Mineral pollutants and coliform contamination in groundwater pose health risks to consumers: a spatiotemporal study in a mining-impacted area.

The presence of mineral pollutants, combined with bacterial contamination, has significantly impacted groundwater quality and led to various health-related issues in mining-impacted areas. Therefore, we measured the concentration of fluoride (F-), phosphate (PO43-), sulphate (SO42-), ammonium (NH4+), nitrate (NO3-), the total coliforms (TCs), and physiochemical characteristics in groundwater samples of South Khorasan, Eastern Iran. For this, we collected water samples from 100 wells in spring and autumn across this mining-impacted area. We then measured the concentrations of mineral pollutants and assessed their associated health risks to children and adults using the Environmental Protection Agency (EPA) models and spatiotemporal zoning maps in ArcGIS. The concentrations of PO43-, NH4+, SO42-, NO3-, and F- were 0.70 ± 0.34, 0.82 ± 0.9, 175.45 ± 123, 15.26 ± 9.41, and 0.53 ± 0.68 mg/L in spring, and 0.71 ± 3.18, 4.68 ± 31, 306.72 ± 615.80, 19.30 ± 15.61, and 0.72 ± 0.65 mg/L in autumn, respectively. PO43-, NH4+, and SO42- exceeded both the World Health Organization (WHO) and EPA, but NO3- exceeded only EPA standards. TCs in both seasons exceeded the standards set by the EPA and WHO. The hazard quotient (HQ) values indicated non-carcinogenic risks for F⁻ and NO3⁻, while posing no risks NH4⁺ and PO43⁻ in both adults and children during autumn and spring.Hazard index (HI) was greater than 1 for all minerals in both children and adults in autumn and spring. No correlation was observed between mineral compounds and TCs in the study area, yet the water samples were highly contaminated by coliform with a significant risk to adults and children. In essence, both mineral pollutants and TCs potentially pose serious risks to human, and more efforts are required to improve the quality of water in this area.

Impact of irrigation source on the dissemination and persistence of coliforms and foodborne pathogens in fresh tomato high tunnel-dripline system from small specialty crop farms.

This study investigated the impact of irrigation sources (pond, stream and well) in high tunnel-dripline systems on the dissemination and persistence of foodborne pathogens (Escherichia coli O157, Listeria monocytogenes, Campylobacter spp., Salmonella spp. and the 'big six' Shiga toxin-producing E. coli [STEC]) in small specialty crop farms (SSCF). Ten SSCF growing fresh tomatoes using high tunnel-dripline systems were sampled between January and November 2022. Selective enrichment combined with PCR was used to detect the selected foodborne pathogens in the irrigation water (n=240), soil (n=240), and tomato fruits (n=120). Overall, surface originated water sources (streams and ponds) having potential contact with farm animals or wildlife harbored higher pathogen burden (cumulative prevalence of all the pathogens) compared to subsurface water source (well and underground spring water). STEC O26, O45 and O103 were detected at high frequency (up to 88% per SSCF per time point) in the water source and associated dripline irrigation system of 4/6 SSCF using stream and pond water. Other foodborne pathogens (especially, L. monocytogenes) were detected in 6/10 SSCF, but at low frequency (<25% per SSCF per time point). The prevalence of foodborne pathogens in the 10 SSCF over time was positively correlated with the length of high tunnel and planting date (r2=0.93 and 0.79, respectively; P<0.006). Our study highlighted that dripline irrigation systems may allow the long-distance transport of foodborne pathogens from the contaminated water source to the field. Risk assessment and mitigation measures should be implemented to assure the quality of the water source used for irrigation in SSCF.

Sucralose and caffeine as chemical indicators of domestic wastewater contamination in the Laurentian Great Lakes Basin.

Surface waters within the basin of the Laurentian Great Lakes are impacted by microbial contamination from municipal wastewater and agricultural runoff, as well as from other sources. In particular, microbial contamination of drinking water is an ongoing problem within many Indigenous communities located in the basin. However, it is difficult to identify the sources of microbial contamination using the traditional monitoring approaches with fecal indicator bacteria, such as total coliforms and Escherichia coli (E. coli). In this study, we evaluated whether surface waters in the basin are contaminated with fecal bacteria of human origin using chemical indicators of domestic wastewater (i.e., caffeine and sucralose) and with Bacteroidales 16S rRNA markers. Study areas included the Grand River watershed within the Lake Erie basin and three nearshore locations within the Great Lakes basin. Two of these sites are sources of drinking water for Indigenous communities. We assessed whether there were relationships between the concentrations of fecal indicator microorganisms and chemical indicators of domestic wastewater at selected study locations. Analysis of genetic markers indicated that about 30% of the Bacteroidales bacteria present at a site in the Grand River were of human fecal origin and the balance were of bovine or general animal origin. The presence of caffeine and sucralose in surface waters indicated that there was upstream contamination by domestic wastewater. However, in the drinking water treatment plant operated by Six Nations of the Grand River, the levels of these chemical indicators and fecal bacteria were reduced by the advanced water treatment technologies. The concentrations of sucralose and caffeine collectively were strongly correlated with the levels of total coliforms in samples from the Grand River (R2 = 0.75) and with levels of E. coli in samples from the Great Lakes basin (R2 = 0.97), but there appeared to be an upper threshold for this relationship. These data indicate that analysis of caffeine and sucralose and genetic markers for strains of Bacteroidales fecal bacteria may be useful tools for identifying the sources of microbiological contamination of surface waters and drinking water.

