Differing Water Quality Research Articles

Water and Nitrogen Dynamics in Drip Fertigated Tomato for Water of Different Qualities under Polyhouse Conditions


 Water and NO3-N dynamics in the soil during the growing season is an important tool in improving the nitrogen management and environmental protection. HYDRUS-2D has been widely used to predict the water and NO3-N distribution in the soil. The objective of this study was to simulate the water and NO3-N distribution in the soil under drip fertigated tomato irrigated with different water qualities under polyhouse conditions. Field data were collected on spatial and temporal distribution of water and available NO3-N during growing season. The model was calibrated for the hydraulic conductivity and parameters were used for the validation of the model. The model performance in simulating the water and NO3-N was evaluated by using coefficient of determination (R2), root mean square error (RMSE), index of agreement and Nash–Sutcliffe model efficiency (NSE). For both calibration and validation, the higher values of R2 from 0.70 to 0.99 for water distribution and 0.70 to 0.96 for NO3-N distribution showed that observed and predicted values are highly correlated. The value of RMSE ranges from 0.004 to 0.0016 for water and 0.002-0.006 for NO3-N distribution. The index of agreement value varied from 0.86-0.98 for water distribution and 0.89-0.99 for NO3-N distribution. The values of NSE (nearer to 1) i.e. 0.17 to 0.98 for water distribution and -0.09 to 0.94 for NO3-N distribution show that HYDRUS-2D was predicting with good accuracy. From these results, it can be concluded that the model performs well for predicting the water and NO3-N distribution in the tomato crop irrigated with different water qualities under polyhouse conditions.

Laboratory tests of the stability of disinfectants for different quality of water

The last water treatment process is disinfection and it has two purposes. The main purpose of disinfection is to kill or inactivate pathogens. A secondary purpose is to provide a residual disinfectant concentration in drinking water and to prevent microbial growth in water distribution systems. Although most pathogens (99 to 99.9%) are removed by coagulation, flocculation, sedimentation, and filtration, disinfection is a critical process for protecting the public from waterborne infections. Common disinfectants include chlorine gas, sodium hypochlorite, chloramines, chlorine dioxide, ozone and ultraviolet radiation. Each disinfection method has its advantages and disadvantages. Among the disadvantages of using sodium hypochlorite, in addition to the formation of disinfection by-products, the stability of the used agent is also important. Laboratory tests of the stability of disinfectants were carried out in drinking water of different quality depending on the pH value, water temperature and total water mineralization at different contact time in water (from 0 to 48 hours). To monitor the stability of disinfectants, chlorine-based disinfectants were selected, namely sodium hypochlorite prepared in the classic way and by electrolysis of brine. The stability of these disinfectants was verified in low-mineralized surface water from the Turček water reservoir, medium mineralized groundwater from the Sihot’ water source and groundwater from a private well in village of Ol’dza with highly mineralized water. Active chlorine doses in the range of 0.28-0.35 mg/L were used to verify the stability of sodium hypochlorite prepared in the classic way in selected drinking waters. When verifying the stability of sodium hypochlorite prepared by electrolysis of brine, doses of active chlorine in the range of 0.25-0.30 mg/L were applied. When verifying the stability of sodium hypochlorite produced by two different methods (chemical process, brine electrolysis), the dependence of the increasing stability of these disinfectants with a decrease in pH value and water temperature was demonstrated. The dependence of chlorine stability is significantly influenced by the water temperature, less so by the pH value of the water. Reaction kinetics of 0th, 1st and 2nd order was studied for better understanding of this process.

