Search Results (40)

The unprecedented development of coastal cities in West Africa is marked by anarchic urbanization accompanied by ineffective environmental management, leading to water pollution. This study is conducted in the southern districts of Lomé, Togo, an area built on sandbars where inappropriate attitudes, behaviors, and inadequate hygiene and sanitation practices prevail. The objective of this study is to characterize the quality of groundwater in the study area. Bacteriological and physicochemical analyses were carried out on 11 wells in 10 districts in the southern districts during the four seasons of the year. The analysis shows that the groundwater is polluted in all seasons. Nitrate concentrations exceed 50 mg/L in 65% of the samples, while chloride levels surpassed 250 mg/L in 18% of the cases. Regardless of the season, the dominant facies is sodium chloride and potassium chloride. In all districts, the analysis of microbiological parameters including total germs (30 °C, 100/mL), total coliforms (30 °C, 0/mL), Escherichia coli (44 °C, 2/250 mL), fecal streptococci (0/100 mL), and anaerobic sulfite reducers (44 °C, 2/20 mL) reveals values exceeding the European Union standards (2007). Groundwater contamination is facilitated by the sandy nature of the soil, which increases its vulnerability to various pollutants. Togo continues to experience cholera outbreaks, aggravated by poor sanitation infrastructure and limited vaccination coverage. Public health efforts are directed toward improving sanitation and raising awareness about waterborne and non-communicable diseases. Full article

Bacteriological water quality monitoring is of utmost importance for safeguarding public health against waterborne diseases. Traditional methods such as membrane filtration (MF), multiple tube fermentation (MTF), and enzyme-based assays are effective in detecting fecal contamination indicators, but their time-consuming nature and reliance on specialized equipment and personnel pose significant limitations. This paper introduces a novel, portable, and cost-effective UV-LED/RGB water quality sensor that overcomes these challenges. The system is composed of a multi-well self-loading microfluidic device for sample-preparation-free analysis, RGB sensors for data acquisition, UV-LEDs for excitation, and a portable incubation system. Commercially available defined substrate technology, most probable number (MPN) analysis, and machine learning (ML) are combined for the real-time monitoring of bacteria colony-forming units (CFU) in a water sample. Fluorescence signals from individual wells are captured by the RGB sensors and analyzed using Multilayer Perceptron Neural Network (MLPNN) and Support Vector Machine (SVM) algorithms, which can quickly determine if individual wells will be positive or negative by the end of a 24 h period. The novel combination of ML and MPN analysis was shown to predict in 30 min the bacterial concentration of a water sample with a minimum prediction accuracy of 84%. Full article

Although climate warming-induced snow cover reduction, as well as the development of ski tourism in hot and dry countries, is shifting industries toward the use of technical snowmaking, its use raises hydrological, health-related, and environmental concerns. This study was aimed at enhancing our current understanding of the impact of technical snowmaking on the environment and human health. Culturable bacteriological indicators of water quality (Escherichia coli, fecal enterococci, Salmonella, and Staphylococcus), the presence and concentration of antimicrobials, genes determining bacterial antibiotic resistance (ARGs), and next-generation sequencing-based bacterial community composition and diversity were examined from river water, technological reservoirs, and technical snow from five ski resorts. The number of culturable bacteria and prevalence of most ARGs decreased during snowmaking. The concentration of antimicrobial agents changed irregularly, e.g., ofloxacin and erythromycin dropped in the snowmaking process, while cefoxitin was quantified only in technical snow. The bacterial community composition and diversity were altered through the technical snowmaking process, resulting in the survivability of freezing temperatures or the presence of antimicrobial agents. Water storage in reservoirs prior to snowmaking allows us to reduce bacterial and ARG contaminants. Frequent and thorough cleaning of snowmaking devices may aid in reducing the negative impact snowmaking can have on the environment by reducing contaminant input and limiting the disturbance of the ecological balance. Full article

