Faecal Contamination Of Groundwater Research Articles

Identification of fecal contamination sources of groundwater in rural areas of Vhembe District Municipality, Limpopo Province, South Africa.

Groundwater is a valuable source of drinking water worldwide, recognized as an improved drinking water source. However, on-site sanitation systems may put groundwater at risk of fecal contamination. In the present study, two approaches were used to ascertain the sources of fecal contamination in groundwater used by communities of the Vhembe District Municipality. Overall, 87.5% of boreholes (n = 70) in the wet and 72.5% in the dry season were contaminated with Escherichia coli, and septic tank (n = 18) wastewaters displayed up to 104 cfu/mL E.coli. Host-specific Bacteroidales quantitative polymerase chain reaction (qPCR) assays established the presence of human (BacHum and HF183) and animal (Cytb, BacCan, and Pig-2Bac) genetic markers in groundwater from 15.7% of boreholes (wet) and 10% of boreholes (dry). No strong associations were founded between culturable E.coli counts and the presence/absence of marker genes for all the markers except for Cytb marker, which showed a weak significant correlation (r = 0.217; p = <0.01) between E.coli and the Cytb marker under dry seasonal conditions. Human markers and Cytb were present in the household septic tank wastewater samples. Significant differences in marker genes distribution in wastewater were observed using the Chi-squared test: HF183 (p = <0.001) and BacHum (p = <0.001). Overall, no association was recorded between markers in groundwater and in wastewater for 18 households' septic tanks. A combined culturable E.coli and host-specific Bacteroidales qPCR assays remain an appropriate approach for the identification of fecal contamination of groundwater. PRACTITIONER POINTS: Households primarily used private boreholes for drinking water, as a primary source. Most households used on-site sanitation systems, including ventilated improved pit latrines and flush toilets connected to septic tanks. Escherichia coli was detected in groundwater, and the sources of fecal contamination were humans and animals (pigs, dogs, and chickens). The presence of human and animal markers in groundwater suggests that humans and animals are liable for fecal contamination. Fecal contamination in drinking water sources poses a significant concern due to pathogenic microorganisms posing potential human health risks.

The Occurrence of Escherichia coli in Groundwater of Bekasi City (Case Study: Jatiluhur, Sumur Batu, and Jatirangga Urban Villages)

The self-supply of groundwater at the household level, and especially in densely populated areas, is vulnerable to fecal contamination. The aim of this study was to assess the level of fecal contamination in groundwater of three urban villages in Bekasi City that depend greatly on groundwater: Jatiluhur, Sumur Batu, and Jatirangga. Water samples were taken from 255 households with various types of water sources in the rainy season from February-March 2020. Escherichia coli (E. coli) concentration was quantified with Colilert-18 using IDEXX Quanti-Tray/2000 based on Most Probable Number (MPN) method. E. coli levels were beyond the WHO standard and found in 60% of the sources; 24% were above 100 MPN/100 mL. The presence of E. coli in groundwater indicated a requirement for further treatment prior to the point of consumption and an urgent need to replace the water supply infrastructure for improved water sources.

Determination of Faecal Contamination of the Groundwater Resources from Tano Districts of Ghana

This paper seeks to report on whether there are faecal contaminants in the groundwater resources within the Tano Districts, where people use groundwater as their source of drinking water and for other domestic purposes. Total Coliforms, Faecal Coliforms, Enterococci, E.coli and Salmonella were employed as faecal indicators in this study. Determination of these faecal indicators in the samples was done using the Most Probable Number (MPN) method. A simple random sampling method was employed to get the sample size of 15 wells. The results of this study indicate that the water in the selected wells had faecal contaminants, proved by the presence of the faecal determinants in the water samples collected The presence of these organisms is an indication that water within the wells from the study area has been faecally contaminated with animal or human faeces. These bacteria are used as faecal indicators as an evidence of possible sewage contamination because, they are commonly found in animal or human faeces. Therefore, the fact that these faecal indicators have been detected in water sampled from the selected wells means that pathogens might also be present. The study recommends treatment of the groundwater supplies or encourages the use of the home water treatment.In an attempt to solve the problem of the faecal contamination of the selected wells, a future research should be conducted to determine the source of faecal contamination of ground water in wells at the Tano Districts.

