Domestic Water Supply Research Articles

Rainwater harvesting (RWH): a supplement to domestic water supply in Mvog-Betsi, Yaoundé-Cameroon

Abstract This research is aimed at assessing the possibility of using a rainwater harvesting (RWH) system to supplement domestic water supply in the Mvog-Betsi neighbourhood of Yaoundé. The research made use of a 63-year long data series on the amount of rainfall available in the study area, an analysis of rainwater quality and an estimate of the population's monthly water demand in relation to the monthly harvestable rainwater supply. Rainwater supply for the months of September, October and November is 53.05 m3 which is considerably greater than the households' water demand of 25.56 m3 during the long dry season. This led to the design of a 27 m3 ferrocement tank as minimum storage requirement. Furthermore, a rainwater quality analysis showed that all tested parameters conform to water quality standards except for microbiological quality. The rainwater needs to be disinfected before consumption as potable water. Finally, cost estimates for installing RWH systems for low ($419), medium ($549) and high standard ($668) habitations were calculated. RWH can effectively serve as a water supply supplement in the Mvog-Betsi neighbourhood.

INVESTIGATIONS OF PEOPLE PERCEPTION ON DOMESTIC WATER SUPPLY SITUATIONS IN KANO METROPOLIS NORTHWESTERN, NIGERIA

The problem of portable water supply has become an issue of global concerned as governments all over the world are trying to make house-holds water accessible to all as easier as possible to meet the challenges for sustainable development goals. This research has been conducted to determine the people’s perception on domestic water supply situation in Kano metropolis, Northwestern Nigeria. A self-designed questionnaire developed and distributed to the subjects using stratified sampling technique, and the data obtained has been presented in frequency and percentage. The results obtained revealed that, there is a scarcity of portable water supply to households in Kano metropolis. The problem emanated from lack of pipe-borne water which necessitated the dependence of the house-holds water supply on vendors that obtained water from boreholes and some hand-dug wells lacking proper hygienic practices. More so, the respondents were willing to pay for pipe borne water delivery, yet, they depend on vendors as their major water suppliers as alternatives. The unhygienic practices of the vendors and water sources posed threat to public health concerned

Urban stormwater harvesting for domestic water supply: a water evaluation and planning approach.

Renewable groundwater and surface water supplies are insufficient for the current worldwide urban population as water demand is increasing rapidly. Usage per capita in urban areas transcends 160 liters per day. Climate change is projected to increase water demand even more. Sources of surface water from stormwater runoff can be used to fulfill this requirement. The main objective of this work is to assess the water supply and demand in the dry conditions of the Coimbatore region, Tamil Nadu, India, and to use the water evaluation and planning method to create a model for supply and demand in the future. There are more than three dozen surface water bodies in and around the metropolitan center. Most sources are heavily encroached upon. By linking stormwater runoff from its respective elevation to the accessible surface water bodies, an additional water supply source can be obtained. By using the water evaluation and planning framework as a guide, models were developed to determine potential needs, and to compare demand and supply, water usage, lack of water use, and population coverage. The enhanced stormwater drainage system for Coimbatore city was designed in such a way that the various roads were connected to the major water bodies. The domestic water demand in the future is predicted to be around 27 million cubic feet (MCFT). Meanwhile, the possible amount of stormwater collected in the selected water bodies is predicted to be 50 million cubic meter (MCM) to 320 MCM. This study concluded that 100% of urban domestic water demand can be met if the urban stormwater is utilized by harvesting and storing in surface water bodies.

