Rural Groundwater Research Articles

Mapping fecal pollution in rural groundwater supplies by means of artificial intelligence classifiers

Fecal contamination poses a threat to groundwater supplies in low income regions. This is often due to the coexistence of pit latrines with domestic wells in densely populated areas. In this context, developing alternative methodologies to map fecal pollution in shallow wells is needed. A thorough survey of over 240 domestic wells and 570 pit latrines was conducted in a rural town of southern Mali. Water samples were collected from all wells and tested for temperature, pH, electric conductivity, total dissolved solids, turbidity and thermotolerant coliforms. The outcomes of the field survey were incorporated into a GIS database. Thirteen machine leaning classifiers, including different statistical algorithms, instance-based learners and tree-based models, were used to determine the spatial distribution of fecal pollution as per five explanatory variables (latrine density, distance to the closest latrine, borehole yield, water table depth and population density). The best performing classifiers, selected on test scores, were then used to develop predictive maps. Random forest and logistic regression rendered prediction scores for fecal pollution in excess of 0.90. Multilayer perceptrons, support vector machines and quadratic discriminant analyses also proved adept at forecasting fecal pollution. Ensemble mapping shows that 30–50 m buffers around domestic wells may be sufficient to prevent contamination of domestic supplies in most instances. This demonstrates that machine learning may provide a versatile methodological alternative to traditional Darcian approaches. On the other hand, the practical difficulties involved in maintaining wellhead protection areas suggests the need to implement piped water supplies.

Evaluation of arsenic field test kits as a learning exercise for engineering students in global water and sanitation class

Around 150 million people in more than 70 countries around the world are exposed to elevated levels of naturally occurring arsenic in groundwater used for drinking and cooking. Inexpensive arsenic field test kits are readily commercially available and have been promoted for classifying the safety of water sources. However, the accuracy and reliability of test kits has been called into question by some researchers. The purpose of this project was to provide decision support to a small nonprofit community development organization in central Mexico regarding the applicability of field test kits for assessing the safety of rural groundwater supplies. Test kit evaluation was conducted as an experiential learning exercise for undergraduate and graduate students in a University engineering course on Global Water and Sanitation. Recounting the scale and scope of the ongoing arsenic crisis in Bangladesh, as well as the sensational epidemic of “arsenical beer” in Manchester, England in 1900 that popularized the Gutzeit chemistry upon which test kits are based, spurred student interest and enthusiasm for the learning activities. Reviewing the contradictory and inconclusive literature from the recent two decades on the use of test kits provided a sobering case study for students to grapple with the difficulties and uncertainties inherent in conducting humanitarian science and engineering in the developing world. This study found generally poor performance of test kits, in particular for waters containing As in excess of 95 mg/L.The field kits tested could not be used to classify waters as “safe,” i.e., below the WHO Guideline Value of 10 mg/L to 95% level of confidence. This study lends further caution to the use of test kits for identification of safe water sources.

Understanding the Functionality and Burden on Decentralised Rural Water Supply: Influence of Millennium Development Goal 7c Coverage Targets

The sustainability of rural groundwater supply infrastructure, primarily boreholes fitted with hand pumps, remains a challenge. This study evaluates whether coverage targets set out within the Millennium Development Goals (MDG) inadvertently increased the challenge to sustainably manage water supply infrastructure. Furthermore, the drive towards decentralised service delivery contributes to the financial burden of water supply assets. A sample size of 14,943 Afridev hand pump boreholes was extracted from a comprehensive live data set of 68,984 water points across Malawi to investigate the sustainability burden as emphasis shifts to the 2030 agenda. The results demonstrate that the push for coverage within the MDG era has impacted the sustainability of assets. A lack of proactive approaches towards major repairs and sub-standard borehole construction alongside aging infrastructure contributes to reduced functionality of decentralised supplies. Furthermore, costly rehabilitation is required to bring assets to operational standards, in which external support is commonly relied upon. Acceleration towards the coverage targets has contributed towards unsustainable infrastructure that has further implications moving forward. These findings support the need for Sustainable Development Goals (SDG) investment planning to move from a focus on coverage targets to a focus on quality infrastructure and proactive monitoring approaches to reduce the future burden placed on communities.