Faecal contamination of groundwater in rural Vanuatu: prevalence and predictors.

Groundwater is an important source of water for coastal communities in Pacific Island Countries. This study assessed the prevalence and predictors of faecal contamination in groundwater sources across 11 islands in Vanuatu. Escherichia coli was detected in 49% of sources and E. coli concentration exceeded 10 MPN (most probable number)/100 mL for 23% of sources. When adjusting for other variables, the detection of E. coli was significantly associated with severe pump stand corrosion, suggestive of contaminated run-off directly entering boreholes. E. coli concentration >10 MPN/100 mL was also significantly associated with: (i) hand-dug wells (as compared to drilled boreholes); (ii) severe pump stand corrosion; (iii) water points underlain by volcanic rocks (as compared to coral limestone); and (iv) rainfall in the previous 24 h. Encasing pump stands in concrete - as some communities had done - was found to have a significant protective effect. While baseline statistics for Sustainable Development Goal target 6.1 suggest that 87% of Vanuatu's rural population have access to at least a basic (improved) water source, the results from this study point to extensive microbial water quality concerns linked to degraded water supply infrastructure in need of rehabilitation.

E. coli CB390: An alternative E. coli host for simultaneous detection of somatic and F+ coliphage viruses in reclaimed and other waters

Somatic and F+ coliphages have been identified and validated as virus indicators of fecal contamination in ground water by US EPA and more recently they are being considered for use in managing both marine and fresh recreational water and wastewater discharges. Studies documenting their usefulness as viral indicator in reclaimed water sources in the USA are limited. However, simultaneous detection of both somatic and F+ coliphages on a single E. coli host is preferred over their separate analysis because both are abundant in wastewater, they may respond differently to wastewater reclamation treatment processes, and separate analysis for each group in separate host bacteria adds complexity and cost. In this study, a new total coliphage host (E. coli CB390, CECT9198) was evaluated for its ability to detect somatic, F+ coliphages, and total coliphages by US EPA Methods 1601 and 1602. No statistical difference was found in the detection coliphages in spiked phosphate buffered saline samples or in natural waters; additionally, no statistical difference was found between the detection of total coliphages by Methods 1601 and 1602.

The public health significance of latrines discharging to groundwater used for drinking

Faecal contamination of groundwater from pit latrines is widely perceived as a major threat to the safety of drinking water for several billion people in rural and peri-urban areas worldwide. On the floodplains of the Ganges-Brahmaputra-Meghna delta in Bangladesh, we constructed latrines and monitored piezometer nests monthly for two years. We detected faecal coliforms (FC) in 3.3–23.3% of samples at four sites. We differentiate a near-field, characterised by high concentrations and frequent, persistent and contiguous contamination in all directions, and a far-field characterised by rare, impersistent, discontinuous low-level detections in variable directions. Far-field FC concentrations at four sites exceeded 0 and 10 cfu/100 ml in 2.4–9.6% and 0.2–2.3% of sampling events respectively. The lesser contamination of in-situ groundwater compared to water at the point-of-collection from domestic wells, which itself is less contaminated than at the point-of-consumption, demonstrates the importance of recontamination in the well-pump system. We present a conceptual model comprising four sub-pathways: the latrine-aquifer interface (near-field); groundwater flowing from latrine to well (far-field); the well-pump system; and post-collection handling and storage. Applying a hypothetical dose-response model suggests that 1–2% of the diarrhoeal disease burden from drinking water is derived from the aquifer, 29% from the well-pump system, and 70% from post-collection handling. The important implications are (i) that leakage from pit latrines is a minor contributor to faecal contamination of drinking water in alluvial-deltaic terrains; (ii) fears of increased groundwater pollution should not constrain expanding latrine coverage, and (iii) that more attention should be given to reducing contamination around the well-head.

