Assessment and Evaluation of Surface Water Quality and Human Health Risk in the Inkomati River Catchment Basin, South Africa

Water quality has been linked to health outcomes across the world. This study evaluated the physico-chemical and bacteriological quality of drinking water supplied by the municipality from source to the point of use at Thulamela municipality, Limpopo Province, South Africa; assessed the community practices regarding collection and storage of water and determined the human health risks associated with consumption of the water. Assessment of water quality was carried out on 114 samples. Questionnaires were used to determine the community’s practices of water transportation from source to the point-of-use and storage activities. Many of the households reported constant water supply interruptions and the majority (92.2%) do not treat their water before use. While E. coli and total coliform were not detected in the water samples at source (dam), most of the samples from the street taps and at the point of use (household storage containers) were found to be contaminated with high levels of E. coli and total coliform. The levels of E. coli and total coliform detected during the wet season were higher than the levels detected during the dry season. Trace metals’ levels in the drinking water samples were within permissible range of both the South African National Standards and World Health Organisation. The calculated non-carcinogenic effects using hazard quotient toxicity potential and cumulative hazard index of drinking water through ingestion and dermal pathways were less than unity, implying that consumption of the water could pose no significant non-carcinogenic health risk. Intermittent interruption in municipal water supply and certain water transportation and storage practices by community members increase the risk of water contamination. We recommend a more consistent supply of treated municipal water in Limpopo province and training of residents on hygienic practices of transportation and storage of drinking water from the source to the point of use.

A comprehensive evaluation of surface water quality and potential health risk assessments of Sisa river, Kumasi

This research examines the condition of the water characteristics of the Pusur River to provide data regarding water quality status and risks to human health. In determining the water quality use the NSF-WQI, or National Sanitation Foundation-Water Quality Index based on the main water quality parameters, including temperature, fecal coliform, turbidity, pH, DO, COD, and nitrate. The WQI at the Sudimoro Village location is 37.50, Cokro is 43.54, Wangen is 39.51, Delanggu is 35.45, Juwiring is 38.05, and Taji Village is 34.92. From these six locations, the WQI values are all included in the bad criteria (scores of 26-50). The low WQI values at the six locations were influenced by the low values of the DO, nitrate, temperature, and fecal coliform sub-indices. This low value is related to anthropogenic activities in the region. Furthermore, the data were subjected to applications of the Chronic Daily Index (CDI) Hazard Quotient (HQ), and Hazard Index (HI) to reveal possible non-carcinogenic health risks from nitrate and cadmium contaminants. The hazard quotient through exposure to ingestion from each sampling point includes low risk, namely the value range of 0.1 < HI < 1 for adults and children. Water from rivers must be adequately treated before being used for domestic purposes.

Freshwater supply is essential to life on Earth; however, land use activities such as mining and agriculture pose a significant danger to freshwater resources and the wellbeing of aquatic environments. This study temporarily assesses the water quality characteristics of Mutangwi River. Physicochemical parameters (pH, temperature, total dissolved solids (TDS), salinity, electrical conductivity (EC), and turbidity) were determined in situ using an Extech multimeter and turbidity meter. The concentration of the selected metals (Mg, Cr, Fe, Cd, Mn, Pb, Ca, and Na) were analysed using an Atomic Absorption Spectrophotometer. Membrane filtration method was used to analyse microbiological parameters (Escherichia coli and Enterococci). The physicochemical water quality parameters as well as basic anions (fluoride, phosphate, sulfate, nitrate, and chloride) determined complied with the regulatory guideline of the World Health Organization (WHO) and the South Africa National Standards (SANS). Some of the trace metals (Mn, Ca, Fe, and Mg) were found below the guideline values, while others (Pb and Cd) exceeded the threshold limit. The counts for E. coli (814.5–2169 cfu/100 mL) and Enterococci (333–9396 cfu/100 mL) in the study did not comply with the regulatory guidelines. The water quality status using the water quality index (WQI) indicated that on the average, the water quality from Mutangwi River is poor (WQI > 100). The hazard quotient through ingestion exposure did not exceed the threshold limit of 1, for adults and children. This implies that there is no potential non-carcinogenic health risk from trace elements via ingestion of drinking water for children and adults. However, cancer risk for adults and children was computed in relation to Cd and Pb levels and exceeded the threshold limit 10−4, indicating a possible carcinogenic risk. Water from the river should be adequately treated prior to domestic and agricultural use.