Application of high-throughput 16S rRNA sequencing to identify fecal contamination sources and to complement the detection of fecal indicator bacteria in rural groundwater.

Residents in rural communities across Canada collect potable water from aquifers. Fecal contaminants from sewage and agricultural runoffs can penetrate aquifers, posing a public health risk. Standard methods for detecting fecal contamination test for fecal indicator bacteria (FIB), but the presence of these do not identify sources of contamination. In contrast, DNA-based diagnostic tools can achieve this important objective. We employed quantitative polymerase chain reaction (qPCR) and high-throughput DNA sequencing to trace fecal contamination sources in Wainfleet, a rural Ontario township that has been under the longest active boil water advisory in Canada due to FIB contamination in groundwater wells. Using traditional methods, we identified FIBs indicating persistent fecal pollution in well waters. We used 16S rRNA sequencing to profile groundwater microbial communities and identified Campylobacteraceae as a fecal contamination DNA marker in septic tank effluents (STEs). We also identified Turicibacter and Gallicola as a potential cow and chicken fecal contamination marker, respectively. Using human specific Bacteroidales markers, we identified leaking septic tanks as the likely primary fecal contamination source in some of Wainfleet's groundwater. Overall, the results support the use of sequencing-based methods to augment traditional water quality testing methods and help end-users assess fecal contamination levels and identify point and non-point pollution sources.

Health risk assessment of nitrate in groundwater resources of Iranshahr using Monte Carlo simulation and geographic information system (GIS)

Because of exposure to a wide range of chemical contaminants such as nitrate via potable water resources, the use of the approaches to set standards for drinking water quality and also to do a risk assessment is necessary for maintaining the public health. High levels of nitrate in drinking water can have adverse health effects; primarily for infants and pregnant women. So, the present study aimed to the assessment of nitrate health risk in drinking water resources of the Iranshahr city, Sistan and Baluchistan province and also, evaluation of the uncertainty of nitrate and the probability of contamination occurrence by Monte-Carlo Simulation (MCS) technique. Besides, the geographic information system (Arc GIS, Ver 10.3) was applied to mapping the nitrate concentration in groundwater resources of the studied area. For these aims, the numbers of 66 samples were collected from rural groundwater resources, and nitrate concentration was measured using a Spectrophotometer in wavelength of 220 nm. According to the results, the nitrate concentration was in the range of 6.49 mg/L, and its average level was 6.15 mg/L. Also, the simulation results with 90% confidence showed that the hazard equitant (HQ) in the infant groups, children-teenagers and adults was less than 0.331, 0.311, 0.312, and 0.3, respectively.

Comprehensive investigation of groundwater quality in the north-west of Iran: Physicochemical and heavy metal analysis

The suitability of rural groundwater quality for drinking purposes were investigated in the north west of Iran. Major anions, cations and heavy metals were measured in 39 water wells during the summer and spring seasons. The spatial distribution of major parameters and hydro-chemical faces were described by developing GIS-based maps and Piper and Gibbs diagrams. According to the results, the EC values were in the range of 461 and 2600 μs/cm with the hardness contents between 220 and 720 mg/L as CaCO3. It was found that, the total hardness is highly correlated with the magnesium concentration than calcium in all samples. The dominant cations and anions were in the order of Mg2+ > Na+ > Ca2+ > K+ and HCO3- > SO42- > Cl- > NO3- > F-, respectively. The major water types in the area were fresh (Ca-HCO3) and saline (Ca-Mg-Cl). Based on Gibbs plot, the main mechanisms controlling groundwater chemistry were rainfall dominance, rock weathering dominance, and evaporation-participation dominance. The lower quality of water resources sited in the southern and northern parts of the area was observed according to the GIS maps. It was found that aluminum, boron, iron and manganese concentrations, in some cases, were higher than the guideline values however, it can be concluded that groundwater quality in the study area, apart from some cases, is suitable for drinking purposes without any specific treatment processes. The present study gives a comprehensive status of groundwater quality for proper management in the area.

