Microbiological quality of water samples obtained from water sources in Ishaka, Uganda

Objectives

This study aimed to evaluate the microbiological quality of water sources in Ishaka division, Bushenyi district.

Methods

Water from taps, wells and springs were sampled for the cross-sectional investigation. The enumeration and identification of microbes (Escherichia coli, Salmonella, Shigella, Proteus, Staphylococcus aureus and total coliforms) in water samples were carried out using a variety of methods. Escherichia coli was enumerated using the membrane filtration method; Salmonella, Shigella and Proteus using a two-step enrichment method; Staphylococcus aureus using the surface spread method and total coliforms using the most probable number technique. Mannitol salt agar was used for enumeration of Staphylococcus Aureus and violet red bile agar was used for enumeration of total coliforms and Escherichia coli; xylose lysine deoxycholate agar was used for both Salmonella spp. and Shigella spp. API-20E was used to phenotypically identify the Enterobacteriaceae contaminants in water. These included Escherichia coli, Proteus mirabilis, Proteus vulgaris, Salmonella spp. and Staphylococcus aureus.

Results

Escherichia coli counts in the water from springs and wells ranged from 0 to 314 cfu/mL (p = 0.173) and 0 to 3 cfu/mL (p = 0.269), respectively, while tap water had no incidence of Escherichia coli. Highest level of bacterial contamination in water sources, beyond acceptable WHO (0 cfu/100 mL) limits for drinking water, was reported: Proteus spp., 34 (54.8%), followed by total coliforms, 24 (38.7%), Shigella spp., 22 (35.5%) and least were Salmonella spp. (8.1%) and Staphylococcus aureus spp. (8.1%).

Conclusion

It is therefore concluded that spring and well community water sources in Ishaka division, Uganda, are significantly contaminated with pathogenic bacteria and thus unsafe for drinking without adequate water treatment (disinfection and filtration).

Identification of Heavy Metals and Organic Micropollutants in Drinking Water Sources in Typical Villages and Towns in Northeast China

This study identified and detected the existence of major pollutants in northeast China. As an alpine region and an agricultural base, this region has representative significance in pollution research. We selected 56 samples from drinking water sources of typical villages and towns, focusing on the analysis of heavy metals and organic micropollutants in northeast China. The analysis results showed that Fe and Mn were the main metal elements exceeding the standard. The exceeding rates were 17.9% and 19.6%. Experiments showed that there were 19 kinds of pesticides, 6 kinds of OPEs, 2 kinds of PAEs, 22 kinds of PPCPs. The detection rate of these 49 kinds of organic micro-pollutants were 1.79~82.14%. The characteristics of organic pollution were extensive and varied. Many underground water samples had high level of micropollutants. The water quality parameters of drinking water sources in villages and towns showed close relation to local geological conditions and agricultural activities. Actions must be taken to control these parameters from the source of pollution.

Quality and Health Risk Assessment of Groundwaters in the Protected Area of Tisa River Basin

This study was conducted in order to assess the chemistry (41 metalloids and heavy metals and 16 physico-chemical indicators) of groundwater sampled from the protected area of the Tisa River Basin during the months of 2021. Pollution indices were used in order to determine the potential metal pollution level. Consequently, a non-carcinogenic risk assessment of metal through the ingestion of water was done. The results indicated general contamination with ammonium, chloride, iron, and manganese. The samples were rich in Cu, Mg, and Pb, but lower than the maximum limits. Significant correlations were noticed between Al-Fe, Mn-Fe, Mn-Ni, and Cr-Zn, as well as the metal content and pollution index scores. The metal pollution indices indicated three pollution levels (low, medium, and high) based on the metal content and standards regarding the water quality used for drinking purposes. The pollution indices scores ranged from 1.52-41.2. A human health risk assessment indicated no potential non-carcinogenic risk for the studied metals through the consumption of groundwater. The results of three different tools (chronic daily intake, hazard quotient, and hazard index) were below the critical value, except for the aluminium in two samples. This study is one of the first attempts to evaluate the quality of groundwater sources associated with the human health risks of the studied metals from the Tisa River Basin protected area. Based on this research, strategies for managing and controlling the risks can be developed.

Drinking natural water unchangeably is associated with reduced all-cause mortality in elderly people: A longitudinal prospective study from China

Objective

Because of rapid economic growth and followed urban expansion in China, many people drinking natural water had to change their water sources to tap water. We aimed to test the unknown association that whether continued use of natural water for drinking is different from switching to tap water in all-cause mortality risks in elderly people.

Methods

In total, based on Chinese Longitudinal Healthy Longevity Survey, 26,688 elderly participants drinking natural water from childhood to young-old were included in the final analyses. Associations between whether changing drinking water sources or not and all-cause mortality risk were then estimated by Cox regression models with the use of multiple propensity score methods, and the primary analysis used propensity score matching, with other propensity score methods confirming the robustness of the results.