Degradation and Human Health Risk Assessment of Underground Water of Trans Ganga-Yamuna Rural Regions of A North Indian district

The present study investigates the physico-chemical qualities and fecal contamination of ground water; and related health risks of rural areas of trans-Ganga and Yamuna region of a North-Indian district, Allahabad, India. The pH, turbidity, TDS, BOD, and COD, total alkalinity, total hardness, chloride and fecal coliform contamination was estimated in 269 water samples of 14 villages. Higher levels of turbidity, alkalinity, chloride and fecal contamination in ground water of trans-Yamuna area were found as compared to trans-Ganga. About 75% samples of trans-Yamuna were contaminated with faecal coliform as compared to trans-Ganga region (55%).Significant positive correlation existed between chloride, TDS, alkalinity (r=0.74- 0.91; p < 0.05), hardness and pH (r = 0.75-0.85; p < 0.05). The Relative Risk (RR) of some waterborne diseases was very high (2.11-8.00) in trans-Yamuna as compared to trans-Ganga region (1.81-3.48). Furthermore, the new treatment requirement parameter (NNT) for waterborne diseases of these rural areas was also estimated, which suggests that the need of a new and improved treatment approach for these diseases is more frequent in the trans-Yamuna area as compared to trans-Ganga. Our results suggest urgent attention and intervention for improving the quality of potable water in these rural areas and to control the waterborne diseases associated to rural health risks. You can submit your Manuscripts at: https://symbiosisonlinepublishing.com/submitManuscript.php

Weekly variations of discharge and groundwater quality caused by intermittent water supply in an urbanized karst catchment

Summary Leaky sewerage and water distribution networks are an enormous problem throughout the world, specifically in developing countries and regions with water scarcity. Especially in many arid and semi-arid regions, intermittent water supply (IWS) is common practice to cope with water shortage. This study investigates the combined influence of urban activities, IWS and water losses on groundwater quality and discusses the implications for water management. In the city of As-Salt (Jordan), local water supply is mostly based on groundwater from the karst aquifer that underlies the city. Water is delivered to different supply zones for 24, 48 or 60 h each week with drinking water losses of around 50–60%. Fecal contamination in groundwater, mostly originating from the likewise leaky sewer system is a severe challenge for the local water supplier. In order to improve understanding of the local water cycle and contamination dynamics in the aquifer beneath the city, a down gradient spring and an observation well were chosen to identify contaminant occurrence and loads. Nitrate, Escherichia coli , spring discharge and the well water level were monitored for 2 years. Autocorrelation analyses of time series recorded during the dry season revealed weekly periodicity of spring discharge (45 ± 3.9 L s −1 ) and NO 3 -N concentrations (11.4 ± 0.8 mg L −1 ) along with weekly varying E. coli levels partly exceeding 2.420 MPN 100 mL −1 . Cross-correlation analyses demonstrate a significant and inverse correlation of nitrate and discharge variations which points to a periodic dilution of contaminated groundwater by freshwater from the leaking IWS being the principal cause of the observed fluctuations. Contaminant inputs from leaking sewers appear to be rather constant. The results reveal the distinct impact of leaking clean IWS on the local groundwater and subsequently on the local water supply and therefore demonstrate the need for action regarding the mitigation of groundwater contamination and reduction of network losses from sewer leakage. Furthermore, these investigations contribute to an improved understanding of urban water cycle systems in the Middle-East which may help water managers in the region to conserve precious resources.

Influence of Climate Extremes and Land Use on Fecal Contamination of Shallow Tubewells in Bangladesh.

