Drinking Water Samples Research Articles

Occurrence and multi-pathway health risk assessment of trihalomethanes in drinking water of Wuxi, China

Chlorination is widely used to disinfect drinking water to keep humans safe from microorganisms. During chlorination, chlorine and its compounds react with contaminants to form disinfection by-products (DBPs). Toxicological and epidemiological studies have demonstrated that trihalomethanes (THMs) are the most widely investigated DBPs in drinking water, and their exposure has been associated with some adverse health effects. However, studies about risk characteristics in this field are limited. We estimated the health risks of THMs exposure in drinking water through multi-pathways, and systematically analyzed the factors influencing health risks of THMs in Wuxi, China. A total of 488 drinking water samples were collected and analyzed for THMs from four water treatment utilities from 2008 to 2016 in Wuxi. And water exposure parameters were obtained from 602 participants by structured questionnaires. The median concentration of THMs ranged from 6.71 μg/L to 9.18 μg/L. The cumulative cancer risk of THMs exposure through multi-pathways was 1.26 × 10−4, and CHBr2Cl made the largest contribution to the total cancer risk (48.25%). The non-cancer risk of THMs exposure was 2.02 × 10−1. Health risks of the exposure to THMs in drinking water in summer were significantly higher than that in winter (P = 0.0003 for cancer risk, and P = 5.95 × 10−7 for non-cancer risk). In our study, the average individual disability-adjusted life years (DALYs) lost was 1.27 × 10−4 per person-year (ppy). This study attempted to use DALYs for risk assessment of THMs, which will provide useful information for risk comparison and prioritization of hazards in drinking water. This suggested that potential higher risk might exist, and possible measures could be considered to decrease the health risks.

Microplastic pollution of drinking water in a metropolis.

This study was conducted to identify microplastics (MPs) in drinking water from various sources in İstanbul that are known to pose potential health risks. One hundred drinking water samples were analysed. Samples were filtered with a glass filter (Ø: 1.0 μm). After filtration, microscopy was used, followed by SEM-EDS and ATR-FTIR identification to characterise MPs. Two shapes (fibers and fragments) and eight polymer types of MPs (ethylene propylene, neoprene, polyethylene, polyethylene terephthalate, polypropylene, polyvinyl chloride, polytetrafluoroethylene, vinyl chloride vinyl acetate copolymer) with sizes of 12-4892 µm (548 ± 777 µm) were detected. These MPs abundances ranged from 10 to 390 MP L-1 (134 ± 93 MP L-1). In the identification of MPs detected in filters by FTIR spectroscopy, bisphenol A, which is used in the production of various plastics and described as an important public health problem, was detected in 9.74% of MPs. Within the scope of the Sustainable Development Goals, UNEP has a specific objective of ensuring access to safe, affordable drinking water (SDG 6). With a clear statement, it should be emphasised that MPs are a significant barrier to the provision of safe drinking water, and a comprehensive plan for overcoming this barrier should be developed.

Water security and health risk assessment of an urban household-level drinking water and sanitation system, Punjab, India.

The water scarcity and deteriorating water quality are major issues of concern to the agrarian state of Punjab, India. The focus of the study is to assess the status of drinking water and sanitation systems of Punjab using an exhaustive dataset of 1575 drinking water samples from 433 sampling locations in 63 urban local bodies of Punjab. Water security index(WSI) indicate that out of 63 urban local bodies, 13 are categorized into good class, 31 fall under fair class, and 19 fall under poor class. The access indicator under sanitation dimension shows that Bathinda region has maximum sewerage network coverage relative to other regions, whereas ca. 50% of the ULBs in Amritsar region do not have sewerage facility. It is clearly depicted that the variation in WSI is mainly attributable to sanitation dimension (10-22.5) as variation in water supply dimension (29-35) is relatively less. Hence,emphasis on indicators and variables of sanitation dimension is required for the improvement of overall WSI. The assessment of qualitative aspects of drinking water and health risk depicts that the drinking water quality of southwest part of the state (i.e. Malwa region) is under good quality class contrary to its poor groundwater quality. Kapurthala district shows high health risk due to the presence of trace metals despite being classified into good class within water security index. The drinking water quality is better and health risks are minimal in regions where drinking water is supplied via treated surface water sources (e.g. Bathinda region). Furthermore, the results of health risk assessment correlate with M[Formula: see text]-WaterQualityIndex outcome owing to presence of trace metals in groundwater above permissible limits. These results will help in identification of shortcomings in water supply and sanitation infrastructure and its management in urban areas.