This study highlights the importance of distinguishing the mechanisms driving spatial and temporal variances in groundwater database analyses, with a particular focus on bacteriological contamination processes. Groundwater quality data from the Bourgogne-Franche-Comté region of France forms the basis of this investigation. Specifically, the SISE-EAUX database includes 3569 groundwater samples collected over various dates from 989 monitoring points. The methodology involves structuring the data into three distinct sets: (1) A spatio-temporal dataset without any conditioning; (2) A spatial dataset that assigns the mean values of each parameter to each sampling point; (3) A temporal dataset that captures deviations from the mean for each sampling point and parameter. These datasets enable a separate analysis of spatial and temporal variances. Principal component analysis (PCA) and parameter hierarchical clustering were used to compare the results, yielding valuable insights into the underlying processes. This analysis helps distinguish between factors related to geological or pedological spatial distributions and those associated with climatic events, such as intense rainfall episodes exhibiting seasonal patterns. Such differentiation enhances the understanding of fecal contamination vectors and nitrate pollution, which are often linked to surface and subsurface runoff in vulnerable catchment areas. While conceptually clear, the practical separation of spatial and temporal variability presents challenges. For example, catchments sensitive to surface water inflows during rainfall events are unevenly distributed across the region, correlating with specific natural environments. As a result, areas of high temporal variability are also well-structured spatially, underscoring the interdependence of these two types of variability. This complexity is exemplified by the behavior of iron, which varies in association with surface and subsurface parameters depending on spatial and temporal contexts. Additionally, asynchronous sampling and varying frequencies across sites lead to discrepancies in the average temporal data acquisition between points. These disparities can influence spatial variability calculations, as temporal variability effects are not entirely removed. Despite these challenges, the distinction between spatial and temporal components is essential for a deeper understanding of groundwater quality mechanisms. This refined approach improves diagnostic precision and supports more targeted and effective water resource management strategies. Full article

Groundwater, widely used for supplying drinking water to populations, is a vital resource that must be managed sustainably, which requires a thorough understanding of its diverse physico-chemical and bacteriological characteristics. This study, based on a 27-year extraction from the Sise-Eaux database (1993–2020), focused on the island of Corsica (72,000 km²), which is diverse in terms of altitude and slopes and features a strong lithological contrast between crystalline Corsica and metamorphic and sedimentary Corsica. Following logarithmic conditioning of the data (662 water catchments, 2830 samples, and 15 parameters) and distinguishing between spatial and spatiotemporal variances, a principal component analysis was conducted to achieve dimensionality reduction and to identify the processes driving water diversity. In addition, the spatial structure of the parameters was studied. The analysis notably distinguishes a seasonal determinism for bacterial contamination (rain, runoff, bacterial transport, and contamination of catchments) and a more strictly spatial determinism (geographic, lithological, and land use factors). The behavior of each parameter allowed for their classification into seven distinct groups based on their average coordinates on the factorial axes, accounting for 95% of the dataset’s total variance. Several strategies can be considered for the inventory and mapping of groundwater, namely, (1) establishing quality parameter distribution maps, (2) dimensionality reduction through principal component analysis followed by two sub-options: (2a) mapping factorial axes or (2b) establishing a typology of parameters based on their behavior and mapping a representative for each group. The advantages and disadvantages of each of these strategies are discussed. Full article

Surface water quality in Skardu, Gilgit-Baltistan, Pakistan, is of immense importance because of the city’s dependence on these resources for domestic uses, agriculture, and drinking water. The water quality index (WQI) was integrated with the Geographic Information System (GIS) to spatially envision and examine water quality data to facilitate the identification of pollution hotspots, trend analysis, and knowledge-based decision-making for effective water resource management. This study aims to evaluate the physiochemical and bacteriological parameters of the Satpara watershed and to provide the spatial distribution of these parameters. This study endeavors to achieve Sustainable Development Goal 6 (SDG 6) by identifying localities with excellent and unfit water for drinking, sanitation, and hygiene. A total of fifty-one surface water samples were collected from various parts of the Satpara watershed during the fall season of 2023. Well-established laboratory techniques were used to investigate water for parameters like Electrical Conductivity (EC), pH, turbidity, total dissolved solids (TDSs), major cations (${\mathrm{K}}^{+}$, ${\mathrm{Na}}^{+}$, ${\mathrm{Mg}}^{2+}$, ${\mathrm{Ca}}^{2+}$), major anions (${\mathrm{Cl}}^{-}$, ${\mathrm{SO}}_4^{2-}$, ${\mathrm{NO}}_3^{-}$, ${\mathrm{HCO}}_3^{-}$), and bacteriological contaminants (E. coli). Spatial distribution maps of all these parameters were created using the Inverse Distance Weighted (IDW) technique in a GIS environment. A significant variation in the quality of water was observed along the study area. The level of Escherichia coli (E. coli) contamination is above the permissible limit at various locations along the watershed, making water unsafe for direct human consumption in these areas. Some regions showed low TDS values, which could adversely affect human health and agricultural yield. From the WQI valuation, 58.82% of the collected samples were “Poor”, 31.8% were “Very poor” and 9.8% were found to be “Unfit for drinking”. The research findings emphasize the pressing need for consistent monitoring and adoption of water management strategies in Skardu City to warrant sustainable soil and water use. The spatial maps generated for various parameters and the water quality index WQI offer critical insights for targeted intercessions. Full article

