-
Tropical Medicine & International... Nov 2021About 18% of urban households in Nigeria depend on packaged sachet water as the primary source of drinking water. This review assessed microbial contamination of these... (Meta-Analysis)
Meta-Analysis
OBJECTIVES
About 18% of urban households in Nigeria depend on packaged sachet water as the primary source of drinking water. This review assessed microbial contamination of these products with an emphasis on total coliforms and the faecal indicator bacteria (FIB) - Escherichia coli (E. coli) and thermotolerant coliforms (TTC).
METHODS
PubMed/Medline, African Index Medicus, AfroLib, Global Health Library, Embase and the ISI Web of Science databases were searched to identify original research published up to October 2020. The literature findings were synthesised narratively in line with the review objectives. To assess prevalence of microbial contamination, a random effects meta-analysis, was also conducted using the R metafor package in RStudio. The protocol for this review is registered on PROSPERO with reference number CRD 42019128474.
RESULTS
Fifty-two of 429 studies were identified for inclusion. At 53.27%, contamination prevalence was higher for total coliforms (95% CI: 39.05-66.98, I = 81%, p < 0.01, 42 studies) than FIB (12.38%, 95% CI: 7.92-18.85, I = 61%, p < 0.01, 33 studies) suggesting that treatment failure is a major contributor to the poor microbial quality reported in the included studies. Within the FIB group, the prevalence of contamination with E. coli was 13.30% (95% CI: 8.23-20.80, I = 65%, p < 0.01, 27 studies) versus 6.24% (95% CI: 1.12-28.06, I = 72%, p < 0.01, six studies) for TTCs. Other microbial contaminants reported were Pseudomonas aeruginosa, Klebsiella and Enterococcus faecalis and these showed multidrug antibiotic resistance.
CONCLUSIONS
The findings of this review highlight the need for improved regulatory oversight with more stringent monitoring of the microbial quality of sachet water products in Nigeria.
Topics: Drinking Water; Escherichia coli; Humans; Nigeria; Water Microbiology; Water Quality; Water Supply
PubMed: 34455673
DOI: 10.1111/tmi.13672 -
Water Research Jan 2021While it seems indisputable that potable water contains microplastics (MP), the actual concentrations are much debated and reported numbers vary many orders of...
While it seems indisputable that potable water contains microplastics (MP), the actual concentrations are much debated and reported numbers vary many orders of magnitude. It is difficult to pinpoint the cause of these differences, but it might be variation between waters, variation between quantification methods, and that some studies did not live up to rigorous analytical standards. Despite the urgent need to understand human exposure by drinking water, there is a lack of trustable methods generating reliable data. Essentially, proper MP assessment requires that quality assurance is in place and demonstrated, that an adequate volume of drinking water is assessed, and that differences in analytical methods are understood. This study presents a systematic and robust approach where MP down to 6.6 µm were assessed in potable water distribution systems in terms of quantity, size, shape, and material. For the first time, sub-samples were analysed by two of the most validated and complementary analytical techniques: µFTIR imaging and Py-GCMS. Both methods successfully determined low contents in drinking water. However, µFTIR and Py-GCMS identified different polymer types in samples with overall low MP content. With increasing concentration of a given polymer type, the values determined by the techniques became more comparable. Most detected MPs were smaller than 150 µm, and 32% were smaller than 20 µm. Our results indicate a potential annual uptake of less than one MP per person, suggesting that drinking potable water produced at a high-performance drinking water treatment plant represents a low risk for human health.
Topics: Drinking Water; Environmental Monitoring; Gas Chromatography-Mass Spectrometry; Humans; Microplastics; Plastics; Water Pollutants, Chemical
PubMed: 33091805
DOI: 10.1016/j.watres.2020.116519 -
Journal of Exposure Science &... May 2022Water arsenic (As) sources beyond a rural household's primary well may be a significant source for certain individuals, including schoolchildren and men working...
BACKGROUND
Water arsenic (As) sources beyond a rural household's primary well may be a significant source for certain individuals, including schoolchildren and men working elsewhere.