Development of a "big data" groundwater microbial contamination index and spatial comparisons with enteric infection rates in southern Ontario.

Big data have become increasingly important for policymakers and scientists but have yet to be employed for the development of spatially specific groundwater contamination indices or protecting human and environmental health. The current study sought to develop a series of indices via analyses of three variables: Non-E. coli coliform (NEC) concentration, E. coli concentration, and the calculated NEC:E. coli concentration ratio. A large microbial water quality dataset comprising 1,104,094 samples collected from 292,638 Ontarian wells between 2010 and 2021 was used. Getis-Ord Gi* (Gi*), Local Moran's I (LMI), and space-time scanning were employed for index development based on identified cluster recurrence. Gi* and LMI identify hot and cold spots, i.e., spatially proximal subregions with similarly high or low contamination magnitudes. Indices were statistically compared with mapped well density and age-adjusted enteric infection rates (i.e., campylobacteriosis, cryptosporidiosis, giardiasis, verotoxigenic E. coli (VTEC) enteritis) at a subregional (N = 298) resolution for evaluation and final index selection. Findings suggest that index development via Gi* represented the most efficacious approach. Developed Gi* indices exhibited no correlation with well density, implying that indices are not biased by rural population density. Gi* indices exhibited positive correlations with mapped infection rates, and were particularly associated with higher bacterial (Campylobacter, VTEC) infection rates among younger sub-populations (p < 0.05). Conversely, no association was found between developed indices and giardiasis rates, an infection not typically associated with private groundwater contamination. Findings suggest that a notable proportion of bacterial infections are associated with groundwater and that the developed Gi* index represents an appropriate spatiotemporal reflection of long-term groundwater quality. Bacterial infection correlations with the NEC:E. coli ratio index (p < 0.001) were markedly different compared to correlations with the E. coli index, implying that the ratio may supplement E. coli monitoring as a groundwater assessment metric capable of elucidating contamination mechanisms. This study may serve as a methodological blueprint for the development of big data-based groundwater contamination indices across the globe.

Impact of operational conditions on drinking water biofilm dynamics and coliform invasion potential.

Biofilms within drinking water distribution systems serve as a habitat for drinking water microorganisms. However, biofilms can negatively impact drinking water quality by causing water discoloration and deterioration and can be a reservoir for unwanted microorganisms. In this study, we investigated whether indicator organisms for drinking water quality, such as coliforms, can settle in mature drinking water biofilms. Therefore, a biofilm monitor consisting of glass rings was used to grow and sample drinking water biofilms. Two mature drinking water biofilms were characterized by flow cytometry, ATP measurements, confocal laser scanning microscopy, and 16S rRNA sequencing. Biofilms developed under treated chlorinated surface water supply exhibited lower cell densities in comparison with biofilms resulting from treated groundwater. Overall, the phenotypic as well as the genotypic characteristics were significantly different between both biofilms. In addition, the response of the biofilm microbiome and possible biofilm detachment after minor water quality changes were investigated. Limited changes in pH and free chlorine addition, to simulate operational changes that are relevant for practice, were evaluated. It was shown that both biofilms remained resilient. Finally, mature biofilms were prone to invasion of the coliform, Serratia fonticola. After spiking low concentrations (i.e., ±100 cells/100 mL) of the coliform to the corresponding bulk water samples, the coliforms were able to attach and get established within the mature biofilms. These outcomes emphasize the need for continued research on biofilm detachment and its implications for water contamination in distribution networks. IMPORTANCE: The revelation that even low concentrations of coliforms can infiltrate into mature drinking water biofilms highlights a potential public health concern. Nowadays, the measurement of coliform bacteria is used as an indicator for fecal contamination and to control the effectiveness of disinfection processes and the cleanliness and integrity of distribution systems. In Flanders (Belgium), 533 out of 18,840 measurements exceeded the established norm for the coliform indicator parameter in 2021; however, the source of microbial contamination is mostly unknown. Here, we showed that mature biofilms, are susceptible to invasion of Serratia fonticola. These findings emphasize the importance of understanding and managing biofilms in drinking water distribution systems, not only for their potential to influence water quality, but also for their role in harboring and potentially disseminating pathogens. Further research into biofilm detachment, long-term responses to operational changes, and pathogen persistence within biofilms is crucial to inform strategies for safeguarding drinking water quality.