Uncovering an Emerging Group of Halogenated Nucleobase-Derived Disinfection Byproducts in Drinking Water: Prioritization of the Highly Cytotoxic 2-Chloroadenine.

Constant efforts have been devoted to exploring new disinfection byproducts in drinking water causally related to adverse health outcomes. In this study, five halogenated nucleobases were identified as emerging disinfection byproducts in drinking water, including 5-chlorouracil, 6-chlorouracil, 2-chloroadenine, 6-chloroguanine, and 5-bromouracil. We developed a solid phase extraction-ultraperformance liquid chromatography-tandem mass spectrometry method with the limits of detection (LOD) and recoveries ranging between 0.04-0.86 ng/L and 54-93%, respectively. The detection frequency of the five halogenated nucleobases ranged from 73 to 100% with a maximum concentration of up to 65.3 ng/L in the representative drinking water samples. The cytotoxicity of the five identified halogenated nucleobases in Chinese hamster ovary (CHO-K1) cells varied with great disparity, in which the cytotoxicity of 2-chloroadenine (IC50 = 9.4 μM) is appropriately three times higher than emerging DBP 2,6-dichloro-1,4-benzoquinone (IC50 = 42.4 μM), indicating the significant toxicological risk of halogenated nucleobase-DBPs. To the best of our knowledge, this study reports the analytical method, occurrence, and toxicity of halogenated nucleobase-DBPs for the first time. These findings will provide a theoretical basis for further research on probing the relationship between its mutagenicity and human health risk.

Simple colorimetric assay using pectin hydrogel reagent coupled with camera-based photometry for trace arsenic determination.

Humans mainly ingest arsenic through contaminated drinking water, causing serious health effects. The World Health Organization (WHO) has set the permissible limit of arsenic in drinking water at 0.01 mg/L and concentrations should be regularly determined to ensure a safe supply. In this study, a leucomalachite green (LMG) pectin-based hydrogel reagent was prepared that selectively reacted with arsenic over other metals including manganese, copper, lead, iron, and cadmium. Pectin, optimized at 0.2% (w/v), was used to form the hydrogel matrix. Arsenic reacts with potassium iodate in sodium acetate buffer medium to liberate iodine that then oxidizes LMG entrapped in pectin hydrogel to form a blue product. Camera-based photometry/ImageJ software was used to monitor the color intensity, eliminating the need for a spectrophotometer. The intensity of gray in the red channel was chosen as optimal for the red, green, and blue (RGB) analysis. The colorimetric assay revealed a dynamic detection range toward arsenic solution standards of 0.003-1 mg/L, covering the WHO recommendation of below 0.01 mg/L arsenic in drinking water. The assay gave recovery rates between 97 and 109% at a 95% confidence interval, with precision of 4-9%. Concentrations of arsenic in the spiked drinking water, tap water, and pond water samples monitored by the developed method agreed well with conventional inductively coupled plasma optical emission spectrometry. This assay showed promise for on-site quantitative analysis of arsenic in water samples.

Silica nanoparticle-modified paper strip-based new rhodamine B chemosensor for highly selective detection of copper ions in drinking water.

A new rhodamine B derivative (RDB) was synthesized and utilized for the colorimetric detection of copper ions (Cu2+). This chemosensor utilized a paper strip as a support and a smartphone as a detector for on-site quantitative detection of Cu2+ in water samples. Silica nanoparticles (SiNPs) were investigated as the modifier nanoparticles to achieve uniform color on the paper strip and showed a color response 1.9-fold higher than the one without SiNPs. The RDB chemosensor-based paper strip provided high selectivity toward Cu2+ with a detection limit of 0.7mg/L, and the working concentrations for Cu2+ ranged from 1 to 17mg/L. Parallel analyses of eight drinking water samples were conducted by inductively coupled plasma optical emission spectroscopy. The results were in good agreement, indicating the practical reliability of the established method with a short assay time and high selectivity. These indicate its great potential for on-site detection of Cu2+.