Циркуляція антибіотикорезистентних ізолятів бактерій родини Enterobacteriaceae у системі людина – водні екосистеми

The rapid development of resistance of microorganisms to antimicrobial drugs has led to the spread of antibiotic-resistant bacteria and their genetic determinants of resistance in the environment. It has led to the emergence of a new threat to human health, the precondition of which is the entry of resistance genes to the human body through the food chain. Modern systems of treatment plants are not capable of complete purification of water from genetic determinants, the largest source of which is known to be hospital effluents and domestic wastewater. In the context of this problem, the study of the influence of ecological resist on the development of antibiotic resistance in the human body becomes very important. The purpose of the study was to determine the relationships between the migration of antibiotic-resistant microorganisms in the system human-aquatic ecosystem. Materials and methods. To achieve the purpose, a number of microbiological studies were performed, which included the isolation of microbial isolates from water samples of the Uzh River (Ukraine), surface waters of which are a source of drinking and domestic water supply, and clinical samples from the oral cavity of patients with inflammatory periodontal diseases. Identified isolates were tested for sensitivity to antibiotics of different groups. Results and discussion. During the research experiment, bacteria of the Enterobacteriaceae family were isolated from the oral cavity of 64 patients with inflammatory diseases of periodontal tissues, the species diversity of which was represented by the following species: Escherihia coli, Enterobacter cloacae, Citrobacter freundii, Klebsiella rhinoskleromatis, Hafnia alvei. According to the study, members of the Enterobacteriaceae family isolated from water samples showed significant resistance to antibiotics of natural origin, such as tetracycline, amipicillin and gentamicin, as well as to beta-lactams and second-generation macrolides. Conclusion. According to the results of the study, the samples of water and oral cavity were dominated by the same spectrum of gram-negative microorganisms belonging to the genera Enterobacter, Citrobacter, Escherichia and characterized by a high degree of resistance to tetracyclines, macrolides and unprotected beta-lactam antibiotics. The formation of such an antibiotic resistance in ecological and clinical samples may indicate probable migration routes of antibiotic-resistant microorganisms and genetic determinants of stability in the system human-aquatic ecosystem. There is a need for further research to study the prevalence of antibiotic-resistant microorganisms in the environment and the development of appropriate regulations governing the conduct of sanitary and epidemiological control over the spread of microorganisms with multiple resistance in the environment

Effect of seasonal variation on the occurrences of high-risk pharmaceutical in drain-laden surface water: A risk analysis of Yamuna River

The occurrence of pharmaceutical residues in the aquatic ecosystem is an emerging concern of environmentalists. This study primarily investigated the seasonal variation of high-priority pharmaceutical residues in the Yamuna River, accompanied by 22 drains discharge from different parts of Delhi. Five sampling sites were selected for analyzing high-priority pharmaceuticals along with physico-chemical and biological parameters for 3 season's viz. pre-monsoon (PrM), monsoon (DuM), and post-monsoon (PoM), respectively. The maximum occurrences were detected during the PoM, compared to the PrM and DuM seasons. The maximum concentration of BOD, COD, and Phosphate was detected at the last sampling station (SP-5). Similarly, all targeted pharmaceuticals concentration were maximum at the last sampling point i.e. Okhla barrage (SP-5, max: DIC = 556.1 ng/l, IBU = 223.4 ng/l, CAR = 183.1 ng/l, DIA = 457.8 ng/l, OFL = 1726.5 ng/l, FRU = 312.2 ng/l and SIM = 414.9 ng/l) except at Barapulla downstream (SP-4, max: ERY = 178.1 ng/l). The mean concentrations of Fecal coliform (FC) ranged from 1700 to 6500 CFU/100 ml. The maximum colonies were detected in PrM season (6500 CFU/100 ml) followed by PoM (5800 CFU/100 ml) and least in DuM (1700 CFU/100 ml). Risk quotient (RQ) analysis of high-priority pharmaceuticals indicated high ecotoxicological risks exposure (>1) from DIC, DIA, OFL, and SIM in all seasons at all the sampling sites. However, lower risk was predicted for IBU, CAR, ERY, and FRU, respectively. This risk assessment indicated an aquatic ecosystem potentially exposed to high risks from these pharmaceutical residues. Moreover, seasonal agricultural application, rainfall, and temperature could influence the levels and compositions of pharmaceutical residue in the aquatic ecosystem. Hence, attention is required particularly to this stream since it is only a local lifeline source for urban consumers for domestic water supply and farmers for cultivation.

