Chemical Composition Of Water Research Articles

Geochemical investigations of the geothermal systems from the Island of Sicily (southern Italy)

• A geochemical study on the fluids discharged in continental Sicily is presented • The models of paths circulation and fluids-rock interaction processes are depicted • The relation between the tectonic setting and the fluids geochemistry is discussed Sicily hosts many natural manifestations that include thermal waters, gas discharges and mud volcanoes. Due to the significant geodynamic and geological differences, the fluid discharges along a NE-WS–oriented transect that run from the Peloritani Mts. to the Sciacca Plain shows a large variability in water and gas chemical and isotopic compositions. The studied waters are characterized by Ca-HCO 3 , Ca(Mg)-SO 4 , Ca-Cl and Na-Cl compositions produced by distinct geochemical processes such as water-rock-gas interactions, mixing between deep and shallow aquifers and seawater and direct and reverse ion exchanges. The gas chemistry is dominated by CO 2 to the east and CO 2 -N 2 to the west of the study area, whereas the central part shows mud volcanoes discharging CH 4 -rich gases. Water isotopes suggest that the thermal waters are fed by a meteoric recharge, although isotopic exchange processes between thermal fluids and host rocks at temperature >150°C are recognized. Accordingly, liquid geothermometry suggests equilibrium temperatures up to 220°C. The carbon in CO 2 and helium isotopes of the emissions from the westernmost sector of Sicily indicate that these two gases consists of up to 40 % of a mantle component, the latter decreasing to the east down to 10% where CO 2 of thermometamorphic origin dominates. Accordingly, conceptual models of the fluid circulation for the western, central and eastern sectors are proposed. The regional geothermal reservoir, hosted in carbonates in the western sector and locally outcropping, is of low to medium temperature. Higher temperature conditions (up to 200-220°C) are suggested by geothermometry and probably related to deeper levels of the system. Sicily can be regarded as a potentially suitable area for future investigations to evaluate specific activities aimed at exploiting the geothermal resource.

Hydrochemical Zoning and Chemical Evolution of the Deep Upper Jurassic Thermal Groundwater Reservoir Using Water Chemical and Environmental Isotope Data

A comprehensive hydrogeological understanding of the deep Upper Jurassic carbonate aquifer, which represents an important geothermal reservoir in the South German Molasse Basin (SGMB), is crucial for improved and sustainable groundwater resource management. Water chemical data and environmental isotope analyses of δD, δ18O and 87Sr/86Sr were obtained from groundwater of 24 deep Upper Jurassic geothermal wells and coupled with a few analyses of noble gases (3He/4He, 40Ar/36Ar) and noble gas infiltration temperatures. Hierarchical cluster analysis revealed three major water types and allowed a hydrochemical zoning of the SGMB, while exploratory factor analyses identified the hydrogeological processes affecting the water chemical composition of the thermal water. Water types 1 and 2 are of Na-[Ca]-HCO3-Cl type, lowly mineralised and have been recharged under meteoric cold climate conditions. Both water types show 87Sr/86Sr signatures, stable water isotopes values and calculated apparent mean residence times, which suggest minor water-rock interaction within a hydraulically active flow system of the Northeastern and Southeastern Central Molasse Basin. This thermal groundwater have been most likely subglacially recharged in the south of the SGMB in close proximity to the Bavarian Alps with a delineated northwards flow direction. Highly mineralised groundwater of water type 3 (Na-Cl-HCO3 and Na-Cl) occurs in the Eastern Central Molasse Basin. In contrast to water types 1 and 2, this water type shows substantial water-rock interaction with terrestrial sediments and increasing 40Ar/36Ar ratios, which may also imply a hydraulic exchange with fossil formation waters of overlying Tertiary sediments.

