A turn-on hydrazide oxidative decomposition-based fluorescence probe for highly selective detection of Cu2+ in tap water as well as cell imaging

Dhaka is the most populous city in Bangladesh and the tenth-largest metropolitan in the world with about twelve million inhabitants. Most people of Dhaka have low or middle ranged incomes and frequently use roadside mid range restaurants to take their meals and drinking water. Water quality is a significant health concern in Bangladesh and is a probable source of many water borne diseases and outbreaks. Tap water and dispenser water samples were collected from ten roadside restaurants. These samples were analyzed for pH, salinity, conductivity, TDS (total dissolved solid) for physicochemical quality analysis while total coliform, faecal coliform and total heterotrophic bacterial counts were determined for microbiological quality analysis. All the samples conformed to the WHO standards of TDS, salinity and conductivity. Except for 20% of the tap water samples, pH of all the samples was found to be satisfactory. The heterotrophic plate count was in a range of 8.0 x 101 cfu/ml to 9.3 x 105 cfu/ml from tap water sample and 6.5 x 101 cfu/ml to TNTC from dispenser water samples. Only 10% of the tap water samples and 30% of the dispenser water samples complied with the WHO stipulated limit of total heterotrophic count (100 cfu/ml). In terms of total coliforms, all the tap water samples and 20% of the dispenser water samples were found to be contaminated, whereas 50% of both the tap water and dispenser water samples were contaminated with faecal coliforms, indicating possible faecal contamination and presence of pathogenic bacteria. By comparing coliform/faecal coliform count on tap and dispenser water it was found that dispenser water is safer than tap water.Bangladesh J Microbiol, Volume 31, Number 1-2,June-Dec 2014, pp 69-72

In Uganda, tap water is always ensured to be potable. However, people are not sure whether tap water is generally safe for drinking without being boiled. Conversely, bottled water consumption is on the increase in Uganda. The main problem lies in the cost of energy for boiling tap water or purchasing bottled water. This study analyzed results of laboratory tests and consumers' perception for comparison of tap and bottled water in Nakawa division, Kampala. Tap water was sampled at four representative locations. At least 16 different brands of bottled water were considered. The top four most consumer-preferred bottled water brands were selected for further analysis. In our study, 28.8%, 6.06%, and 13.64% of the 142 respondents indicated that bottled water had taste, color, and smell, respectively. However, 27.5%, 25.4%, and 34.5% of the respondents agreed that tap water had taste, color, and smell, respectively. Both tap and bottled water met the World Health Organization (WHO) guidelines for pH, total dissolved solids, chloride, copper, sodium, sulfate, and nitrate. However, a tap water sample was found to contain Coliform bacteria. In this line, affected communities need to thoroughly boil the raw tap water to kill the pathogens. All tap water samples yielded iron concentrations above the WHO recommended limit. Student's t-tests showed that tap and bottled water samples were significantly (p<0.05) different with respect to total dissolved solids, pH, chloride, calcium, magnesium, iron, sodium, sulfate, and nitrate. We emphasize the need for routine maintenance of the water distribution system to check for leakages which can be potential source of contaminations.

In this study, the concentrations of anions and potentially toxic elements in thirty-four drinking water samples consumed in the Nevşehir province located in the Cappadocia region were determined to assess their chemical quality for human consumption using an ion chromatography system and inductively coupled plasma optical emission spectrometer. The average concentrations of Cl, F, NO3, and SO4 2 analysed in tap and bottled drinking water samples were found as 19,485, 521, 31,840 and 34,456 μg L−1 and 2290, 35, 2631 and 5242, μg L−1, respectively. The average concentrations of Pb, Cd, Co, Sr, Hg, Cu, Fe, Mn, Ni and Zn analysed in tap water samples were found as 5.2, 2.4, 2.4, 429.0, 1.7, 12.7, 94.7, 1.7, 1.3 and 199.5 μg L−1, respectively. The chemical analysis results obtained were compared with permissible maximum concentrations set by the national and international regulations. The Pb concentrations analysed in two tap water samples are above the maximum concentration of 10 µg L−1. The Hg concentrations analysed in 54% and 62% of tap and bottled drinking water samples are above the maximum concentration of 1 µg L−1, respectively. Also, average daily dose (ADD), health quotient (HQ), and cancer risk index (CRI) were estimated for adults to assess the health hazards caused by potentially toxic elements in drinking water samples. The HQ values estimated for selected potentially toxic elements are below the risk limit of 1 and there is no significant non–carcinogenic risk to the exposed adults. The average values of CRI estimated for As in three tap water samples and Cd in tap and bottled water samples exceeded the safe index range and these elements can pose a significant carcinogenic risk to the exposed adults.

