Thermotolerant Coliforms Contamination Research Articles

Evaluation of the status of water quality of three swimming pools in Bujumbura city, Burundi

Poor water quality is problematic for the health of public swimmers. This study focused on the water quality of three main swimming pools coded as MS, ES and HC in the city of Bujumbura, Burundi. Water samples were collected from June to the end of August 2020 and analyzed for physicochemical parameters such as pH, turbidity, conductivity, nitrates, free chlorine and microbiological parameters (total coliforms and faecal coliforms). Our results indicated that 2/3 of the sampling days showed pH >7.8 and pH<7.2 in the MS and HC pools, respectively. All these pools exhibited high turbidity whereas ES manifested very high value (6.05NTU). Free chlorine appeared very low in the MS pool with contamination by total coliforms (<1MPN 1mL-1 and 1.17x107MPN 1mL-1, <1MPN 1mL-1 and 6.32x106MPN 1mL-1, and < 1MPN 1mL-1 and 5x102 MPN 1mL-1) for MS, ES, and HC respectively. Both MS and ES pools revealed higher thermotolerant coliforms contamination of (<1MPN 1mL-1 and 2.18x104MPN 1mL-1) in MS and (<1MPN 1mL-1 and 2.32x104MPN 1mL-1) in ES, but the HC pool showed a single contamination case with values of <1UFC 1mL-1 and 5UFC1mL-1 throughout the sampling period. Additionally, extreme concentrations of nitrates (104.89 mgL-1) were observed at the ES pool. The findings showed a non-compliance with WHO standards for all three swimming pools and therefore advocates for an urgent need to monitor and treat or change the water frequently for quality assurance of swimming pools.

Impact of flooding on microbiological contamination of domestic water sources: a longitudinal study in northern Ghana

Flooding is the most frequent natural hazard globally, but evidence of its impact on domestic water point contamination remains limited. This study aimed to assess dam-related flooding’s impact on microbiological contamination of rural water points and to evaluate agreement of satellite-derived flood maps with ground-based observations of water point flooding. Fieldwork took place in two Ghanaian districts frequently flooded following dam overspill. Fifty-seven water points were tested for bacterial parameters during and immediately after flooding. Forty water points were resampled in the dry season, with the remainder having run dry. Ground-based observations of flooding were compared with three satellite-derived flood maps. Boreholes were less contaminated than wells or surface waters (geometric mean E. coli = 20.2, 175.6, and 590.7 cfu/100 ml, respectively). Among groundwater points, a Wilcoxon signed-rank test indicated significantly greater median E. coli and thermotolerant coliform contamination during flooding (p = 0.025 and p < 0.001, respectively), but Shigella, salmonella, and intestinal enterococci counts were not significantly different between seasons. In contrast, among surface water points, E. coli, Shigella, and Salmonella counts were significantly greater in dry season samples (p < 0.005 for all parameters), possibly reflecting a “concentration” effect. Satellite-derived flood maps had no or low agreement with ground-based observations of water point flooding. Although groundwater quality deteriorated during and after flooding, surface waters were the most microbiologically contaminated in both seasons. The greatest public health risk thus occurred where households switched to surface water collection during or following flood season. Flood risk should be assessed before borehole installation and existing flood-prone boreholes remediated to mitigate population exposure to contaminated water.

Boiled or Bottled: Regional and Seasonal Exposures to Drinking Water Contamination and Household Air Pollution in Rural China.

Background:Inadequate access to safe drinking water remains a global health problem, particularly in rural areas. Boiling is the most commonly used form of point-of-use household water treatment (HWT) globally, although the use of bottled water in low- and middle-income countries (LMICs) is increasing rapidly.Objectives:We assessed the regional and seasonal prevalence of HWT practices (including bottled water use) in low-income rural areas in two Chinese provinces, evaluated the microbiological safety of drinking water and associated health outcomes, and estimated the air pollution burden associated with the use of solid fuels for boiling.Methods:We conducted cross-sectional surveys and collected drinking water samples from 1,033 rural households in Guangxi and Henan provinces. Temperature sensors affixed to pots and electric kettles were used to corroborate self-reported boiling frequencies and durations, which were used to model household air pollution (HAP) in terms of estimated particulate matter in aerodynamic diameter () concentrations.Results:Based on summer data collection in both provinces, after controlling for covariates, boiling with electric kettles was associated with the largest log reduction in thermotolerant coliforms (TTCs) ( TTC most probable number), followed by boiling with pots (), and bottled water use (); all were statistically significant (). Boiling with electric kettles was associated with a reduced risk of TTC contamination [risk ratio , ] and reported diarrhea (, ). TTCs were detected in 51% () of bottled water samples. For households boiling with biomass, modeled concentrations averaged ().Discussion:Our findings suggest that where boiling is already common and electricity access is widespread, the promotion of electricity-based boiling may represent a pragmatic stop-gap means of expanding safe water access until centralized, or decentralized, treated drinking water is available; displacing biomass use for water boiling could also reduce HAP concentrations and exposures. Our results also highlight the risks of increasing bottled water use in rural areas, and its potential to displace other sources of safe drinking water, which could in turn hamper efforts in China and other LMICs toward universal and affordable safe water access. https://doi.org/10.1289/EHP7124