The primary cause of water-borne disease epidemics, particularly in underdeveloped nations, is the consumption of drinking water tainted with dangerous bacteria that originated in excrement. Water bodies have been essential to the development of civilizations throughout history, and they are still important for the modern economic expansion of all modern cultures. Microbes can get into water sources through agricultural inputs and rainfall runoff, which can combine with sewage effluents. The coliform group of bacteria, which signals the possible presence of harmful organisms, is the organism that is typically searched for during the standard water analysis technique. Microbes that cause disease in humans multiply and spread through the medium of water. For this reason, one of the most crucial criteria for public health is the drinking of safe water. Water samples were collected from various sources (surface water and groundwater sources) throughout March to May 2023. Ten water samples were taken from the surface and groundwater in and around Ranchi Municipality Nagra Toli and Karamtoli areas The MPN index, fungal tests, colony count, and other biochemical test parameters were all analyzed. Comparing surface water to groundwater, it was discovered that the MPN index of the former was higher. Up to 140 MPN/100 mL of total coliform count were found. Samples of surface and groundwater revealed the presence of two distinct bacterial species. It becomes clear that Escherichia coli and Bacillus Enterococcus faecalis bacterial isolates were common. The current study's objectives were to identify the various microbial groups and perform several microbiological studies. To maintain the hygienic quality of the water supply, it is strongly advised to do bacteriological examinations on both the water entering the distribution system and the water already in the system on a frequent and regular basis. Regular inspections are necessary for both sanitary management and testing portable water.

A regional approach to the environmental risk assessment - Human health risk assessment case study in the Campania region

Assessment of human health risks of environmental agents has often been limited to consideration of the potential for the agent to cause cancer or general systemic toxicity after long-term exposure. The U.S. Environmental Protection Agency (U.S. EPA) is increasingly moving toward the development of integrated assessments, which consider all potential health end points including developmental toxicity, neurotoxicity, immunotoxicity, reproductive effects, and germ cell mutagenicity. The U.S. EPA has a responsibility to assess risks to nonhuman species or ecosystems when appropriate data are available. An example of a recent integrated human health and ecological risk assessment can be found in the U.S. EPA Mercury Study Report to Congress. This report covers the following topics in separate volumes: an inventory of anthropogenic mercury emissions in the United States; an exposure assessment using measured and predicted values and including indirect dietary exposure; an evaluation of human health risks; an assessment of ecologic risk wherein water criteria are presented for several wildlife species; an overall integrated characterization of human and nonhuman risk; and a discussion of risk management considerations. In the evaluation of human health risk, genetic toxicology data were considered for three forms of mercury: elemental, inorganic (divalent), and methylmercury. These data were used in judgments of two types of potential health effects (carcinogenicity and germ cell mutagenicity). In assessment of potential carcinogenicity of inorganic and methylmercury, genetic toxicity data were key. Data for clastogenicity in the absence of mutagenicity supported the characterization of inorganic and methylmercury as materials that produce carcinogenic effects only at high, toxic doses. The evidence for clastogenicity, coupled with information on metabolism and distribution, resulted in a judgment of a moderate degree of concern (or weight of evidence) that inorganic mercury can act as a human germ cell mutagen. For methylmercury, the degree of concern for germ cell mutagenicity is high.

Preface

This work was carried out for the determination of the water quality in the Talagang District of Pakistan, as water is essential for agriculture and drinking uses. This study aims to assess the water quality for irrigation, drinking, and health risks using the Water Quality Index (WQI) and Human Health Risk Assessment (HHRA) tools to identify regions with contaminated water, and to evaluate the associated risks. A total of 98 water samples were taken at various points from diverse sources such as hand pumps, streams, springs, dug wells, and tube wells for physio-chemical assessment. In the current study, the effectiveness of the irrigation water quality index (IWQI), human health risk assessment (HHRA), and water quality index (WQI) tools have been assessed. The characteristics of subterranean water are influenced by evaporation, ion exchange, rock-water interaction, and parent-rock weathering, as shown by the Piper and Gibbs diagram. According to the WQI results, the water quality is 20. 89% and 27.46% of the sample sites are moderate and poor, making them unfit for human intake. Based on HHRA, compared to adult males and females in the study area, children are deemed to be at a higher risk. A larger number of the sample localities are appropriate for irrigation purposes. The study assists in identifying contaminated regions and in monitoring newly implemented remediation actions to manage the source of contaminants in the study area.

