National Water Quality Research Articles

Water Quality and Prevalence of Extended Spectrum Beta Lactamase Producing Escherichia coli (ESBL E. coli) in Sungai Terengganu, Malaysia

Antimicrobial resistance (AMR) is a significant global issue impacting human, animal, and environmental health, as well as economic security. Water bodies, especially, are now recognized for their role in the spread of antimicrobial-resistant pathogens, though standardized monitoring methods are lacking. This study investigates the presence of extended-spectrum beta-lactamase (ESBL) producing Escherichia coli in the Sungai Terengganu River in Malaysia, focusing on water quality and ESBL E. coli monitoring. Sampling was conducted twice in 2023 at 13 locations along the river. Overall, the water quality index (WQI) classified the river as Class II (WQI = 81), with upstream regions rated as Class I, indicating minimal anthropogenic impact. Higher Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Total Suspended Solids (TSS) in downstream areas suggested organic pollution from anthropogenic activities. Four metal elements exceeded the National Water Quality Standards (NWQS): Al (0.88 mg/L), Fe (3.45 mg/L), Cu (0.102 mg/L), and Hg (2.525 mg/L). No Pb, Cr, Se, Sn, or As were detected. Statistical analysis showed better water quality correlates with lower microbial contamination. ESBL E. coli was found in 8 of 13 sampling sites (61.5%), with the highest concentration at 800 CFU/100 mL. From 40 presumptive ESBL isolates tested, 87.5% (35 isolates) were positive for ESBL and carried additional drug resistance genes, including mcr-1, tetW, sul-1, and sul-2. These findings indicate a concerning presence of multidrug-resistant E. coli in the river, representing a potential public health risk.

Low-level ionizing radiation-induced DNA responses in the Asian green mussel Perna viridis

Cesium-137 (Cs-137) is a radioactive isotope present in marine environments due to the operation of nuclear power plants and weapons testing. Radiocesium poses a potential risk to marine life due to its long half-life and bioaccumulation. This study evaluated the genotoxicity of low doses of Cs-137 in the Asian green mussel Perna viridis, a sentinel species for marine pollution monitoring, by performing the comet assay and micronucleus test on hemolymph samples. Genotoxicity was assessed after exposing mussels to Cs-137 at dose rates of 0, 5, 10, and 15 μGy/h for 48 h. Cs-137's organ-specific distribution was also determined using HPGe gamma spectrometry. Even at low radiation doses, Cs-137 was found to exert genotoxic effects. Significant increases in DNA strand breaks (%Tail DNA) and micronucleus formation (MNF) were observed at all tested dose rates compared with the levels in controls, with dose-dependent responses. Cs-137 predominantly accumulated in the soft tissues, specifically the gills and digestive gland. The findings support the recommended safety level of 10 μGy/h for aquatic organisms, suggesting its appropriateness as a fundamental criterion for developing the national marine water quality standard for Cs-137 in Thailand.

Water quality assessment using national Water Quality Index (WQI): a case study of the Song Be River, Bing Duong Province, Vietnam

Abstract The Song Be River is a vital water source in Binh Duong Province, Vietnam, playing a crucial role in supplying water for domestic use and agriculture, as well as supporting local ecosystems. However, due to the recent rapid economic and industrial growth, the river’s water quality has encountered significant challenges, particularly from the improper discharge of untreated wastewater from various sources and activities. This study conducts a comprehensive analysis of the Song Be River’s water quality by employing the Water Quality Index (WQI) in conjunction with Geographic Information System (GIS) technology. Subsequently, several strategies are also proposed to effectively manage and enhance the water quality of the Song Be River. Over the period from March 2023 to March 2024, 52 samples were collected from four monitoring points (SB1, SB2, SB3, and SB4) along the Song Be River, with a frequency of once per month. All analytical parameters (such as NH4 +_N: 0.01–0.61 mg l−1, NO2 −_N: 0.014–0.03 mg l−1, Fe: 0.01–0.81 mg l−1, Chemical Oxygen Demand (COD): 4–26 mg l−1, Dessolved Oxygen (DO): 3.8–6.6 mg l−1, Suspendid Solids (SS): 5–69 mg l−1, Coliform: 1200–4300 MPN/100 ml, Total phosphorous: 0.01–0.08 mg l−1 and Total nitrogen: 1.16–4.5 mg l−1) fell within the permissible limits according to the Vietnamese National Standards. Furthermore, the WQI ranged from 73 to 100, indicating that the water quality of The Song Be River is good and suitable for domestic use.