Study of Rural Groundwater Quality in Brestea Village, Romania

Abstract Water is a social requirement and an important factor in the ecological balance. Water from wells is good for direct consumption if the soil is not contaminated. The quality of drinking water is regulated by Law no. 458/2002 (transposing the Directive 98/83/EC on the quality of drinking water). The aim of this paper was to assess the physicochemical qualities of groundwaters from Brestea village, commune Denta, Timis County. The water samples were taken in 2015 from 10 functional wells. For the source whose physical and chemical parameters have exceeded the limit values, the monthly monitoring of the water quality (microbiological and physico-chemical properties) has been performed for 2 years. At the same time, the pH of the soil near the water sources was also measured. The results highlighted a good connection between the microorganisms from water and the nitrite, nitrate and ammonium content of water. The information can be further used to identify and eliminate the specific pollutants, areas and pollution sources.

Relationship between modification of activated sludge wastewater treatment and changes in antibiotic resistance of bacteria

Biological treatment processes at wastewater treatment plants (WWTPs), which are the most common methods of sewage treatment, could cause selective elimination and/or changes in the proportions of phenotypes/genotypes within bacterial populations in effluent. Therefore, WWTPs based on activated sludge used in sewage treatment constitute an important reservoir of enteric bacteria which harbour potentially transferable resistance genes. Together with treated wastewater, these microorganisms can penetrate the soil, surface water, rural groundwater supplies and drinking water. Because of this, the aim of this study was to determine the impact of various modification of sewage treatment (the conventional anaerobic/anoxic/oxic (A2/O) process, mechanical-biological (MB) system, sequencing batch reactors (SBR), mechanical-biological system with elevated removal of nutrients (MB-ERN)) on the amount of antibiotic resistant bacteria (ARB) (including E. coli) and antibiotic resistance genes (ARGs) in sewage flowing out of the 13 treatment plants using activated sludge technology. There were no significant differences in ARB and ARGs regardless of time of sampling and type of treated wastewater (p > 0.05). The highest percentage of reduction (up to 99.9%) in the amount of ARB and ARGs was observed in WWTPs with MB and MB-ERN systems. The lowest reduction was detected in WWTPs with SBR. A significant increase (p < 0.05) in the percentage of bacteria resistant to the new generation antibiotics (CTX and DOX) in total counts of microorganisms was observed in effluents (EFF) from WWTPs with A2/O system and with SBR. Among all ARGs analyzed, the highest prevalence of ARGs copies in EFF samples was observed for sul1, tet(A) and qepA, the lowest for blaTEM and blaSHV. Although, the results of presented study demonstrate high efficiency of ARB and ARGs removal during the wastewater treatment processes, especially by WWTPs with MB and MB-ERN systems, EFF is still an important reservoir of ARGs which can be transferred to other microorganisms.

A thought leadership piece: Where are the rural groundwater quality data for the assessment of health risks in northern Malawi?

The Sustainable Development Goals place a strong emphasis on water quality. However, what is the local capacity to ensure safe water availability in a low-income country such as Malawi where groundwater is still the primary source of drinking water for rural communities? We conducted a systematic review of peer-reviewed literature containing primary data on groundwater used for drinking water in northern Malawi published over the period from 2006 to 2016. We also interviewed district, regional, and national government representatives supporting the water quality management sector. The results showed that the government cannot tell if groundwater is safe for drinking in the northern region of Malawi. Current literature provides only minimal information on groundwater quality for the assessment of human health risks, and there are limited laboratory services. Nitrate and pH were the most commonly available data. There is evidence that the following constituents need further investigation about possible human health risks: antimony, arsenic, barium, calcium, chloride, color, cyanide (CN-), Escherichia coli and/or thermotolerant coliform bacteria, fluoride, iron, lead, manganese and turbidity. Water quality monitoring needs to especially consider mining activities, including uranium. Varied levels of engagement appear in that while there is some strengthens in the national government capacity, as this is decentralized to districts weaknesses are most evident with no laboratories and either limited data or no data in the case of the most rural districts. Malawi needs to build human capacity, laboratory infrastructure and a publicly available water quality database under national government regulatory oversight with real time monitoring data available to both district and national government decision makers, practitioners and water users to determine groundwater quality for the assessment of possible health risks.