Short-term effect of reclaimed wastewater quality gradient on soil microbiome during irrigation

To investigate the effect of wastewater (WW) treatment on soil bacterial communities, water of different quality was used to irrigate eight lettuces per tank: raw municipal wastewater (RWW), WW treated with an aerated constructed wetland (CWW) and WW treated with a membrane bioreactor (MBW), and tap water (TW). The physicochemical and microbiological characteristics (quality indicators) of these water types were characterized, and the water and soil bacterial communities were monitored by quantitative PCR (qPCR) and 16S rRNA gene sequencing. Despite marked differences in microbial load and diversity of waters, soil communities remained remarkably stable after irrigation. Microbial biomass was increased only in soils irrigated with RWW. At the end of the irrigation period (day 84), soil and water shared a large fraction of their bacterial communities, from 43 % to 70 %, depending on the water quality, indicating a transfer of bacterial communities from water to soil. Overall, the relative abundance of Proteobacteria and Acidobacteria was increased and that of Actinobacteria was decreased in soils irrigated with MBW, CWW and even more with RWW. Multivariate ordination clearly separated soils in three groups: soils irrigated with the cleanest water (TW), with treated WW (MBW and CWW), and with untreated WW (RWW). Nitrifying, denitrifying, and nitrogen-fixing bacteria were quantified by qPCR targeting amoA, narG, and nifH, respectively. Nitrifying bacteria were the most affected by the water quality, as indicated by amoA copy number increase in RWW-irrigated soil and decrease in CWW-irrigated soil. Overall, the abundance of all three genes was positively influenced by RWW treatment. In conclusion, the 84 days of irrigation influenced the soil microbial communities, and the impact depended on the quality of the used water.

THE INFLUENCE OF PHOSPHOGYPSUM ON THE SALT COMPOSITION OF SALINATED SOIL

Global climate changes in many countries of the world lead to the need to use irrigation as a driving factor for obtaining guaranteed and stable harvests of agricultural crops. Irrigation with water of different quality leads not only to an increase in the yield, but also to a change in the salt composition of the soil. The change in the salt composition of soils occurs much faster during irrigation with mineralized water, which leads to the accumulation of soluble salts in the arable layer of the soil and the deterioration of the composition of the soil absorption complex. Accumulation of sodium ions leads to salinization of irrigated soils. It is possible to stop or suspend the salinization processes by introducing chemical melioration with calcium-containing meliorants. As an ameliorant in this work, the use of a by-product of the mineral fertilizers production – phosphogypsum, which contains a significant amount of calcium (up to 95%), replacing exchangeable sodium in the soil absorption complex is proposed. Our researches are related to the establishment of optimal calculation norms and terms of phosphogypsum application, their influence on the change in the components of the soil’s saline extract. The research was conducted on soils that had been irrigated with mineralized water from the Samara River (Ukraine) for a long time (over 50 years). According to the amount of exchangeable sodium, the soils of the experimental sites belonged to low-sodium soils with physical signs of salinization processes, and according to the content of toxic salts-moderately saline. For phosphogypsum in the soil-ameliorative conditions of the Northern Steppe of Ukraine, the ameliorative, agronomic, and ecologically safe rates of introduction in spring and autumn were calculated. The scheme of experiments provided options with sprinkler irrigation and without irrigation. The composition of the aqueous extract was determined by indicators of anion-cation content. During the research, a gradual decrease in the number of sulfates was observed: by 1.5% in the second year after exposure, and by 7.5% in the third year after exposure to phosphogypsum. The number of hydrocarbons decreased in irrigated areas where phosphogypsum was applied, and an increase in their content was observed in areas where irrigation was not carried out. Irrigation options were characterized by a significant increase in the content of chlorine ions, which is explained by the arrival of these ions exclusively with irrigation water. The degree of salinity was determined by pH and sodium adsorption ratio (SAR). Based on these indicators, it was established that the soils are slightly saline in all variants of the experiments. As a result of multi-year research, a positive effect of phosphogypsum melioration on the anion-cation composition of water extract and the degree of soils salinity irrigated with mineralized water for a long time was noted. According to the anionic composition, the chemistry of the soils in the experimental plots was sulfate in the variants where phosphogypsum was applied and vegetation irrigation was carried out and without irrigation, while in the control plots (without phosphogypsum and without irrigation) soda-sulfate chemistry was characterized. The chemistry of the soils in the experimental areas according to the cationic composition was sodium in all versions of the experiments. According to the sodium-adsorption ratio (SAR), the degree of soil salinization belonged to the slightly saline type, while the average type of salinity remained in the control plots without phosphogypsum.