Using Pgst-4::GFP-transformed Caenorhabditis elegans for drinking water quality monitoring

Biological effect-based monitoring is essential for predicting or alerting to a possible deterioration in drinking water quality. In the present study, a reporter gene assay based on oxidative stress-mediated Pgst-4::GFP induction in the Caenorhabditis elegans strain VP596 (VP596 assay) was assessed for its applicability in evaluating drinking water safety and quality. This assay was used to measure the oxidative stress response in VP596 worms exposed to six ubiquitous components (As3+, Al3+, F-, NO3--N, CHCl3, and residual chlorine) in drinking water, eight mixtures of these six components designed through orthogonal design, ninety-six unconcentrated water samples from source to tap water in two supply systems, and organic extracts (OEs) of twenty-five selected water samples. Pgst-4::GFP fluorescence was not induced by Al3+, F-, NO3--N, and CHCl3, and was significantly enhanced by As3+ and residual chlorine only at concentrations higher than their respective drinking water guideline levels. Pgst-4::GFP induction was not detected in any of the six-component mixtures. Induction of Pgst-4::GFP was observed in 9.4% (3/32) of the source water samples but not in the drinking water samples. However, a notable induction effect was revealed in the three OEs of drinking water, with a relative enrichment factor of 200. These results suggest that the VP596 assay has limited utility for screening drinking water safety by testing unconcentrated water samples; however, it offers a supplemental in vivo tool for prioritizing water samples for an enhanced quality assessment, monitoring pollutant removal performance by drinking water treatment plants, and evaluating water quality in water supplies.

Selectivity and affinity of heavy metals and radiometals for organic biomass: Implications for water remediation

ABSTRACT Due to both natural and anthropogenic causes, waterways have a history of contamination with different heavy metals and radiometals. Among these, thorium (Th,) uranium (U,) arsenic (As,) and strontium (Sr) are noteworthy threats to humans due to chemical and radiological toxicity. Previous research has focused on inorganic materials to remove these metals. However, the use of recyclable and biodegradable waste materials to remove toxic metals has risen. This study seeks to use pistachio shells as a model for heavy metal selectivity and affinity for organic biomasses. The influence of kinetics and pH on selectivity/affinity of the shell for the metals was investigated. The individual metal affinity seen was Th > U > As > Sr. Selectivity for Th and U over As and Sr was seen at pH < 6, beginning to equalize at pH > 6. The maximum uptake for all metals tested occurs at pH 5 and t ≥2 h. Uptake of these metals follows pseudo-second order, intraparticle kinetics, and Freundlich isotherm. Finally, the selectivity of the shells for heavy metals was investigated using drinking water and seawater samples, with concurrent pronounced uptake of actinides and Sr being observed.

Assessment of Selected Heavy Metals Concentration Level of Drinking Water in Gazer Town and Selected Kebele, South Ari District, Southern Ethiopia.

Drinking water quality is fundamental to human physiology and health. The aim of this study was to assess the quality of drinking water in Gazer Town and selected kebele, in south Ari district, South Omo zone, Southern Ethiopia. A total of four drinking water samples were collected from densely populated urban areas of the Gazer Town and one rural Kebele. All the collected samples were analyzed for eight heavy metals, (Cd, Co, Cu, Cr, Fe, Mn, Pb, and Zn) using standard procedures. The results were compared with other national and international standards. Among the analyzed samples, drinking water samples collected from selected kebele (Aynalem kebele), show mean concentrations heavy metals in (μg/L), (Mn (973 ± 10), Cu (1068 ± 1.5), Cr (2785 ± 25), Fe (4302 ± 15), Cd (1218 ± 18), Pb (720 ± 12), Co (1478 ± 3), and Zn (1790 ± 5)), and the results revel except, Co and Zn metals, all show concentrations higher than the national and international standards (such as USEPA (2008), WHO (2011), and New Zealand) recommended values. Among the eight heavy metals analyzed from drinking waters in Gazer Town, Cd and Cr were below the method detection than that of all sampling area. However, the concentration of Mn, Pb, Co, Cu, Fe, and Zn were ranged from mean values of 9 μg/L, 17.6 μg/L, 7.6 μg/L, 12 μg/L, 765 μg/L, and 494 μg/L, respectively. Except Pb metals, the analyzed metals in waters were below the currently recommended guidelines for drinking. Therefore, the government should adopt some treatment technologies such as sedimentation and aeration to minimize the concentration of zinc for safe drinking the water to the community of Gazer Town.