Groundwater is becoming increasingly important as surface water is decreasing and becoming more and more polluted. In particular, rural areas in the arid region of Central Asia face problems with both water quantity and quality. In view of this, we investigated the drinking water quality in the Maysky district in the Pavlodar region, Kazakhstan. The organoleptic properties, together with microbiological indicators, as well as organic and inorganic substances of drinking water before and after treatment, and tap water were studied and compared to recommended levels. The bacteriological indicators of the drinking water, especially, showed that the water represents health risks since the presence of bacteria of the genus Pseudomonas aeruginosa was confirmed. Water treatment reduced the total microbial count (TMC) indicator by 3.6 times. However, TMC still exceeded permissible levels in the tap water, indicating that the drinking water is sanitary and epidemiologically not acceptable. Pathogenic contamination of drinking water can severely affect weaker individuals and children. It has been estimated that the infant mortality rate in Kazakhstan is six times higher as compared to the EU and less than 30% of Kazakhstan’s population have access to safe water. Also, 50% of the population drink water that does not comply with the international standards, e.g., bacteriological levels. Thus, it is important to continuously monitor the groundwater quality to minimize health risks and work towards access to safe drinking water, in line with the UN SDGs. Full article

Groundwater, a vital resource for providing drinking water to populations, must be managed sustainably to ensure its availability and quality. This study aims to assess the groundwater quality in the Bourgogne-Franche-Comté region (~50,000 km²) of France and identify the processes responsible for its variability. Data were extracted from the Sise-Eaux database, resulting in an initial sparse matrix comprising 8723 samples and over 100 bacteriological and physicochemical parameters. From this, a refined full matrix of 3569 samples and 22 key parameters was selected. The data underwent logarithmic transformation before applying principal component analysis (PCA) to reduce the dimensionality of the dataset. The analysis of the spatial structure, using both raw and directional variograms, revealed a categorization of parameters, grouping major ions according to the regional lithology. Bacteriological criteria (Escherichia coli and Enterococcus) displayed strong spatial variability over short distances, whereas iron (Fe) and nitrates showed intermediate spatial characteristics between bacteriology and major ions. The PCA allowed the creation of synthetic maps, with the first seven capturing 80% of the information contained in the database, effectively replacing the individual parameter maps. These synthetic maps highlighted the different processes driving the spatial variations in each quality criterion. On a regional scale, the variations in fecal contamination were found to be multifactorial, with significant influences captured by the first four principal components. The 22 parameters can be grouped into six categories based on their spatial and temporal variations, allowing for the redefinition of a resource management and monitoring strategy that is adapted to the identified spatial patterns and processes at the regional scale, while also reducing analytical costs. Full article

Cryptosporidium and Giardia are infectious parasitic forms widely distributed in aquatic ecosystems and resistant to disinfection of drinking water. Their presence was investigated in the lower areas of the city’s four rivers through a four-stage methodology. Between December 2017 and April 2018, three monitoring campaigns were conducted, with results ranging between not detected to 500 oocysts/L for Cryptosporidium, and between not detected and 300 for Giardia. Cryptosporidium was more abundant, especially in the Machángara River. In the same period, the bacteriological quality of the rivers was also reviewed using Total Streptococci and Fecal Enterococci expressed in colony-forming units (CFU)/100 mL as indicators. The results showed a progressive increase in pollution as the course of the rivers progressed. The sensitivity of bacterial indicators to changes in quality is also observed, which is why their use in specific studies is recommended. It is concluded that untreated domestic wastewater discharges may be the main source of contamination by bacteria and parasites and that there is a relationship between their concentration and the seasonal period. In dry weather, the concentration is higher for both microorganisms. This study fills a gap in knowledge in the region, due to the absence of data on parasitic indicators with great impacts on public health. Full article