Evaluation of an autonomous smart system for optimal management of fertigation with variable sources of irrigation water.

Modern irrigation technologies and tools can help boost fertigation efficiency and sustainability, particularly when using irrigation water of varying quality. In this study, a high-tech irrigation head using a new fertigation optimization tool called NutriBalance, which is designed to manage feed waters of different qualities, has been evaluated from technical and economic perspectives. NutriBalance computes the optimal fertigation dose based on specific data about the equipment, the crop, the irrigation water, and the fertilizers available, in order to enable autonomous and accurate water and fertilizer supply. The system was trialed in a grapefruit orchard irrigated with fresh and desalinated water for several values of crop nutritional requirements and considering different fertilizer price scenarios. The results showed the good interoperability between the tool and the irrigation head and the nearly flawless ability (error below 7% for most ions) of the system to provide the prescribed fertigation with different combinations of irrigation water. Fertilizer savings of up to 40% were achieved, which, for the lifespan of the equipment, were estimated to correspond to around 500 EUR/ha/year. The results of this study can encourage the adoption of novel technologies and tools by farmers.

Ефективність застосування поліоксихлориду алюмінію для очищення питної води

The article presents the results of research of the effectiveness of aluminum-containing coagulants for the purification of water of the Dnipro River.The surface waters of the Dnipro River basin are characterized by a high content of organic compounds of natural origin, the presence of which determines the coloration of the water and significantly affects the course of its purification processes. If the aluminum sulfate reagent is used to purify such water, there is need to increase the dose of the reagent, which can cause an increase in the content of residual aluminum in the purified water. One of the technological solutions for increasing the efficiency of water purification is the replacement of traditional aluminum sulfate with modern highly effective reagents, in particular aluminum polyoxychloride. Based on the results of expe¬rimental studies, there was conducted a comparative analysis of the effectiveness of the use of aluminum sulfate coagulants and aluminum polyoxychlorides with different degrees of basicity. It was established that for the water of the Dnipro River, which is characterized by a high content of organic substances and coloration, the best results were obtained in case of using aluminum polyoxychloride with a degree of basicity of 35—45%. In general, the efficiency of water purification with polyoxychlorides is higher in comparison with aluminum sulfate according to the following quality indicators: coloration — by 10—15%; turbidity — 10%, total iron content — 20—25%; permangana¬te oxidizability — 15—20%. The regression equation whichdescribe the dependence of the above indicators of the quality of purified water on the dosage of reagentswas developed. On the basis of the methods of optimization of technological processes, it was established that the rational dosage of polyoxychlorides for cleaning slightlytur¬bid colored water of the Dnipro River is about 40—50 mg/dm3, and for aluminum sulfate — 90—100 mg/dm3. The application of mathematical modeling and optimization methods in the practical determination of the rational dosage of coagulants for surface water of different quality makes it possi¬ble to effectively adjust the technological process in order toen¬sure the high quality of drinking water in accordance with regulatory requirements.

A comparative study of water of different quality in the cleaning of reusable medical instruments

A comparative study of water of different quality in the cleaning of reusable medical instruments

Groundwater quality assessment using GIS, the case of Omdurman area, central Sudan

Omdurman area, located west of the River Nile and White Nile is witnessing rapid urban expansion and land use change. Several axial irrigation schemes have developed accelerating the demand for water supply. This indeed, will place more pressure over the available groundwater resources. In order to measure any change of groundwater quality it is necessary to initially evaluate the background condition. This contribution employs a GIS- based Groundwater Quality Index (GQI) which synthesizes different variable water quality data (e.g. Cl-, Na+ and SO42+) by indexing them numerically relative to the World Health Organization (WHO) standards in order evaluate the overall groundwater quality in the study area.The GQI computed for Omdurman area indicated that the water quality is generally high (mean GQI = 90 out of 100) with respect to the WHO standards. Spatially the groundwater quality of the study area increased from the central area in the northeastern direction and decrease in the southeastern direction. This result was interpreted in terms of general groundwater flow, the recharge zone, geology and soil composition. Drilling at close distances and over pumping specially in the central region might create local variations of groundwater flow resulting in mixing of waters of different qualities deteriorating the quality of water in previously safe zones. This is expected due to the low hydraulic gradient (< 0.001) characterizing some parts of the study area as well as the minimum recharge far from the River Nile and the White Nile.

