be useful to identify enantiomeric modifications and to select the variables that should be used for modelling such transformations.

scholarly journals Cost-Effective Detection of Perfluoroalkyl Carboxylic Acids with Gas Chromatography: Optimization of Derivatization Approaches and Method Validation

2019 ◽  
Vol 17 (1) ◽  
pp. 100 ◽  
Author(s):  
Zhen Li ◽  
Hongwei Sun
Keyword(s):  
Gas Chromatography ◽  
Surface Water ◽  
Solid Phase Extraction ◽  
Carboxylic Acids ◽  
Water Samples ◽  
Solid Phase ◽  
Cost Effective ◽  
Phase Extraction ◽  
Surface Water Samples

The reliable quantification of perfluoroalkyl carboxylic acids (PFCAs) in environmental samples like surface water by using gas chromatography (GC) remains challenging because the polar PFCAs call for derivatization before injection and problems involving the integration of sample pretreatment and derivatization procedures. Here we proposed a cost-effective method for the GC based determination of C4–C12 PFCAs in surface water samples by integrating solid phase extraction and PFCAs anilide derivatization. First, we assessed the performance of different PFCAs derivatization methods, namely esterification and amidation. Esterification was unable to derivatize C4–C6 PFCAs. On the contrary, amidation procedures by using 2,4-difluoroaniline (DFA) and N,N′-dicyclohexylcarbodiimide (DCC) could successfully transform all the PFCA analogs to produce anilide derivatives, which could be easily detected by GC. Then the reaction conditions in the amidation approach were further optimized by using orthogonal design experiments. After optimizing the instrumental parameters of GC, the limits of detection (LOD) of this derivatization method were determined to be 1.14–6.32 μg L−1. Finally, in order to establish an intact method for the quantification of PFCAs in surface water samples, solid phase extraction (SPE) was used for extraction and cleanup, which was further integrated with the subsequent amidation process. The SPE-amidation-GC method was validated for application, with good accuracy and precision reflected by the PFCAs recoveries and derivatization of triplicates. The method reported here could provide a promising and cost-effective alternative for the simultaneous determination of C4–C12 PFCAs in environmental water samples.

scholarly journals Monitoring of surface water and bottom sediments at the area of the gas transportation objects in the cryolithozone

2018 ◽  
pp. 64-68 ◽  
Author(s):  
S. D. Ganova ◽  
O. V. Skopintseva
Keyword(s):  
Surface Water ◽  
Bottom Sediments ◽  
Surface Waters ◽  
Environmental Risk ◽  
Water Loss ◽  
Control Points ◽  
Regulatory Requirements ◽  
Large Lakes ◽  
Low Levels

This paper presents a program of observation of the surface water and bottom sediments. In accordance with existing regulatory requirements, these elements are directly connected, which allows determination of the water loss and the level of geochemical contamination of rivers and large lakes due to dissolution, migration and accumulation of chemicals in the proper water intake areas, in background and in control points of water bodies. Since monitoring of the surface waters and of the bottom sediments is a part of the complex geoecological monitoring, it is necessary to reflect the feasibility of the work and, accordingly, its objectivity. In addition, results should be reliable and complete, and information received during the observations should be presented in a manner that is convenient for the consumer, which requires additional steps of systematization of the information obtained, data processing and formation of the information banks. When designing a network of monitoring points in the study area, we should follow the same principle that is used for determination of sustainability category of geoecological systems: with other identical conditions, monitoring points should be located in places characterized by low levels of stability and within the zones of exposure to high environmental risk objects.

Colorimetric Determination of Aniline Derivatives in Natural Waters

1971 ◽  
Vol 54 (6) ◽  
pp. 1383-1387 ◽  
Author(s):  
M A El-Dib
Keyword(s):  
Surface Waters ◽  
Natural Waters ◽  
Colorimetric Method ◽  
Colorimetric Determination ◽  
Color Intensity ◽  
Aniline Derivative ◽  
Aniline Derivatives ◽  
Coefficients Of Variation ◽  
Effects Of Ph

Abstract A rapid, direct, and sensitive colorimetric method has been proposed for the determination of aniline derivatives in surface waters. The method is based on diazotization of the primary aromatic amine and coupling with resorcinol or 1-naphthol. Hydroxy-azo dyes obtained have considerably high absorptivities, rendering the method sensitive enough to determine anilines at 0.1 ppm. The effects of pH, saline constituents of waters, coupling phenols, and substituents on color intensity are discussed. Coefficients of variation ranged between 6 and 0.5, according to the nature of aniline derivative and the amount determined. Precision of the method is greatly increased when the amount of the existent aniline ranges between 40 and 100 μg.

Methods for accurate measurements of small fixed wing UAV inertial properties

2016 ◽  
Vol 120 (1233) ◽  
pp. 1785-1811 ◽  
Author(s):  
K. Lehmkühler ◽  
K.C. Wong ◽  
D. Verstraete
Keyword(s):  
Degrees Of Freedom ◽  
Wind Tunnel Test ◽  
Cost Effective ◽  
Mass Effect ◽  
Small Scale ◽  
Pendulum Motion ◽  
Single Degree Of Freedom ◽  
Cost Effective Method ◽  
Aerial Vehicle