Climate extremes in conjunction with some land use practices are expected to have large impacts on water quality. However, the impacts of land use and climate change on fecal contamination of groundwater has not been well characterized. This work quantifies the influences of extreme weather events and land use practices on Escherichia coli presence and concentration in groundwater from 125 shallow wells, a dominant drinking water resource in rural Bangladesh, monitored over a 17 month period. The results showed that E. coli presence was significantly associated with the number of heavy rain days, developed land and areas with more surface water. These variables also had significant impacts on E. coli concentration, with risk ratios of 1.38 (95% CI = 1.16, 1.65), 1.07 (95% CI: 1.05, 1.09), and 1.02 (95% CI = 1.01, 1.03), respectively. Significant synergistic effects on E. coli presence and concentration were observed when land use and weather variables were combined. The findings suggest that climate extremes and land use practices, particularly urbanization, might promote fecal contamination of shallow well water, thus increasing the risk of diarrheal diseases.

New perspectives on microbial community distortion after whole-genome amplification.

Whole-genome amplification (WGA) has become an important tool to explore the genomic information of microorganisms in an environmental sample with limited biomass, however potential selective biases during the amplification processes are poorly understood. Here, we describe the effects of WGA on 31 different microbial communities from five biotopes that also included low-biomass samples from drinking water and groundwater. Our findings provide evidence that microbiome segregation by biotope was possible despite WGA treatment. Nevertheless, samples from different biotopes revealed different levels of distortion, with genomic GC content significantly correlated with WGA perturbation. Certain phylogenetic clades revealed a homogenous trend across various sample types, for instance Alpha- and Betaproteobacteria showed a decrease in their abundance after WGA treatment. On the other hand, Enterobacteriaceae, an important biomarker group for fecal contamination in groundwater and drinking water, were strongly affected by WGA treatment without a predictable pattern. These novel results describe the impact of WGA on low-biomass samples and may highlight issues to be aware of when designing future metagenomic studies that necessitate preceding WGA treatment.

Assessing Fecal Contamination in Groundwater from the Tulum Region, Quintana Roo, Mexico

The Yucatan Peninsula’s groundwater is experiencing increases in degradation due to swelling population and tourism; yet little is known about sources and transport of contaminants in drinking water supplies. The karst allows for rapid transport of microbial and chemical contaminants to the subsurface, resulting in significantly increased potential for pollution of groundwater. The objective of this research is to determine the occurrence, source, and extent of fecal contamination in the Tulum region of the Peninsula. A multi-analytical approach was undertaken in impacted and unimpacted groundwater locations; measurements included physicochemical parameters, total coliform and E. coli, Bacteroides (human vs total) and caffeine. The results indicate a variation in geochemistry from impacted to protected sites. The total coliform and E. coli show fecal contamination is wide spread. However, the presence of human Bacteriodes and caffeine in the water in the Tulum well field indicates that the recent human activities next to the well field are impacting the drinking water supply. This project is an assessment of the area’s current water quality conditions and the probable impact that the aforementioned growth would have on the area’s water supply. By applying multiple source parameter measurements, including molecular microbiology and chemical indicators it was confirmed the extent of fecal contamination of human origin covered the entire sampling region.

Sanitary Hazards and Microbial Quality of Open Dug Wells in the Maldives Islands

Concern for saline and microbial quality post-December 2004 tsunami, led to a field based surveillance study to systematically investigate the sanitary hazards which cause faecal contamination of groundwater. In seven islands, two duplicate sample sets, in two surveys, revealed that only 6.4% of the 173 well water samples (combining both surveys) satisfied the WHO Drinking Water Quality Guideline for 44°C thermo-tolerant (Faecal) Coliform (FC) indicator value (zero cfu/100 ml sample). Based on a combined risk analysis of Sanitary Hazard Score (SHS) and FC counts, more than 57.7% of the study wells were classified as at very high (FC: 100 to >1,000 cfu/100ml; and SHS: ≥ 9) microbial health risk. During this study, fundamental changes were made to the published generic sanitary inspection method (WHO, 1997) for identifying sanitary hazards, for its application in the extremely vulnerable hydro-geological setting of the Maldives. However, the most important hazard controlling the intensity of faecal contamination in the Maldives is the safe separation distance between a latrine seepage point and the well. It was demonstrated that, due to the prevailing hydro-geological conditions and the well and sanitation system densities, safe separation distance cannot be achieved. Consequently, septic tank effluent quality must be greatly improved.