Towards potential applications of cement-polymer composites based on recycled polystyrene foam wastes on construction fields: Impact of exposure to water ecologies

Cement-polymer composites were developed to enhance the mechanical durability and reduce the porosity of cement, and to acquire a value-added end product useful for many applications in the construction sector. The novel product should be stable during exposure to various challenging environments, e.g., water of different quality, origin, and dissolved ions. The present work evaluated the impact of immersing the new cement-polymer composites (CPs), containing different fractions of recycled waste polystyrene foam, in plain, ground and sea water on the composites’ properties. After 420 days of immersion in all studied types of water, the obtained CPs showed acceptable compressive strength values (more than 30 MPa); in addition, corrosion resistance coefficients (K) were increased more than unity in comparison to non-immersed samples. Moreover, this study also determined alterations of internal architecture of composite specimens cured for 28 days after immersion for up to 420 days in water of different composition. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for these studies.

Effect of fertilization on the yield and fruit quality of perennial plantations under drip irrigation

According to the results of previous studies it was specified that the soils of the research areas in south of Ukraine are not provided with the optimal content of nutrients for normal growth and development of fruit crops. As a result of that, a long-term field experiment was set up, which aimed at increasing soil fertility, yield and fruit quality of intensive plantations of peach and apple trees under drip irrigation as well as at improving soil management principles. The field experiment was set up in 2009 on the perennial plantations in Kherson and Mykolaiv regions on the soils with different properties using the water of different quality when applying traditional cultivation technology in the south of Ukraine. It was observed the positive effect on the yield of perennial plants when applying the following fertilizer systems: organic-mineral ("Rost-concentrate"), mineral (N120P30-90K75-120), and organic ("Gumoplant") when irrigating with water of different quality. Thereat, the soil moisture in the layer of 0-60 cm was in the range of 75–90% of MMHC depending on the soil grading. The highest increase in peach yield (33%), in comparison with the check plot was observed on sod sandy soils in SE "DAF named after Solodukhin" in Kherson region when applying mineral fertilizers. The higher dry matter content in fruits by 2,6% and nitrate content by 29% were also observed when using mineral fertilizers on this farm. The highest yield increase up to 21,16 t/ha on dark chestnut medium loam soils in private joint stock company "Radsad" in Mykolayiv region in apple orchards was obtained when using organic-mineral fertilizers and irrigating with partially suitable water. The yield increase up to 26,81 t/ha was obtained on chornozem southern heavy loam soil in private joint stock company "Kamyanskyi" in Kherson region when irrigating with water suitable for irrigation and up to 32,62 t/ha of yield increase was obtained on dark chestnut medium loam soil in "Bilozerskyi" state farm in Kherson region when irrigating with water suitable for irrigation. Higher dry matter contents were recorded under mineral fertilizers, higher sugar content - under organic-mineral and mineral fertilizers, nitrate content under organic fertilizers. The content of nitrates under different fertilization systems for all fruit trees did not exceed the maximum concentration limit of 60 mg/kg. It was also found out that the highest effect on the yield of perennial plantations had organic-mineral fertilizers with a correlation coefficient of 0,75.The results of mathematical data processing showed that the fertilizers applied along with drip irrigation (fertigation) had a positive effect on the yield of peach and apple trees and the quality of their fruits.

