Microbiological Water Quality Research Articles

Microbiological quality and genotoxicity of domestic water sources: A combined approach using Micro Biological Survey method and mutagenesis assay (micronucleus test) in root tips of Vicia faba in the West region of Cameroon.

At least 2.1 billion people around the world use contaminated drinking water, causing 485,000 diarrheal deaths each year, mostly among children under 5 years old. A study conducted 10 years ago in Bafoussam (West Cameroon) recorded concentrations of bacteria among surface and groundwater. High levels of bicarbonates, phosphates, chlorides and suspended matters were also found. The aim of this study was to assess the microbiological and chemical qualities of domestic water sources in 5 localities of the West region of Cameroon. Water samples from 22 water sources (wells, springs, water drilling and river) were aseptically collected in plastic bottles and transferred in 50 ml sterile tubes. For chlorinated water sources, 1 ml of Thiosulfate was added to the water sample; immediately placed in an ice box and transported to the laboratory for analysis. Water temperature and pH were measured on site. The microbiological quality of water was determined by testing Total Coliforms (TC) using the Micro Biological Survey method. 1 ml of each water sample was inoculated in the MBS vial initially rehydrated with 10 ml of sterile distilled water. The initial color of the vials is red. Color changes were monitored at three different time intervals (12h, 19h and 24h), corresponding to three levels of contamination. The chemical quality of water was assessed using micronucleus (MN) test in selected Vicia faba seeds secondary root tips permanently mounted in Dibutylphthalate Polystyrene Xylene mountant for histology after 72 hours of direct exposition in water samples and in dark. The mitotic indices and MN frequencies were evaluated in 10 root tips per site analysing 5000 cells per tip. Statistical analyses were done using Stata IC/15.0 software. The Student t-test was used for mean comparison and the significance level was set at 1%. The majority of samples were collected from wells (63.6%). The mean water pH ranged from 5.5 to 8.3 and the temperature varied from 23 to 26°C. A very high concentration of TC [>103 CFU/ml] was found in 8 (36.4%) samples. 10 (45.5%) and 2 (9.1%) samples turned yellow at 19 and 24 hours respectively after incubation corresponding to TC concentration of [10<x<103 CFU/ml] and [1<x< 10 CFU/ml]. The MN frequency was higher (P ≤ 0.01) compared to the negative control in 9 (40.9%) water samples indicating significant genotoxic effects of these water sources. This study highlighted the poor quality of domestic water sources in West region of Cameroon and the need to conduct regular monitoring of drinking water sources. Community capacity building on water treatment methods, including good wastes management should be implemented to help improve water quality.

Preliminary Microbiological Coastal Water Quality Determination along the Department of Atlántico (Colombia): Relationships with Beach Characteristics

Beach water quality is an important factor concerning public health and tourism linked to the “Sun, Sea and Sand” market and is usually assessed in international regulations by the quantification of Escherichia coli and enterococci counts. Despite Salmonella spp. detection not being included in international normative, the presence/absence of this bacteria is also an indicator of seawater quality. The objective of this study was to determine microbiological quality of beach water at 14 beaches along the Department of Atlántico (Colombia) and its relationship with beach characteristics as beach typology (i.e., urban, village, rural and remote areas), presence of beach facilities (e.g., bars, restaurants, etc.) and streams outflowing into the coastline. Sampling program aimed to analyse E. coli and Salmonella spp., by culture-based and real time PCR methods, respectively. Microbiological outcomes were compared with beach characteristics, and a cluster analysis was performed. E. coli and Salmonella spp. were detected in 70% and 20% of samples, respectively. Highest E. coli counts were observed at beaches classified as urban and at Sabanilla, a rural beach with presence of numerous beach restaurants/bars. Salmonella spp. presence was associated with streams that lack wastewater treatment systems. Cluster analysis clearly evidenced the relationship between E. coli and Salmonella spp. and beach characteristics, allowing to obtain indications to implement management programs. According to data obtained, monitoring programs have to be especially carried out in urban areas and at places with beach facilities. This could enhance microbiological water quality and consequently, beachgoers safety and touristic beach attractiveness to international visitors.