Spatial and temporal model for WQI prediction based on back-propagation neural network, application on EL MERK region (Algerian southeast)

For the aims of evaluate the groundwater suitability for human consumption, and modelling the water quality index, temporally and spatially, using Artificial Neural Network. 37 samples were harvested from eight different wells in the region during the period from 2016 to 2019 in pre-monsoon and post-monsoon to conduct the necessary analyses of pH, mineralisation, TH, TA, Ca2+, Mg2+, K+, Na+, Cl−, HCO3−, SO42−, NO2− and NO3−. Based on WQI results, the groundwater of MioPliociene is classified as good and poor water in 34.5% and 65.5% of the samples, respectively. The seasonal variations of the chemical composition of water indicate a presence of NO3− and NO2− in an ascending way. It is also appeared that the aquifer was very sensitive to weathering. PCA illustrates the corelations. The WQI was always posed in a homogeneous group with TH and mineralization, which indicate that TH and mineralisation are main factors in controlling water quality. ANN method is used to create a model to predict WQI using mineralisation, TH, NO3− and NO2− as inputs. The model shows a performance of 1.64 as MSE. The suitability of model confirmed using Bland-Altman test. The test shows that the model is suitable for predicting WQI with an error rate of 9.3%.

Direct oxidation of peroxymonosulfate under natural solar radiation: Accelerating the simultaneous removal of organic contaminants and pathogens from water

This study investigates the effectiveness of non-activated peroxymonosulfate (PMS) as oxidative agent for water purification in the presence and absence of natural solar radiation. The inactivation of three pathogens (Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa) and degradation of three Contaminants of Emerging Concern (CECs) (Trimethoprim-TMP, Sulfamethoxazole-SMX and Diclofenac-DCF) was simultaneously assessed in isotonic water (IW) by testing a wide range of PMS concentrations (from 0.0001 to 0.01 mM). A significant oxidative effect of PMS in darkness was obtained for both bacteria and CEC abatement, but when irradiated with solar light, results demonstrated a great enhancement on all bacterial kinetic rates, reaching >5 Log reduction in 30 min (1.5 kJL−1 of QUV) with 0.005 mM of oxidant as the best concentration. For CECs, higher degradation performance was obtained with 0.01 mM, 80% removal of DCF, SMX and TMP was achieved in 16 min (1.5 kJL−1), 27 min (9.4 kJL−1) and 150 min (16.8 kJL−1), respectively. Besides, the influence of inorganic species on the global PMS/solar system performance was assessed by testing its effectiveness in distilled water (DW), natural well water (WeW) and diluted well water (d-WeW) at 0.01 mM. Results revealed that (i) high chloride concentration (IW) has an important positive effect, (ii) the presence of a complex inorganic chemical water composition reduced the system efficiency (WeW), and (iii) no differences were obtained from the presence of low or high contents of carbonates/bicarbonates (WeW versus d-WeW), obtaining the following global PMS/solar efficiency performance order: IW > DW > WeW = d-WeW.

Impact of freeze-thaw cycles on organic carbon and metals in waters of permafrost peatlands

Despite the importance of soil and surface waters freezing in permafrost landscapes, the behaviour of dissolved organic carbon (DOC), nutrients and metals during periodic freeze-thaw cycles (FTC) remains poorly known. The on-going climate warming is likely to increase the frequency of FTC in continental aquatic settings, which could modify the chemical composition of waters. In this study, we conducted 9 repetitive cycles of overnight freezing (−20 °C) and 5 h thawing (4 °C) in the laboratory using representative 0.22 μm-filtered waters from NE European permafrost peatland: leachates of vegetation and soil, and natural surface waters (depression, thermokarst lake and river). Only minor (<5%–15%) changes of DOC concentrations, SUVA254 and molecular weight were observed in all leachates and the depression water. In contrast, several trace elements (Fe, Al, P, Mn, As, and REE) exhibited sizable variations during FTC (>10%). The leachates and the depression water were enriched in trace elements, whereas the thermokarst lake and the river demonstrated a decrease in concentration of Fe (−39 and −94%, respectively), Al (−9 and −85%), and Mn (−10 and −79%) during FTC. Overall, the observations demonstrated an increase in aliphatic low molecular weight organic matter (OM), and the precipitation of Fe, Al hydroxides and organo-mineral particles. Therefore, enhanced of frequency of FTC can favour the release of metals and toxicants from acidic OM-rich surface waters and maintain stable OM-metals-colloids in large lakes and rivers, thus regulating aquatic transport of DOC and metals from soils to the Arctic Ocean.