Advanced processed wastewater for different uses: constellations favouring future implementation of a multimodal water reuse concept

Abstract Advanced wastewater treatment is often used to produce one single water quality. In recent years, technologies have been developed that allow the production of different qualities that are fit for their purpose. These technology bundles are still not being marketed, and market requirements are unclear. Two constellations in West Basin, California and in Oman were analysed to shed light on the different constellations of actors, resource situations and institutions. The first led to the industrial reuse of several water qualities, while the second produced an application in holiday resorts, leisure and food production. A hypothetical solution was contrasted with an historical case. The analysis of the constellations showed that multi-sectoral investments and dependencies require strong cooperation arrangements and long-term agreements. Governmental institutions were revealed to be suitable for coordinating the process, especially during the initial phase, but also in view of security of supply. A (comparative) examination allows an initial, still provisional systematic overview of other constellations that favour systems with recycled water of different qualities. Further research is required to understand the welfare and distribution effects of multimodal water pricing policies and the feasibility of co-financing of agricultural irrigation and opportunities for more sustainable water reuse.

Experiences of running a hydroponic system in a pilot scale for resource-efficient water reuse

Abstract Within the research project HypoWave, a hydroponic system for plant production was investigated. The hydroponic system was fed with wastewater that had undergone specially adapted treatment. The principal aim was to develop a combined system for water treatment and hydroponic plant production, where water and nutrients were reused efficiently to produce marketable food products. Another goal was to find out whether the reuse of pre-treated wastewater for plant growth in a hydroponic system could also present an additional alternative wastewater treatment step for enhanced nutrient removal. A pilot plant, consisting of various treatment steps such as activated sludge process, ozonation and biological activated carbon filtration, was used to produce lettuce with irrigation water of different qualities. The hydroponic pilot plant was operated in two different modes – flow-through and feed & deplete. This paper focuses on the influence of the various modes of operation and accordingly varying nutrient concentrations (N, P, K) on plant growth. Furthermore, heavy metal content in the various types of treated wastewater and in the produced plants was investigated. In addition, the results of the different modes of operation were verified by mass balances for N, P and K.

Sunflower biometrics and chemical salinity attributes of soil irrigated with waters of different qualities

Poor quality water, such as sewage, has become an alternative to reduce the consumption of good quality water by irrigation, especially in arid and semi-arid regions; however, water rich in salts can be harmful to agricultural systems. This research evaluated the impacts of salinity of waters of different qualities on the development of the sunflower culture and on the soil. The research was developed in the area of the Environmental Studies Team (EEA/UEFS), and the experimental design used was completely randomized, consisting of four treatments: rain water (0.20 dS m-1), well water (1.50 dS m-1), cesspool effluent (3.50 dS m-1) and brackish water (5.00 dS m-1), with the irrigation manually done and the blade calculated based on daily evapotranspiration. Irrigation with effluent promoted a better development of the sunflower crop, and the increase in the salinity of the irrigation water in the other treatments promoted a decrease in the total fresh and dry phytomasses, plant height, stem diameter, number of leaves, leaf area, internal and external diameters of the capitula and in the consumption and efficiency of water use. The use of rainwater, well water and cesspool effluent proved to be suitable for irrigation of the sunflower crop; however, the latter sodified the soil, which would already be recommended for the application of treatments for soil recovery.

Emitters and Filters Performance under Treated Sewage Water Reuse with Drip Irrigation

An experiment was carried out under open field conditions on black cotton soil at Agriculture College, Nagpur to study the performance of different types of emitters and filters while using irrigation water of different qualities for different periods of operation. Eight treatments comprising of irrigation water quality as main treatment [domestic treated sewage water (DTSW) from a phytorid sewage treatment plant and deep open well water (WW)], sub-treatments comprising of emitter type (inline and online) and time of operation (60 h and 120 h) of drip system were planned. Gravel filter, followed by disk filter, was used to filter water of different quality. Partial clogging percentage of gravel filter was higher in case of DTSW. Emission uniformity coefficient decreased rapidly in DTSW compared to WW. Mean discharge reduction percentage was 13.23 % in gravel filter, and 18.72 % in disk filter. Emitter’s emission uniformity percentage in WW was better than in DTSW. The manual operation time (i.e. time interval between two consecutive maintenance events) for disk filter was shorter than gravel filter in both treatments. Domestic treated sewage water could be used for crop production with proper maintenance of filter, lateral and emitters.