Annual and nycthemeral studies of the survival and circulation of indicator bacteria in a schist aquifer

Escherichia coli and Enterococci are widely used as indicators of faecal contamination of groundwater while total coliforms, which are of environmental but also of faecal origin, are indicators of the overall quality of the water. The survival of bacteria in groundwater is dependent on many factors including temperature, competition with indigenous bacteria and entrapment in aquifer material. Previous studies showed two sources of faecal contamination of a schist aquifer: infiltration into the ground from nearby septic tank effluents and seepage of landfill leachate. Water samples for bacterial analysis were collected from a piezometer on a monthly basis (15 months) and every six hours over two non‐consecutive days. The intermittent sampling showed relatively stable concentrations of bacteria over time after the removal of stagnant water. Therefore, a continuous bacterial contamination without significant daily variation exists. The ratio of E. coli densities to total coliforms densities (EC/TC) allowed differentiation between the sources of faecal pollution in groundwater by comparing the populations of faecal bacteria with those of environmental bacteria. Enumeration indicated that the densities of bacteria were much higher in this schist aquifer than those in alluvial aquifers contaminated by a septic tank reported in the literature.

Fecal Contamination of Groundwater in a Small Rural Dryland Watershed in Central Chile

Research on microbiological groundwater quality was conducted in Chile in a rural watershed that has almost no other water source. Forty-two wells were randomly selected and levels of indicator bacteria - total coliforms (TC), fecal coliforms (FC), and fecal streptococci (FS) - were repeatedly measured during the four seasons of 2005. The aim of this study was to characterize microbiological groundwater quality, relate indicator levels to certain watershed features and management characteristics which are likely to affect water quality. The dynamics of seasonal temporal contamination was determined with statistical analyses of indicator organism concentrations. Nonparametric tests were used to analyze relationships between bacterial indicators in well water and other variables. TC, FC, and FS were found in all samples indicating the wells had been contaminated with human and animal fecal material. The frequency distribution of microorganisms fitted a logistic distribution. The concentrations appeared to be temporal and levels varied between seasons with higher concentrations in winter. The cause of contamination could be linked to the easy access of domestic animals to the wells and to the permeable well casing material. Local precipitation runoff directly influenced the bacterial concentrations found in the wells.

Evaluation of indicators of fecal contamination in Groundwater

Detecting fecal waste contamination of groundwater is usually accomplished by testing for fecal “index” or “indicator” bacteria. The authors examined 128 samples from 26 public groundwater sources in New Jersey and compared the ability of nine potential indicators to detect fecal contamination. Each sample was tested for heterotrophic plate count; total coliform (TC); fecal coliform (FC); Escherichia coli, enterococci, and Clostridium perfringens bacteria (100 mL); somatic and F+ coliphage (100 mL); and coprostanol (1 and 4 L). Data from a source with known contamination showed that the TC test was the most reliable indicator, followed by the FC test. Fecal pollution contains high concentrations of TC bacteria, but because some TC bacteria in the environment may not be of fecal origin, a positive TC test result should be followed by an FC, E. coli, or enterococci test to confirm contamination. The sanitary significance of the occasional presence of TC bacteria or coliphage without other fecal indicators was uncertain. Methods capable of analyzing 1‐L volumes should be investigated. A groundwater should be analyzed multiple times (i.e., 10 or more) to confidently determine its sanitary status.

Detection of Cryptosporidium sp. oocysts in groundwater for human consumption in Itaquaquecetuba city, S. Paulo-Brazil

Cryptosporidium is an emergent pathogen that causes profuse diarrhea in humans. Outbreaks of human cryptosporidiosis have implicated water as a possible source of contamination. In this study the presence of Cryptosporidium sp. oocysts was investigated as well as the fecal contamination in groundwater for consumption in Itaquaquecetuba - Sao Paulo. Therefore, it was possible to notice that the septic tanks were located close to the wells, exposing them to risk of contamination. As a consequence of these results and observations efficient disinfecting practices and groundwater monitoring are recommended.