Occurrence of coliforms and biofilm-forming bacteria in raw, treated, and distributed water from two waterwork systems in Osun State, Southwestern Nigeria.

This study assessed the bacteriological quality of raw, treated, and distributed water from Ede-Erinle and Opa reservoirs in Osun State, Nigeria. This was to determine the potability of water from these waterwork stations. Eighteen sampling points were established across the two reservoir networks for this study. Samples were collected bi-monthly for two annual cycles. Serial dilution and pour plate methods were employed for the enumeration of bacterial load. Total heterotrophic bacteria count (THBC) and total coliform bacteria count (TCBC) were enumerated on nutrient and MacConkey agar at 37 °C, respectively. Bacterial isolates were characterized using biochemical identification methods with reference to Bergey's Manual of Determinative Bacteriology. Bacterial isolates and biofilm formation were further identified molecularly through the PCR method using specific universal primers. Mean values of THBC and TCBC in distributed water from Ede-Erinle (9.61 × 104 ± 1.50 × 104 CFU/mL; 69.56 ± 26.81 CFU/mL) and Opa waterworks (9.58 × 104 ± 2.55 × 104 CFU/mL; 142.94 ± 44.41 CFU/mL) exceeded permissible limits for drinking water. Paenibacillus lautus, Bacillus pseudomycoides, Pseudomonas aeruginosa, and Pseudomonas stutzeri showed biofilm-forming capacity. The study concluded that the presence of coliforms and biofilm-forming bacteria in distributed water implies that the water is unfit for consumption without further treatment.

Impact of environmental factors on Biomphalaria pfeifferi vector capacity leading to human infection by Schistosoma mansoni in two regions of western Côte d'Ivoire.

ABSTRACT: BACKGROUND: Intestinal schistosomiasis remains a worrying health problem, particularly in western Côte d'Ivoire, despite control efforts. It is therefore necessary to understand all the factors involved in the development of the disease, including biotic and abiotic factors. The aim of this study was to examine the factors that could support the maintenance of the intermediate host and its vectorial capacity in western Côte d'Ivoire. METHODS: Data on river physicochemical, microbiological, and climatic parameters, the presence or absence of snails with Schistosoma mansoni, and human infections were collected between January 2020 and February 2021. Spearman rank correlation tests, Mann-Whitney, analysis of variance (ANOVA), and an appropriate model selection procedure were used to analyze the data. RESULTS: The overall prevalence of infected snails was 56.05%, with infection reaching 100% in some collection sites and localities. Of 26 sites examined, 25 contained thermophilic coliforms and 22 contained Escherichia coli. Biomphalaria pfeifferi was observed in environments with lower land surface temperature (LST) and higher relative air humidity (RAH), and B. pfeifferi infection predominated in more acidic environments. Thermal coliforms and E. coli preferred higher pH levels. Lower maximum LST (LST_Max) and higher RAH and minimum LST (LST_Min) were favorable to E. coli, and lower LST_Max favored coliforms. The presence of B. pfeifferi was positively influenced by water temperature (T °C), LST_Min, RAH, and precipitation (Pp) (P < 0.05) and negatively influenced by pH, total dissolved solids (TDS), electrical conductivity (EC), LST_Max, and mean land surface temperature (LST). The parameters pH, TDS, EC, LST_Min, LST, and Pp had a positive impact on snail infection, while LST_Max had a negative impact on infection. Only pH had a positive effect on coliform and E. coli abundance. Of the 701 people examined for human schistosomiasis, 73.13% were positive for the point-of-care circulating cathodic antigen (POC-CCA) test and 12.01% for the Kato-Katz (KK) test. A positive correlation was established between human infections and the abundance of Biomphalaria (r2 = 0.879, P = 0.04959). CONCLUSIONS: The results obtained reflect the environmental conditions that are conducive to the maintenance of S. mansoni infection in this part of the country. To combat this infection as effectively as possible, it will be necessary not only to redouble efforts but also to prioritize control according to the level of endemicity at the village level.

Total coliforms, microbial diversity and multiple characteristics of Salmonella in soil-irrigation water-fresh vegetable system in Shaanxi, China.