Mobility and persistence of pesticides and emerging contaminants in age-dated and redox-classified groundwater under a range of land use types

Understanding groundwater contamination patterns is hampered by the heterogeneous groundwater age and redox status over the depth range typically sampled for identifying pesticides and emerging contaminants threats. This study explores depth patterns of groundwater age and redox status across various land use types, unraveling spatial and temporal trends of pesticides and emerging contaminants using data from groundwater quality monitoring in the south of the Netherlands. The Netherlands is an ideal testing ground due to its high population density and widespread groundwater contamination from multiple sources. 146 multi-level observation wells were age-dated using 3H/3He, and contaminant concentrations were analyzed based on recharge year, land use type, and redox conditions, mitigating uncertainties from spatial and depth-dependent variations in both groundwater age and redox status. Redox-recharge year diagrams were developed to visually evaluate contaminant patterns in relation to these factors and to assess concentration patterns in relation to contamination history. Most detections of pesticides, metabolites, and emerging contaminants occurred in the youngest recharge periods (2000–2010 and 2010–2020) and in agricultural areas. However, certain contaminants, including BAM, desphenyl-chloridazon, short-chain PFCAs, PFOA, and EDTA, were consistently found in older water and Fe- or SO4-reduced conditions, indicating their mobility and persistence in the regional groundwater system. Comparing the presence of contaminants in specific redox classes and recharge periods with known application or leaching history provides insights into retardation (e.g., PFOS) and degradation (e.g., 2-hydroxy-atrazine, benzotriazole), explaining lower detection frequencies in earlier recharge periods. Identifying recharge years from age-dated groundwater helps relate contaminants to farmland application or river water recharge periods, revealing leaching history and contamination origins. The presented framework has the potential to enhance the interpretation of large groundwater datasets from dedicated, short-screened observation wells, such as those from the Danish GRUMO network, the Dutch monitoring networks, and parts of the US National Water Quality Program.

Application of batch electrocoagulation treatment system with aluminium electrodes for simultaneous removal of organic and heavy metal contaminants from Borneo urban rivers

The challenges of sludge management and complex water treatment systems hinder the effectiveness of chemical coagulation in treating heavily contaminated urban river water. Realizing these issues, this study aims to develop a batch electrocoagulation system using aluminum electrodes to generate in-situ aluminum hydroxide coagulants for simultaneous removal of organic contaminants and heavy metals from Borneo urban river water. Subsequent, the treatment system achieves a reduction of 91.67 % of turbidity, 98.29 % of color, 95.16 % of total suspended solids (TSS), 97.78 % of iron, 94.21 % of lead, 21.94 % of pH, and 98.58 % of chemical oxygen demand (COD) with an electric current of 5 A and a residence time of 25 min. Besides, the treated water meets the Malaysia National Water Quality Standards for Class I which making it suitable for domestic consumption. The energy consumption cost for the treatment is only RM 1.48 (USD 0.31) per cubic meter of treated water. Additionally, the analysis of the electrocoagulation flocs reveals the presence of carbon, iron, lead, and various dissolved minerals which indicates effective contaminant removal from urban river. Overall, this study demonstrates the potential of the batch electrocoagulation treatment system as an effective and cost-efficient solution for treating urban river water in Borneo industrial areas.

Rainwater Quality Disparities Across Malaysian Peninsula Sites

This research describes the physicochemical quality of harvested rainwater at four distinct locations in Peninsula Malaysia. The evaluation of rainwater quality across different geographic areas aims to provide valuable insights into potential variations and trends in rainwater quality to reduce water demand globally. This analysis is conducted to determine seven properties, namely ammoniacal nitrogen, biochemical oxygen demand (BOD5), chemical oxygen demand (COD), dissolved oxygen (DO), pH, total dissolved solids (TDS), and turbidity. The results demonstrate that the quality of harvested rainwater meets the raw water quality standards set by the World Health Organization (WHO) and the National Water Quality Standards for Malaysia (NWQSM), indicating good quality rainwater in Malaysia. However, the COD for rainwater in all locations exceeded the limit, with a range of 14.1 to 29.7 mg/L, while the maximum limit for COD set by WHO is 10 mg/L, and according to NWQSM standards, it is 10–100 mg/L. The average pH of the collected rainwater is acidic ranged from 4.7 to 5.56. BOD5 for the collected rainwater is excellent; however, L2 has a slightly higher BOD5 at 6.5 mg/L, whereas the recommended limit by WHO is 6 mg/L, and the NWQSM standard suggests a range of 1–12 mg/L, with a standard limit of 5–7 mg/L. Nevertheless, DO levels ranged from 7.71 to 7.76 mg/L, indicating an ambient gas concentration in the rainwater. The collected rainwater can be used for portable purposes, gardening, smart farming, and toilet flushing.