The Hounsinou scale: Its development and use to determine the overall quality of groundwater used for drinking and bathing in the municipality of Abomey-Calavi in Benin

Study regionAbomey-Calavi is located in the southern part of the Republic of Benin in the department of Atlantic, between latitudes 6° 20’23.4’’ and 6° 42’6.6’’ North and longitudes 2° 14’13.8’’ and 2°25’7.8’’ East. Study focusThe aim of this study is to develop and use a new universal scale to determine the overall quality of water intended for drinking or bathing.Weighted arithmetic sums of the values of the physico-chemical and microbiological parameters and of the World Health Organization (WHO) standards, are used to calculate the chemical water quality index (CWQI) and the microbiological water quality index (MWQI). The marking of water on the Hounsinou scale consists of two alphabetical letters assigned respectively to the CWQI and MWQI of this water.The Hounsinou scale was used to assess the overall water quality of 68 wells in the municipality of Abomey-Calavi in Benin using about twenty physico-chemical parameters and three microbiological parameters measured according to the methods described in the book "Le Rodier". New hydrological insights for the region8.82 % of the sampled wells had BA, CA and EA rating and were suitable for drinking and bathing. 91.18 % of the sampled wells had CB, BB, DB, EB, AC, AB and GB rating and were not suitable for drinking but were suitable for bathing.This new scale can be used by international institutions to mark and monitor the quality of water resources in all countries in order to assess the efforts made by each country to protect and purify its water resources.This scale is particularly suitable for African countries where water resources are often polluted on the physico-chemical and microbiological levels.

Modelling the impact of water temperature, pipe, and hydraulic conditions on water quality in water distribution networks

Abstract Identifying and controlling the drivers of change in the quality of water within distribution systems requires a comprehensive understanding of the individual and interactive effects of relevant factors. This article examines the impact of water temperature, pipe characteristics, and hydraulic conditions on the microbiological, physical, and chemical parameters of water quality in the distribution network using Bayesian Dirichlet process mixture of linear models and random forest method. The study was based on a database of the distribution network for the city of Ålesund in Norway and records of water quality data measured at seven different locations in the network from 2013 to 2019. In both modelling approaches applied, temperature was identified as the main factor that controls the microbiological stability of water in the network. From the minimum to the maximum values of temperature in the pipes (3.35 °C–11.14 °C respectively), the probabilities of occurrence of bacteria in water increased from 0.36 to 0.95. Temperature was also shown to be an important factor that affects the chemical parameters of water quality (pH, alkalinity and electrical conductivity). Among the input parameters included in this study, concentration of residual chlorine was shown to have the strongest growth-inhibiting effect on Total Bacteria in the pipes. The results further showed that changes in the hydraulic conditions in the pipes (residence time and flow) were among the most important determinants of the physical, chemical and microbiological quality of water in the distribution network. The random forest models assigned minimal importance to the pipe characteristics and conditions on changes in the water quality parameters. However, the Bayesian models revealed that these parameters have significant impact on the quality of water in the pipes.

BACTERIAS Y PARÁSITOS PATÓGENOS HUMANOS AISLADOS DE AGUAS ESTANCADAS DURANTE EL FENÓMENO EL NIÑO-COSTERO EN PERÚ

Varios países son extremadamente susceptibles al cambio climático y el fenómeno El Niño-costero afectó a más de dos millones de personas en Ecuador, Colombia y Perú. Nuestro objetivo fue evaluar la calidad microbiológica de las aguas estancadas en la región de Lambayeque, Perú, durante el estado de emergencia causado por el fenómeno El Niño-costero mediante un estudio transversal realizado en cuatro distritos de Lambayeque: (Centro de Chiclayo, Mocupe, San José y Pimentel), Perú. Se tomaron dos muestras simultáneas de cada distrito de evaluación, y se trasladaron a Lima para su análisis microbiológico completo. Aislamos parásitos patógenos humanos (Trichuris trichiura (Linnaeus, 1771) y Entamoeba histolytica Schaudinn, 1903) y bacterias (Staphylococcus aureus Rosenbach, 1884 y Salmonella typhi (Schroeter, 1886)) que presentaban patrones de resistencia a los antimicrobianos convencionales de primera línea (penicilina, ácido nalidíxico, nitrofurantoína y cloranfenicol). Asimismo, mostramos evidencia de microorganismos relacionados con el sitio de muestreo (distrito) y con el grado de afectación por el fenómeno. Nuestro resultado sugiere que las aguas estancadas de cuatro distritos de Lambayeque presentaron parásitos patógenos humanos y bacterias de alta importancia médica por los cambios repentinos en el clima a través del fenómeno El Niño-costero.