Global occurrences of foodborne disease outbreaks have been documented, involving fresh agricultural produce contaminated by various pathogens. This contamination can occur at any point in the supply chain. However, studies on the prevalence of total coliforms, Salmonella and microbial diversity in vegetable and associated environments are limited. This study aimed to assess 1) the number of total coliforms (n = 299) and diversity of microbial communities (n = 52); 2) the prevalence, antibiotic susceptibility, genomic characteristics, and potential transmission relationships of Salmonella in soil-irrigation water-vegetable system (n = 506). Overall, 84.28 % samples were positive to total coliforms, with most frequently detected in soil (100 %), followed by irrigation water (79.26 %) and vegetables (62.00 %). A seasonal trend in coliform prevalence was observed, with significantly higher levels in summer (P < 0.05). Detection rates of Salmonella in soil, vegetable and irrigation water were 2.21 %, 4.74 % and 9.40 %. Fourteen serotypes and sequence types (STs) were respectively annotated in 56 Salmonella isolates, ST13 S. Agona (30.36 %, 17/56), ST469 S. Rissen (25.00 %, 14/56), and ST36 S. Typhimurium (12.50 %, 7/56) were dominant serotypes and STs. Thirty-one (55.36 %) isolates were multi-drug resistant, and the resistance was most frequently found to ampicillin (55.36 %, 31/56), followed by to sulfamethoxazole (51.79 %, 29/56) and tetracycline (50.00 %, 28/56). The genomic characteristics and antibiotic resistance patterns of Salmonella isolates from soil, vegetables, and irrigation water within a coherent geographical locale exhibited remarkable similarities, indicating Salmonella may be transmitted among these environments or have a common source of contamination. Microbial alpha diversity indices in soil were significantly higher (P < 0.05) than that in vegetable and irrigation water. The microbial phylum in irrigation water covered that in the vegetable, demonstrating a significant overlap in the microbial communities between the vegetables and the irrigation water.

Rapid measurement of bacterial contamination in water: A catalase responsive-electrochemical sensor.

The present study describes the development of a potentiometric sensor for microbial monitoring in water based on catalase activity. The sensor comprises a MnO2-modified electrode that responds linearly to hydrogen peroxide (H2O2) from 0.16 M to 3.26 M. The electrode potential drops when the H2O2 solution is spiked with catalase or catalase-producing microorganisms that decompose H2O2. The sensor is responsive to different bacteria and their catalase activities. The electrochemical sensor exhibits a lower limit of detection (LOD) for Escherichia coli at 11 CFU/ml, Citrobacter youngae at 12 CFU/ml, and Pseudomonas aeruginosa at 23 CFU/ml. The sensor shows high sensitivity at 3.49, 3.02, and 4.24 mV/cm2dec for E. coli, C. youngae, and P. aeruginosa, respectively. The abiotic sensing electrode can be used multiple times without changing the response potential (up to 100 readings) with a shelf-life of over six months. The response time is a few seconds, with a total test time of 5 min. Additionally, the sensor effectively tested actual samples (drinking and grey water), which makes it a quick and reliable sensing tool. Therefore, the study offers a promising water monitoring tool with high sensitivity, stability, good detection limit, and minimum interference from other water contaminants.

Evidence for long-term efficacy of a membrane filtration device in rural villages in Ghana.

Drinking water contaminated by pathogenic micro-organisms increases the risk of infectious gastrointestinal disease which could potentially lead to acute kidney injury and even death, particularly amongst the young and the elderly. Earlier studies have shown a substantial reduction in the incidence of diarrheal disease over a period of one year using a polysulfone membrane water gravity-powered water filtration device. The current report is a continuation of these studies to assess the long-term effects of the innovative method on diarrheal incidence rates over a 4-year follow-up period. This follow-up study monitored the trend of self-reported diarrheal events in all households in the previously studied villages for 5 months, in the last half of each study year, using the same questionnaire utilized in the earlier study. Three villages that had no device yet installed served as controls. We computed monthly diarrheal incidence rates for all study years (standardized to per 100 person-months) and compared these to the pre-device incidence rate in 2018 and in the control group, using the Wilcoxon rank sum exact test. The average diarrheal incidence rates of 1.5 p100pm in 2019, 2.19 p100pm in 2021, and 0.54p100pm in 2022 were significantly different from an earlier study that reported 17.8 p100pm rates before the devices were installed in 2018, (all p-values < 0.05). Concomitantly, self-reported diarrheal infections were substantially higher in the "control villages" not yet having the filtration device installed (80.9, 77.6, and 21.5 per 100 pm). The consistent and large reduction in diarrhea incidence documents the long-term efficacy of the use of the membrane filtration device. This simple water purification method using gravity flow improves public health in remote regions with limited resources.

Wastewater contaminants in a fractured bedrock aquifer and their potential use as enteric virus indicators.