INVESTIGATIONS OF PEOPLE PERCEPTION ON DOMESTIC WATER SUPPLY SITUATIONS IN KANO METROPOLIS NORTHWESTERN, NIGERIA

The problem of portable water supply has become an issue of global concerned as governments all over the world are trying to make house-holds water accessible to all as easier as possible to meet the challenges for sustainable development goals. This research has been conducted to determine the people’s perception on domestic water supply situation in Kano metropolis, Northwestern Nigeria. A self-designed questionnaire developed and distributed to the subjects using stratified sampling technique, and the data obtained has been presented in frequency and percentage. The results obtained revealed that, there is a scarcity of portable water supply to households in Kano metropolis. The problem emanated from lack of pipe-borne water which necessitated the dependence of the house-holds water supply on vendors that obtained water from boreholes and some hand-dug wells lacking proper hygienic practices. More so, the respondents were willing to pay for pipe borne water delivery, yet, they depend on vendors as their major water suppliers as alternatives. The unhygienic practices of the vendors and water sources posed threat to public health concerned.

Assessment of morphometric changes in Lake Hawassa by using surface and bathymetric maps

Study regionLake Hawassa, Ethiopian Rift Valley, Southern Region, Ethiopia. Study focusLake Hawassa is one of the major Ethiopian Rift Valley Lakes with an endorheic basin system located near Hawassa town. The Lake water is vital to the surrounding communities for irrigation, domestic water supply, recreation, and fish harvesting. The morphological changes due to flood water from the surrounding agricultural areas were noticed and the water quality deteriorates which will be reflecting the agricultural productivity in the region and negatively impacted the socio-economic development. The lake morphometric changes were investigated by using cartographic ArcGIS mapping and bathymetric mapping and during the analysis, the thermal Infrared data of Landsat ™ was used in the digital elevation model (30 × 30 m) and Google Earth Engine (GEE) platform. The morphometric changes for a period of 46 years were considered in this study. The Secchi discs and echo-sounder were used to during the preparation of bathymetric maps and kriging interpolation was used for the water depth assessment of the lake. New hydrological insights for the LakeThe surface area of the Lake increased by 11.28 % from 1973 to 2019. The depth and volume decreased by 33.04 % and 25.32 %, respectively over the same period. The observed Secchi disc depth was 2.06 m. It was found that the increased surface area due to sedimentation and eutrophication in the Lake.

Performance study of split type ground source heat pump systems combining with solar photovoltaic-thermal modules for rural households in North China

Ground source heat pump systems are gradually accepted and used for space heating in winter and air-conditioning in summer for rural households in North China. To keep geothermal equilibrium,a split type ground source heat pump system combining with solar photovoltaic-thermal (STGSHP-PV/T) simulation model is established. The operating performance of the STGSHP-PV/T system has been investigated. Results show that the coefficient of performance (COP) of heat pump units during the heating and cooling period is 3.53 and 2.81, respectively. Except providing spacing heating and cooling for separated rural households, the system offers other accessibility options including power generation and domestic hot water supply. During the operation of STGSHP-PV/T system, thePV panel temperature maintains at a relatively lower operating temperature and higher PV efficiency. The comprehensive performance coefficient of PV/T component is about 66%, and the power generated by PV/T module is greater than that consumed by heat pump units by approximately 1278.1 kWh, which can achieve zero-energy buildings during the whole year. Moreover, the average soil temperature increases gradually under the long term operation of the STGSHP-PV/T system, and the increase rate is 0.12 to 0.26 °C per year, within an acceptable range.

WATER VENDORS PARTICIPATION IN DOMESTIC WATER SUPPLY IN UNGUWA UKU, TARAUNI LOCAL GOVERNMENT, KANO STATE, NIGERIA

Water vending is seen as a signing of a failure in piped-borne water supply systems, it still plays significant role in providing water especially to urban dwellers in many parts of developing countries, Nigeria inclusive. Therefore, this study examined water vendors participation in domestic water supply in Unguwa Uku, Tarauni LGA Kano state. The data used in this research collected from both primary and secondary sources. The data collected was analyzed using descriptive statistics, where simple percentages and tables used. The data analysis revealed that 57.4% of the residents in the study area patronized the services of water vendors. Patronage of vendor service dominated the frequency with 64.9% of respondent’s patronage of vended water. Seasonal variation in vended water supply patterns exist in the study area, with dry season account for the highest water demand and most supplies occurred during morning and evening hours. Based on the challenges bedevilled water-vending activities, the study recommends that vendors should be recognized as an integral part of the system as this may help in the design and implementation of more comprehensive policies that better serve poor end-users, by ensuring greater accessibility and affordability of water vendor’s service.