OBJECTIVE
To improve exposure assessment by estimating the fraction of drinking water that comes from wells other than the household's primary well in a densely populated area.
METHODS
We use well water and urinary As data collected in 2000-2001 within a 25 km area of Araihazar upazila, Bangladesh, for 11,197 participants in the Health Effects of Arsenic Longitudinal Study (HEALS). We estimate the fraction of water that participants drink from different wells by imposing a long-term mass-balance constraint for both As and water.
RESULTS
The mass-balance model suggest that, on average, HEALS participants obtain 60-75% of their drinking water from their primary household wells and 25-40% from other wells, in addition to water from food and cellular respiration. Because of this newly quantified contribution from other wells, As in drinking water rather than rice was identified as the largest source of As exposure at baseline for HEALS participants with a primary household well containing ≤50 µg/L As.
SIGNIFICANCE
Dose-response relationships for As based on water As should take into account other wells. The mass-balance approach could be applied to study other toxicants.
Topics: Arsenic; Bangladesh; Child; Drinking Water; Environmental Exposure; Humans; Longitudinal Studies; Male; Water Pollutants, Chemical; Water Supply
PubMed: 34625714
DOI: 10.1038/s41370-021-00387-5 -
Journal of the Royal Society of Medicine Dec 2019
Topics: Data Science; Drinking Water; Evidence-Based Medicine
PubMed: 31825281
DOI: 10.1177/0141076819893209 -
PloS One 2020Microplastics (MPs) are omnipresent in the environment, including the human food chain; a likely important contributor to human exposure is drinking water.
BACKGROUND
Microplastics (MPs) are omnipresent in the environment, including the human food chain; a likely important contributor to human exposure is drinking water.
OBJECTIVE
To undertake a systematic review of MP contamination of drinking water and estimate quantitative exposures.
METHODS
The protocol for the systematic review employed has been published in PROSPERO (PROSPERO 2019, Registration number: CRD42019145290). MEDLINE, EMBASE and Web of Science were searched from launch to the 3rd of June 2020, selecting studies that used procedural blank samples and a validated method for particle composition analysis. Studies were reviewed within a narrative analysis. A bespoke risk of bias (RoB) assessment tool was used.
RESULTS
12 studies were included in the review: six of tap water (TW) and six of bottled water (BW). Meta-analysis was not appropriate due to high statistical heterogeneity (I2>95%). Seven studies were rated low RoB and all confirmed MP contamination of drinking water. The most common polymers identified in samples were polyethylene terephthalate (PET) and polypropylene (PP), Methodological variability was observed throughout the experimental protocols. For example, the minimum size of particles extracted and analysed, which varied from 1 to 100 μm, was seen to be critical in the data reported. The maximum reported MP contamination was 628 MPs/L for TW and 4889 MPs/L for BW, detected in European samples. Based on typical consumption data, this may be extrapolated to a maximum yearly human adult uptake of 458,000 MPs for TW and 3,569,000 MPs for BW.
CONCLUSIONS
This is the first systematic review that appraises the quality of existing evidence on MP contamination of drinking water and estimates human exposures. The precautionary principle should be adopted to address concerns on possible human health effects from consumption of MPs. Future research should aim to standardise experimental protocols to aid comparison and elevate quality.
Topics: Drinking Water; Environmental Monitoring; Food Chain; Microplastics; Polyethylene Terephthalates; Polypropylenes; Public Health; Water Pollutants, Chemical
PubMed: 32735575
DOI: 10.1371/journal.pone.0236838 -
Archives of Razi Institute Apr 2022Protozoan parasites are very important in drinking water production systems because their cystic forms are stable in the environment and resistant to conventional...