Drinking water quality from rural handpump-boreholes in Africa

Groundwater provides a vital source of drinking water for rural communities in many parts of Africa, particularly in the dry season when there are few safe alternative sources. This paper summarises results from a study (n = 428) assessing dry season water quality, both microbiological and inorganic chemistry, in handpump equipped boreholes (HPBs) across the Ethiopia Highlands (n = 142), Malawi (n = 162) and Uganda (n = 124) using a stratified, randomised sampling design. This study seeks to examine general water quality by randomly sampling rural groundwater supplies across larger areas with different geology and climate. The majority, 72%, of HPBs surveyed provide good quality dry season drinking water as defined by WHO drinking water quality criteria. Within this overall picture, the most notable constraints were from thermotolerant coliforms (TTCs), which exceeded the WHO drinking water guideline of zero colony forming units (cfu/100 ml) in 21% of sites (range 0–626 cfu/100 ml). TTC contamination was found to have a significant and positive correlation with annual average rainfall (ρ = 0.2, p = 0.00003). Across all three countries, WHO health based chemical drinking water quality values were exceeded at 9% of sites and were found for manganese (4%), fluoride (2.6%) and nitrate (2.5%); arsenic concentrations were below the guideline value of 10 μg l−1 (range < 0.5–7 μg l−1). The high percentage of Mn exceedances (14% ± 5.2% >400 μg l−1) found in drinking water sources in Uganda challenges the decision by WHO not to formalise a health-based guideline for Mn. While the overall level of microbiological contamination from HPBs is low, results from this study strongly suggest that at a national and regional level, microbiological contamination rather than chemical contamination will provide a greater barrier to achieving targets set for improved drinking water quality under the UN-SDG 6. Efforts should be made to ensure that boreholes are properly sited and constructed effectively to reduce pathogen contamination.

Real-time detection of faecally contaminated drinking water with tryptophan-like fluorescence: defining threshold values

We assess the use of fluorescent dissolved organic matter at excitation-emission wavelengths of 280nm and 360nm, termed tryptophan-like fluorescence (TLF), as an indicator of faecally contaminated drinking water. A significant logistic regression model was developed using TLF as a predictor of thermotolerant coliforms (TTCs) using data from groundwater- and surface water-derived drinking water sources in India, Malawi, South Africa and Zambia. A TLF threshold of 1.3ppb dissolved tryptophan was selected to classify TTC contamination. Validation of the TLF threshold indicated a false-negative error rate of 15% and a false-positive error rate of 18%. The threshold was unsuccessful at classifying contaminated sources containing <10 TTC cfu per 100mL, which we consider the current limit of detection. If only sources above this limit were classified, the false-negative error rate was very low at 4%. TLF intensity was very strongly correlated with TTC concentration (ρs=0.80). A higher threshold of 6.9ppb dissolved tryptophan is proposed to indicate heavily contaminated sources (≥100 TTC cfu per 100mL). Current commercially available fluorimeters are easy-to-use, suitable for use online and in remote environments, require neither reagents nor consumables, and crucially provide an instantaneous reading. TLF measurements are not appreciably impaired by common intereferents, such as pH, turbidity and temperature, within typical natural ranges. The technology is a viable option for the real-time screening of faecally contaminated drinking water globally.