Interlaboratory comparisons of cyanotoxin analysis by ELISA and LC–MS/MS

AbstractTwo commonly used methods for cyanotoxin analysis are enzyme‐linked immunosorbent assay (ELISA) and liquid chromatography/tandem mass spectrometry (LC–MS/MS). Two rounds of interlaboratory comparisons of ELISA and LC–MS/MS analyses were conducted with 12 participating laboratories to evaluate method performances in various matrices, including cyanobacterial bloom and drinking water samples. Fifteen cyanotoxins, including 12 microcystin variants, nodularin, anatoxin‐a, and cylindrospermopsin were evaluated. The impact of sample matrices, preservatives, and quenching reagents was assessed, and no substantial effects were observed. Overall, comparable results were obtained among laboratories performing ELISA and LC–MS/MS analyses, respectively. ELISA results for fortified samples matched more closely with those from LC–MS/MS when microcystin cross‐reactivities were considered, providing data 26% closer to theoretical values on average. This study demonstrates that understanding the effect of cross‐reactivities when comparing ELISA and LC–MS/MS results and considering potential variabilities in commercial standards is important when interpreting data from these two methods.

Highly efficient ultrafiltration membrane performance of PES@microcrystalline cellulose extracted from waste fruits for the removal of BrO3− from drinking water samples

New mixed-matrix ultrafiltration membranes (MMMs) made of polyethersulfone (PES) and microcrystalline cellulose (MCC) were created utilizing a nonsolvent induced phase separation (NIPS) approach for the remediation of bromate (BrO3−) from aqueous medium. The influence of MCC integrated on the contact angle, porosity, water flux, and BrO3− adsorption performance was also examined. The addition of MCC, up to 5 wt%, resulted in a significant decline in the contact angle from 60.1° of neat PES to 43.1°, indicating an increase in membrane hydrophilicity. Moreover, MCC incorporation at 1, 3, and 5 wt% concentrations led to an enhancement in the water flux to 169, 178, and 180 L m−2 h−1, respectively, indicating the improved membrane permeability. MCC-integrated PES membranes exhibited enhanced antifouling properties, as demonstrated by the achieved high flux recovery ratio (99%) of the 5% MCC-containing membrane. Furthermore, all MCC-integrated PES membranes exhibited superior performance in the removal of bromate ions (BrO3−), with rejection rates of 60.8%, 80.2%, and 92% for 1%, 3%, and 5% MCC, respectively, which was much greater than that of the virgin PES membrane.

Fingerprinting of heavy metal and microbial contamination uncovers the unprecedented scale of water pollution and its implication on human health around transboundary Hudiara drain in South Asia

Environment and health hazards posed by the contamination of existing underground water resources are amongst the leading anthropogenic challenges in South Asia. One such major environmental hazard is posed by the transnational wastewater drain – Hudiara, which is degrading the quality of underlying aquifers. Towards a spatiotemporal assessment of Hudiara’s wastewater quality and drinking water from its adjoining areas, a total of 56 wastewater and 42 drinking water samples were obtained over seven months. Analysis of spatiotemporal data revealed a complex interplay of geogenic and anthropogenic factors underlying the HM burden leading to a high contamination factor(CF) (>6 for Mercury in wastewater and >150 for Arsenic in drinking water) and heavy metal pollution index(HPI) (>100 for 9 heavy metals). Moreover, high health risk assessment(HRA) scores (>1 for Arsenic, Mercury, Chromium, Lead, Cadmium, and Copper) indicated the unprecedented scale of drinking water contamination. A concomitant public health survey conducted in the surrounding population reported a high prevalence of gastrointestinal diseases (40%), chronic obstructive pulmonary diseases (COPD) (38.7%), dermatitis (34%), bone deformities (31%), and hepatic disorders (12%). Lastly, 16S rRNA sequences of Hudiara were submitted to the Comprehensive Antibiotic Resistance Database (CARD) and point mutations in the sequences were potentially found to confer antimicrobial resistance (AMR) against three classes of drugs including aminoglycosides, peptides, and tetracyclines. Taken together, this pilot study attempts to uncover the unprecedented scale of water contamination along the transboundary Hudiara drain thus highlighting the critical need for international regulatory action towards ameliorating its catastrophic effects on the environment.