Domestic wastewater is a source of persistent organic pollutants and pathogens to the aquatic environment, including groundwater aquifers. Wastewater contaminants include a variety of personal care products, pharmaceuticals, endocrine disrupters, bacteria, and viruses. Groundwater from 22 wells completed in a semi-confined to confined, fractured Silurian dolostone aquifer in southern Wellington County, Ontario, Canada, was analyzed for 14 organic wastewater contaminants (4 artificial sweeteners, 10 pharmaceuticals) as well as E. coli, total coliforms, and 6 human enteric viruses. Enteric viruses were detected in 8.6% of 116 samples, and at least one organic wastewater contaminant was detected in 82% of the wells (in order of decreasing detection frequency: acesulfame, ibuprofen, sulfamethoxazole, triclosan, carbamazepine, and saccharin). Virus indicator metrics [positive and negative predictive values (PPV, NPV), sensitivity, specificity] were calculated at the sample and well level for the organic wastewater compounds, E. coli, and total coliforms. Fecal bacteria were not good predictors of virus presence (PPV = 0%-8%). Of the potential chemical indicators, triclosan performed the best at the sample level (PPV = 50%, NPV = 100%), and ibuprofen performed the best at the well level (PPV = 60%, NPV = 67%); however, no samples had triclosan or ibuprofen concentrations above their practical quantification limits. Therefore, none of the compounds performed sufficiently well to be considered reliable for assessing the potential threat of enteric viruses in wastewater-impacted groundwater in this bedrock aquifer. Future studies need to evaluate the indicator potential of persistent organic wastewater contaminants in different types of aquifers, especially in fractured rock where heterogeneity is strong.IMPORTANCEAssessing the potential risk that human enteric viruses pose in groundwater aquifers used for potable water supply is complicated by several factors, including: (i) labor-intensive methods for the isolation and quantification of viruses in groundwater, (ii) the temporal variability of these viruses in domestic wastewater, and (iii) their potentially rapid transport in the subsurface, especially in fractured rock aquifers. Therefore, aquifer risk assessment would benefit from the identification of suitable proxy indicators of enteric viruses that are easier to analyze and less variable in wastewater sources. Traditional fecal indicators (e.g., E. coli and coliforms) are generally poor indicators of enteric viruses in groundwater. While many studies have examined the use of pharmaceutical and personal care products as tracers of domestic wastewater and fecal pollution in the environment, there is a paucity of data on the potential use of these chemical tracers as enteric virus indicators, especially in groundwater.

Assessment of microbial population in integrated CW-MFC system and investigation of organics and fecal coliform removal pathway.

The current study is focused on understanding the operational mechanism of an integrated constructed wetland-microbial fuel cell (CW-MFC) reactor emphasizing fecal coliform (FC) removal. Few studies are available in the literature investigating the inherent mechanisms of pathogen inactivation in a CW-MFC system. Raw domestic wastewater was treated in three vertical reactors, one planted constructed wetland (R1), one planted CW-MFC (R2), and one unplanted CW-MFC (R3). Spatial analysis of treated effluents showed a considerable amount of organics and fecal coliform removal at the vicinity of the anode in R2. Assessment of the microbial population inside all the reactors revealed that EABs (Firmicutes, Bacteroidetes, and Actinobacteria) were more abundant in R2 compared to R1 and R3. During the activity study, biomass obtained from R2 showed a maximum substrate utilization rate of 1.27 mg COD mgVSS-1 d-1. Kinetic batch studies were carried out for FC removal in all the reactors, and the maximum first order FC removal rate was obtained at the anode of R2 as 2.13 d-1 when operated in closed circuit mode. This value was much higher than the natural die-off rate of FCs in raw wastewater which was 1.16 d-1. Simultaneous bioelectricity monitoring inferred that voltage generation can be correlated to faster FC inactivation, which was probably due to EABs outcompeting other exogenous microbes in a preferable anaerobic environment with the presence of an anode. Reactor R2 was found to be functioning as a symbiotic bio-electrochemical mesocosm.

Drinking water quality of various sources in Peshawar, Mardan, Kohat and Swat districts of Khyber Pakhtunkhwa province, Pakistan / Qualidade de água potável de váris fontes dos distritos de Peshawar, Mardan, Kohat e Swat da província de Khyber Pakhtunkhwa, Paquistão

Abstract The present study involves the chemical and bacteriological analysis of water from different sources i.e., bore, wells, bottle, and tap, from Peshawar, Mardan, Swat and Kohat districts of Khyber Pakhtunkhwa (KP) province, Pakistan. From each district, 50 water samples (10 samples from each source), regardless of urban and rural status, were collected from these sources and analysed for sulphates, nitrates, nitrites, chlorides, total soluble solids and coliforms (E. coli). Results indicated that majority of the water sources had unacceptable E. coli count i.e.> 34 CFU/100mL. E. coli positive samples were high in Mardan District, followed by Kohat, Swat and Peshawar district. Besides this, the some water sources were also chemically contaminated by different inorganic fertilizers (nitrates/nitrites of sodium, potassium) but under safe levels whereas agricultural and industrial wastes (chloride and sulphate compounds) were in unsafe range. Among all districts, the water quality was found comparatively more deteriorated in Kohat and Mardan districts than Peshawar and Swat districts. Such chemically and bacteriologically unfit water sources for drinking and can cause human health problems.