Background, aim, and scope Freshwater reservoirs can be impacted by several hazardous substances through inputs from agricultural activity, sewage discharges, and groundwater leaching and runoff. The water quality assessment is very important for implementation of the monitoring and remediation programs to minimize the risk promoted by hazardous substances in aquatic ecosystems. Evaluation of the degree of contamination of aquatic environments must not take in account only its chemical characterization but it must be complemented with biological assays, which determine potential toxic effects and allows an integrated evaluation of its effects in populations and aquatic ecosystem communities. The application of this type of strategy has clear advantages allowing a general evaluation of the effects from all the water components, including those due to unknown substances and synergic, antagonistic, or additive effects. There are only a few studies that reported ecotoxicological acute end points, for the assessment of surface water quality, and the relationship among toxicity results and the anthropogenic pollution sources and the seasonal period. The aim of this study was to assess the ecotoxicological characterization of the surface water from Alqueva reservoir (South of Portugal) and to evaluate the influence of anthropogenic sources of pollution and their seasonal variation in its toxicity. The construction of Alqueva reservoir was recently finished (2002) and, to our knowledge, an ecotoxicological assessment of its surface water has not been performed. Because of that, no information is available on the possible impact of pollutants on the biota. The surface water toxicity was assessed using acute and chronic bioassays. The results are to be used for developing a monitoring program, including biological methods.

To investigate the quality of domestic groundwater and assess its risk to inhabitants of the Guanzhong Basin, China, 191 groundwater samples were collected to analyze major ions, nitrate, pH, total dissolved solids (TDS), total hardness (TH), and electrical conductivity (EC). The physiochemical parameters, hydrochemical facies, and sources of major ions were analyzed using Durov diagrams, bivariate diagrams, and chloro-alkaline indices (CAI-I and CAI-II). The suitability of groundwater for drinking, the nitrate distribution, and human health risk (HHR) for different age groups were evaluated. The results showed that the relative abundance of cations in the groundwater samples was K++Na+ > Ca2+ > Mg2+, while that of anions was HCO3− > SO42− > Cl− > NO3−. Groundwater samples mainly contained HCO3-Na and HCO3-Ca, which were introduced mainly by rock weathering and ion exchange. The groundwater in the Guanzhong Basin contained mainly good and medium water, and the groundwater in the southern part of the Wei River was better than that north of the Wei River. Areas containing high nitrate concentrations were mainly located in the central and western parts of the Guanzhong Basin. The percentages of low risk (<45 mg/L), high risk (45–100 mg/L), and very high risk (>100 mg/L) of nitrate pollution in the study area were 90.58%, 8.9%, and 0.52%, respectively. The HHR assessment results indicated that people in the 6–12 month age group were more likely to suffer from health complications due to a higher nitrate concentration, followed by 6–11 years, 21–65 years, 18–21 years, ≥65 years, 11–16 years, and 16–18 years age groups, which was mainly due to the different exposure parameters. The results of this study will be useful in regional groundwater management and protection.

Although the short-term effectiveness of remedial sediment dredging (RSD) on mitigating sediment contamination in the lower Passaic river (LPR), New Jersey, USA, was previously established in previous studies, dredging impacts on overlying water and consequential effects on aquatic life and human health were not investigated through model-based risk assessment methods. This study assessed the influence of RSD on metal pollution and toxicological risks upstream and downstream of River Mile-3.4, which was the subject of a 2012 RSD. Over the pre-, during-, and post-dredging periods, threats to aquatic life and humans were greater upstream at River Mile-4 (WQIavg. ≥ 50, PIavg. = 0.9) compared to downstream (River Miles-0 &1), where WQIavg. < 50 and PIavg. = 0.6 & 0.4, respectively. Monte Carlo probabilistic health risk assessment revealed significant probabilities of carcinogenic (≥ 98%) and non-carcinogenic health risks (2–50%) across all study areas and periods, with the highest risks recorded during and shortly after dredging, underscoring the associated toxicant exposure risks to humans from RSD. Significant (p < 0.05; 0.01) inter-correlations between metals were recorded pre-, during, and post-dredging, with observed negative correlation indicating concentration changes between the dredging and post-dredging periods. Principal component analysis of measured parameters explained two potential categories of pollution sources—(i) in-situ recontamination from dredging residuals and remobilized metals, and (ii) ongoing anthropogenic contributions from combined sewer outfalls and surface runoff. Recent pollution trends in the study areas underscore the effect of seasonality and anthropogenic influences on toxic metal pollution in the LPR and highlight the need for a robust and consolidated protective remedial action comprising engineered and natural measures, policy and engineering control of ongoing pollution sources, and institutional controls to limit human exposure.Graphical abstract