Artificial Sweeteners Discovered in Rural Groundwater

Artificial Sweeteners Discovered in Rural Groundwater

Drinking-water treatment, climate change, and childhood gastrointestinal illness projections for northern Wisconsin (USA) communities drinking untreated groundwater

This study examined the relative importance of climate change and drinking-water treatment for gastrointestinal illness incidence in children (age <5 years) from period 2046–2065 compared to 1991–2010. The northern Wisconsin (USA) study focused on municipalities distributing untreated groundwater. A time-series analysis first quantified the observed (1991–2010) precipitation and gastrointestinal illness associations after controlling for seasonality and temporal trends. Precipitation likely transported pathogens into drinking-water sources or into leaking water-distribution networks. Building on observed relationships, the second analysis projected how climate change and drinking-water treatment installation may alter gastrointestinal illness incidence. Future precipitation values were modeled by 13 global climate models and three greenhouse-gas emissions levels. The second analysis was rerun using three pathways: (1) only climate change, (2) climate change and the same slow pace of treatment installation observed over 1991–2010, and (3) climate change and the rapid rate of installation observed over 2011–2016. The results illustrate the risks that climate change presents to small rural groundwater municipalities without drinking water treatment. Climate-change-related seasonal precipitation changes will marginally increase the gastrointestinal illness incidence rate (mean: ∼1.5%, range: −3.6–4.3%). A slow pace of treatment installation somewhat decreased precipitation-associated gastrointestinal illness incidence (mean: ∼3.0%, range: 0.2–7.8%) in spite of climate change. The rapid treatment installation rate largely decreases the gastrointestinal illness incidence (mean: ∼82.0%, range: 82.0–83.0%).

An Investigation of Groundwater Monitoring in Zimba District. Towards Sustainable Rural Groundwater Development and Management

An Investigation of Groundwater Monitoring in Zimba District. Towards Sustainable Rural Groundwater Development and Management

Screening and health risk of organic micropollutants in rural groundwater of Liaodong Peninsula, China

Groundwater serves as a main drinking water source for rural residents in China. However, little is known regarding the pollution of organic micropollutants in groundwater that may pose health risks. In this study, more than 1300 organic micropollutants were screened in the groundwater samples collected from 13 drinking water wells distributed across five rural regions of Liaodong Peninsula in China. A total of 80 organic micropollutants including 12 polycyclic aromatic hydrocarbons, 11 alkanes, 9 pesticides, 7 substituted phenols, 7 perfluoroalkyl acids, 6 heterocyclic compounds, 5 alcohols, 5 phthalic acid esters, 5 pharmaceutical and personal care products, 3 ketones, 2 polychlorinated biphenyls (PCBs), 2 alkylbenzenes and 2 chlorinated benzenes were detected, with their total concentration of 32–1.5 × 104 ng/L. Noncarcinogenic and carcinogenic risks of a part of pollutants were assessed. Exposure through skin absorption and oral ingestion was considered in the assessment. Generally the risks are within the acceptable limits, except for that the carcinogenic risk at two sites in Jinzhou is higher than 10−6. To the best of our knowledge, this is the first report on health risks of groundwater micropollutants in China.

Current Status of Groundwater Monitoring Networks in Korea

Korea has been operating groundwater monitoring systems since 1996 as the Groundwater Act enacted in 1994 enforces nationwide monitoring. Currently, there are six main groundwater monitoring networks operated by different government ministries with different purposes: National Groundwater Monitoring Network (NGMN), Groundwater Quality Monitoring Network (GQMN), Seawater Intrusion Monitoring Network (SIMN), Rural Groundwater Monitoring Network (RGMN), Subsidiary Groundwater Monitoring Network (SGMN), and Drinking Water Monitoring Network (DWMN). The Networks have a total of over 3500 monitoring wells and the majority of them are now equipped with automatic data loggers and remote terminal units. Most of the monitoring data are available to the public through internet websites. These Networks have provided scientific data for designing groundwater management plans and contributed to securing the groundwater resource particularly for recent prolonged drought seasons. Each Network, however, utilizes its own well-specifications, probes, and telecommunication protocols with minimal communication with other Networks, and thus duplicate installations of monitoring wells are not uncommon among different Networks. This mini-review introduces the current regulations and the Groundwater Monitoring Networks operated in Korea and provides some suggestions to improve the sustainability of the current groundwater monitoring system in Korea.