Demographic study of fluoride excretion vs intake: Influence of variables

Urinary fluoride is a widely used biomarker in public health and epidemiological studies, globally. The present study investigates fluoride exposure and compares the effect of different variables on the sampled population of the Rohtak district, Haryana, India. The relation between fluoride intake, excretion, and retention of fluoride across different age groups is unveiled. Cross-sectional study of urine samples of 207 inhabitants between the ages 5- to 96 years and of 83 drinking water samples were analyzed to determine fluoride using an ion selective fluoride electrode (potentiometric method). Drinking water was sourced from supply water (n = 28), hand-pumped water (n = 45), well water (n = 3) and RO water (n = 7). Urine samples were categorized based on three different generations: Grandfather (GF), Father (F), and Son (S) from the 71 villages covered in the study. Mean urinary fluoride excretion was significantly correlated to age with values 4.50 ± 2.56, 3.42 ± 2.00 and 2.44 ± 1.30 mg/L, in declining order of these age groups, respectively. The percent increase in fluoride excretion in the urine over that consumed in the intake water was 83.67, 48.05 and 5.62% for GF, F and S respectively, indicating that other sources of fluoride intake were responsible for the increment. The eigenvalues of PCA are 1.36, 1.25, 1.19 and 1.18 for PC1, PC2, PC3 and PC4, respectively. In all plots p-values show statistical significance (p<0.05), except for those abstaining from alcohol in the father (FA) category. Sons in the smoking category (R2 = 0.30, P<0.001) exhibited higher fluoride excretion than non-smokers. Linear regression, PCA, Tukey's test, and radar chart methods were used to examine the relation between fluoride exposure and other variables like the water source (hand-pump, well, supply, reverse osmosis), diet (vegetarian/non-vegetarian), habits (smokers/non-smokers, alcohol consumers/non-consumers, regular/irregular brushing). Study concluded that age is the most significant variable which influences the retention and excretion of fluoride.

Hand hygiene and water quality assessment in schools of Muthanna province, Southern Iraq.

The severe drought and prolonged heat waves in Iraq have adversely affected the water quality supplied to public facilities. Schools are among the most affected facilities by water scarcity. This work aims to evaluate the level of students' hand hygiene, and the quality of municipal (MW) and drinking water (DW) in some schools of Al-Muthanna Province, Iraq. Between October 2021 and June 2022, a total of 324 water samples from 162 schools and 2,430 hand swabs (HSs) from 1,620 students (1,080 males and 540 females) were collected. Some physicochemical standards of water were assessed besides investigating faecal contamination in water and students' hands using Escherichia coli as an indicator. All MW samples were faecally contaminated with poor standards of pH, turbidity, total dissolved solids, color, and chlorine. Despite the good physicochemical standards of all DW samples, E. coli was observed in 12% of samples. Hand hygiene levels dropped by 2.5-fold within a few hours after school entry compared to early-morning levels (before school entry). Male students were 1.5- and 1.7-fold more prone to hand contamination than female students either inside or outside school, respectively. An increasing chlorine tolerance by E. coli was observed in water samples with turbidity > 5 NTU and pH > 8. The students' hand hygiene level decreases within a few hours of entering school, particularly among male students. Residual-free chlorine < 0.5 mg/L with high turbidity and alkalinity in water is insufficient for 100% prevention of E. coli contamination.