Resumo O presente estudo envolve a análise química e bacteriológica de água de diferentes fontes, ou seja, furo, poços, garrafa e torneira, dos distritos de Peshawar, Mardan, Swat e Kohat da província de Khyber Pakhtunkhwa (KP), Paquistão. De cada distrito, 50 amostras de água (10 amostras de cada fonte), independentemente do status urbano e rural, foram coletadas dessas fontes e analisadas para sulfatos, nitratos, nitritos, cloretos, sólidos solúveis totais e coliformes (E. coli). Os resultados indicaram que a maioria das fontes de água tinha uma contagem inaceitável de E. coli, ou seja, > 34 UFC / 100 mL. As amostras positivas para E. coli foram elevadas no distrito de Mardan, seguido por Kohat, Swat e distrito de Peshawar. Além disso, algumas fontes de água também foram contaminadas quimicamente por diferentes fertilizantes inorgânicos (nitratos/nitritos de sódio, potássio), mas em níveis seguros, enquanto os resíduos agrícolas e industriais (compostos de cloreto e sulfato) estavam em níveis inseguros. Entre todos os distritos, a qualidade da água foi considerada comparativamente mais deteriorada nos distritos de Kohat e Mardan do que nos distritos de Peshawar e Swat. Essas fontes de água química e bacteriologicamente impróprias para beber podem causar problemas à saúde humana.

Drinking water quality of various sources in Peshawar, Mardan, Kohat and Swat districts of Khyber Pakhtunkhwa province, Pakistan

Abstract The present study involves the chemical and bacteriological analysis of water from different sources i.e., bore, wells, bottle, and tap, from Peshawar, Mardan, Swat and Kohat districts of Khyber Pakhtunkhwa (KP) province, Pakistan. From each district, 50 water samples (10 samples from each source), regardless of urban and rural status, were collected from these sources and analysed for sulphates, nitrates, nitrites, chlorides, total soluble solids and coliforms (E. coli). Results indicated that majority of the water sources had unacceptable E. coli count i.e.> 34 CFU/100mL. E. coli positive samples were high in Mardan District, followed by Kohat, Swat and Peshawar district. Besides this, the some water sources were also chemically contaminated by different inorganic fertilizers (nitrates/nitrites of sodium, potassium) but under safe levels whereas agricultural and industrial wastes (chloride and sulphate compounds) were in unsafe range. Among all districts, the water quality was found comparatively more deteriorated in Kohat and Mardan districts than Peshawar and Swat districts. Such chemically and bacteriologically unfit water sources for drinking and can cause human health problems.

Resumo O presente estudo envolve a análise química e bacteriológica de água de diferentes fontes, ou seja, furo, poços, garrafa e torneira, dos distritos de Peshawar, Mardan, Swat e Kohat da província de Khyber Pakhtunkhwa (KP), Paquistão. De cada distrito, 50 amostras de água (10 amostras de cada fonte), independentemente do status urbano e rural, foram coletadas dessas fontes e analisadas para sulfatos, nitratos, nitritos, cloretos, sólidos solúveis totais e coliformes (E. coli). Os resultados indicaram que a maioria das fontes de água tinha uma contagem inaceitável de E. coli, ou seja, > 34 UFC / 100 mL. As amostras positivas para E. coli foram elevadas no distrito de Mardan, seguido por Kohat, Swat e distrito de Peshawar. Além disso, algumas fontes de água também foram contaminadas quimicamente por diferentes fertilizantes inorgânicos (nitratos/nitritos de sódio, potássio), mas em níveis seguros, enquanto os resíduos agrícolas e industriais (compostos de cloreto e sulfato) estavam em níveis inseguros. Entre todos os distritos, a qualidade da água foi considerada comparativamente mais deteriorada nos distritos de Kohat e Mardan do que nos distritos de Peshawar e Swat. Essas fontes de água química e bacteriologicamente impróprias para beber podem causar problemas à saúde humana.

Efecto de la actividad truchícola sobre la concentración de coliformes totales y Escherichia coli en aguas de la cuenca alta del río Savegre, Costa Rica