Glyphosate residues in rural groundwater, Nottawasaga River Watershed, Ontario, Canada.

The objective of this study was to investigate the occurrence of glyphosate residues (glyphosate and its metabolite AMPA) in shallow groundwater in a catchment dominated by agriculture, and to examine the potential for this groundwater to store and transmit these compounds to surface waters. Glyphosate residues were found in some of the groundwater samples collected in riparian (surface seeps), upland (mostly <20 m below ground) and wetland settings (<3 m below ground). Overall, glyphosate and AMPA were detected in 10.5 and 5.0%, respectively, of the groundwater samples analyzed as part of this study. All concentrations of glyphosate were well below Canadian guidelines for drinking water quality and for protection of aquatic life. Seasonal differences in concentrations in riparian seeps were possibly related to cycles of weather, herbicide application and degradation of glyphosate. Highest concentrations were at upland sites (663 ng L(-1) of glyphosate, 698 ng L(-1) of AMPA), apparently related to localized applications. Most glyphosate detections in wetlands were >0.5 km distant from possible areas of application, and, combined with other factors, suggest an atmospheric transport and deposition delivery mechanism. In both upland and wetland settings, highest glyphosate concentrations were sometimes not at the shallowest depths, indicating influence of hydrological factors. The glyphosate/AMPA detections in riparian seeps demonstrated that these compounds are persistent enough to allow groundwater to store and transmit glyphosate residues to surface waters. Detections in the wetlands support earlier evidence that atmospheric transport and deposition may lead to glyphosate contamination of environments not intended as targets of applications. This interpretation is further supported by detections of both glyphosate and AMPA in precipitation samples collected in the same watershed. © 2016 Her Majesty the Queen in Right of Canada Pest Management Science © 2016 Society of Chemical Industry.

An Analysis of Groudwater Budget in a Water Curtain Cultivation Site

In Korea, rural groundwater development faces new challenge, which have not been experienced so far. The problem is a groundwater depletion by the water curtain cultivation (WCC) during winter season. This study investigates the groundwater depletion using three-dimensional finite difference groundwater flow program, MODFLOW to verify the water budget of the shallow aquifer of Cheongweon area. Interdisciplinary research, which has become a worldwide trend, has been adopted in studying groundwater modeling in field scale. In particular, the method of groundwater recharge estimation adopted precise modeling techniques, SWAT to groundwater flow modeling. Based on qualified field data, the model calibrated and validated its reliability. The objective of this study is to simulate various stream-aquifer interactions according to groundwater pumping with artificial boundaries, such as weirs and drainage system. We also analyzed a seasonal variation of cumulative water budget of the site to quantify the groundwater depletion and recovery in the pumping field.

Blueprint for breakdown? Community Based Management of rural groundwater in Uganda

The belief that groundwater in rural areas is best managed according to the Community Based Management (CBM) model is the dominant paradigm across Sub-Saharan Africa. While donors and governments focus on extending the supply network to meet the post-2015 Sustainable Development Goal (SDG) of universal access to clean water, at any one time a third of handpumps are non-functional. Basing our case on ethnographic fieldwork, surveys and interviews, and working closely with policy implementers over the course of three years in mid-west Uganda, we argue that non-functionality of handpumps, and the precarious status of many, cannot be blamed solely on poor technology or siting of wells: rather the problem stems from a dearth of maintenance funds and management failings. The CBM model is an uneasy coalition of ideologies from across the political spectrum that meshes neo-liberal inspired commodification with theories of collective action and Common Property Resources. We demonstrate conceptually and empirically how the wings of the CBM model individually and collectively are contributing to the disappointing outcomes amid the messy complex reality of rural environments. Recommendations calling for modifying participatory processes, technological solutions and more external support all fall within the existing CBM framework, which we will empirically demonstrate is a blueprint for breakdown in these contexts. A resolution to the financing of handpump maintenance must be found if the SDG is to be realised, and we argue that academics, policy makers and practitioners need to accept this may lie outside the CBM paradigm.