Management of Microbiological Contamination of the Water Network of a Newly Built Hospital Pavilion.

The good installation, as well as commissioning plan, of a water network is a crucial step in reducing the risk of waterborne diseases. The aim of this study was to monitor the microbiological quality of water from a newly built pavilion before it commenced operation. Overall, 91 water samples were tested for coliforms, Escherichia coli, enterococci, Pseudomonas aeruginosa and Legionella at three different times: T0 (without any water treatment), T1 (after treatment with hydrogen peroxide and silver ions at initial concentration of 20 mg/L and after flushing of water for 20 min/day for seven successive days) and T2 (15 days later). Coliforms were detected in 47.3% of samples at T0, 36.3% at T1 and 4.4% at T2. E. coli was isolated in 4.4% of the samples only at T1, while enterococci appeared in 12.1% of the samples at T1 and in 2.2% at T2. P. aeruginosa was isolated in 50.5% of the samples at T0, 29.7% at T1 and 1.1% at T2. Legionella pneumophila serogroup 8 was isolated in 80.2% of the samples at T0, 36.3% at T1 and 2.2% at T2. Our results confirmed the need for a water safety plan in new hospital pavilions to prevent the risk of waterborne diseases.

DRINKING WATER QUALITY IN SOME SELCTED SLUMS OF DHAKA CITY, BANGLADESH

— Over the last decade, Dhaka city of Bangladesh has experienced significant changes throughout its landscape and an extreme growth in population. As a result of environmental, economic, or demographic crises, Pressure increase on housing due to rapid urbanization and rural urban migration causes growth of slums and squatter settlements. Slums are residential areas of very high population density, high room density and poor housing with inadequate access to basic civic amenities. The specific objectives of the study are to explore the to investigate the existing water supply facilities and to know the drinking water quality of selected slums in Dhaka city. Korail slum and Geneva Camp slum have been randomly selected. Overall environment of the slum areas is disappointing due to unplanned housing, drains, roads and different authorized &amp; unauthorized shops. The chemical quality of drinking water is satisfactory but microbiological quality of water is not up to the standard of drinking water. Due to the involvements of the Government, DWASA, and other national and international Non-Government Organization (NGO) s, the slums are getting access to pure drinking water supply although these are still insufficient.

Assessment of Decontamination and Reuse of Disposable Filter Funnels Used in Microbiological Water Quality Tests.

To monitor safely managed drinking water services, an increasing number of countries have integrated water quality testing for Escherichia coli into nationally-representative household surveys such as the Multiple Indicator Cluster Surveys (MICS). However, plastic waste generated during such water quality testing programs, mostly through the use of pre-sterilized disposable materials, is non-negligible. The objective of this study was to evaluate several re-use protocols for disposable filter funnels used by the MICS water quality test kits. Decontamination and re-use protocols were assessed in centralized laboratory and decentralized field settings and neither yielded positive results. Re-use of 100 mL sterile funnels decontaminated with an alcohol wipe resulted in a higher incidence of false positive results (i.e., positive contamination when processing sterile water), both in the laboratory and field; therefore, a higher proportion of positives tests can be expected if these components are re-used. Further improvements to the decontamination technique and training are needed before material re-use can be reliably adopted. Autoclaving the funnels for re-use is feasible, provided that there is capacity to re-package and distribute funnels in a sterile manner.