Introducción: La acuacultura de truchas ha incrementado gradualmente en las tierras altas de Costa Rica. Las aguas residuales de esta actividad son descartadas directamente en los ríos, sin tratamientos previos. Como consecuencia, la actividad truchícola puede contaminar severamente el agua de los ríos con bacterias que pueden afectar la salud humana. Objetivo: Evaluar la contaminación bacteriana por la acuacultura de truchas en el río Savegre, Costa Rica. Métodos: Contamos los coliformes totales y Escherichia coli de muestras mensuales (2015-2018) en tres secciones del proyecto de acuacultura más grande de la cuenca alta del río. Recolectamos las muestras en la entrada de los estanques para las truchas, a la salida, y 200 m hacia abajo. Resultados: Encontramos menos coliformes totales y E. coli en el agua recolectada justo en la salida del agua de los estanques. El número de coliformes totales fue mayor en el 2016 y 2017, y de E. coli en el 2016. Conclusiones: Conteos de coliformes y de E. coli es muy alto en el río, pero inesperadamente, su número disminuye en el agua residual descartada de los estanques. Podría ser que el mucus producido por las truchas o sustancias liberadas del musgo que cubre la pared de los estanques reduzca el crecimiento de bacterias, como se ha sido sugerido en otros estudios. La contaminación del río parece venir de otras fuentes.

Introduction: The trout aquacultural activity has gradually increased in Costa Rican highlands. Residual waters from this activity are discarded directly in the rivers without any previous treatment process. Consequently, this activity could severely contaminate the river with bacteria that can affect human health. Objective: To evaluate bacterial contamination from trout aquaculture on Río Savegre, Costa Rica. Methods: We counted total coliforms and Escherichia coli from monthly samples (2015-2018) at three sections of the largest aquacultural development in the upper drainage of the river. We collected samples at the fish ponds entrance, exit and 200 m downwards. Results: We found fewer total coliforms and E. coli in the water collected just at the exit of the fish ponds. We counted more total coliforms in 2016 and 2017, and more E. coli in 2016. Conclusions: Coliform and E. coli counts are high in the river, but, unexpectedly, low in the water discarded from the fish tanks. Perhaps the mucus produced by the trouts or substances released by mosses on the fish tank walls reduce bacterial growth, as suggested by other studies. River pollution appears to come from other sources.

Microbiological quality of water samples obtained from water sources in Ishaka, Uganda.

Objectives: This study aimed to evaluate the microbiological quality of water sources in Ishaka division, Bushenyi district. Methods: Water from taps, wells and springs were sampled for the cross-sectional investigation. The enumeration and identification of microbes (Escherichia coli, Salmonella, Shigella, Proteus, Staphylococcus aureus and total coliforms) in water samples were carried out using a variety of methods. Escherichia coli was enumerated using the membrane filtration method; Salmonella, Shigella and Proteus using a two-step enrichment method; Staphylococcus aureus using the surface spread method and total coliforms using the most probable number technique. Mannitol salt agar was used for enumeration of Staphylococcus Aureus and violet red bile agar was used for enumeration of total coliforms and Escherichia coli; xylose lysine deoxycholate agar was used for both Salmonella spp. and Shigella spp. API-20E was used to phenotypically identify the Enterobacteriaceae contaminants in water. These included Escherichia coli, Proteus mirabilis, Proteus vulgaris, Salmonella spp. and Staphylococcus aureus. Results: Escherichia coli counts in the water from springs and wells ranged from 0 to 314 cfu/mL (p = 0.173) and 0 to 3 cfu/mL (p = 0.269), respectively, while tap water had no incidence of Escherichia coli. Highest level of bacterial contamination in water sources, beyond acceptable WHO (0 cfu/100 mL) limits for drinking water, was reported: Proteus spp., 34 (54.8%), followed by total coliforms, 24 (38.7%), Shigella spp., 22 (35.5%) and least were Salmonella spp. (8.1%) and Staphylococcus aureus spp. (8.1%). Conclusion: It is therefore concluded that spring and well community water sources in Ishaka division, Uganda, are significantly contaminated with pathogenic bacteria and thus unsafe for drinking without adequate water treatment (disinfection and filtration).

The efficacy of hydrogen sulfide (H2S) tests for detecting microbial contamination in rooftop-harvested rainwater.

As climate change strains the world's freshwater resources, access to safe and clean water becomes limited. The use of alternative water sources, such as rooftop-harvested rainwater, has become one mechanism to address freshwater scarcity in the American Southwest, particularly when it comes to home gardening. The University of Arizona's Project Harvest, in partnership with the Sonora Environmental Research Institute, Inc., is a multi-year, co-created citizen science project aimed at increasing current understanding of harvested rainwater quality. Citizens in four Arizona, USA, communities (Hayden/Winkelman, Globe/Miami, Dewey-Humboldt, and Tucson) submitted harvested rainwater samples over 3 years. The harvested rainwater samples were then analyzed using IDEXX Colilert® for total coliforms and E. coli and using Hach PathoScreen™ test for sulfate-reducing bacteria (SRB). This study design allows for the validation of a low-cost, at-home alternative methodology for testing rainwater for bacteria that may indicate fecal contamination. In total, 226 samples were tested using both methodologies, revealing a positive correlation (r=0.245; p<0.002) between total coliform MPN and SRB MPN, but no discernable correlation between E. coli MPN and SRB MPN. This work indicates a potential value of SRB testing for harvested rainwater if cost, laboratory access, and fecal contamination are of concern.

