Depth and Well Type Related to Groundwater Microbiological Contamination.
ABSTRACT: Use of groundwater from private wells in households has increased considerably, owing to a better cost/benefit ratio than that of water provided by local utilities for a fee. However, this water is usually untreated, which makes it a vehicle for diseases. Thus, monitoring this water is necessary to ensure its integrity and quality. We aimed to evaluate the physical, chemical, and microbiological parameters of untreated groundwater drawn from different types of wells, and the antimicrobial susceptibility profile of the bacteria isolated from this water. Wellwater samples were collected in two Brazilian cities. Although physical and chemical parameters of the water were suitable for drinking, Escherichia coli was detected in 33% of the samples. E. coli contaminated 65% of dug wells and 10.25% of drilled wells. Many bacteria isolated were resistant to multiple antibacterial agents, including ?-lactams. Microbial contamination of this water was related to the well depth, and was more common in dug wells, making this water unfit for human consumption. Consumption of such contaminated and untreated water is a public health concern. Thus, individuals who regularly use such water must be alerted so they may either take preventive measures or connect to the water distribution system operated by local utilities.
Project description:The groundwater of volcanic aquifers, dissected by various structures and affected by several volcanic eruption events, varies in quality. A large number of rural people depend on shallow aquifers tapped by shallow hand wells and springs. On the other hand, the urban population is dependant on deep aquifers using drilled boreholes. The location of springs, shallow hand-dug wells and boreholes inside or close to farmlands, and the advancement of irrigation water use from groundwater by the government entail the assessment of groundwater quality. Therefore, the focus of the present study is to determine the quality and suitability of groundwater around Dangila Town, Northwest Ethiopia, for drinking and irrigation uses. The water quality assessment was conducted by collecting groundwater samples from 14 shallow hand-dug wells, 4 springs, and 7 deep boreholes then analysing for different physical and chemical parameters.A total of 25 selected groundwater samples from shallow and deep aquifers were analysed in a laboratory for physical and chemical parameters. The physical parameters measured both in the field and the laboratory included pH, electrical conductivity (EC) and total dissolved solids (TDS). The chemical parameters analysed in the laboratory comprised cations of calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), Iron (Fe), manganese (Mn2+) and anions of bicarbonate (HCO3-), sulfate (SO42-), carbonate (CO32-), chlorine (Cl-), nitrate (NO3-), fluoride (F-), and boron (B). Based on the laboratory results, the variation in groundwater facies, and major cation and anion sources were determined. Furthermore, the groundwater quality for human consumption was assessed and sodium adsorption ratio (SAR), Na%, and the residual sodium carbonate (RSC) values, which are crucial to determine the overall groundwater quality for irrigational uses, were calculated. Detailed interpretations of the data have been presented in the paper entitled “Hydrogeological framework of the volcanic aquifers and groundwater quality in Dangila Town and the surrounding area, Northwest Ethiopia” . The presented dataset demonstrates the necessity of water quality assessments that would be helpful to water sectors, government, and policymakers for sustainable groundwater management.
Project description:Background:Groundwater quality can be poor in Nigeria due to indiscriminate refuse dumping. Exposed dumps serve as point source pollution that discharge potentially toxic heavy metals into the environment. Objectives:The present research aimed to assess the impact of metal pollution on groundwater quality in hand-dug wells around an active dumpsite and to evaluate the long-term human health effects of this pollution. Methods:Water samples from hand-dug wells used for drinking, irrigation and domestic purposes were collected around the dumpsite. Two samples were collected at each location for cation and anion analyses. Samples for cation analysis were acidified with concentrated hydrochloric acid to preserve the elements in the samples, while those for anion analysis were not acidified. Collected samples were analyzed using inductively coupled plasma mass spectrometry and atomic absorption spectroscopy. Results:Mean concentrations of metals and physical parameters were compared with the World Health Organization's standards (2012). All samples were found to be within permissible limits, except for arsenic (As) (0.13 mg/L), potassium (K) (29.94 mg/L), lead (Pb) (0.38 mg/L), cadmium (Cd) (0.003 mg/L) and average temperature (31.93°C) as a result of corroded service pipes containing Pb in the dumpsites and the reaction of leachates with various materials such as used battery, tins, and electronic wastes which later leaked into the groundwater. The geoaccumulation index revealed Pb to be moderately to highly contaminated in groundwater. Conclusions:Heavy metal pollution can cause deleterious health effects that can lead to short- and long-term diseases such as keratosis (skin hardening), lung cancer, bladder cancer and ultimately death if proactive steps are not taken. Disposal bags should be provided to all houses in the area, as well as guaranteed waste disposal trucks and dispose of waste at approved sites. In addition, enforcement agents should ensure compliance with rules and regulations. A centralized, deep, double-cased well should be constructed in a clean environment in the study area for drinking and domestic use. Competing Interests:The authors declare no competing financial interests.