Recognition of fish acoustic patterns at monitoring of freshwater ecosystems

The basic sources of contamination and obstruction of reservoirs are cleared not enough sewer water of industrial and communal enterprises, large stock-raising complexes, wastes of production; upcast of water and railway transport; wastes of roughing-out of flax, pesticides and other. Сontaminents, getting in natural reservoirs, result in the quality changes of water, that, mainly, appear in the change of physical properties of water, in the change of chemical composition of water, in a presence floating substances on the surface of water and laying of them on the bottom of reservoirs. The increases of population, expansion of old and origin of new cities considerably increased entering of domestic flows internal reservoirs. Synthetic cleansers that is widely used in the way of life contaminate reservoirs in a yet greater degree. In the total the capacity of waters goes down for oxigenating, activity of bacteria that mineralize organic substances is paralysed. The unfavorable ecological state of many freshwater ecosystems inflicts substantial harm to the fish resources of reservoirs and puts under a threat possibility not only to develop fish industry, conducting fish artificially, but also simply to catch her. All of it stimulate to do events in relation to the improvement of the ecological state of fresh reservoirs. Voice vibrations are the important constituent of the ecological monitoring of the biota state of fresh reservoirs. Information is about formation of sound in a reservoir part of that is activity of fishes turns out by means of acoustic sensors, that farther yields to computer treatment. The modern methods of recognition of fish acoustic patterns are based on the standards of signals, with properties of average estimations, or on comparisons of acoustic signals with a standard. It is shown that for creation of standards, as a rule, executed: previous signal processing, extraction of features of acoustic signal. Acoustic signals that act from movable objects – fishes can change depending on objective external terms and physical state of reservoirs. The hard algorithms of recognition of acoustic patterns are characterized high probability of error. In this connection repressing are adaptive algorithms of recognition of acoustic patterns. In the process of forming of standards clarification of software comes true according to the features of acoustic signal. Realization of process of creation of standards allows to determine the measure of functional readiness of parameters and knowledge base for the decision of recognition tasks of acoustic signals. In the process of recognition the probability terms of the correct comparing are set to the standard, on default of that an algorithm stops to be executed and requires additional studies. It requires creation of standards that reflect the characteristic features of fish signals. Presently for authentication mostly choose such pattern of acoustic signals, as period length of signal fundamental wave. It can be determined or by the search of maximal value in an autocorrelation function, or by the search of minimum value in the function of mean value of difference of signal amplitudes, or by the search of difference of two maximal values in the sequence of going into detail wavelet-coefficients. It is shown that for the tasks of recognition of fish acoustic patterns, most exact and requiring the least studies there is presentation of acoustic signal as a set of sign vectors of frames. In detail methodologies of the period selection of fundamental wave of acoustic signal were analysed: SIFT, EFT-А and EFT-WT. Methodology of EFT-WT is characterized absence of the thresholds set in good time; by the rapid search of period of fundamental wave; by absence of dependence on a noise-level, as a certain range of frequencies is investigated. At the same time calculable complication of wavelet transform is relatively high, in this connection it is necessary optimization of calculation algorithms.