Assessment of Urban Domestic Water Demand and Supply in Edo North, Nigeria

An exponential increase in the global population has seriously put pressure on land and water resources. It is projected that 33% of the worldwide people will be highly water-stressed by the 2050s if effective strategies are not developed. The study assessed urban domestic water demand and supply in Edo North senatorial district in Edo State, Nigeria. This is with the view of exploring some critical water resource variables to determine water security, distribution, and accessibility of safe drinking water in Edo North in Edo State in Nigeria. Integrated Water Resource Management Tools (IWRT) such as Water Poverty Index (WPI) and Water Accessibility Indicator (WAI) was applied. The results show that Auchi is highly water-stressed at the Estako-west area with MPI and WAI values of 0.24 and 0.33. Conversely, Okpella and Agenebode in Eskako central have MPI and WAI values 0.34 and 0.31, and 0.31 and 0.32. Sabo Gida Ora and Isobe in Owan East and West have better safe drinking water coverage and accessibility with the indicator values of 0.54, 0.53 [WPI], and 0.61 and 0.59 [WAI]. It is generally observed that the supply of potable water in the Edo North is highly unsecured and unsustainable to meet the current and future demand. Valuable and economic time is wasted to gather water from an average closest distance of 1.3 km from home to some designated water taps. In conclusion, it is imperative to design a robust integrated water policy that should include Private-Public-Partnership (PPP) to invest in the provision of safe drinking water.

Assessment of Urban Domestic Water Demand and Supply in Edo North, Nigeria

An exponential increase in the global population has seriously put pressure on land and water resources. It is projected that 33% of the worldwide people will be highly water-stressed by the 2050s if effective strategies are not developed. The study assessed urban domestic water demand and supply in Edo North senatorial district in Edo State, Nigeria. This is with the view of exploring some critical water resource variables to determine water security, distribution, and accessibility of safe drinking water in Edo North in Edo State in Nigeria. Integrated Water Resource Management Tools (IWRT) such as Water Poverty Index (WPI) and Water Accessibility Indicator (WAI) was applied. The results show that Auchi is highly water-stressed at the Estako-west area with MPI and WAI values of 0.24 and 0.33. Conversely, Okpella and Agenebode in Eskako central have MPI and WAI values 0.34 and 0.31, and 0.31 and 0.32. Sabo Gida Ora and Isobe in Owan East and West have better safe drinking water coverage and accessibility with the indicator values of 0.54, 0.53 [WPI], and 0.61 and 0.59 [WAI]. It is generally observed that the supply of potable water in the Edo North is highly unsecured and unsustainable to meet the current and future demand. Valuable and economic time is wasted to gather water from an average closest distance of 1.3 km from home to some designated water taps. In conclusion, it is imperative to design a robust integrated water policy that should include Private-Public-Partnership (PPP) to invest in the provision of safe drinking water.

Bacteriological and Physicochemical Quality of Mono-pumps and Boreholes used as Sources of Domestic Water Supply in Abonnema Rivers State, Nigeria