Drinking Water Quality of Water Refill Station in Gebang Raya Tanggerang

Introduction: As a drinking water provider, refill drinking water station must comply with hygiene and sanitation standards for water quality, including the microbiological value standard for clean water. This study was conducted to determine the microbial levels in refill drinking water station and analyze the drinking water quality based on sanitation hygiene observations. Methods: The study included laboratory test methods, cross-sectional analysis tests, and a descriptive analysis. Drinking water sampling and sanitation observations were performed using the total sampling technique on 17 water station. As much as 100 ml of drinking water samples were taken directly from the faucet to refill water with a sterile bottle container. Sanitary hygiene was studied through interviews using an observation sheet. Results and Discussion: The most bacteria were found at 108 per 100ml in Escherichia coli parameters and 866 per 100ml in coliform parameters in the station water samples with the Station 8 (SK) code. The interviews showed that seven station did not meet the criteria for good sanitation hygiene. Conclusion: Sanitary hygiene is carried out to reduce or eliminate bacterial contamination in drinking water. Observations and laboratory tests show that good sanitation is related to drinking water quality.

Three-dimensional porous AuNPs-decorated polyaniline array for ultrasensitive determination of trace Cd(II) and Pb(II) in drinking water

Herein, a three-dimensional porous nanomaterials AuNPs-decorated polyaniline nanowire arrays/carbon nanotube (Au-PANI-array@CNT) was constructed by modified dilute polymerization and redox reaction. The Au-PANI-array@CNT exhibited a larger specific surface area (50.03 m2 g−1) and abundant mesopores (average pore size: 19.6 nm), due to the vertical growth of PANI nanowire arrays on CNT. The Au-PANI-array@CNT composite with a three-dimensional interconnected porous structure exhibited abundant electroactive sites and high adsorption capacity, significantly enhancing the deposition and electrochemical reaction process of heavy metals. The AuNPs embedded on PANI nanowries can provide high catalytic activity and multidimensional electron transport channels, further improving the detection sensitivity. A sensing platform with ultra-high sensitivity (2091, 3890 μA μM−1 cm−2) and lower limit of detection (0.18, 0.15 nM) for Cd(II) and Pb(II) determination was developed based on the three-dimensional porous PANI composite. Furthermore, the sensing mechanism of Au-PANI-array@CNT with Cd(II) was explored by XPS and FTIR spectroscopy. The current response only decreased by 5% after being stored at room temperature for 2 months, indicating that the sensor has high reproducibility and stability. Finally, the analysis of drinking water samples verified the excellent practicability of the sensor for the simultaneous measurement of trace levels (nM) of Cd(II) and Pb(II).

An Electrochemical Screen-Printed Sensor Based on Gold-Nanoparticle-Decorated Reduced Graphene Oxide-Carbon Nanotubes Composites for the Determination of 17-β Estradiol.

In this study, a screen-printed electrode (SPE) modified with gold-nanoparticle-decorated reduced graphene oxide-carbon nanotubes (rGO-AuNPs/CNT/SPE) was used for the determination of estradiol (E2). The AuNPs were produced through an eco-friendly method utilising plant extract, eliminating the need for severe chemicals, and remove the requirements of sophisticated fabrication methods and tedious procedures. In addition, rGO-AuNP serves as a dispersant for the CNT to improve the dispersion stability of CNTs. The composite material, rGO-AuNPs/CNT, underwent characterisation through scanning electron microscopy (SEM), ultraviolet-visible absorption spectroscopy (UV-vis), Fourier-transform infrared (FTIR) spectroscopy, and atomic force microscopy (AFM). The electrochemical performance of the modified SPE for estradiol oxidation was characterised using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The rGO-AuNPs/CNT/SPE exhibited a notable improvement compared to bare/SPE and GO-CNT/SPE, as evidenced by the relative peak currents. Additionally, we employed a baseline correction algorithm to accurately adjust the sensor response while eliminating extraneous background components that are typically present in voltammetric experiments. The optimised estradiol sensor offers linear sensitivity from 0.05-1.00 µM, with a detection limit of 3 nM based on three times the standard deviation (3δ). Notably, this sensing approach yields stable, repeatable, and reproducible outcomes. Assessment of drinking water samples indicated an average recovery rate of 97.5% for samples enriched with E2 at concentrations as low as 0.5 µM%, accompanied by only a modest coefficient of variation (%CV) value of 2.7%.