Trends and perceptions of rural household groundwater use and the implications for smallholder agriculture in rain-fed Southern Laos

In Laos, the extent of rural groundwater use is largely unknown. This paper presents results of a study conducted in Champasak province, Southern Laos, to examine rural household attitudes to groundwater use and management; and to gauge farmer perceptions of the opportunities/constraints of increased groundwater use for smallholder agriculture. Significant differences in groundwater use, total cash income and perceived groundwater quality were found. Further agricultural expansion was constrained by insufficient labour and the limited area of individual landholdings, not by the limited groundwater supply, which was the preferred source to fulfil increased demands for domestic/agricultural use. There were no groundwater regulations.

Pesticides residue in drinking groundwater resources of rural areas in the northwest of iran.

The majority of rural population in Iran depends on groundwater resources for drinking purposes. In recent years, pesticide contamination of limited water resources has become a serious challenge worldwide. This study quantified the pesticides residue in rural groundwater resources in the northwest of Iran. A total of 78 groundwater samples were collected in June and Sep-tember 2011 from all 39 drinking water wells. Liquid-liquid extraction (LLE) followed by Gas Chroma9tography/Mass Spectrometry (GC/MS) was used to determine the selected pesticides. Detection frequencies of profenofos, malathion, diazinon, endosulfan, trifluralin, deltamethrin, methyl parathion, and fenitrothion were determined with the concentrations exceeded 0.1 μg/L in 2.6, 17.9, 15.4, 10.3, 2.6, 2.6, 7.7, and 44.9% of the samples, respectively. Total pesticides residue was also ob-served in 26.9% of the samples with concentrations exceeded 0.5 μg/L. Among them, profenofos, malathion and diazinon were detected as the most frequently observed pesticides with the maximum concentrations of 0.542, 0.456 and 0.614 μg/L, respectively. Higher pesticides residue than European Economic Commission (EEC) guidelines occurred in a number of monitored resources.

Quantification of nitrate sources in groundwater using hydrochemical and dual isotopic data combined with a Bayesian mixing model

To determine the contributions of various sources to nitrate loads in groundwater (n=103) from three farmed rural sites in South Korea, we assessed the dual isotopic composition of nitrate, coupled with hydrochemical parameters. The measured isotopic values of nitrate varied widely, with 10th and 90th percentiles of 2.8‰ and 14.2‰ for δ15N, and 0.7‰ and 8.9‰ for δ18O, respectively and suggested that nitrification of anthropogenic N compounds is a predominant process of nitrate pollution. To overcome the known uncertainties of quantitative source apportionment for groundwater nitrate, arising from isotope fractionation during N transformations and the significant overlap in isotopic values of different sources, the combined hydrochemical and isotopic datasets were interpreted with orthogonal regression of a principal component analysis (PCA) and a Bayesian mixing model. The PCA projected the observed δ15NNO3 values onto a mixing subspace in the multivariate variability of the dataset, and the regression fits of the sample data were presumed to be conservative mixtures. This procedure also allowed for an assessment of the sample uncertainty, as influenced by natural nitrate contributions and denitrification. The Bayesian mixing model was used to estimate the probability distributions of the proportional contributions of three anthropogenic sources: chemical fertilizers, composted manure, and manure slurries. Nitrate is largely derived from chemical fertilizers with fractional contributions of 0.35–0.71, and organic fertilizers including composted manure with mixing fractions of 0.39–0.49. The relative contribution of nitrate from composted manure compared to chemical fertilizers increased with increasing nitrate concentrations, suggesting that composted manure significantly increases nitrate pollution and therefore its use should be carefully controlled to manage rural groundwater quality. This study also suggests that PCA and Bayesian isotope mixing models are effective for quantitative assessment of the sources of pollutants, such as nitrate.