Aim: This study was carried out to compare the bacteriological and physicochemical qualities of boreholes and mono-pumps water samples used as sources of domestic water supply, in Abonnema Community, Akuku-Toru Local Government Area, Rivers State.
 Methodology: A total of forty-eight water samples were collected twice monthly for four months and evaluated. The bacteriological parameters such as total heterotrophic bacterial, total coliform, faecal coliform, Vibrio, Salmonella - Shigella and Pseudomonas were analyzed using standard microbiological methods. The coliform was determined using the Most Probable number technique while, the physicochemical parameters were determined using Standard methods for the examination of water and wastewater.
 Results: The total heterotrophic bacterial, coliform, faecal coliform, Vibrio, Salmonella-Shigella and Pseudomonas counts of the borehole samples ranged from 7.2×102 - 2.4×103, 2.3×102–4.0×102, 3.6×102-4.8×102, 7.3×102-1.4×103, 2.1×102-2.8×102 and 0.0×100Cfu/ml, respectively. The total heterotrophic bacterial counts, coliform counts, faecal coliform counts, Vibrio counts, Salmonella-Shigella counts and Pseudomonas counts for the mono-pump samples ranged from: 1.1×103- 1.8×103, 2.0×102– 9.1×102, 2.4×102- 3.8×102, 4.5×102-8.6×102, 1.4×102 - 4.2×102 and 0.0×100Cfu/ml, respectively. The bacterial genera identified were: Bacillus, Lynsinibacillus, Staphylococcus, Vibrio, Serratia, Enterobacter, Klebsiella, Shigella, Salmonella, Paenibacillus, Aeromonas and Geobacillus. The means of physicochemical parameters for borehole and mono-pump, respectively were: alkalinity: 41.72±0.01-60.85±0.20 and 29.14±0.01-214.87±1.36mg/l; BOD: 8.26±0.01-10.44±0.0 and 5.12±0.01-5.79±0.01; COD: 126.52±0.01-172.41±0.04 and 83.20±0.44-218.00±0.57; DO: 6.31±0.01 and 3.05±0.07-8.29±0.01; calcium: 5.10±0.28-; 4.83±0.00-10.15±0.00 and 2.71±0.00-14.04±0.00; iron: 2.01±0.00-3.37±0.00 and 1.90±0.00-4.73±0.00; lead: 0.38±0.00-1.07±0.00 and 1.24±0.00-1.63±0.00; nitrate: 0.42±0.00-1.08±0.00 and 1.14±0.00-1.75±0.00; zinc:1.10±0.00-3.18±0.00 and 0.39±0.00-1.82±0.00; phosphate: 0.03±0.00-0.13±0.00 and 0.15±0.00-0.87±0.00; pH: 6.54±0.00-7.05±0.07 and 6.29±0.00-6.93±0.01; salinity: 4.02±0.00-5.14±0.00 and 2.83±0.00-5.88±0.00; total organic carbon: 1.39±0.01-2.81±0.010 and 1.64±0.00-3.42±0.01; polycyclic aromatic hydrocarbon: 32.69±0.00-55.73±0.00 and 45.10±0.00-61.49±0.00mg/l; total petroleum hydrocarbon:58.90±0.00-66.15±0.00 and 60.31±0.00-92.11±0.00 mg/l.
 Conclusion: The high counts of bacterial groups of public health importance identified from this study, including the presence of: COD, DO, Fe, Pb, Phosphate, Zinc, TPH and PAH in high concentrations reveals contamination of the water sources. Thus, treatment before drinking is recommended.

Hydrochemistry and Entropy-Based Groundwater Quality Assessment in the Suining Area, Southwestern China

Groundwater is an essential resource for sustainable development, whose quality is significant for human health. In the present study, twenty-eight groundwater samples were collected from domestic tube wells and public water supply wells in the Suining area, southwestern China. The integration of statistical analysis, correlations of ions, geomodelling, and entropy-weighted water quality index (EWQI) was carried out to clarify the hydrochemistry and groundwater quality in the study area. By the statistical analysis, the cations followed the concentration order as Ca2+> Na+> Mg2+> K+, while anions’ concentrations were HCO3− > SO42− > Cl− > NO3− > F−. Piper trilinear diagram showed the hydrochemical type was characterized as Ca-HCO3. Correlations of ions and geomodelling revealed the concentrations of major ions were mainly determined by carbonate dissolution and ion exchange process, and NO3− concentrations were controlled by agriculture activities. EWQI computation demonstrated that most of the groundwater samples possessed EWQI values higher than 100. Therefore, groundwater quality is lower than the permissible limit of the World Health Organization (WHO), suitable for drinking purposes in the Suining area. Our study provides vital knowledge for groundwater management in the Suining and other similar areas.