Air pollution with nitrates as one of the major factors in the chemical composition of water in shallow-supplied mountain springs

The prolonged pressure of air pollutants on ecosystems weakens their resistance and changes the way they function. An example of this phenomenon can be found in the Silesian Beskid Mountains, which have long been influenced by pollutants such as NO3− coming from the Upper Silesia and Ostrava industrial districts. Air pollution containing nitrates has contributed to the spruce stand diebacks in the area. The depositional influence of NO3− can be even greater. NO3− ions accompany precipitation into the region's surface waters and are found in high concentrations in spring water. In this study NO3− concentrations exceeding 5 mg∙dm−3 and 10 mg∙dm−3 were found in 46% and 11% respectively, of 751 samples taken from 98 springs located in the Skrzyczne range. All these springs represented shallow water supply systems, meaning that they were supplied by precipitation only. Vegetation plays a significant role in the NO3− cycle by taking up NO3− ions from underground water to build biomass. In the research area, this process was most efficient in the youngest tree stands. Tree stands younger than 21 years old reduced NO3− concentration in spring water to a median value of 1.95 mg∙dm−3. The factor connected with the NO3− cycle was found to be one of four major factors determining spring water chemistry in the research area and explained from 7.99% to 10.71% of the variability in that chemistry, depending on the measuring session. The other three factors were connected with bedrock and soil weathering (which explained about 50% of the variance), terrain physiography and plant cover (which explained about 15% of variance) and organic matter decomposition (which explained about 8% of the variance).

Cotton nonwovens with unidirectional water-transport properties produced by atmospheric plasma deposition

Cotton based nonwovens with unidirectional water-transport through the thickness of the fabric were prepared using atmospheric plasma technology. In controlling the plasma deposition parameters, a thin layer of polymerized Hexamethyldisiloxane was locally deposited onto a cotton nonwoven fabric, so that only the treated surface was hydrophobic, while the untreated surface remained hydrophilic. The water contact angle, surface morphology and chemical composition of the fabric surfaces were characterized, and the unidirectional water-transport performance, vapor transmission rate, thermal stability and durability of the treated nonwovens were tested. It was found that a super-hydrophobic surface could be durably achieved on one side of the fabric while maintaining a completely wettable surface on the other. The resulting asymmetric wettability enables the nonwovens to exhibit unidirectional water liquid-transport, without negatively affecting vapor transmission and air permeability. Such differential moisture management properties in sustainable cotton nonwovens are highly desirable for applications in hygiene, infection control and medical device applications.Graphic abstract

MANIFESTATION OF HARMFUL EFFECTS OF WATER IN THE SETTLEMENTS ON THE EXAMPLE TATARBUNARY DISTRICT OF ODESSA REGION

Abstract. One of the main manifestations of the harmful effects of water in the southern, central and eastern territories of Ukraine is the flooding of lands, and especially settlements (SM). For various reasons, reliable data on the extent of flooding are not available or they are incomplete and do not reflect the real picture. An objective assessment of the harmful effects of water can be given only on the basis of monitoring the level and hydrochemical composition of ground (GW) and surface waters. To do this, it is necessary to carry out systematic monitoring observations: to have a network of observation posts and the corresponding cartographic material. The main purpose of the work is to show an effective approach to solving the issue of the negative impact of water on the example of 33 SM of the Tatarbunary district. Determine the current state of flooding, the chemical composition of groundwater aquifers to optimize managerial decision-making to prevent the development of dаngerous geological and ecological processes. At the same time, the subject of the study was the factors of formation and dynamics of levels and the chemical composition of GW of the first aquifers from the surface, the correspondence of the chemical composition of water to the MPC for drinking needs. To solve this problem, an approach is proposed consisting of five stages using GIS programs Arc Map, 3D analysis method. As a result of the work, the average values for the period 2011-2019 were calculated and were built within each SM in electronic form a map diagram of the GW level and the exposed capacity of aquifers; chemical composition and mineralization; for individual chemical components and exceeding the MPC for drinking water supply. The approach indicated in this work allows us to assess the state of flooding and potential flooding in a separate oil reservoir and, at the same time, to obtain a complete picture of the state of flooding and water quality in dynamics at any time and period of the year and to make balanced engineering decisions to eliminate them.