Assessment of perfluoroalkyl substances levels in tap and bottled water samples from Turkey

In this study, the concentrations of potentially toxic elements (Cd, Co, Cr, Cu, Fe, Ni, Mn, Zn, Pb, and As) and radon (222Rn) in forty-five drinking water (tap and bottled water) samples consumed in Kastamonu (Turkey) were analysed using an inductively coupled plasma optical emission spectrometry and radon gas analyser, respectively. Also, the total annual effective dose due to ingestion and inhalation of 222Rn in drinking water samples was estimated for infants, children, and adults to assess the radiological risk caused by hazards by considering three different annual water intake scenarios. While the concentrations of Cd, Co, Cr, Fe, Mn, and Pb analysed in tap water samples were below the detection limit, the As concentration analysed in two tap water samples was higher than the maximum concentration recommended by national and international organisations. The concentration of Cd and Pb analysed in one bottled water sample was higher than the recommended maximum concentration values. The average activity concentration of 222Rn analysed in tap and bottled water samples was found as 35.7 mBq L−1 and 16.1 mBq L−1, respectively. The average total annual effective dose was found as 0.28, 0.18 and 0.24 µSv for infants, children and adults, respectively. These radiological values are lower than the recommended limits for drinking water by the WHO. The results of the study revealed that tap water is of better chemical quality than bottled water in terms of some toxic elements analysed and the radiological risk caused by radon in drinking water samples studied is at a negligible level.

The present work focussed on the concerns of the existence of coliform, faecal coliform, and other pathogens in both tap water and commercially available bottled water, along with the drug resistant pattern of the isolates. The physico-chemical features of the bottled water samples were satisfactory, but most of the tap water exceeded the marginal limit. A total of 21 samples (10 of tap water and 11 of bottled water) were collected and processed for microbiological analysis. All the samples were found to be contaminated with total viable bacteria up to 108 CFU/mL. Among the 21 samples, seven samples were found to be contaminated with E. coli up to 106 CFU/mL, and six samples had Klebsiella spp. up to 102 CFU/mL. Faecal contamination was totally absent in all bottled water, but present in four tap water samples. Fungi was found in six samples within the range of 102 to 103 CFU/mL. Surprisingly, Staphylococcus spp. were observed in all bottled water. Vibrio spp. were detected in three samples. An elevated number of faecal coliforms, Klebsiella spp., Salmonella spp., Shigella spp., Vibrio spp., and Pseudomonas spp. were estimated among the tap water samples up to 105 CFU/mL. The water samples, especially tap water, collected from the different areas were microbiologically unsafe, as few pathogenic microorganisms were found in several samples. This indicated as public health threat. Most of the isolates from both tap and bottled water samples were found to be resistant against more than one antibiotic tested, which is extremely alarming for the consumers. Very few antibiotics were found to be effective against the bacterial isolates.

Occurrence, efficiency of treatment processes, source apportionment and human health risk assessment of pharmaceuticals and xenoestrogen compounds in tap water from some Ghanaian communities

Synthetic Microplastics in UK tap and bottled water; Implications for human exposure