Access to safe drinking water remains a fundamental issue in rural areas of Ethiopia. This study aimed to evaluate the physicochemical and bacteriological quality of drinking water at protected sources in the Farta district, South Gondar Zone, Ethiopia. The study covered 16 rural Kebeles and was conducted on 75 protected dug wells with hand pumps (HDWs) and 17 protected springs (PSs). Data were collected during the wet and dry season, and field measurement were conducted on water samples pH, turbidity, electrical conductivity, and temperature, while laboratory analysis focused on E. coli prevalence. Additionally, sanitary risk assessment was also performed. The result showed that, the pH values ranged from 5.4 to 8.1, turbidity levels varied between 0 to 100 nephelometric turbidity unit (NTU), electric conductivity ranged from 62 to 584 µS/cm, and temperature ranged from 12.1 to 27 °C. Among all the samples, 39.1% had a pH below the minimum standard value of 6.5, close to 50.5% did not meet the turbidity requirement (5NTU), and all samples were safe against electric conductivity levels. The E. coli contamination was widespread, and only a small percentage of water sources, such as 21.7% HDWs, 6.7% PSs during dry season, and 13% HDWs during wet season were negative to E. coli detection. A significant proportion of water sources, such as 18% HDWs and 13% PSs during dry season, as well as 44.9% HDWs and 46.7% PSs during wet season, fell into the high microbial health risk category. Sanitary inspections revealed that only 16.7% of water sources were classified as low sanitary risk. This study revealed that majority of water sources were unfit to drinking and may endanger the public health. To ensure safe water availability frequent cleaning and disinfection of water sources, implementation of household water treatment, and improvement of WASH (water, sanitation and hygiene) infrastructure is needed. Full article

The Salmonella enterica serovars Typhimurium (S. Typhimurium), Heidelberg (S. Heidelberg), and their monophasic variants (S. 1,4,[5],12:i:-, S. 1,4,[5],12:r:- and S. 1,4,[5],12:-:1,2) are highly disseminated in poultry farming and can contaminate chicken meat, eggs, and other foods of avian origin. A time-consuming bacteriological and serological analysis is usually required to identify serovars by traditional methods. Incomplete and inconclusive serological results are frequent in routine analysis, mainly due to the occurrence of bacterial isolates presenting similar antigenic profiles. Molecular biology assays have been developed to improve the detection of specific Salmonella serovars and strains. This study aimed to develop a multiplex real-time PCR (SHTAmp) for the rapid DNA detection of S. Typhimurium, S. Heidelberg, and their monophasic variants from poultry samples. The methodology was used in the analysis of 147 field isolates from Brazilian poultry flocks previously evaluated with serological analysis. The results demonstrated that it was able to specifically and rapidly detect 21 S. Typhimurium and 57 S. Heidelberg isolates with complete antigenic formulae. Furthermore, SHTAmp was able to differentiate nine S. Typhimurium and 44 S. Heidelberg isolates with incomplete serological formulae (monophasic and aphasic variants). The complete methodology was also successfully used to detect these bacteria directly from 34 poultry samples after pre-enrichment in buffered peptone water (BPW). In conclusion, SHTAmp is a fast and accurate method to detect the two frequent and concerning serovars S. Typhimurium and S. Heidelberg directly from poultry samples. Full article

Bivalves can concentrate biological and chemical pollutants, causing foodborne outbreaks whose occurrence is increasing, due to climatic and anthropic factors that are difficult to reverse, hence the need for improved surveillance. This study aimed to evaluate the hygienic qualities of bivalves sampled along the production and distribution chain in Sicily and collect useful data for consumer safety. Bacteriological and molecular analyses were performed on 254 samples of bivalves for the detection of enteropathogenic Vibrio, Arcobacter spp., Aeromonas spp., Salmonella spp., and beta-glucuronidase-positive Escherichia coli. A total of 96 out of 254 samples, collected in the production areas, were processed for algal biotoxins and heavy metals detection. Bacterial and algal contaminations were also assessed for 21 samples of water from aquaculture implants. Vibrio spp., Arcobacter spp., Aeromonas hydrophila, Salmonella spp., and Escherichia coli were detected in 106/254, 79/254, 12/254, 16/254, and 95/254 molluscs, respectively. A total of 10/96 bivalves tested positive for algal biotoxins, and metals were under the legal limit. V. alginolyticus, A. butzleri, and E. coli were detected in 5, 3, and 3 water samples, respectively. Alexandrium minutum, Dinophysis acuminata, Lingulodinium polyedra, and Pseudonitzschia spp. were detected in water samples collected with the biotoxin-containing molluscs. Traces of yessotoxins were detected in molluscs from water samples containing the corresponding producing algae. Despite the strict regulation by the European Commission over shellfish supply chain monitoring, our analyses highlighted the need for efficiency improvement. Full article