Empowering Navajo Nation's Water Quality Monitoring through State-of-the-Art Paper-Electrochemical Sensors

The NSF-PREM research collaborative effort between Navajo Technical University (NTU) and Harvard University aims to address the critical issue of water contamination within the Navajo Nation. Decades of uranium mining and mineral extraction have left a lasting mark on the Navajo land and groundwater resources, necessitating effective solutions. The Nano-electrochemical Analysis and Energy Storage Laboratory (NEST LAB) at NTU has developed flexible paper-based sensors integrated with advanced electrochemical techniques to detect heavy metal concentrations in water samples. These sensors are cost-effective, easy to fabricate, and highly reliable, offering real-time monitoring capabilities. The projects core goal is to expedite water quality analysis and empower the Navajo community to detect potential contamination promptly. By distributing these sensors to local chapter houses, residents can independently assess groundwater quality, fostering a sense of ownership and proactive environmental stewardship. This partnership exemplifies the power of community-driven solutions and trains Navajo students to get involved in scientific innovation to safeguard the environment for future generations in the Navajo Nation.

Comparative analysis of water quality index and river classification in Kereh River, Penang, Malaysia: Impact of untreated swine wastewater from Kampung Selamat pig farms.

The Kereh River in Penang, Malaysia, has faced severe pollution for over 40 years due to untreated wastewater from swine farms in Kampung Selamat, discharged via stormwater drains. Despite official claims that all 77 swine farms treat their wastewater to meet regulatory standards, local non-governmental organizations and villagers have challenged this, though their concerns lack scientific backing. This study evaluates the river's water quality by analyzing samples from upstream (US), midstream (MS), and downstream (DS), and from Parit Cina-Parit Besar, a conduit for untreated swine wastewater. Fourteen parameters were measured against Malaysia's National Water Quality Standards (NWQS). Significant differences were found in six parameters: ammonium nitrogen (AN), biochemical oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen (DO), total suspended solids (TSS), and oil and grease (OG). While Dunn's post hoc pairwise comparison showed no significant differences among river segments, mean values indicated increased pollution downstream, particularly after the convergence with untreated swine wastewater. River classification worsened, with water quality index dropping from 69.88 ± 11.37 score (Class III) US to 38.49 ± 12.74 and 50.44 ± 3.14 scores (Class IV) MS and downstream, respectively. A significant positive correlation between E. coli and AN (r = 0.71, p < 0.01) suggests a common point source pollutant, particularly the untreated swine wastewater. The river exhibits low oxygen levels and high organic matter and nutrient concentrations, especially MS and downstream, highlighting substantial ecological and public health risks. Effective enforcement of waste treatment regulations and enhanced monitoring are crucial for mitigating pollution and restoring the river's ecosystem. Collaboration between authorities and pig farmers is essential to improve water quality and maintain the river's ecological balance. PRACTITIONER POINTS: Severe Kereh River pollution: Untreated swine wastewater from Kampung Selamat pig farms, primarily via Parit Cina-Parit Besar, has degraded the river for over 40 years. Regulatory non-compliance: Despite official claims, untreated swine wastewater continues to pollute the river, challenging regulatory standards. Significant pollution indicators: Elevated levels of AN, BOD, COD, DO, TSS, OG, and E. coli signal severe pollution midstream and downstream. Water quality index drop: WQI scores classify midstream and downstream sections as polluted, indicating worsening conditions downstream. Urgent need for action: Enforcing regulations, improving wastewater treatment, and relocating pig farms are crucial for restoring the Kereh River.

How does the citizens' choice of water use actions based on their empirical knowledge affect the water quality in a rural community of the Philippines?