Emitters and Filters Performance under Treated Sewage Water Reuse with Drip Irrigation

An experiment was carried out under open field conditions on black cotton soil at Agriculture College, Nagpur to study the performance of different types of emitters and filters while using irrigation water of different qualities for different periods of operation. Eight treatments comprising of irrigation water quality as main treatment [domestic treated sewage water (DTSW) from a phytorid sewage treatment plant and deep open well water (WW)], sub-treatments comprising of emitter type (inline and online) and time of operation (60 h and 120 h) of drip system were planned. Gravel filter, followed by disk filter, was used to filter water of different quality. Partial clogging percentage of gravel filter was higher in case of DTSW. Emission uniformity coefficient decreased rapidly in DTSW compared to WW. Mean discharge reduction percentage was 13.23 % in gravel filter, and 18.72 % in disk filter. Emitter’s emission uniformity percentage in WW was better than in DTSW. The manual operation time (i.e. time interval between two consecutive maintenance events) for disk filter was shorter than gravel filter in both treatments. Domestic treated sewage water could be used for crop production with proper maintenance of filter, lateral and emitters.

SCIENTIFIC SCHOOL OF MICROIRRIGATION: ACHIEVEMENTS AND DEVELOPMENT PROSPECTS

Microirrigation is by far the most progressive irrigation method, with efficiencies reaching 92-98 %. According to the International Commission on Irrigation and Drainage, the world's agricultural land, which is irrigated through micro-irrigation systems, is constantly growing and now stands at over 20 million hectares. By the "Irrigation and drainage strategy in Ukraine until 2030" micro-irrigation methods are defined as one of the strategic directions of the state policy of the branch.
 Research on the direction of "micro-irrigation of crops" in Ukraine began from the late 60's of the last century. The historical aspect of the development of research in this area is thoroughly covered in previous scientific papers. Therefore, the purpose of this study is a comprehensive analysis of the basic fundamental and applied results of research of the scientific school on micro irrigation IWPaLR NAAS in the early XXI century and substantiation of perspective directions of their development.
 Using theoretical methods of scientific research (analysis and synthesis, comparison, classification and generalization), the authors systematized the most significant scientific results in terms of normative, methodological, technical and technological components. The list of normative and methodological documents prepared by IWPaLR NAAS in the direction of microirrigation is given. The results of developments in the technological component are detailed according to the research objects: water regime and processes of water consumption of crops, fertigation, pestigation, the influence of local moistening, fertilizers and water of different quality on the soil-plant-technical means of irrigation system, the formation of soil moisture zones, methods of appointment timing of vegetation irrigation and irrigation management systems. The key scientific results of the irrigation facilities’ testing laboratory are highlighted. The list of developed and implemented by the IWPaLR NAAS technical means of microirrigation systems is given. The strategic directions of further scientific research are substantiated, which should meet the global trend for environmentally friendly irrigation, as well as resource and energy conservation. The need of Ukraine in the systems of microirrigation of agricultural crops for the period up to 2030, the role of current and future developments of the scientific school of micro irrigation IWPaLR NAAS on their implementation are determined.

Intermittent Multi-column Sand Filter: A Unique Solution to Multiple Applications

Management of storm runoff is one of the ways to reduce stress on the existing freshwater resources. However, soil erosion and/or the operational steps like its trapping, conveyance, and storage lead to its mixing with foreign matter (inorganic/organic). Thus, filtration is an essential step before its use for various applications, but every application of water does not warrant its potable quality. The filtration efficiency of any porous medium increases with increase in the passing of cumulative volume of raw water, and the response of medium with finer size granules is quicker than the medium with larger size granules. The need of a filter having the flexibility to provide water of different qualities leads to the development of a newly designed intermittent multi-column filter whose different columns were containing graded sand granules. The experimental results showed that the multi-column filter removed the turbid matter in the range of 61–93% for the passing of net 2189 l of raw water. The filtrate from different columns can be regulated at any stage depending upon the application requirement. It has the ability to reduce the turbidity of raw water below the minimum standard prescribed for injecting in the freshwater aquifers, according to which the water turbidity should be less than or equal to two nephelometric turbidity units.