Groundwater quality in the alluvial plains of Punjab has special significance and needs great attention since it is the foremost source of drinking, irrigation and industrial uses. The present research work emphasizes the integrated hydrogeochemical and chemometric statistical approaches to appraise the geochemical processes and source apportionment of the groundwater in the alluvial plains of Jalandhar district, Punjab, India. The human health risk assessment was also performed to quantify the potential non-carcinogenic impacts of nitrate and fluoride on human health through ingestion of groundwater. For this purpose, 41 groundwater samples were collected from different groundwater abstraction units and analysed for pH, electrical conductivity, total dissolved solids, total hardness, total alkalinity and major ions (Ca2+, Mg2+, Na+, K+, HCO3-, CO32-, SO42-, NO3-, F-, Cl- and PO43-) using standard protocols. Drinking water quality index and Revelle index showed that groundwater samples fall under poor to unfit water class and salinization along the south-western portion of the study region shows poor water quality. The results of the hazard index (HIingestion) show 68% and 46.34% of the groundwater samples have HI > 1 for children and adults. The non-carcinogenic health risk assessment of nitrate (NO3-) and fluoride (F-) on the local population indicated that the children are more vulnerable through direct ingestion of drinking water than adults. Piper diagram and saturation index reveal that Ca2+-Mg2+-HCO3- is the dominant hydrochemical facies and oversaturated with calcite, dolomite and aragonite minerals in the groundwater. Gibbs diagrams, chloro-alkaline indices and scatter plots show that the hydrochemistry of the groundwater is mainly governed by aquifer material interaction such as weathering of silicate, carbonate rock, halite dissolution and cation exchange process. Chemometric statistical techniques revealed that the source identification of parameters such as Ca2+, Mg2+, Na+, K+, HCO3-, CO3- and F- is originated from geogenic factors, whereas NO3-, SO42-, Cl- and PO43- are from the anthropogenic origin. Therefore, urgent and efficient measures must be taken to combat groundwater pollution and reduce human health risk in the study area.

Water quality is an important factor for health and safety issues associated with public health and also for aquatic life. More and more water quality issues are becoming a significant concern due to the growth of population, urban expansion and development. Thus, assessment of surface water quality has become an important issue. Water Quality Index (WQI) is a single number which can be calculated easily and used for overall description of the quality of water bodies used for different purposes. In this study, the water quality data obtained from 10 sampling stations during one year monitoring period at Kirmir basin was evaluated. Kirmir basin is one of the important drinking water sources of the capital city of Turkey, Ankara. The analyses of 44 water quality parameters were done for all water samples at the General Directorate of State Hydraulic Works (DSI), Department of Chemistry, Water Analysis Laboratory. It was found that DO, BOD, phosphate, color, turbidity, T. coli, E. coli, Enterococci, iron, manganese, arsenic, aluminum, boron, and barium values which exceed the limit values given in the water quality standards are the major pollutants that affect the water quality in this basin. For easy interpretation of the data, five different WQI models were applied for the selected parameters. The suitability of these WQI models is discussed with respect to their applicability in similar studies. For this study it is concluded that the Canadian WQI (CWQI) and Oregon WQI (OWQI) would provide the best results.

Surface water is the best source of drinking water available. However, climate change, over-pumping, and a variety of contaminants have all led to the depletion of this valuable resource. Conducting surface water quality assessments for home usage, especially drinking water, is essential to safeguarding human health and effectively managing resources. In this study, this work has highlighted an evaluation of surface water quality of river Mahanadi, Odisha, for drinking purposes using Relief Algorithm (RA) based WQI (RA-WQI), with reliability-based MLs (Machine Learning) such as Weight of Evidence (WOE) have been employed. For this, water samples from 19 locations were taken for a period of 2018-2023, to test 20 physicochemical parameters in the selected sampling sites. The findings indicated that although pH changes, the water is alkaline and its value spanned from 7.73 to 7.9. The concentration of coliform and TKN is found to be higher at all locations. The highest levels of Cl- and SO42- are located close to the downstream area. Based on the results, anions and cations are observing a shift in the trend, i.e., Fe2+ &gt; B+ and Cl- &gt; SO42- &gt; NO3- &gt; F- respectively, throughout the occupied duration. Further, the calculated RAWQI revealed that 63.16% belong to poor water quality while 31.57% of sites come under the zone of excellent water. However, 5.26% of samples indicated an unsuitable water class. The analysis primarily revealed that at 8 samples, the main cause could be deterioration of domestic water, illegally dumped municipal solid waste, and agricultural runoff were the leading sources causing adulteration of the river’s water quality. As a result, a renowned ML models, such as WOE, were adopted and it suggests location SP-(9) was the most polluted in comparison with other locations, followed by SP-(8), (19), and (2) respectively. Following this, the analytic findings also suggests from the highest RA-WQI values that consists of 488, 243, 277 and 285 at this location. However, it was relevant that the degree of pollution at these stations was more closely linked to a wide range of expanding human activities, such as excessive water use, fertilizer effects, agricultural runoff, and industrial activity in and around the river corridor. According to the drinking water quality indices, the surface water in the area under investigation is classified as suitable for human consumption. Thus, the results illuminate the preservation and distribution of drinkable and irrigable surface water supplies, and provide decision-makers with a valuable resource for implementing successful surface water protection strategies in the area under study.