Environmental and Anthropogenic Influences on Coliform Concentrations in the Octopus insularis Production Chain in the Veracruz Reef System, Gulf of Mexico.

Coliforms are relatively common in aquatic environments, but their concentrations can be increased by environmental changes and anthropogenic activities, thus impacting fisheries resources. To determine the microbiological quality in the octopus production chain (capture, post-capture, processing and commercialization), total (TC) and fecal (FC) coliforms were quantified in sea water, fresh octopus, fresh water, ice and octopus in two presentations: packed in ice and boiled. Samples came from fishing zones Enmedio, Chopa and La Gallega at the Veracruz Reef System (VRS) during dry, rainy and windy seasons. The coliforms were determined using the most probable number technique (MPN). The most relevant results indicated that octopus packed in ice coming from the commercialization stage had FC levels >540 MPN/100 g, which exceeded the permissible limits (230 MPN/100 g). Therefore, these products present a risk for human consumption. Differences in FC were observed in octopuses between the three fishing zones (H = 8.697; p = 0.0129) and among the three climatic seasons, increasing during the rainy season, highlighting La Gallega with 203.33 ± 63 MPN (H = 7.200; p = 0.0273). The results provide evidence of the environmental and anthropogenic influences on coliform concentrations and the urgent need to implement an efficient cold chain throughout octopus production stages with adequate handling practices to reverse this situation.

Effect of Type of Mulch on Microbial Food Safety Risk on Cucumbers Irrigated with Contaminated Water.

Mulches are used to block light and retain soil moisture which may affect the survival of bacterial pathogens on soil. This study examined the effectiveness of different types of mulches to minimize microbial risk from contaminated water used for irrigation of cucumbers. A production bed of 120 ft2 with 18 beds (30 ft long) covered with five different types of mulch (paper, paper with fertilizer incorporated (PF), maize-based mulch, biodegradable plastic covering, and conventional plastic) including three beds with no cover was planted with Dasher 2 Variety cucumber. Soil samples from each bed were collected for the first five weeks to examine natural E. coli and coliforms. Well water contaminated with or without nalidixic acid-resistant mutant of E. coli (8 Log CFU/mL) was used for drip irrigation for 7 days before harvesting. Prior to irrigation with contaminated water, naturally present E. coli and coliform in the soil samples with or without mulch were in the range of 3.45-3.78 Log CFU/g and 4.18-5.31 Log CFU/g, respectively. E. coli levels on cucumbers harvested from mulched beds and irrigated with contaminated irrigation water had significantly higher (P < 0.05) levels of E. coli as compared with samples from similar beds irrigated with noncontaminated water. However, Cucumber, harvested within each irrigation water quality were not significantly different regardless of the type of mulch with E. coli levels from 1.72 to 3.30 Log CFU/cm2 (contaminated water) and 0.28-1.86 Log CFU/cm2 (noncontaminated water). A significant die-off of inoculated E. coli was observed on cucumber within 3 days (>1.17 Log CFU/cm2) and >1.38 Log CFU/cm2 after 4 days. Beds with maize mulch were effective on minimizing E. coli contamination on cucumber from contaminated irrigation water.

Treatment of clinical laboratory sewage using a decentralized treatment unit and risk reduction for its reuse in irrigation using hybrid disinfection.

The disinfection efficacy of standalone chlorine, UV and their combined approach (hybrid) was investigated for the coliform removal in BioKube 1 and 2 treated effluents collected from different environmental settings of clinical and domestic wastes. Chlorine and UV disinfection were applied to BioKube treated wastewater with doses from 0 to 4 mg L-1 and 0-166 mJ cm-2 respectively. Combined disinfection strategies were designed to reduce the dose of chlorine and UV and to exploit the synergistic effect of them. The culturable coliforms were enumerated in treated wastewater sample (control), immediately after (reduction), and 24 h post disinfections (regrowth) using culture media plating and colilert-18 media. Both the BioKube systems (1 and 2) were effective in achieving the strict norms of physicochemical parameters, but not following the coliform counts of treated effluent for reuse in irrigation. A hybrid strategy of chlorine followed by UV was found to be the most effective among various standalone and combination approaches for the removal of coliforms (>4 log ER or <1000 CFU/100 mL) from both the treated effluents. However, coliform present in treated effluent of BioKube 1 were resisting (regrowth) against all kind of applied disinfectants except chlorine followed by UV dose at or more than 0.5 mg L-1 + 41 mJ cm-2. Limited reports are available on hybrid disinfection approaches with decentralized packaged sewage treatment units and this study would help to adopt as an effective tertiary treatment strategy for reuse of treated sewage for irrigation while ensuring public health safety.