Faecal contamination of household drinking water in Rwanda: A national cross-sectional study

Unsafe drinking water is a leading cause of morbidity and mortality, especially among young children in low-income settings. We conducted a national survey in Rwanda to determine the level of faecal contamination of household drinking water and risk factors associated therewith. Drinking water samples were collected from a nationally representative sample of 870 households and assessed for thermotolerant coliforms (TTC), a World Health Organization (WHO)-approved indicator of faecal contamination. Potential household and community-level determinants of household drinking water quality derived from household surveys, the 2012 Rwanda Population and Housing Census, and a precipitation dataset were assessed using multivariate logistic regression. Widespread faecal contamination was present, and only 24.9% (95% CI 20.9–29.4%, n=217) of household samples met WHO Guidelines of having no detectable TTC contamination, while 42.5% (95% CI 38.0–47.1%, n=361) of samples had >100TTC/100mL and considered high risk. Sub-national differences were observed, with poorer water quality in rural areas and Eastern province. In multivariate analyses, there was evidence for an association between detectable contamination and increased open waste disposal in a sector, lower elevation, and water sources other than piped to household or rainwater/bottled. Risk factors for intermediate/high risk contamination (>10TTC/100mL) included low population density, increased open waste disposal, lower elevation, water sources other than piped to household or rainwater/bottled, and occurrence of an extreme rain event the previous day. Modelling suggests non-household-based risk factors are determinants of water quality in this setting, and these results suggest a substantial proportion of Rwanda's population are exposed to faecal contamination through drinking water.

Fecal contamination of drinking water in Kericho District, Western Kenya: role of source and household water handling and hygiene practices.

Inadequate protection of water sources, and poor household hygienic and handling practices have exacerbated fecal water contamination in Kenya. This study evaluated the rate and correlates of thermotolerant coliform (TTC) household water contamination in Kericho District, Western Kenya. Culture and multiplex polymerase chain reaction (PCR) techniques were used to characterize TTCs. The disk diffusion method was used for antibiotic susceptibility profiling of pathogenic Escherichia coli. Out of the 103 households surveyed, 48 (46.6%) had TTC contaminated drinking water (TTC levels of >10 cfu/100 mL). Five of these households were contaminated with pathogenic E. coli, including 40% enteroaggregative E. coli, 40% enterotoxigenic E. coli, and 20% enteropathogenic E. coli. All these pathogenic E. coli strains were multidrug resistant to sulfamethoxazole/trimethoprim, ampicillin, tetracycline and ampicillin/sulbactam. Rural household locality, drinking water hand contact, water storage container cleaning practice, hand washing before water withdrawal, water source total coliforms <10 cfu/100 mL, temperature, and free chlorine levels were associated with TTC contamination of household drinking water. Significant proportions of household drinking water in Kericho District are contaminated with TTCs including with pathogenic multidrug-resistant E. coli. Source and household hygiene and practices contribute significantly to drinking water contamination.

Examining the influence of urban definition when assessing relative safety of drinking-water in Nigeria

Reducing inequalities is a priority from a human rights perspective and in water and public health initiatives. There are periodic calls for differential national and global standards for rural and urban areas, often justified by the suggestion that, for a given water source type, safety is worse in urban areas. For instance, initially proposed post-2015 water targets included classifying urban but not rural protected dug wells as unimproved. The objectives of this study were to: (i) examine the influence of urban extent definition on water safety in Nigeria, (ii) compare the frequency of thermotolerant coliform (TTC) contamination and prevalence of sanitary risks between rural and urban water sources of a given type and (iii) investigate differences in exposure to contaminated drinking-water in rural and urban areas. We use spatially referenced data from a Nigerian national randomized sample survey of five improved water source types to assess the extent of any disparities in urban–rural safety. We combined the survey data on TTC and sanitary risk with map layers depicting urban versus rural areas according to eight urban definitions. When examining water safety separately for each improved source type, we found no significant urban–rural differences in TTC contamination and sanitary risk for groundwater sources (boreholes and protected dug wells) and inconclusive findings for piped water and stored water. However, when improved and unimproved source types were combined, TTC contamination was 1.6 to 2.3 times more likely in rural compared to urban water sources depending on the urban definition. Our results suggest that different targets for urban and rural water safety are not justified and that rural dwellers are more exposed to unsafe water than urban dwellers. Additionally, urban–rural analyses should assess multiple definitions or indicators of urban to assess robustness of findings and to characterize a gradient that disaggregates the urban–rural dichotomy.