Physicochemical mechanisms responsible for the filtration and mobilization of a filamentous bacteriophage in quartz sand

This study examines the influence of pore water chemistry on the filtration and physicochemical properties of a male-specific filamentous bacteriophage isolated from chlorinated effluent of the San Jose Creek Water Reclamation Plant in Los Angeles County, California. The isolate belongs to a class of bacteriophage that are naturally present in sources of sewage, and hence may be an indicator of fecal contamination in groundwater. Furthermore, there is some evidence that this class of bacteriophage are mobilized in the subsurface following rainfall events, although the mechanism responsible for this process is not yet clear. Using a model filtration system consisting of packed columns of quartz sand, we found that the filtration of this isolate was strongly dependent on the concentration and valence of the dominant cation in the pore fluid. In one set of experiments involving columns 19 cm in length, virus retention in the column increased from 0% to 99.999% when the electrolyte composition of the pore fluid was changed from 10 mM NaCl to 10 mM CaCl 2. With one exception, filtration efficiencies calculated from the column experiments were inversely proportional to the electrophoretic mobility of the virus, implying that electrostatic interactions between the virus and the quartz surface dominate the filtration dynamics of this particular bacteriophage. From a practical perspective, these results indicate that small changes in the hardness and total dissolved solids of pore fluids –as might occur following a rainfall event– can dramatically affect both the filtration and mobilization of filamentous bacteriophage in subsurface systems.

Coliphage prevalence in high school septic effluent and associated ground water

At the present time, somatic and male-specific coliphage and human enterovirus groups are being considered as indicators of possible pathogenic human enteric virus contamination from fecal contamination. A primary attribute for any indicator of fecal contamination is its prevalence at the source and in associated ground water. It must be consistently found in the source material at concentrations that are measurable with available techniques. Over a period of ten months, male-specific and somatic coliphage ranged from ∼7000 to ∼4,000,000 PFU/L in the effluent from a multi-user septic-tank. Unlike the values determined for septic-tank effluent, coliphage concentrations measured in ground water over this same period only varied by five-fold. Coliphage concentration in ground water under the down-gradient edge of the drainfield contained ∼1000 PFU/L. This concentration decreased at −1 log 10/5 m during 17.4 m of ground-water transport. From these data, coliphage concentrations in septic-tank effluent seem sufficient to allow their use as indicators of fecal contamination in ground water.

Fecal Bacteria in Agricultural Waters of the Bluegrass Region of Kentucky

AbstractAgricultural runoff influenced by nonpoint pollution frequently exceeds the USEPA standards for bacterial contamination of primary contact water (200 fecal coliforms/100 mL). Few studies have evaluated the effect of cattle (Bos taurus) grazing on fecal contamination of ground water in the karst topography of central Kentucky. Our objectives were to: (i) observe the extent and pattern of fecal bacteria in agricultural waters from two central Kentucky watersheds; (ii) determine if monthly sampling accurately assessed the extent and variability of fecal contamination; and (iii) assess the fecal coliform/fecal streptococci ratio (FC/FS) as an indicator of fecal bacteria source. Springs, streams, and wells in two agricultural watersheds typical of central Kentucky were monitored for fecal coliform and fecal streptococci from December 1991 to January 1993. Springs and wells exceeded primary contact water standards, between 28 and 74% of the time; streams exceeded water quality standards between 87 and 100% of the time. When fecal bacteria were present, rainfall rapidly moved them from the soil surface into spring and well water. At two springs in Fleming county, only 29% of samples exceeded primary contact standards before cattle were present; 80% exceeded standards after cattle began grazing the surrounding pasture. Monthly sampling adequately reflected the extent of fecal contamination in our study, which had relatively continuous cattle grazing. Although the FC/FS ratio identified domestic animal contamination sources, it did not distinguish between domestic animal and human sources of contamination.