Results

Baseline characteristics were fairly well balanced by the three post-randomization methods. During a median follow-up period of 3.00 (IQR: 1.52, 5.73) years, 21,379 deaths were recorded. The primary analysis showed people using natural water unchangeably was associated with a lower risk of all-cause mortality than those switching to tap water in later life (HR: 0.94, 95% CI: 0.91-0.97, p < 0.001). Other propensity score methods, as well as Cox regression analysis without using propensity score methods, showed similar results.

Conclusions

Among elderly people depending on natural water for drinking from their childhood to young-old in China, continued use of natural water was associated with a lower all-cause mortality risk than conversion to tap water later. Further studies in different countries and populations are needed to verify our conclusions.

[Spatiotemporal Distribution and Risk Assessment of Pharmaceuticals in Typical Drinking Water Sources in the Middle Reaches of the Yangtze River]

The seasonal variation and spatial distribution of pharmaceuticals in typical drinking water sources in the middle reaches of the Yangtze River were analyzed using the solid-phase extraction and high-performance liquid chromatography-tandem mass spectrometry methods. Combined with the risk entropy method, the corresponding ecological risks for aquatic organisms were evaluated. The results showed that 80% of the target pharmaceuticals were detected in the drinking water sources, with average concentrations of 0.07-13.00 ng·L^-1. The concentrations of the target pharmaceuticals were lower than or comparable with those in other drinking water sources reported in China. The spatiotemporal distribution of different pharmaceuticals varied. Generally, the detection level in winter was higher than that in summer, and there was no significant difference between that upstream and that downstream. This might be mainly attributed to seasonal/regional use and emissions of the pharmaceuticals, the impact of flow rate on dilution, and the impact of temperature on biodegradation. Compared with those before the COVID-19 epidemic, the detection concentrations of the target pharmaceuticals were relatively low. The reason for this might be that the prevention and control of the epidemic reduced the use and emission of the pharmaceuticals to a certain extent, and the high rainfall and runoff strengthened the dilution of water flow. The target pharmaceuticals, especially antibiotics, posed medium or low risks to aquatic organisms (especially algae). Considering the ecological risks and genotoxicity of pharmaceuticals and the potential risks of antibiotic-resistant genes, it is suggested to strengthen the investigation, evaluation, treatment, and control of pharmaceuticals in the water environment.

[Pollution Characteristics and Risks of Polycyclic Aromatic Hydrocarbons in Underground and Surface Drinking Water Sources in Northeast Inner Mongolia]

Polycyclic aromatic hydrocarbons (PAHs) are hazardous and ubiquitous pollutants in the aquatic environment, and understanding the pollution characteristics and risk levels of PAHs is of great significance to the sustainable development of drinking water sources and drinking water safety. Hence, PAHs residues were measured qualitatively and quantitatively with solid-phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS) in 33 water samples (including 22 groundwater and 11 surface water samples) of the drinking water sources in the Manzhouli and Xinyouqi areas of northeast Inner Mongolia, and assessments of the pollution level of PAHs and the health and ecological risks were carried out. The results showed that PAHs were detected in all 33 sampling points of Manzhouli drinking water sources, except for benzo[k] fluoranthene, benzo[a] pyrene, and dibenzo[a,h] anthracene, with detection rates ranging from 36.36% to 95.45%; the detection rates of the other 13 PAHs monomers were 100%. The detection range of ρ（ΣPAHs） was 42.76-164.50 ng·L^-1, and the mean value was 90.82 ng·L^-1. The detection ranges of ρ（ΣPAHs） in surface water and groundwater were 66.39-164.50 ng·L^-1 and 42.76-147.70 ng·L^-1, respectively. The concentration of the detected naphthalene was the highest, with a mean value of 36.91 ng·L^-1, and the concentration of anthracene was the lowest, with a mean value of 0.81 ng·L^-1; there were no significant differences among the concentrations of all the PAHs monomers of the surface and groundwater (P>0.05). The pollution of PAHs was at a median level in China and abroad, mainly in the middle and low loops (3-4 loops). The analysis of the sources of PAHs in groundwater and surface water in Manzhouli using the ratio feature method and principal component analysis showed that the PAHs in the drinking water source water bodies in the Manzhouli area were mainly affected by the combustion of coal and biomass and oil, and some surface water sources were affected by the oil source. The human health and ecological risk assessment results showed that the water body of drinking water would not cause health risks to the human body, and the ecological risk was at a medium level; however, the high risk of benzo[b] fluoranthene (BbF) monomer production should be continuous cause for concern. From the perspective of the sustainable development of drinking water sources and drinking water safety, the necessary supervision and protection measures should be considered to prevent further pollution. The results of this research provide a scientific basis for the pollution control and prevention and control of PAHs in drinking water sources.