The role of bioplato in conservation of the ichthyofauna of small river ecosystems

When wastewater enters water bodies, it changes both physical properties and chemical composition of water. Qualitative and quantitative composition of aquatic organisms and the biological structure of phytocenopopulations change as well. A special form of pollution is eutrophication of water bodies. The ability of photosynthetic organisms to accumulate and use substances, primarily phosphorus and nitrogen, makes them actively involved in self-purification of natural waters. The anthropogenic impact on aquatic ecosystems is increasing, therefore, monitoring and global environmental protection systems are of great relevance. The paper deals with a range of issues: the impact of gas station discharges on chemical composition of water is studied and assessed; the concentration of pollutants in water is analyzed before and after a backwater inhabited with higher aquatic plants; the effect of hydrophytes on processes of self-purification of the water body is considered. Solution of the issues made it possible to assess the impact of higher plants on chemical composition of water and self-purification processes, and biota. The impact of higher plants on concentration of pollutants in the water body was analyzed. The study revealed that higher plants reduce an adverse effect of pollutants on the biotic potential of the river ecosystem.

Geochemical Variability of Surface Sediment in Post-Mining Lakes Located in the Muskau Arch (Poland) and Its Relation to Water Chemistry

Water and sediment chemical compositions were investigated in 75 post-mining lakes in the eastern part of the Muskau Arch region (Western Poland, Central Europe). The lakes, originating from lignite and clay surfaces and underground mining activity, exhibited a wide gradient of physical and chemical water parameters. The most pronounced variability in water parameters was observed in pH values, conductivity, and oxygen concentration in the mixolimnion and monimolimnion. In addition, the lakes varied in terms of their trophic status, indicated by their dissolved organic carbon (DOC) and phosphorous concentrations. In general, lakes with higher pH values had higher trophic states, and some even exhibited hypertrophic conditions. The Monte Carlo test indicated that the water pH, phosphorus, DOC, and silicon concentrations could significantly explain the chemical characteristics of sediments.

Interrelation of hydrochemical indicators and the microbial community structure in the rivers within oil fields of the Khanty-Mansi Autonomous Okrug – Yugra

Assessing the quality of environmental objects, identifying the causes of pollution and predicting the future state is an urgent and important task, since it is the quality of natural objects that largely determines the state of human health. This paper presents results of the statistical analysis of the data of water quality monitoring in the rivers within oil fields of the Khanty-Mansi Autonomous Okrug Yugra during 20182019. The correlation analysis (according to Pearson) was carried out to identify the relationships between the samples of hydrochemical parameters and the number of microorganisms of various ecological-trophic groups. As a result of the correlation analysis of the relationship between the indicators of the chemical composition of water, a direct and inverse correlation was obtained for the following indicators: total iron, anionic surfactants, nickel, phenols, copper, sulfates, ammonium ions, lead, phosphates, manganese. The maximum value of the correlation coefficient is observed for Ni and Cr concentrations. For total iron and manganese, a significant positive correlation is also revealed. The distribution of chemical compounds in the rivers doesnt have a pronounced correlation dependence, which is probably due to the heterogeneity of the composition of the waters, as well as to the increasing impact on the environment of the oil and gas complex.

The Evolution of the Waters Chemical Composition in the Areas of Lead-Zinc Deposits Mining in East Transbaikalia