Demand response potential of district heating in a swimming hall in Finland

In this paper, the demand response of district heating for swimming pools and pool space air is proposed and applied in a swimming hall in Finland. Swimming halls have significant heat demands e.g., domestic hot water supply, space heating and pool water heating, and thus have much large heat storage capacity for the realization of district-heat based demand response. A dynamic building simulation tool IDA ICE was used to simulate whole swimming hall including pools and HVAC systems. In addition, a rule-based demand response algorithm which utilized dynamic district heat price was proposed and applied in the district heating control of the studied swimming hall. The results show that the large storing capacity of pool water promises the large amount of charged and discharged heat energy, and ensure the application of demand response of district heating in swimming hall. The application of demand response of district heating can increase the average pool water temperature from the normal setpoint of 26.5 °C to 27.3 °C. In addition, demand-response district heating control for the swimming pool water and pool space air decreases the total district heat costs of the swimming hall by 1.1%. During the repayment periods of 7 and 15 years, the energy cost savings and maximum cost of profitable investment for the demand response control are between 10 000 € and 20 000 €.

Hybrid causal multivariate linear modelling (H_CMLM) method for the analysis of temporal rivers runoff

This paper describes the joint development of two different methods for temporal riveŕs runoff assessment. This is performed through a hybrid approach by means of Multivariate General Linear Models (MGLM; inspired by MLR as a statistical method), and Causal Reasoning (CR; as non-linear ones). This innovative methodological approach, named Hybrid Causal Multivariate Linear Modelling (H-CMLM), is mainly aimed to empower the analysis of temporal hydrological records behaviour. H-CMLM has been successfully applied to three different Spanish basins (Adaja, Mijares and Porma) which were chosen due to their disparate features. Results were divided in quantitative and qualitative. Numerical results show a very high level of equivalence between the average value of temporal dependence provided by MLM module and the continuous behaviour of temporal dependence computed by CR module and visualized through Dependence Mitigation Graph (DMG). This high coherent outcome from both modules makes the analysis much more robust from a stochastic hydrology point of view. Values for average temporal dependence are very useful for the optimal dimensioning of hydraulic infrastructures like reservoirs. Furthermore, given the annual scale of the analysis, water planning and management of several water uses such as domestic water supply, agriculture, industrial demands, among others, can be highly assisted by this new H_C-MLM method.

Resiliencia en el agua doméstica en comunidades del río Sonora ante el derrame de 2014

Este estudio analiza los componentes de la resiliencia en el abastecimiento de agua doméstica de localidades del río Sonora ante el derrame minero de 2014: instituciones, sistemas y agentes. La metodología incluye entrevistas a encargados y usuarios del agua en tres localidades. Como resultados, en las instituciones locales del agua existe una mejor gestión con respecto a las estatales y federales. Con respecto a los sistemas de abastecimiento de agua, concluimos que estos son insuficientes o inexistentes. Por otra parte, los agentes a nivel local-comunitario tienen una diferenciada capacidad de gestión entre las localidades, pero similar en el nivel de hogares.

Meeting energy needs of low-income Sub-Saharan households with a Partially Hybridised Solar Technology (PHST): Experimental performance evaluation based on simulated solar radiation and demand profiles

Renewable energy technologies for sustainable development are rapidly attracting attention across many disciplines despite technical, economic, and social barriers that limit application beyond the laboratory. This study proposes novel semi-automated and automated domestic hot water and electricity demand simulation experiments to evaluate the performance of a proof-of-concept prototype under simulated solar conditions. The prototype is a Partially Hybridised Solar Technology (PHST) which integrates photovoltaic (PV) and low-temperature solar thermal technology for low-cost electricity and domestic hot water supply. The domestic hot water and electrical demand profiles, and the solar radiation utilised during the study represent typical conditions of off-grid households in Sub-Saharan Africa. The prototype delivered a thermal energy supply potential of 2,073±75kJ per day at an average solar thermal conversion efficiency of 29.4±1.0%. The average yield of Direct Current (DC) electricity was 273 Wh per day at a corresponding PV module efficiency of 12.1% but depended on the type of charge controller. These results provide essential baselines for future computer modelling work and techno-economic predictions for Sub-Saharan Africa. The study has important future implications to test standards guiding laboratory-based evaluation of Solar Home Systems (SHSs) for electricity and domestic hot water.