Protozoan parasites are very important in drinking water production systems because their cystic forms are stable in the environment and resistant to conventional disinfection methods. The present study aimed to investigate protozoan parasites in the drinking water of different places in Samarra, Iraq. To this end, 100 samples of tap drinking water were collected from 10 places in Samarra, Iraq (i.e., Al-Sekek, Al-Kadesia, Alzeraa, Al-Shuhdaa, Al-Muthana, Al-Shorta, Al-Mamal, Al-Khedraa, Al-Efraz, and Al-Jubereaa), from the beginning of December to the end of February. After sample collection, water samples were examined to detect oocysts or cysts of protozoan parasites by using Direct wet smear, Lugol's iodine, and Modified Ziehle Nelseen stain methods. The results indicate that 80% of the samples under investigation were infected with protozoan parasites, and the ratio of diagnostic parasites in the samples under investigation was determined at 36% with , 23% with , and 21% with . The findings reveal the presence of protozoan parasites in the drinking water of the area under study and specify the need for a rapid improvement of the monitoring systems for the treatment of drinking water to control diseases caused by these pathogens, as well as to identify the sources of contamination.
Topics: Animals; Drinking Water; Cryptosporidiosis; Cryptosporidium; Parasites; Iraq
PubMed: 36284936
DOI: 10.22092/ARI.2022.357106.1977 -
Environmental Geochemistry and Health Dec 2023This study analyzed the effect of China's fluorosis prevention and control program, which has been in effect for more than 40 years, and the impact of fluorosis on...
This study analyzed the effect of China's fluorosis prevention and control program, which has been in effect for more than 40 years, and the impact of fluorosis on children's health. Relevant research studies were retrieved from the following online databases from the time of their inception to May 2022: PubMed, ScienceDirect, Embase, Cochrane, China National Knowledge Infrastructure, and Wanfang. The Review Manager 5.3 software was used in statistical analyses. This article included seventy studies: Thirty-eight studies reported the effect of improving water quality and reducing fluoride content, the incidence rate of dental fluorosis in children, and the level of urinary fluoride, and thirty-two studies reported the intelligence quotient (IQ) and health status of children. Following water improvement strategies, the fluoride levels in drinking water decreased significantly; urinary fluoride levels and dental fluorosis decreased significantly in children. With regard to the effect of fluorosis on the IQ of children, the results showed that the IQ of children in areas with a high fluoride of fluorosis was lesser than that in areas with a low fluoride, and this difference was significant. Based on the prevalence of dental fluorosis and its effect on the intelligence of children, it appears that reducing fluoride levels in drinking water and monitoring water quality are important strategies for the prevention and treatment of fluorosis.
Topics: Child; Humans; Fluorides; Fluorosis, Dental; Drinking Water; Child Health; Fluoride Poisoning; China; Prevalence
PubMed: 37906380
DOI: 10.1007/s10653-023-01772-9 -
Dental and Medical Problems 2023Endemic fluorosis (skeletal and dental) is a serious public health problem in many parts of the world, especially in India. Age, sex, dietary calcium (Ca), the hormonal...
BACKGROUND
Endemic fluorosis (skeletal and dental) is a serious public health problem in many parts of the world, especially in India. Age, sex, dietary calcium (Ca), the hormonal status, the dose and duration of the fluoride intake, and renal efficiency in handling fluoride all influence fluoride metabolism.
OBJECTIVES
The aim of the study was to evaluate the effect of the fluoride present in drinking water on the serum alkaline phosphatase (ALP) and phosphate levels in pregnant women and newborn infants.
MATERIAL AND METHODS
In the present cross-sectional study, the participants were categorized into 2 groups based on a fluoride concentration in their drinking water: the low/optimum-fluoride group (<1 ppm); and the high-fluoride group (≥1 ppm). Each group was comprised of 90 pregnant women who were recruited from the hospital at the time of admission for delivery. Fluoride was measured in their drinking water, urine, maternal serum, and cord blood. The ALP and phosphate levels were measured in serum using a fully automated analyzer.
RESULTS
The drinking water consumed by the pregnant women contained fluoride, which was significantly positively correlated with the urine and blood serum fluoride levels. There were significant differences in the ALP levels between the 2 groups in both maternal serum and cord blood. The level of phosphate in maternal serum was significantly higher in the high-fluoride group. The results of both simple and multivariate regression analyses revealed that the fluoride content in drinking water was significantly associated with the ALP level in cord blood and the phosphate level in maternal serum.