This research assessed water quality, based on the purpose of water consumption, in households in the municipality of Barbaza, the Province of Antique, Philippines, according to the national water quality guidelines. The effects of the empirical/traditional water use actions taken by local people on the quality of the water they use were investigated through a descriptive study using water quality measurements. Most of the drinking water in the community did not meet the required standards of pH, total dissolved solids (TDS), or coliform. Tap water and well water samples generally met the pH and TDS standards. However, Escherichia coli (E. coli) and coliform were detected, and nitrogen pollution in well water was also confirmed. Local practices, such as using old clothes as filters for well pumps, increased the coliform concentration from 0-10 CFU/mL to too numerous to count (TNTC) levels of more than 100 CFU/mL. Storing well water in a bucket also affected both E. coli and coliform concentrations. Such empirical/traditional water use actions create a high risk of exposing local people to harmful microorganisms. This research integrated citizen science into the methodology for local water management, which could assist governors, practitioners, and citizens, particularly in Southeast Asia, where strong community relationships exist.

Towards a Canadian National River Water Quality-Modelling System: State of Science and Future Prospects

Water quality is of significant concern and ultimately critical to every Canadian’s quality of life and security. Canada has diverse and vast landscapes and stressors that impact various waterbodies differentially, with influencing factors including contaminant and nutrient loads from human activity (mining effluent, wastewater, agricultural runoff, plastics), landscape change (wetland drainage, urbanization) and climate change (warming water temperatures, longer open water seasons, extreme hydrological events, intensifying wildfires). Canadian rivers are especially important to the overall biogeochemistry, hydrology, biodiversity, and ultimate health of aquatic and terrestrial ecosystems. While each of Canada’s provinces and territories has extensive river water quality (physical, chemical, biotic) data and monitoring programs, Environment and Climate Change Canada coordinates various national programs that contribute to the collection and consolidation of these data and conducts extensive research into the study and modelling of key river water quality processes. Despite program-specific efforts, there remains poor capacity to predict current and future conditions in monitored and unmonitored Canadian rivers, particularly remote or northern rivers, due to a myriad of factors including lack of coordination amongst groups and examination of areas in which modelling efforts might be integrated. Herein, we review and analyse the current state of data availability, process studies, and modelling systems for Canadian river water quality. Our synthesis reveals that specific physical processes (water temperature, ice formation, permafrost thaw, sediment dynamics), biogeochemical processes (dissolved oxygen, dissolved organic matter, nutrient cycling, metals/contaminants) and ecological/biological features (biota mass, functional indicators) are well understood, though complex, and are amenable to empirical or mechanistic modelling. Review of this information assists us in identifying opportunities and challenges for developing a national water quality modelling system (NWQMS), that would eventually include similar modelling activities for parallel processes in lakes and integrated watersheds. We identify needs for stronger coordination of monitoring programs in remote areas, recommend use of novel remote sensing technologies, and development of a flexible, iterative ‘process’ for integrated modelling to which stakeholders beyond government can contribute. Such a platform would support short and long-term predictive models of Canadian water quality and ecosystem health, inform effluent concentration limits, and be an early warning system for source waters.

Environmental implication identification on water quality variation and human health risk assessment in the middle and lower reaches of the Hanjiang River, China

As the longest tributary of the Yangtze River, the Hanjiang River has been a “lifeline” for the “Yangtze River Economic Belt of China”. The water quality of the middle and lower reaches of the Hanjiang River (MLHR) has received considerable attention due to environmental degradation, increasing population, and water diversion project operations during the past decade. In this study, 16 water quality parameters from 14 national water quality monitoring stations along the MLHR were collected monthly from January 2021 to December 2022. Water quality index (WQI) methods coupling multivariate statistical techniques, e.g., seasonal Mann-Kendall test (SKT) and Mantel’s test, were applied to analyze and evaluate the spatiotemporal variations of water quality under different environmental and hydrological conditions. The Hazard Quotients (HQs) were used to assess the non-carcinogenic and carcinogenic risk for adults and children via ingestion and dermal pathways. The results showed that the overall water quality in the MLHR was classified as “excellent”, with the average WQI higher than “91”, and each single water quality indicator met Class I or Class II surface water quality standards of China. Ammonia (NH3-N), Total phosphorus (TP), Permanganate (CODMn), pH, and Arsenic (As) were significantly correlated with water level variations. CODMn and TP were decisive in explaining the WQI variations of the MLHR. NH3-N, water temperature, pH, and dissolved oxygen were key parameters for explaining WQI variations in most regions of the MLHR. As, Cadmium (Cd), and Chromium (Cr) presented potential health risks in the MLHR and should warrant close monitoring due to their significant health implications. Due to the continuous construction and operation of cascade hydro-projects, the synchronous monitoring of water quality and hydrological data of the MLHR should be conducted in the future. This study provides a scientific reference for managing water quality in the MLHR and similar natural riverine water bodies.