A feature of the studied objects is the formation of waters under conditions of combination in the mineral composition of the tailings of sulfide and carbonate mineralization. The studied drainage waters are mainly fresh (salinity 0.33-1.82 g/L), neutral and alkaline (pH 7.25-8.30). They belong to the bicarbonate, sulfate-bicarbonate, bicarbonate-sulfate and sulfate magnesium-calcium and calcium-magnesium chemical types. Arsenic, zinc, cadmium, lead, antimony and manganese in the microelement composition of drainage waters are predominant. Drainage waters of lead-zinc deposits are characterized by a significant excess of the heavy metals concentrations (As, Zn, Cd, Pb, Sb, Mn, Mo, U, La, Se) over the average composition of leaching zone waters, with a maximum for arsenic – more than 800 and for zinc – 200 times. The waters are saturated with respect to secondary carbonates and arsenates, which indicates the existence of thermodynamic conditions for the removal from the solution of Ca, Mg, Cu, Zn, Pb, As into the solid mineral phase. The neutralizing effect of host rocks carbonates and ore bodies carbonates causes a neutral reaction of waters and low heavy metal concentration.

Mapping of potential environmental risks associated to formation water in the Oriente Basin, Ecuador

Formation water is the water produced jointly with oil as part of oil production process, which in Ecuador it is performed mainly within the Amazon region. Despite this region is highly vulnerable, due to its biodiversity and hydrological richness, formation water is produced in large volumes, contains toxic substances and receives limited treatment. This research determined the spatial distribution of the potential environmental risks associated to formation water chemical composition using geographic information systems to generate risk and vulnerability maps. Specifically, the objectives were 1) to analyze the chemical composition of formation water; 2) to compare formation water chemical composition between oil fields; 3) to determine the level of vulnerability of the environment and nearby populations; 4) to map the potential environmental risks associated to formation water; and 5) to review the current water treatment methods. Results show that formation water contains elements that are carcinogenic and with high bioaccumulation potential, like cadmium. Moreover, their concentration varies depending on the reservoir from where the water is extracted and the geographical location of the field. The potential risk of an area is determined by its well density, formation water quality and production volume, and the course of any nearby river. Therefore, Blocks 15 and 57 and the basin of the Aguarico River are associated to high environmental risk. Finally, water treatment process removes suspended solids and oil, while production chemicals slightly contribute to its toxicity. To track environmental potential risks, it is suggested periodical water quality evaluations of nearby rivers, similar environmental studies, and better land use planning by the local governments considering the potential risks associated to oil production activities.

Application of Partial Least Squares-Discriminate Analysis Model Based on Water Chemical Compositions in Identifying Water Inrush Sources from Multiple Aquifers in Mines

Mine water inrush seriously threatens the safety of coal mine production. Quick and accurate identification of mine water inrush sources is of great significance to preventing mine water hazards. This paper combined partial least squares-discriminate analysis (PLS-DA) with inrush water chemical composition to identify the source of water inrush from multiple aquifers in mines. The Renlou Coal Mine in the Linhuan mining area was selected for this study, and seven conventional water chemical compositions from 54 water samples in three aquifers were collected and tested, of which 45 water samples were used to establish the PLS-DA discriminant model, and nine were used to test the prediction effect. To improve model accuracy and predictive ability, hierarchical clustering analysis method was used to eliminate seven unqualified water samples to reduce the errors caused by improper data. PCA and PLS-DA methods were used to analyze and process the remaining water sample data, and on the basis of PCA analysis, the remaining 38 water samples were used to establish the PLS-DA discriminant model. The model was validated using permutation and external prediction tests. The research shows the following results: (1) Both PCA and PLS-DA methods can distinguish water samples from three different water sources, but the classification effect of PLS-DA was better than PCA because it can strengthen the difference of water chemical composition between different water sources. (2) The correct discrimination rate of the PLS-DA discriminant model was as high as 100%, and permutation tests showed that the model was not overfit. External validation found that the model had good stability and discrimination. (3) HCO3- and total dissolved solids (TDS) were the most important differential marker compositions that affected the discrimination results based on Variable Importance for the Projection (VIP) scores. The discriminant model established in this study combined the advantages of principal component analysis and multiple regression analysis, providing a new method for accurately identifying the sources of water inrush in mines.