This study evaluates the suitability of treated wastewater (TWW: secondary effluent and membrane effluent) for crop irrigation and the resultant impact on crop growth and soil physicochemical characteristics. Carrot seeds (Daucus carota subsp. sativus) were grown on loam soil and irrigated with tap water (Tap), secondary effluent (SE), and membrane effluent (ME) until maturity. Bacteriological analyses showed four log counts of E. coli and thermotolerant coliforms for secondary effluent, making it unsafe for the irrigation of carrots. Tap water and membrane effluent fulfilled the microbial limit for water reuse and were suitable for irrigation. The sodium absorption ratio, Kelly index, and magnesium hazard assessments indicated that all three irrigation water streams were suitable for irrigation. The average mass of carrot fruits for Tap, SE, and ME was 2.14 g, 3.96 g, and 3.03 g, respectively. A similar trend was observed for the dry matter composition: Tap had 15.9%, SE had 18.3%, and ME had 16.6%. The soil pH increased from 7.08 to 7.26, 7.39, and 7.33 for tap water-, secondary effluent-, and membrane effluent-irrigated soils, respectively. Nitrate-nitrogen and potassium levels increased in the TWW-irrigated soil, while that of the tap water-irrigated soil decreased. Sodium levels in the TWW-irrigated soil increased significantly but did not induce soil sodicity. The application of the TWW enhanced the growth of the carrot plants and increased the soil nutrient levels. Hence, using TWW in agricultural irrigation could promote food production and also limit the overdependency on freshwater resources. However, TWW should be disinfected by using UV disinfection and ozonation to reduce the risk of microbial contamination. Such disinfection methods may not lead to the formation of toxic byproducts, and therefore secondary pollution to crops is not anticipated. Full article

The aim of this work is to gain a better understanding of the diversity of groundwater resource quality in the Auvergne-Rhône-Alpes region (France) using the national Sise-Eaux database. Three matrices were extracted, which included a hollow matrix (approximately 120,000 observations and 21 variables) and two complete matrices (8078 observations with 13 variables each and 150 observations with 20 variables each, respectively). The mapping of these parameters, the chemical profiles of the water, and the characteristics of the variograms make it possible to estimate the importance of the temporal variance compared with the spatial variance. This distinction led to a typology separating 4 groups of chemical parameters and 2 groups of bacteriological parameters, highlighting the information redundancies linking several parameters. A PCA was used to considerably reduce the size of the hyperspace of the data. The study of the factorial axes combined with their distribution over the study area made it possible to discriminate and identify certain mechanisms for acquiring the physico-chemical and bacteriological characteristics of groundwater, the importance of lithology, the components of faecal contamination, and the role of environmental conditions. A typology of the parameters by hierarchical clustering on the major part of the information makes it possible to reduce the information to that carried by a few representative parameters. This work is a new step in understanding the diversity of groundwater resources in general, with a view to more targeted monitoring based on this diversity. Full article

Ouagadougou is a city with three million inhabitants and an increasing demand for water of sufficient quality. New boreholes are drilled to match demand, but their protection from anthropogenic contamination is insufficient. To assess the quality of urban groundwater in Ouagadougou for the first time, a total of 32 borehole water samples were collected and assessed for bacteriological and physicochemical features using established methods. Health risk inspections and hazard assessments were undertaken at sampling sites to identify potential hazards and contributing factors. Statistical analysis was used to identify associations between risk factors and water pollution. The study revealed poor quality of groundwater in Ouagadougou with major nonconformities related to total coliforms, Escherichia coli, and turbidity. Water samples from 19 boreholes (59%) were contaminated with coliforms, and 11 (34%) with E. coli. Additionally, Pseudomonas aeruginosa, Enterococcus, and anaerobic sulphite-reducing bacterial spores were detected. Deviations from physicochemical quality requirements were observed for water turbidity, pH, nitrate, fluorine, and iron. Risk analysis showed the major high-risk practices to be sludge spreading or having a garbage heap, a latrine, a septic tank, or dirty water near a borehole. Based on these results, for public health protection, authorities must take strict measures to prohibit such practices around these important sources of drinking water in Ouagadougou. Full article