Comparative evaluation of spatiotemporal variations of surface water quality using water quality indices and GIS

AbstractThere is a need for a comprehensive comparative analysis of spatiotemporal variations in surface water quality, particularly in regions facing multiple pollution sources. While previous research has explored the use of individual water quality indices (WQIs), there is limited understanding of how different WQIs perform in assessing water quality dynamics in complex environmental settings. The objective of this study is to evaluate the effectiveness of three WQIs (Canadian Council of Ministers of the Environment (CCME), National Sanitation Foundation (NSF) and System for Evaluation of the Quality of rivers (SEQ-Eau) and a national water quality regulation in assessing water quality dynamics. The pilot study area is the Acısu Creek in Antalya City of Turkey, where agricultural practices and discharge of treated wastewater effluents impair the water quality. A year-long intensive monitoring study was conducted includig on-site measurements, analysis of numerous physicochemical and bacteriological parameters. The CCME and SEQ-Eau indices classified water quality as excellent/good at the upstream, gradually deteriorating to very poor downstream, showing a strong correlation. However, the NSF index displayed less accuracy in evaluating water quality for certain monitoring stations/sessions due to eclipsing and rigidity problems. The regulatory approach, which categorized water quality as either moderate or good for different sampling sessions/stations, was also found less accurate. The novelty of this study lies in its holistic approach to identify methodological considerations that influence the performance of WQIs. Incorporating statistical analysis, artificial intelligence or multi-criteria decision-making methods into WQIs is recommended for enhanced surface water quality assessment and management strategies.

Occurrence, transport and sources of metals and metalloids in the Bangpakong River in the eastern economic corridor area of Thailand

The occurrence of elements in river water is affected by various factors, including mobility, weathering and transport processes and anthropogenic contributions. A total of six water sampling campaigns were conducted from 2021 to 2022 to study the factors affecting the occurrence of twelve elements (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn and Se) in the Bangpakong River. The total concentrations of all the elements were within the levels set by the national surface water quality standard. Comparisons of dissolved elemental concentrations in the study area with the global average for dissolved elemental concentrations in pristine rivers indicated contamination with Al, As, Co, Mn, Zn and Se in the river water. Based on the percentage of each element in particulates to the total concentration, Al (80.6 %), Cr (71.9 %), Cu (69.9 %), Fe (95.6 %), Mn (76.6 %), Pb (74.7 %), and Zn (70.6 %) were mainly transported in the particulate phase in both the dry and wet seasons. However, As (65.5 %), Co (60.3 %), and Se (77.6 %) were mainly transported in the dissolved phase in both seasons. The ratios of the dissolved Se concentration in river water to the Se concentration in the Earth's crust indicated significant and high mobility, especially in downstream sites, likely due to Se leaching from alluvial sediments. Seawater intrusion is likely the cause of As and Zn contamination in the dry season. Weathering of rocks and soils likely causes Al, Co, and Mn contamination in the wet season. The anthropogenic sources of contamination include the discharge of Mn and Zn from fertilizers in agriculture and the use of formulated feed in aquaculture. Approximately 52.98, 25.23, 5.68 and 0.63 tons of Fe, Al, Mn and Zn, respectively, are estimated to be transported from the river into the Gulf of Thailand each year.

Chlorophyll a in lakes and streams of the United States (2005–2022)

The concentration of chlorophyll a in phytoplankton and periphyton represents the amount of algal biomass. We compiled an 18-year record (2005–2022) of pigment data from water bodies across the United States (US) to support efforts to develop process-based, machine learning, and remote sensing models for prediction of harmful algal blooms (HABs). To our knowledge, this dataset of nearly 84,000 sites and over 1,374,000 pigment measurements is the largest compilation of harmonized discrete, laboratory-extracted chlorophyll data for the US. These data were compiled from the Water Quality Portal (WQP) and previously unpublished U.S. Geological Survey’s National Water Quality Laboratory (NWQL) data. Data were harmonized for reporting units, pigment type, duplicate values, collection depth, site name, negative values, and some extreme values. Across the country, data show great variation by state in sampling frequency, distribution, and methods. Uses for such data include the calibration of models, calibration of field sensors, examination of relationship to nutrients and other drivers, evaluation of temporal trends, and other applications addressing local to national scale concerns.