Гидрохимическая характеристика и качество подземных вод Сосновского района Челябинской области для целей орошения

Abstract. The purpose of the study was to assess the quality of groundwater used for irrigation of individual plots of land, belonging to the residents of the Sosnovskiy district of the Chelyabinsk region. Material: 73 samples taken in wells and boreholes on the territory of private land plots, villages, villa communities and garden non-profit partnerships. Methods: 30 indicators of water composition were determined (common indicators – 6, major ions and carbonate ion – 8, compounds of nitrogen, phosphorus and organic matter – 5, heavy metals and silicon – 11) using capillary electrophoresis, atomic absorption, potentiometry, spectrophotometry and conductometry. Statistical analysis included: estimation of means with 95 % confidence intervals (95 % CI) calculated by bootstrap (Kaplan – Meier method was used for censored observations), relative frequencies (in percent) with 95 % CI (Jeffreys method and simultaneous CI by Wilson). Data was visualized using Piper’s and Gibbs’ diagrams. Software: PAST, Scout 2008, R, DescTool, GW_Chart, KyPlot, QGIS. Results. On the territory of the Sosnovsky district of the Chelyabinsk region, (Ca2+–Mg2+ and HCO3––CO32–) type groundwater prevails with a pH 7.39 (95 % CI: from 7.30 to 7.48) and a TDS 651 mg/dm3 (95 % CI: from 598 to 720). Using Piper and Gibbs diagrams, it was established that the leading processes of the water chemical composition formation are: 1) the dissolution of the calcite-dolomite series’ minerals of sedimentary rocks, 2) the dissolution and the ion exchange of feldspars in the composition of granites with calcite. For mineralization and risks of chloride salinization, sodium salinization, magnesium salinization and soda formation, the proportion of samples with quality for irrigation purposes I and II category is 65.7 %. There are excesses of standards in the concentration of NO3- (24.7 % of samples), Ba (68.3 %), Cd (30.4 %), Fe (15.3 %), Mn (12.9 %), Pb (6.3 %).

Phototransformation study of the antidepressant paroxetine in surface waters

In this work, the photochemistry of the antidepressant paroxetine (PXT) and its photochemical fate in surface waters were investigated. The direct photolysis quantum yield, as well as the second-order rate constants of the reactions between PXT and the photochemically produced reactive intermediates (i.e., HO•, 3CDOM* and 1O2) were assessed with steady-state irradiation experiments, while the reaction rate constant with CO3•− was known from the literature. Using these results, the PXT photochemical fate (i.e., pseudo-first order photodegradation rate constant and half-life time) was modelled in a surface-water scenario by varying the chemical composition of water and its depth. Nine transformation products were identified, formed upon PXT direct and indirect photolysis, and a photodegradation pathway was proposed that is initiated by photohydrolysis of PXT to 4-(4-fluorophenyl)-3-(hydroxymethyl)piperidine.The results showed that PXT reacts with HO• radicals approaching a diffusion-controlled kinetics, while the direct photolysis quantum yield is ΦPXT = (4.03 ± 0.25) × 10−2. Direct photolysis, together with reactions with HO• and CO3•− radicals would be the main photodegradation pathways for PXT in surface waters. Reaction with CO3•− is particularly important for low amounts of dissolved organic matter (DOM), high pH and high inorganic carbon, which are for instance typical of surface waters in Slovenia. Finally, PXT reaction with 3CDOM* is little important because it is significantly inhibited in the presence of antioxidant compounds, which reduce the partially oxidized intermediates back to the parent PXT.