ABSTRACTTwo methods have been compared for the determination of the inertial properties of a small, fixed-wing un-manned aerial vehicle. The first method uses the standard single degree of freedom pendulum method and the second method implements a novel, potentially easier, 3 degrees of freedom pendulum method, which yields the entire inertia tensor from a single swing test. Both methods are using system identification of the pendulum motion to estimate the inertial properties. Substantial corrections (up to 25%) have to be applied to the experimental results. These corrections are caused by the acceleration of the pendulum being immersed in the surrounding air, also called the added mass effect. It has been found that the methods presented in literature to determine the corrections for full-scale aircraft do not give the correct results for the small-scale un-manned aerial vehicle under consideration. The only feasible, cost-effective method to generate these corrections utilise swing tests with a geometrically similar object of known inertial properties. It has also been found that the corrections are unique with respect to the experimental methods. Several benchmarking methods, including the innovative use of static and dynamic wind-tunnel test data, give high confidence in the results.

scholarly journals ANALYSIS OF THE MAIN CHARACTERISTICS OF POLLUTION IN THE VILNIA RIVER / PAGRINDINIŲ VANDENS UŽTERŠTUMO VILNIOS UPĖJE CHARAKTERISTIKŲ ANALIZĖ

2012 ◽  
Vol 5 (4) ◽  
pp. 435-440
Author(s):  
Laura Margenytė ◽  
Eduardas Tomaševskis ◽  
Aušra Zigmontienė
Keyword(s):  
Surface Water ◽  
Dissolved Oxygen ◽  
Surface Waters ◽  
Natural Waters ◽  
Suspended Solids ◽  
Ecological Status ◽  
Investigation Period ◽  
Surface Water Bodies ◽  
The City

The article discusses pollution characteristics in natural waters and reasons for fluctuations in their levels of surface waters. The samples were collected in the city and region of Vilnius, i.e. the places where industry objects that may affect the quality of surface water bodies are mainly erected. The obtained results have revealed that the highest demand for biochemical oxygen (BOD) in the Vilnia river over the whole period have reached 32.3 mg/l in June, for dissolved oxygen (O2) –10.63 mg/l O2 in winter and for the concentration of suspended solids (SS) –53.44 mg/l in April. The results of the annual main concentration characteristics of pollution in the Vilnia river over the investigation period have been compared with assessment criteria for evaluating an ecological status of water. Santrauka Straipsnyje aptariamos pagrindinės vandens užterštumo charakteristikos: skendinčiosios medžiagos, ištirpęs deguonies kiekis bei biocheminio deguonies suvartojimo (BDS) gamtiniuose vandens telkiniuose priežastys, kurios lemia šių medžiagų koncentracijų kiekių svyravimus. Straipsnyje taip pat nagrinėjama šių charakteristikų paviršiniuose vandens telkiniuose šaltuoju metų laikotarpiu Vilnios upėje kaita. Mėginiai buvo imami tose Vilniaus miesto bei Vilniaus rajono vietose, kur yra susitelkę pramonės objektai, kurie savo antropogenine veikla daro įtaką paviršiniams vandens telkiniams. Per visą tiriamąjį laikotarpį iš visų atliktų tyrimų skaičiaus nustatyta, jog biocheminio deguonies koncentracija šiltuoju metų laikotarpiu didžiausia birželio mėnesį – 32,3 mg/l, ištirpusio deguonies kiekis (O2) žiemą – 10,63 mg/l O2, skendinčiųjų medžiagų koncentracija (SM) balandžio mėnesį – 53,44 mg/l. Gautos metinės tiriamojo laikotarpio pagrindinių užterštumo charakteristikų koncentracijos Vilnios upėje lyginamos su ekologinės būklės vertinimo kriterijais.

Development of Greener and Safer Assays for Hydrochloride Drugs: Photometric Microtitration of Phenylpropanolamine Hydrochloride and Metformin Hydrochloride

2011 ◽  
Vol 361-363 ◽  
pp. 1892-1896
Author(s):  
Theerasak Rojanarata ◽  
Kwanrutai Waewsa-Nga ◽  
Parin Buacheen ◽  
Praneet Opanasopit ◽  
Tanasait Ngawhirunpat
Keyword(s):  
Silver Nitrate ◽  
Mercuric Acetate ◽  
Raw Materials ◽  
Ammonium Thiocyanate ◽  
Cost Effective ◽  
Metformin Hydrochloride ◽  
Sustainable Environment ◽  
Accuracy And Precision ◽  
Phenylpropanolamine Hydrochloride

An environmentally friendlier, safer and saver method is described for the assay of drugs as hydrochloride salts namely metformin hydrochloride and phenylpropanolamine hydrochloride via the determination of their chloride contents. In this method, an aqueous solution of drug was treated with measured excess of silver nitrate in the presence of nitric acid, followed by the determination of unreacted silver nitrate by Volhard’s method using ammonium thiocyanate titrant and iron(III) alum indicator. To minimize the reagents consumed and wastes generated, the reactions were scaled down to less than 2 mL carried out in microcentrifuge tubes and using micropipettes for the transfer of reagents. The equivalence point was determined by spectrophotometry to diminish visual errors by reading the absorbance of red iron(III) thiocyante complex at 450 nm on microplates, which quickened the measurements of multi-samples. After validation, the method showed satisfactory accuracy and precision and was successfully applied for the assay of both drugs in raw materials, giving the results comparable to the pharmacopeial methods. In addition, the proposed assay was free from the use of harsh, toxic and environmentally harmful chemicals i.e. glacial acetic acid, acetic anhydride, mercuric acetate which are employed in the USP non-aqueous titration methods. Thus, the method is considerably safer for analysts and is a cost-effective and green analytical method suitable for a sustainable environment.

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