Physicochemical and microbiological assessment of multi‐village drinking water source in diarrheal hotspot areas of north Shoa zone, Amhara region, Ethiopia

AbstractQuality water is essential to people's health and social and economic well‐being. Evaluation of the quality of the water sources provides benchmark data on quality status and insights into the development of further protective measures. A laboratory‐based cross‐sectional study design was conducted in the diarrheal hotspot area of the North Shewa zone. The contamination risks of water sources were assessed using the World Health Organization (WHO) sanitary inspection checklist. A grab water sample was collected from 138 multi‐village drinking water sources according to WHO guidelines. The collected sample was processed for physicochemical and microbiological analysis. Data were recorded and analyzed using SPSS version 25 software. The inspection survey indicated there was no proper handling of the water sources. The water temperature range was between 7 and 32°C, while the turbidity values ranged from 1.8 to 6 NTU. Electrical conductivity, pH, and total dissolved solutes were 100% within the acceptable limits of WHO and the Ethiopian Ministry of Health (EMoH) water quality guidelines. However, only (77/138, 55.79%) and (101/138, 73.29%) drinking water sources were within the acceptable range of temperature and turbidity, respectively. The mean bacteriological counts in multi‐village drinking water sources were a mean value of 72.14, 29.78, 21.09, and 15.64 for TMC, TCC, FC, and FSC, respectively. A total of (19/138, 13.8%) drinking water samples were positive for total coliform (Tc) and/or fecal coliforms (Fc). The remaining (119/138, 86.2%) water samples were bacteriologically potable. The physicochemical quality of the drinking water sources was consistent with WHO and national water quality standards, except that turbidity exceeded the acceptable range. The results also showed that some water sources were contaminated with fecal and total coliform, which was supported by an inspection survey in which most water sources were poorly protected. These research findings can serve as a valuable evidence base for informing policy decisions and guiding practical interventions aimed at ensuring access to safe drinking water in diarrheal hotspot areas.

Ocean parameter and hydrographic measurement around Cirebon port channel

Abstract One of the largest ports in West Java is Cirebon, which serves an important role in supporting the surrounding economy and becoming the alternatives of the biggest port in Java. Numerous loading and unloading activities are recorded with coal as one of the commodities. Sedimentation and water quality is a common issue facing any port. To assess the recent condition of the port, an oceanographic parameter and hydrography survey is one approach. A field survey in the Cirebon port, particularly around the channel and outside part was carried out in February 2023. The bathymetry result at the channel varied within 0 - 10 m depth. The mixed semidiurnal type in this area has a tidal range around 1.1 m. Sea current inside the port has low speed within 0-0.03 m/s meanwhile outside of the port can reach 0.13 m/s. Through the weathering system, the average temperature is 26.3°C, average wind speed of 2.25 m/s dominantly blowing from west, relative humidity around 88.6%, and rain rate also low. In the study, the sea condition of surface temperature, salinity, turbidity, DO, and pH is 28.5°-29.3°C, 29.9-30.1 psu, 3.65-17.68 FTU, 3.69-4.83 mg/L and pH 7.9-8.2, respectively. Based on the national water quality standard for the port, the condition is within threshold for several parameters.

Source-specific nitrate intake and all-cause mortality in the Danish Diet, Cancer, and Health Study