Project description:The objective of this study was to examine three well designs: drilled wells (20-30 m deep), closed dug wells (>5 m deep), and hand-dug open wells (<5 m deep), to determine the water quality for improving access to safe and clean water in rural communities. Heterotrophic plate count (HPC), total coliforms (TC), Escherichia coli (E. coli) and turbidity, were used to assess the water quality of 97 wells. Additionally, the study looked at the microflora diversity of the water, focusing on potential pathogens using outgrowth, PCR, and genome sequencing for 10 wells. Concentrations of TC for the open dug wells (4 × 10? CFU/100 mL) were higher than the drilled (2 × 10³ CFU/100 mL) and closed dug wells (3 × 10³ CFU/100 mL). E. coli concentration for drilled and closed dug wells was <22 MPN (most probable number)/100 mL, but higher for open wells (>154 MPN/100 mL). The drilled well turbidity (11 NTU) was within the standard deviation of the closed well (28 NTU) compared to open dug wells (49 NTU). Drilled and closed wells had similar microbial diversity. There were no significant differences between drilled and closed dug wells. The covering and lining of hand-dug wells should be considered as an alternative to improve access to safe and clean water in rural communities.
Project description:The dataset for this article contains geostatistical analysis of the level to which groundwater quality around a municipal waste dumpsite located in Oke-Afa, Oshodi/Isolo area of Lagos state, southwestern has been compromised for drinking. Groundwater samples were collected from eight hand-dug wells and two borehole wells around or near the dumpsite. The pH, turbidity, salinity, conductivity, total hydrocarbon, total dissolved solids (TDS), dissolved oxygen, chloride, Sulphate (SO4), Nitrate (NO3) and Phosphate (PO4) were determined for the water samples and compared with World Health Organization (WHO) drinking water standard. Notably, the turbidity, TDS, chloride and conductivity of some of the samples were above the WHO acceptable limits. Also, high quantities of heavy metals such as Aluminum and Barium were also present as shown from the data. The dataset can provide insights into the health implications of the contaminants especially when the mean concentration levels of the contaminants are above the recommended WHO drinking water standard.
Project description:Bladder cancer mortality rates have been elevated in northern New England for at least five decades. Incidence rates in Maine, New Hampshire, and Vermont are about 20% higher than the United States overall. We explored reasons for this excess, focusing on arsenic in drinking water from private wells, which are particularly prevalent in the region.In a population-based case-control study in these three states, 1213 bladder cancer case patients and 1418 control subjects provided information on suspected risk factors. Log transformed arsenic concentrations were estimated by linear regression based on measurements in water samples from current and past homes. All statistical tests were two-sided.Bladder cancer risk increased with increasing water intake (Ptrend = .003). This trend was statistically significant among participants with a history of private well use (Ptrend = .01). Among private well users, this trend was apparent if well water was derived exclusively from shallow dug wells (which are vulnerable to contamination from manmade sources, Ptrend = .002) but not if well water was supplied only by deeper drilled wells (Ptrend = .48). If dug wells were used pre-1960, when arsenical pesticides were widely used in the region, heavier water consumers (>2.2?L/day) had double the risk of light users (<1.1?L/day, Ptrend = .01). Among all participants, cumulative arsenic exposure from all water sources, lagged 40 years, yielded a positive risk gradient (Ptrend = .004); among the highest-exposed participants (97.5th percentile), risk was twice that of the lowest-exposure quartile (odds ratio = 2.24, 95% confidence interval = 1.29 to 3.89).Our findings support an association between low-to-moderate levels of arsenic in drinking water and bladder cancer risk in New England. In addition, historical consumption of water from private wells, particularly dug wells in an era when arsenical pesticides were widely used, was associated with increased bladder cancer risk and may have contributed to the New England excess.