Tap water quality concerns and advertisements often drive increased bottled water consumption, especially in communities with historical tap water quality problems (e.g., Nogales, Arizona). The study objective was to assess contamination of municipal tap and bottled water in Nogales, Arizona. Bottled (sealed, open/partially consumed bottles, and reusable containers for vended water) and tap water samples were collected from 30 homes and analyzed for chemical and microbial contaminants. Fisher exact tests and Wilcoxon rank sum tests were used to compare proportions of positive samples and contaminant concentrations between tap and bottled water samples. While none of the chemical contaminants were above MCLs, there were statistically significantly greater concentrations and proportions of positive samples for some contaminants, including arsenic, in tap vs. bottled water. E. coli concentrations were >0 CFU/100mL in some unsealed bottled water samples but not for sealed bottles. This study demonstrates that 1) the measured concentrations in tap and bottled water likely pose low risks, as they are below the MCLs, 2) more education in this community on hygiene maintenance of refillable or opened bottled water containers is needed, and 3) using tap water over bottled water is advantageous due to likely lower E. coli risk and lower cost.

Strontium isotope analysis has proven useful in geo‐location investigations of organic and inorganic materials and may complement the region‐of‐origin information provided by hydrogen and oxygen stable isotope analysis. In this study, we analyzed 99 drinking (tap) water samples collected from 95 municipal water systems across the USA to investigate the potential that 87Sr/86Sr can be used to provenance samples from managed hydrological systems. Results from a leaching and exchange experiment demonstrated that non‐ideal storage conditions did not prohibit Sr isotope analysis of previously archived water samples stored in glass. Tap water samples were analyzed via multi‐collector inductively coupled plasma mass spectrometry, which was preceded by a novel, automated, in‐line Sr purification method. Measured tap water 87Sr/86Sr was compared to expected 87Sr/86Sr for collection location, which was predicted using four published isotope landscape (isoscape) models: age of bedrock (bedrock model), age plus major and minor lithology of bedrock (major bedrock model), weathering of Sr from rock (local water model), and surface fluxes within watershed (catchment model). The geologic history of the geographic regions represented by collected tap waters was diverse and we therefore expected significant covariation in measured and modeled 87Sr/86Sr values. Tap water exhibited large ranges in both Sr concentration (0–1.9 mg/L) and 87Sr/86Sr (0.7037–0.7320). Measured tap water 87Sr/86Sr ratios were significantly and positively correlated with predictions based on bedrock and catchment models. However, these bedrock and catchment models explained relatively little of the tap water Sr isotopic variation (∼10% and 17%, respectively), suggesting that the factors affecting drinking water 87Sr/86Sr are complex and more numerous than the variables included in current water models. This could be due to the reliance of some municipal water systems on groundwater, rather than surficial water sources; the natural movement of water across distinct geologic gradients; and/or the managed transport of water from source to point‐of‐use. Although published isoscape models for predicting Sr isotopic variation within the continental USA are reasonable approaches for estimating surface water 87Sr/86Sr, additional efforts are needed to develop a prediction model specifically for tap water 87Sr/86Sr.

Elevated concentrations of bromate in Drinking water and groundwater from Kuwait and associated exposure and health risks

Boron exposure assessment using drinking water and urine in the North of Chile

In this paper, we report a highly selective and sensitive ratiometric NIR fluorescent probe that can be used for real-time detection of the biologically important hypochlorite with colorimetric and significant NIR fluorescent turn-on signal changes at NIR excitation wavelength. In addition, experiments showed that this probe can be applied to detect hypochlorite in tap water, serum samples, and living cells with low cytotoxicity.

In order to research the origin of taste of so-called "delicious natural water", chemical components of tap and natural water samples were measured and compared to each other. The values of pH, carbonate ion, KMnO4-consumed values and ion levels in the samples were determined by the officially established methods for drinking water. Twenty-one kinds of tap water samples were collected from the domestic water supply of Hyogo, Osaka and Nara prefectures. On the other hand, 10 kinds of natural water samples were collected from Hyogo, Osaka and Nara prefectures, while the other 11 samples purchased at markets were originated from several parts of Japan. The tap water samples gave significantly higher values on the KMnO4-consumed values and the concentrations of chloride and sulfate ions and iron (Fe2++Fe3+) than the respective data in the natural water samples. In contrast, the concentrations of carbonate ion in the natural water samples were significantly higher than those in the tap water samples.

Evaluation of methods used to concentrate and detect hepatitis A virus in water samples