A hydrologic-economic-agronomic model with regard to salinity for an over-exploited coastal aquifer

The present work considers a management model for the sustainable development of an exploited coastal aquifer of the Gaza Strip, which includes different demands depending on water quality types into a regional hydrologic-economic-agronomic model. The uniqueness of this study is its consideration of two-separated demand functions one for fresh water and the other one for saline water, as well as effect of saline-water quality relationship on agriculture. This study identifies the optimum infrastructure of desalinated seawater and treated wastewater to fresh and saline levels. It also allocates water of different qualities (fresh and saline) among water sectors and between districts. Results show several important management outcomes: (i) the shadow value of saline water for all districts is larger than the cost of treating brackish water to fresh level is $0.30/m3. Therefore, the desalination of saline groundwater water to saline water level may be beneficial in Gaza districts. (ii) The shadow value of fresh water for all districts is larger than the cost of desalination ($0.6/m3). Accordingly, the desalination of brackish water to fresh water level is also beneficial. (iii) The areas of potential crops that use treated wastewater to saline level are proportionally increased to reduced abstraction from groundwater. Moreover, the sensitivity analysis indicated that, reduced abstraction from the groundwater would better allocate scarce water among competing users and better predict infrastructure sizing to fresh and saline treatment levels.

Manure contamination of drinking water influences dairy cattle water intake and preference

Water intake is closely related to feed intake and its reduction associated with negative welfare and production implications. This study aimed to assess the intake and preference for drinking water of different quality; clean (tap water), and water contaminated with either 0.05 mg (Low) or 1 mg (High) fresh manure/g water. Water and feed intake of 18 non-lactating, pregnant cows were monitored in individual, indoor pens. Each cow was given one of the three water treatments for 5 days, then a different treatment for a second 5-day period (no choice), and finally access to both in a choice test (5 days). Data were analysed using REML and paired t-tests. Contamination of water significantly affected intake in the no choice phase (P < 0.001). Cows provided with Low or High contaminated water had 10 and 28%, respectively, lower water intake than those provide with clean water (Clean: 37.0 L/day, range: 28.4–53.6; Low: 33.2 L/day, range: 26.0–44.9; High: 26.6 L/day, range: 13.6–37.8). Feed intake was not influenced by water treatment. During the choice test, cows showed a clear preference for clean water over water contaminated with manure (Clean vs. Low: 19.8 vs. 6.5 L, P = 0.014, SED: 3.60 L; Clean vs. High: 29.8 vs. 0.21 L, P < 0.001, SED: 1.82; and Low vs. High: 27.2 L vs. 0.29 L, P < 0.001, SED: 1.70). Cows only consumed 1% of their daily water intake from the High treatment when they had another option. In conclusion, dairy cattle can detect low levels of manure contamination in their drinking water, and avoid drinking it if possible. The preference to drink clean water was particularly clear. This study highlights the importance of providing cattle with clean drinking water.

THE IMPACT OF DRINKING WATER OF VARIOUS QUALITY ON INTACT AND IRRADIATED MICE

In experiments on intact mice provided by continuous access to drinking water with reduced oxidation-reduction potential (ORP) only for 30-49 days there are revealed following signs of a modification of the vital status: a slowdown in body weight gain, a decrease in behavioral activity, a decrease in the thymus and spleen mass, signs of a change in intestinal microflora composition, in comparison with the original tap water and distilled water. Reduction of ORP was achieved by distillation of water, and also by electrochemical treatment at the "Ideal" plant. In addition, water samples were used in the experiment with the addition of antioxidants: ascorbic acid and melanin, which also reduced the ORP. At X-ray irradiation in a non-lethal dose of 1.5 Gy, 24 hours after exposure to radiation, there were no statistically significant differences in the damaging effect of radiation in animals that drank water of different quality. At the same time, with an irradiation dose of 5 Gy, an acceleration in the recovery of hematological indices and behavioral activity in the use of water with reduced ORP was noted. The intake of these water samples after irradiation contributed to a statistically significant increase in the number of endogenous hematopoiesis colonies in the spleen as compared to the use of tap water.