WATER POTABILITY OF CACIMBAS: CASE STUDY IN A DISTRICT OF THE CITY OF BARRO, CEARÁ

Nesse sentido, o presente trabalho buscou analisar a qualidade físico-química e microbiológica da água proveniente de cacimbas na zona rural do distrito de Iara, cidade de Barro, Ceará. As amostras de água foram coletadas diretamente nas cacimbas em fracos esterilizados, depois foram armazenadas em caixas térmicas com gelo para conservação e transportadas para análises em laboratório. Foram realizadas análises físico-químicas para determinação da turbidez, condutividade elétrica, dureza total, cloretos, nitrogênio amoniacal, nitrato, nitrito, pH, alumínio, ferro total, sólidos totais dissolvidos e manganês, e análises microbiológicas para determinação de coliformes totais e Escherichia coli. Os resultados mostraram que a maioria das amostras de água proveniente das cacimbas apresentaram qualidade em relação aos parâmetros físico-químicos, mas algumas mostraram alterações em relação a dureza, e aos teores de nitrato e ferro. Todas as amostras apresentaram contaminação microbiológica por coliformes totais e somente uma não teve contaminação por E. coli. Os dados reforçam a questão da susceptibilidade das cacimbas a vários fatores de contaminação e a necessidade de maiores medidas para se rever hábitos da população que provocam a contaminação de cacimbas.

Sanitary Status and Occurrence of Some Water-Borne Pathogens in Well and Surface Waters of Panhauya Community and Ahmadu Bello University Farm, Zaria

The Sustainable Development Goal on sanitation aims to achieve universal access to good health, affordable drinking water, sanitation and an end to open defeacation by 2030. The recent ranking of Nigeria as first globally for open defecation is of public and environmental health concern. This study assessed the sanitary condition and the microbiological quality of well and surface waters of Panhauya community and Ahmadu Bello University farm, Zaria, and the antibiogram of the bacterial isolates.. Based on the WHO criteria, the sanitary inspection showed that 16.7%, 54.2%, 25% and 4.2% of the water sampling points had a very high, high, intermediate and low risk of contamination respectively. Occurrence of Escherichia coli, Giardia lamblia, Entamoeba histolytica, Pseudomonas aeruginosa, Salmonella spp and Vibrio cholerae in water samples from Panhuaya community was 87.5%, 75%, 68.8%, 50%, 25% and 12.5% respectively. In ABU farm Shika, the occurrence was; E. coli (75%), E. histolytica (63%), lamblia and Salmonella spp. All E. coli isolates exhibited high multidrug resistance to antibiotics screened with a MAR index of 0.3-0.8. The drinking water sources in Panhuaya and ABU farm were unsafe and the presence of these pathogens in the water samples may be attributed to a number of factors including poor sanitation, manure application and open defecation practice. This indicates a public health risk to the residents and emphasises the need for safe water supplies sanitation and antibiotic stewardship.

A systematic review of microorganisms as indicators of recreational water quality in natural and drinking water systems

Abstract The purpose of this review was to highlight the most frequent biological indicators used to estimate the microbiological quality of drinking and recreational water. It was observed that the incorporation of other microbiological indicators should be considered to strengthen the decision-making process on water quality management and guarantee its safe consumption in recreational activities.

Changes in biofilm composition and microbial water quality in drinking water distribution systems by temperature increase induced through thermal energy recovery

Drinking water distribution systems (DWDSs) have been thoroughly studied, but the concept of thermal energy recovery from DWDSs is very new and has been conceptualized in the past few years. Cold recovery results in a temperature increase of the drinking water. Its effects on drinking water quality and biofilm development are unclear. Hence, we studied both bulk water and biofilm phases for 232 days in two parallel pilot scale distribution systems with two temperature settings after cold recovery, 25 °C and 30 °C, and compared these with a reference pilot system without cold recovery. In all three pilot distributions systems (DSs) our results showed an initial increase in biomass (ATP) in the biofilm phase, along with occurrence of primary colonizers (Betaproteobacteriales) and subsequently a decrease in biomass and an increasing relative abundance of other microbial groups (amoeba resisting groups; Xanthobacteraceae, Legionellales), including those responsible for EPS formation in biofilms (Sphingomonadaceae). The timeline for biofilm microbial development was different for the three pilot DSs: the higher the temperature, the faster the development took place. With respect to the water phase within the three pilot DSs, major microbial contributions came from the feed water (17–100%) and unkown sources (2–80%). Random contributions of biofilm (0–70%) were seen between day 7–77. During this time period six-fold higher ATP concentration (7–11 ng/l) and two-fold higher numbers of high nucleic acid cells (5.20–5.80 × 104 cells/ml) were also observed in the effluent water from all three pilot DSs, compared to the feed water. At the end of the experimental period the microbial composition of effluent water from three pilot DSs revealed no differences, except the presence of a biofilm related microbial group (Sphingomonadaceae), within all three DSs compared to the feed water. In the biofilm phase higher temperatures initiated the growth of primary colonizing bacteria but this did not lead to differences in microbial diversity and composition at the end of the experimental period. Hence, we propose that the microbiological water quality of DWDSs with cold recovery should be monitored more frequently during the first 2–3 months of operation.