Estimation of the influence of deicing materials influence on single-cell organisms: a case study of Tetrahymena pyriformis

Introduction. Deicing materials (DIM) have technical recommendations for the application to ensure road safety. However, they do not have shared values governing their permissible levels for environmental objects and public health. There are no guidelines for assessing their toxic properties either. The research shows that to solve practical goals, it is necessary to scientifically substantiate the methodology of hygienic assessment of DIMs as a separate group of substances, taking into account their effective concentrations bio testing methods. DIM are saline solutions, and therefore it is worth considering a cell or a unicellular organism as a model to predict their effect on biological objects. However, the methodology for assessing environmental objects’ toxicity using Tetrahymena pyriformis ciliates has been approved only for domestic water supply. The purpose of this study is to update the methodology for determining the toxicity of DIM solutions by the generative function of Tetrahymena pyriformis ciliates. It considers the high salt content appropriate within the framework of a comprehensive hygienic assessment of reagents. Materials and methods. The research made an ecotoxicological assessment of 2 deicing materials with different ratios of chlorides of alkali and alkaline-earth metals and evaluating the same reagents’ actual chemical composition using inductively coupled plasma mass spectrometry (ICP-MS) and ion chromatography. Results. The obtained data indicated less pronounced toxicity of DIM with increased content of calcium ions. The permissible levels of DIM influence on the studied test object have been determined. A control comparison sample is provided. Conclusion. The obtained results specify the need to expand the list of controlled indices in the existing methodology. To assess the toxicity of saline solutions using ciliates, the substantial additions must include studying the morphology of cells in the acute experiment (6 hours), in case of their death within the first hour; it is necessary to control their secondary appearance.

Water quality as one of the criteria for the comprehensive assessment of the safety of dairy products

Improving the safety of dairy products is one of the tasks of ensuring comprehensive food safety. The analysis of water from 4 systems of centralized domestic drinking water supply was carried out in terms of quality indicators, as well as the degree of water pollution with heavy metals and chloro-organic pesticides. It has been established that a significant level of water pollution with iron, lead and cadmium compounds exceeds the MPC by 10.6, 1.3 and 3.0, respectively, and organochlorine pesticides by 24.3 times. The research results show the need for additional water purification used in the production of dairy products.

Harmful Algal Blooms in Aquaculture Systems in Ngerengere Catchment, Morogoro, Tanzania: Stakeholder's Experiences and Perception.

The aquaculture sector has experienced fast growth as a result of livelihood diversification initiatives among small-scale farmers in Tanzania. Regrettably, the dynamics of harmful algal blooms (HABs) have been overlooked despite the noticeable forcing of climate variability, the interaction between social-economic activities, and domestic water supply reservoirs. This study aimed at surveying the occurrence, experiences, and perceptions of HABs in aquaculture systems from stakeholders in the Ngerengere catchment, Morogoro, Tanzania. A cross-sectional survey focus group discussion (FDG), key informant interviews, and anecdotal observation were adopted. A convenient and purposive sample population was drawn from pond owners, registered water users, and government officials in the catchment. For data analysis, descriptive statistics and constant comparison were performed. Most respondents (95%) were able to recognize the image of blooms displayed. Approximately 70% of the respondents agreed that water quality has deteriorated over time, and blooms occur during the dry season. Further, 60% of the respondents agreed that water pollution is a serious problem attributed to sources other than industrial discharge. There was no consensus regarding the health impacts associated with HABs. Raising awareness on HABs is of paramount importance as it will provide the basis for the development of HABs management framework and health risk assessment.