Perfluoroalkyl Substances (PFASs) in Rivers and Drinking Waters from Qingdao, China

Perfluoroalkyl substances (PFASs) in rivers; drinking water sources (reservoirs and groundwater); and various types of drinking waters (tap waters, barreled pure waters, and bottled mineral waters) in Qingdao, Eastern China were quantified by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The total concentrations of PFASs (ΣPFASs) in the river waters ranged from 28.3 to 292.2 ng/L, averaging 108 ± 70.7 ng/L. PFBS was the most abundant compound, with a maximum concentration of 256.8 ng/L, followed by PFOA (maximum concentration: 72.4 ng/L) and PFBA (maximum concentration: 41.6 ng/L). High levels of PFASs were found in rivers in the suburban and rural areas. The estimated annual mass loading of the total PFASs to Jiaozhou Bay (JZB) was 5.9 tons. The PFASs in the drinking water reservoirs were relatively low. The ΣPFASs in the tap water ranged from 20.5 ng/L to 29.9 ng/L. Differences in the PFAS levels and composition profiles were found among barreled water at different market sites and for different brands of mineral water products. The sequence of the contamination levels of the waters related to drinking water was reservoir water > tap water > barrel water > groundwater > bottled mineral water. The PFASs in drinking water may not pose a serious risk to the drinking water consumers of Qingdao City.

Occurrence of antibiotics in rural drinking water and related human health risk assessment

Antibiotic residues in drinking water can have a negative impact on both human and environmental health. However, drinking water purification processes employed in rural areas are often less complicated than those used in urban areas. The occurrence of antibiotic residues in rural drinking water and their potential effects on residents' health remains to be established. In this study, we measured antibiotic levels in rural drinking water using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and evaluated the associated health risks based on Chinese population exposure parameters. Twenty-three antibiotics were detected in drinking water samples, of which fluoroquinolones and macrolides were the most common. The type and concentration of antibiotics in drinking water were affected both by the quality of the water source and by the water purification process used. The health risks associated with antibiotics in drinking water were within acceptable levels and likely to have little impact on human health. Of the antibiotics detected, salinomycin presented the greatest risk to human health. These findings can help to play a role in devising strategies to ensure drinking water safety.

[Distribution and Ecological Risk Assessment of PPCPs in Drinking Water Sources of Henan Province]

The occurrence of emerging pollutants pharmaceuticals and personal care products (PPCPs) in aquatic environments has potential adverse effects on aquatic organisms, and the presence of PPCPs in drinking water sources is very likely to cause harm to human health. The PPCPs pollution in five typical drinking water sources in Henan province was investigated. Moreover, the source of pollutants was analyzed and the relevant ecological risks were evaluated. The results showed that the cumulative concentrations of 20 PPCPs at different sampling sites ranged from 24.2 to 317.6 ng·L^-1. Caffeine (CFI) was the highest level contaminant, with the concentration up to 186.4 ng·L^-1, followed by sulfamethoxazole (SMX) and ofloxacin (OFC), with detected concentrations up to 70.8 ng·L^-1 and 24.2 ng·L^-1, respectively. The pollution of PPCPs in Heigangkou drinking water sources was higher than those of other drinking water sources. The comparation of the labile indicator CFI and the conservative indicator carbamazepine (CBZ) concentrations implies that the pollutions from the upstream water and around scattered domestic sewage might be responsible for the PPCPs present in these drinking water sources. The risk quotient (RQ) calculation results indicated that the detected PPCPs in 5 drinking water sources have moderate to high risks to algae, while low to moderate risks to invertebrates and fish. Therefore, attention should be paid to relevant pollution control.

Water Supply Challenges in Rural Areas: A Case Study from Central Kazakhstan

Rural water supplies have traditionally been overshadowed by urban ones. That must now change, as the Sustainable Development Goals calls for water for all. The objective of the paper is to assess the current access to and the perceived water quality in villages with various types of water supply. The survey was carried out during July–December 2017 in four villages in central Kazakhstan. Overall, 1369 randomly selected households were interviewed. The results revealed that even though villagers were provided with tap water, significant numbers used alternative sources. There were three reasons for this situation: residents’ doubts regarding the tap water quality; use of other sources out of habit; and availability of cheaper or free sources. Another problem concerned the volume of water consumption, which dropped sharply with decreased quality or inconvenience of sources used by households. Moreover, people gave a poor estimate to the quality and reliability of water from wells, open sources and tankered water. The paper suggests that as well decentralization of water management as monitoring of both water supply and water use are essential measures. There must be a tailor-made approach to each village for achieving the Sustainable Development Goal of providing rural Kazakhstan with safe water.