CONCLUSIONS
The ALP levels were negatively associated with drinking water fluoride concentrations in both maternal serum and cord blood. The phosphate levels in maternal serum were positively associated with drinking water fluoride concentrations.
Topics: Infant, Newborn; Humans; Female; Pregnancy; Fluorides; Drinking Water; Alkaline Phosphatase; Pregnant Women; Cross-Sectional Studies; Phosphates
PubMed: 37555277
DOI: 10.17219/dmp/132692 -
Analytical and Bioanalytical Chemistry Oct 2021Microplastics are a widespread contaminant found not only in various natural habitats but also in drinking waters. With spectroscopic methods, the polymer type, number,... (Review)
Review
Analysis of microplastics in drinking water and other clean water samples with micro-Raman and micro-infrared spectroscopy: minimum requirements and best practice guidelines.
Microplastics are a widespread contaminant found not only in various natural habitats but also in drinking waters. With spectroscopic methods, the polymer type, number, size, and size distribution as well as the shape of microplastic particles in waters can be determined, which is of great relevance to toxicological studies. Methods used in studies so far show a huge diversity regarding experimental setups and often a lack of certain quality assurance aspects. To overcome these problems, this critical review and consensus paper of 12 European analytical laboratories and institutions, dealing with microplastic particle identification and quantification with spectroscopic methods, gives guidance toward harmonized microplastic particle analysis in clean waters. The aims of this paper are to (i) improve the reliability of microplastic analysis, (ii) facilitate and improve the planning of sample preparation and microplastic detection, and (iii) provide a better understanding regarding the evaluation of already existing studies. With these aims, we hope to make an important step toward harmonization of microplastic particle analysis in clean water samples and, thus, allow the comparability of results obtained in different studies by using similar or harmonized methods. Clean water samples, for the purpose of this paper, are considered to comprise all water samples with low matrix content, in particular drinking, tap, and bottled water, but also other water types such as clean freshwater.
Topics: Drinking Water; Guidelines as Topic; Microplastics; Practice Guidelines as Topic; Spectrophotometry, Infrared; Spectrum Analysis, Raman; Water Pollutants, Chemical
PubMed: 34283280
DOI: 10.1007/s00216-021-03498-y -
Journal of Affective Disorders Feb 2022In recent decades, a series of ecological studies from various countries have attempted to reveal whether there is an association between trace amounts of lithium in...
BACKGROUND
In recent decades, a series of ecological studies from various countries have attempted to reveal whether there is an association between trace amounts of lithium in drinking water and suicide mortality. With some notable exceptions, results have indicated that there is an inverse association between these two variables. Since Hungary had extremely high rates of suicide with a persistent spatial pattern, we consider that our country is ideal to investigate this research question.
METHODS
We carried out our research on Hungarian data at the level of districts (n = 197). The dependent variable was the age- and gender-standardized mortality ratio for suicide (sSMR). Our main explanatory variable was the tap water lithium level (Li) from public drinking water supply systems using their own water source (n = 1 325). Those data, which give full national coverage, were aggregated to the level of districts. Confounding factors were religiosity, alcohol consumption and income. Various regression models were used for statistical calculations.
RESULTS
Findings from our most appropriate regression model - adjusted for relevant confounding variables and able to handle spatial autocorrelation and heteroscedasticity - suggest a significant (p < 0.05) and a trend-like (p < 0.1) negative association between Li and sSMR in the total population and among males, respectively. However, such an association was not found between these two variables among females.
CONCLUSION
In line with the majority of findings from other countries, our results indicate that the intake of lithium with drinking water may have a gender-dependent suicide-protective effect.
Topics: Drinking Water; Female; Humans; Hungary; Income; Lithium; Male; Suicide
PubMed: 34800573
DOI: 10.1016/j.jad.2021.11.041