IntroductionNitrate and nitrite are naturally occurring in both plant- and animal-sourced foods, are used as additives in the processing of meat, and are found in water. There is growing evidence that they exhibit a spectrum of health effects, depending on the dietary source. The aim of the study was to examine source-dependent associations between dietary intakes of nitrate/nitrite and both all-cause and cause-specific mortality.MethodsIn 52,247 participants of the Danish Diet, Cancer and Health Study, associations between source-dependent nitrate and nitrite intakes––calculated using comprehensive food composition and national drinking water quality monitoring databases––and all-cause, cardiovascular disease (CVD)-related, and cancer-related mortality over 27 years were examined using restricted cubic splines within Cox proportional hazards models adjusting for demographic, lifestyle, and dietary confounders. Analyses were stratified by factors hypothesised to influence the formation of carcinogenic N-nitroso compounds (namely, smoking and dietary intakes of vitamin C, vitamin E, folate, and polyphenols).ResultsPlant-sourced nitrate intake was inversely associated with all-cause mortality [HRQ5vsQ1: 0.83 (0.80, 0.87)] while higher risks of all-cause mortality were seen for higher intakes of naturally occurring animal-sourced nitrate [1.09 (1.04, 1.14)], additive permitted meat-sourced nitrate [1.19 (1.14, 1.25)], and tap water-sourced nitrate [1.19 (1.14, 1.25)]. Similar source-dependent associations were seen for nitrite and for CVD-related and cancer-related mortality except that naturally occurring animal-sourced nitrate and tap water-sourced nitrate were not associated with cancer-related mortality and additive permitted meat-sourced nitrate was not associated with CVD-related mortality. No clear patterns emerged in stratified analyses.ConclusionNitrate/nitrite from plant sources are inversely associated while those from naturally occurring animal-sources, additive-permitted meat sources, and tap water-sources are positively associated with mortality.

Spatial Distribution Patterns of Phytoplankton and Their Relationship with Environmental Factors in the Jinjiang River, China

Our study aims to investigate the water quality and distribution patterns of phytoplankton communities in the Jinjiang River Basin in Quanzhou, as well as their relationship with environmental factors. We integrated data from the national water quality databases of the two main tributaries of the West and East Jinjiang Rivers between 2020 and 2023, supplemented by field surveys. Redundancy analysis was used to explore the effect of environmental factors on phytoplankton communities. Our findings revealed that the West Jinjiang River experienced a significant influence from excessive fertilizer use in tea cultivation, leading to an increase in TN concentrations compared to the East Jinjiang River. The abundance of phytoplankton in the Jinjiang River Basin was 105 cells·L−1, with phytoplankton being dominated by Chlorophyta, Cyanphyta, and diatoms, accounting for an average of 50%, 20%, and 19% of the total phytoplankton abundance, respectively. Redundancy analysis indicated that temperature, pH, and nutrient concentrations were important factors influencing the phytoplankton communities. With increasing temperature and nutrients concentrations, the abundance of Chlorophyta and Dinophyta significantly increased. This study provides a solid foundation for the regular “health diagnosis” of crucial rivers and lakes in Quanzhou and supports the establishment of a health guarantee system for rivers and lakes.

Analysing the interlinkage between diarrhoea and drinking water faecal contamination in India

ABSTRACT Diarrhoea is one of the major waterborne diseases spread through the faecal–oral route causing over 10 million cases and over 1,000 deaths per year in India. This study critically evaluates the interlinkage between bacteriological water quality, i.e. faecal coliforms and diarrhoea cases for the three pre-pandemic years 2017, 2018 and 2019 based on multiple sources. With around 17% of households tap water connectivity as of August 2019, the majority of the Indian population depends on raw groundwater (GW) and surface water sources. For this, faecal coliform (FC) levels in surface and GW have been mapped at district levels using data from India's National Water Quality Monitoring Programme. Health Management Information System's data on diarrhoea have been used to understand the monthly and district-wise variation of diarrhoea. The trends of FC, diarrhoea inpatient cases, and diarrhoea inpatient rates have been discussed. The analysis showed issues associated with the reliability and usefulness of these datasets with 43% of total India districts with no reported FC values for the study period. This study reveals a clear gap in the interlinkage between diarrhoea and bacteriological water quality with the unavailability of granular water quality data as a major challenge.

Determination of the Radioactive Nature of the Sediments of the Bays of the Ebrié Lagoon of Abidjan, Ivory Coast

In Ivory Coast, the lagoons represent the transit point for the majority of continental inputs. They are thus increasingly vulnerable and their ecological balance is rapidly modified under the influence of certain natural or anthropogenic factors. The objective of this study is to evaluate the level of presence of lead 210 in sediments. The sediments were sampled during the campaigns of the National Water Quality Observation Network on the bays spread over thirteen study sites. Analysis by alpha spectrometry was carried out in three stages (mineralization with concentrated acids, self-deposition on a silver disk, counting in an alpha detector with a silicone surface barrier). The highest lead-210 activities were obtained in the bays of Koumassi 1 (228.57 ± 12.21 Bq/kg) and Marcory (198.91 ± 9.46 Bq/kg). However, no seasonal variation in lead-210 contamination of sediments in the bays of Abidjan was observed. We wish to extend this study to other aquatic matrices.