Quail egg safety and trade on beaches of Salvador (BA): a study from a child labor perspective

OBJECTIVE: This study aimed to describe the trade and microbiological quality of boiled quail eggs on the waterfront of Salvador , Bahia, Brazil, from the child labor perspective. METHODS: This cross-sectional study administered semi-structured questionnaires to 40 underage vendors and performed the microbiological assessment of 40 quail egg samples as follows: mesophilic aerobic microorganism count, coagulase-positive staphylococcus count, estimation of the most probable number of total and thermotolerant coliforms/Escherichia coli, and testing for Salmonella spp.. The results were compared with the standards provided by the Resolution RDC nº 12/2001, National Sanitary Surveillance Agency. RESULTS: The vendors were mostly female (57.5%) students (95.0%) aged 8 to 17 years. The most common reason for working was supplementation of the family income (57.5%). The mean gross income was R$38.31/day. Most of them presented inadequate personal hygiene but they recognized that foods could cause diseases. Many (47.5%) vendors reported washing their hands up to twice daily. Mean mesophilic aerobic microorganism and coagulase-positive staphylococcus counts were 2.43 and 2.01 log colony-forming unit/g, respectively, and the estimated thermotolerant coliform contamination was 0.98 log most probable number/g. Escherichia coli was found in 15.0% of the samples and none contained Salmonella spp. Most (55.0%) samples were noncompliant with the legislation. CONCLUSION: The results evidenced the presence of minors selling quail eggs on beaches of Salvador and suggest risk to consumers' health because of the detected contamination and vendors' ignorance of principles of hygiene.

Qualidade microbiológica de empadão goiano comercializado em uma feira de lazer de Goiânia/GO e teste de susceptibilidade antimicrobiana de cepas isoladas

The purpose of this study was to verify the microbiological quality of chicken piescommercialized in a fair in the city of Goiânia, Brazil, and to carry out the test ofantimicrobial susceptibility of isolated microorganisms. From 24 different tents,144 chicken pies samples were collected. The samples were analyzed accordingto Brazilian legislation including the counting of thermotolerant coliforms,Escherichia coli, coagulase positive Staphylococcus, Bacillus cereus, sulfitereducing Clostridium and the research of Salmonella sp. Forty-one (28.5 %) ofthe samples presented thermotolerant coliforms contamination, 22 (15.3 %) werepositive for E. coli and nine (6.2%) for coagulase positive Staphylococcus. Allof the samples were negative for B. cereus, C. perfringens and Salmonella sp.contamination. The strains were submitted to antimicrobial susceptibility test. TheS. aureus isolates showed greater resistance for penicillin (88.9 %). The strainswere grouped in five phenotypic profiles (A-E), suggesting different sources ofcontamination. The E. coli strains tested, showed greater resistance to tetracycline(41.0 %) and cephalothin (41.0 %). The E. coli strains were grouped in sevenphenotypic profiles (A-G). The results evidenced the poor microbiological qualityof the chicken pies commercialized in those conditions, signaling for the potentialrisk of foodborne diseases. Educative works with food handlers with the aim tominimize the identified errors and, consequently, to promote the protection of theconsumers’ health are recommended.

The possible reuse of wastewater treated by lagooning for the irrigation of field crops

At the output from the lagooning system in the rural community of Saint-Coulomb, the effluent is of acceptable physical-chemical quality for the purposes of irrigation but care should be taken with regard to the irrigation of boron-sensitive plants. As far as contamination by metals is concerned, the effluent is of the domestic type and can therefore be used without restriction. Monitoring of effluent quality during the summer months reveals that levels of thermotolerant coliform contamination do not always lie below the value fixed by the C.H.S.P.F. for the irrigation of plants eaten raw (104 1-1). However, no intestinal helminth eggs or salmonellaewere detected. The levels of thermotolerant coliform contamination do not reveal any significant differences (at the 5% level) between plants irrigated with treated wastewater and plants not irrigated at all. Nor is there any significant difference between plants irrigated with standard water (TTC &amp;lt; 104 1-1) and substandard water. The thermotolerant coliform contamination does not only correspond to contamination by faecal coliforms.

The possible reuse of wastewater treated by lagooning for the irrigation of field crops

At the output from the lagooning system in the rural community of Saint-Coulomb, the effluent is of acceptable physical-chemical quality for the purposes of Irrigation but care should be taken with regard to the irrigation of boron-sensitive plants. As far as contamination by metals Is concerned, the effluent is of the domestic type and can therefore be used without restriction. Monitoring of effluent quality during the summer months reveals that levels of thermotolerant coliform contamination do not always lie below the value fixed by the C.H.S.P.F. for the Irrigation of plants eaten raw (104 1−1 ). However, no intestinal helminth eggs or salmonellae were detected. The levels of thermotolerant coliform contamination do not reveal any significant differences (at the 5% level) between plants irrigated with treated wastewater and plants not Irrigated at all. Nor is there any significant difference between plants irrigated with standard water (TTC < 104 1−1) and substandard water. The thermotolerant coliform contamination does not only correspond to contamination by faecal coliforms.