Occurrence of Coliforms and Enterococcus Species in Drinking Water Samples Obtained from Selected Dairy Cattle Farms in Portugal

Microbial water quality is a major concern in the world, since the ingestion of water contaminated with microorganisms poses risks to human and animal health. The aim of this study was to evaluate the microbiological quality of drinking water on dairy cattle farms. The study was carried out to determine the occurrence of coliforms and enterococcus species in drinking water samples obtained from selected dairy cattle farms located in four different areas of Portugal (north, central, south and islands). A questionnaire was used to collect relevant information regarding farmer demographics, characteristics of the cattle farms, as well as number of animals per herd, number of adult cows, production type, water source, use of disinfectants and pasture area. In this study, a convenience sample of 32 dairy cattle farms was subjected to screening for water quality. The numbers of animals in the study were 8086 cattle, with a mean herd size of 253, of which 51.7% were cows. Coliform and enterococcus bacterial species were identified by performing the membrane filtration method. The occurrence of poor water quality was recorded in 19 (59.4%) cattle farms. Isolated bacteria included Escherichia coli (20.0%), Enterococcus faecalis (25.0%), total coliforms (65.6%) and fecal coliforms (43.8%). Farms that did not routinely perform disinfection had the worst water quality (70.8%) when compared with farms that performed disinfection (25.0%) (p = 0.022). This research revealed the importance of screening the quality of drinking water on cattle farms, which could contribute to improved animal, human and environmental health in a One Heath approach.

Toxicological characteristics of drinking water in two large-scale municipal water supply systems of a metropolitan city in Central China.

Drinking water safety is threatened by numerous toxic organic pollutants difficult to chemically monitor. This study aimed to determine the toxicological profiles of organic extracts (OEs) of water samples from source to tap in two drinking water supply systems in a metropolitan city, Central China, during different hydrological periods. Mortality, DNA damage, growth, and development of Caenorhabditis elegans were evaluated following exposure to OEs. The median lethal doses of OEs of drinking water samples (n = 48) ranged from 266 REF (relative enrichment factor) to > 1563 REF. When tested at a dose of 100 REF, 56.25% (27/48) of OEs induced genotoxicity, 4.17% (2/48) inhibited the growth, and 45.83% (22/48) decreased the offspring number in C. elegans. No clear temporal-spatial variation patterns of the OEs toxicity indicators were observed. The correlations among the toxicity indicators were generally poor. The observed toxicities were not closely related to the level of dissolved organic carbon in drinking water. These findings support using multiple endpoint bioassays, such as C. elegans-based approaches, as complementary tools to conventional chemical analysis for drinking water quality monitoring.

70 analyte PFAS test method highlights need for expanded testing of PFAS in drinking water

In this community-led pilot study we sought to investigate the utility of expanded per- and polyfluoroalkyl substances (PFAS) testing for drinking water, using a targeted analysis for 70 PFAS and the Total Oxidizable Precursor (TOP) Assay which can indicate the presence of precursor PFAS. PFAS were detected in 30 out of 44 drinking water samples across 16 states; 15 samples would exceed US EPA's proposed maximum contaminant levels for six PFAS. Twenty-six unique PFAS were identified, including 12 not covered by either US EPA Methods 537.1 or 533. An ultrashort chain PFAS, PFPrA, had the highest frequency of detection, occurring in 24 of 30 samples. It was also the PFAS reported at the highest concentration in 15 of these samples. We created a data filter to model how these samples would be reported under the upcoming fifth Unregulated Contaminant Monitoring Rule (UCMR5) requirements. All of the 30 samples with PFAS quantified by the 70 PFAS test had one or more PFAS present that would not be captured if the UCMR5 reporting requirements were followed. Our analysis suggests the upcoming UCMR5 will likely underreport PFAS in drinking water, due to limited coverage and higher minimum reporting limits. Results were inconclusive on the utility of the TOP Assay for monitoring drinking water. The results from this study provide important information to community participants regarding their current PFAS drinking water exposure. In addition, these results suggest gaps that need to be addressed by regulatory and scientific communities, in particular, the need for expanded targeted analysis of PFAS, the development of a sensitive, broad spectrum PFAS test, and further investigation into ultrashort chain PFAS.