Project description:Arsenic contamination of drinking water is a serious public health threat. In Bangladesh, eight major safe water options provide an alternative to contaminated shallow tubewells: piped water supply, deep tubewells, pond sand filters, community arsenic-removal, household arsenic removal, dug wells, well-sharing, and rainwater harvesting. However, it is uncertain how well these options are accepted and used by the at-risk population. Based on the RANAS model (risk, attitudes, norms, ability, and self-regulation) this study aimed to identify the acceptance and use of available safe water options. Cross-sectional face-to-face interviews were used to survey 1,268 households in Bangladesh in November 2009 (n = 872), and December 2010 (n = 396). The questionnaire assessed water consumption, acceptance factors from the RANAS model, and socioeconomic factors. Although all respondents had access to at least one arsenic-safe drinking water option, only 62.1% of participants were currently using these alternatives. The most regularly used options were household arsenic removal filters (92.9%) and piped water supply (85.6%). However, the former result may be positively biased due to high refusal rates of household filter owners. The least used option was household rainwater harvesting (36.6%). Those who reported not using an arsenic-safe source differed in terms of numerous acceptance factors from those who reported using arsenic-safe sources: non-users were characterized by greater vulnerability; showed less preference for the taste and temperature of alternative sources; found collecting safe water quite time-consuming; had lower levels of social norms, self-efficacy, and coping planning; and demonstrated lower levels of commitment to collecting safe water. Acceptance was particularly high for piped water supplies and deep tubewells, whereas dug wells and well-sharing were the least accepted sources. Intervention strategies were derived from the results in order to increase the acceptance and use of each arsenic-safe water option.
Project description:The present study was conducted to evaluate the groundwater quality and its suitability for irrigation purpose through GIS in villages of Chabahr city, Sistan and Baluchistan province in Iran. This cross-sectional study was carried out from 2010 to 2011 the 1-year-monitoring period. The water samples were collected from 40 open dug wells in order to investigate the water quality. Chemical parameters including EC, SAR, Na+, Cl-, pH, TDS, HCO3- and IWQI were analyzed. In order to calculate the irrigation water quality index subsequent five water quality parameters (EC, SAR, Na+, Cl-, and HCO3- ) were utilized. Among the total of 40 samples were analyzed for IWQI, 40% of the samples classified as excellent water, 60% of the samples in good water category.
Project description:Deep aquifers in South and Southeast Asia are increasingly exploited as presumed sources of pathogen- and arsenic-free water, although little is known of the processes that may compromise their long-term viability. We analyze a large area (>1,000 km(2)) of the Mekong Delta, Vietnam, in which arsenic is found pervasively in deep, Pliocene-Miocene-age aquifers, where nearly 900 wells at depths of 200-500 m are contaminated. There, intensive groundwater extraction is causing land subsidence of up to 3 cm/y as measured using satellite-based radar images from 2007 to 2010 and consistent with transient 3D aquifer simulations showing similar subsidence rates and total subsidence of up to 27 cm since 1988. We propose a previously unrecognized mechanism in which deep groundwater extraction is causing interbedded clays to compact and expel water containing dissolved arsenic or arsenic-mobilizing solutes (e.g., dissolved organic carbon and competing ions) to deep aquifers over decades. The implication for the broader Mekong Delta region, and potentially others like it across Asia, is that deep, untreated groundwater will not necessarily remain a safe source of drinking water.
Project description:As rural African communities experience more frequent and extreme droughts, it is increasingly important that water supplies are climate resilient. Using a unique temporal dataset we explore rural water supply (n?=?5196) performance during the 2015-16 drought in Ethiopia. Mean functionality ranged from 60% for motorised boreholes to 75% for hand-pumped boreholes. Real-time monitoring and responsive operation and maintenance led to rapid increases in functionality of hand-pumped and, to a lesser extent, motorised boreholes. Increased demand was placed on motorised boreholes in lowland areas as springs, hand-dug-wells and open sources failed. Most users travelled >1?h to access motorised boreholes but <30?min, increasing to 30-60 mins, for hand-pumped boreholes. Boreholes accessing deep (>30?m) groundwater performed best during the drought. Prioritising access to groundwater via multiple improved sources and a portfolio of technologies, such as hand-pumped and motorised boreholes, supported by responsive and proactive operation and maintenance, increases rural water supply resilience.
Project description:During floods, human exposure to pathogens through contaminated water leads to the outbreak of epidemic diseases. This research presents the first extensive assessment of surface and groundwater samples collected immediately after a flood (December 2015) and post-flood (April 2016) from the Adyar River of Chennai, a major city in India, for major ions, trace metals, bacterial population, and pathogens. Severe rains in a short period of time resulted in flooding which inundated the wells, allowing the entry of sewage contaminated river water into the groundwater zone. This has led to bacterial counts and chemical ions exceeding Bureau of Indian Standard's recommended limits in most flood affected areas. Pathogens isolated from the groundwater showed resistance to antibiotics, namely ceftriaxone, doxycycline and nalidixic acid. However, they were sensitive to chloramphenicol, ciprofloxacin, norfloxacin, and tetracycline. Determining the antibiotic susceptibility of pathogens will help in the treatment of humans affected by contaminated water through an appropriate selection of prescribed medication.