Review on the Effect of Irrigation Interval on Different Crop Production

In these review I have been review the effect of irrigation intervals on growth and yield of onion, effect of irrigation intervals to optimize maize yield, effect of irrigation interval on growth characteristics for Chile pepper, effect of irrigation interval on vegetative growth and yield, effects of irrigation interval on growth analysis of soybean, effect of irrigation intervals on forage production, effect of irrigation interval on growth and development of tomato, effect of irrigation level and irrigation frequency on the growth of mini Chinese cabbage and Influence of irrigation interval, nitrogen level and crop geometry on production lettuce. The best performance irrigation interval for maize, pepper, okra, soybean, forage, tomato, cabbage and lettuce are 5, 6, 1, 12, 8, 20, 1, 4 and 2 day respectively. Crop type, crop growth stage soil type, climate condition (temperature, rainfall, humidity, sunshine hour and wend speed) duration of the environment should be properly addressed and potential evapotranspiration and reference evapotranspiration should be estimated for determine of irrigating interval. In in these case some of the studies are properly addressed these important parameters but some of the study not indicates. On the other hand chemical composition of water and soil, fertilizer application, method of research design and plant geometry are should be identify to eradicate the misjudgment of your best productivity of irrigation interval. Keywords : interval, yield, irrigation, growth, crop DOI: 10.7176/JNSR/12-4-04 Publication date: February 28 th 2021

EPIDEMIOLOGY, PROGNOSIS AND RISK FACTORS FOR DEVELOPMENT OF ONCOLOGICAL DISEASES AS EARLY DIAGNOSTIC OF DENTAL PROBLEMS IN THE CHILDREN

Introduction. In the world trends in incidence and death rates for all cancers combined and for the leading cancer types by sex, racial/ethnic group, and age were estimated by analysis and characterized by the average annual percent change during recent 5 years. Aim of research: to determine epidemiology of oncological diseases in the children population of rural clusters due to the chemical contamination of drinking water sources. Materials and methods. Analysis of water-related health indicators in the children population. Drinking water quality monitoring included studies of chemical and salt composition of water from centralized (38260 studies) and decentralized (24586 studies) water supply systems carried out in rural clusters of Dnipropetrovsk region. Results. As a result of discriminant analysis, a plausible model probable development of cancer among children population in rural clusters of Dnipropetrovsk region, which consumed drinking water from decentralized drinking water sources was obtained. Conclusions. According to the correlation analysis was determined that oncological morbidity among children population responded quickly to the changes in salt and chemical composition of water from centralized and decentralized drinking water systems. In 3, 4, 5, 6 clusters of Dnipropetrovsk region high levels of morbidity this class of diseases (r=0,763, p=0,077) were observed in children who consume wells water with high nitrate content (at the limit of MPC 45 mg / dm3). It was established that prognostic capacity for a model of development cancer in children under 14 years is 34%. During 2014–2019 years tendency of negative growth of tumors in the children population of Dnipropetrovsk region in all clusters was established: 1 (-20.9 %), 2 (-37.5 %), 3 (-31.1 %), 4 (-33.8 %), 5 (-22.3 %), 6 (-29.2 %).

Dominant geochemical reactions and hazardous metal contamination status in the Kabul’s aquifers, Afghanistan

Water is an essential resource for all people, particularly those who live in arid areas, such as Kabul city, Afghanistan. In last decade, development of academic communities and contribution from international organizations have provided opportunities for researchers to address the environmental issues, including problems related to drinking water in Kabul city. Although most of these researches focused on the capital, due to shortage of financial support for water quality studies as well as security concerns, there are in fact very limited publications in that area of interest. Based on an extensive literature search and comprehensive review, four major processes have been identified as controlling factors for water quality in the studied area, which include mineral weathering, redox-sensitive processes, role of adsorption/desorption, and effects of NO3 influx. Among these factors, the most important one was the redox-sensitive processes that have considerable impacts on the chemical composition of water reserves in the Kabul area. Even though there are significant inputs of domestic sewage that released protons into the aquifers, the presence of carbonates with a great buffering capacity has prevented the dissolution of most pH-sensitive minerals; in most cases, these minerals contain hazardous metals. In terms of metal contamination in the Kabul Basin, three metals have displayed elevated levels above the World Health Organization guidelines: uranium, arsenic, and nickel. Based on the literature review, the origin of these toxic metals has revealed, and the associated weathering reactions are presented.