Modelling the interplay of future changes and wastewater management measures on the microbiological river water quality considering safe drinking water production

Rivers are important for drinking water supply worldwide. However, they are often impacted by pathogen discharges via wastewater treatment plants (WWTP) and combined sewer overflows (CSO). To date, accurate predictions of the effects of future changes and pollution control measures on the microbiological water quality of rivers considering safe drinking water production are hindered due to the uncertainty of the pathogen source and transport variables. The aim of this study was to test an integrative approach for an improved understanding of these effects, i.e. climate change and population growth as well as enhanced treatment at WWTPs and/or prevention of CSOs. We applied a significantly extended version of QMRAcatch (v1.0 Python), a probabilistic-deterministic model that combines fate and transport modelling with quantitative microbial infection risk assessment. The impact of climatic changes until the period 2035–2049 was investigated by a conceptual semi-distributed hydrological model, based on regional climate model outputs. QMRAcatch was calibrated and validated using site- and source-specific data (human-associated genetic microbial source tracking marker and enterovirus). The study showed that the degree to which future changes affect drinking water safety strongly depends on the type and magnitude of faecal pollution sources and are thus highly site- and scenario-specific. For example, if the load of pathogens from WWTPs is reduced through enhanced treatment, climate-change driven increases in CSOs had a considerable impact. Preventing CSOs and installing enhanced treatment at the WWTPs together had the most significant positive effect. The simultaneous consideration of source apportionment and concentrations of reference pathogens, focusing on human-specific viruses (enterovirus, norovirus) and cross-comparison with bacterial and protozoan pathogens (Campylobacter, Cryptosporidium), was found crucial to quantify these effects. While demonstrated here for a large, wastewater-impacted river, the approach is applicable at other catchments and pollution sources. It allows assessing future changes and selecting suitable pollution control measures for long-term water safety planning.

Sanitary, Hygienic and Epidemiological Aspects of Recreational Water Use of the Population of the Upper Don River Basin

Introduction: The problem of safe recreational water use is closely related to conditions of surface water bodies (rivers, reservoirs, lakes, and ponds) experiencing a significant anthropogenic load and their water quality. The purpose of the study was to assess safety of recreational water use of the population based on the results of testing water quality in the bodies of water of the Upper Don River basin. Materials and methods: In 2015–2019, surface water samples were taken at 73 water quality checkpoints of 26 water bodies and tested for chemical, microbiological and parasitological indicators. Test results were then used to assess hazards related to recreational water use of the population. Results: It was found that in 26 of 73 surveyed recreation areas (35.6 %) water quality failed to meet recreational water quality criteria. Poor microbiological water quality indicators were established at 21 of 73 sites (26.7 %) with the proportion of water samples with high thermotolerant and total coliform counts varying from 1.5 to 75.0 %. Risks of epidemic hazard posed by recreational water use were assessed to be the highest in three recreation areas (4.1 %) and moderate – in 18 areas (24.7 %). Conclusions: The estimated reliability of differences in the long-term incidence rates of infectious diseases probably related to microbiological surface water quality indicators (by Student’s t-test) confirmed the hypothesized association between poor microbiological water quality parameters and high incidence rates of acute intestinal infections and bacillary (Flexner) dysentery (p &lt; 0.05). The findings demonstrate the necessity of implementing measures to ensure health and epidemic safety of recreational water use of the population.

Skip the Dip—Avoid the Risk? Integrated Microbiological Water Quality Assessment in the South-Eastern Baltic Sea Coastal Waters

The bathing water microbiome consists of pathogenic and non-pathogenic microorganisms, such as bacteria, viruses, and protozoa. However, the targets of the Bathing Water Directive (2006/7/EC) focus exclusively on fecal pollution. This study aims to investigate fecal indicator bacteria (FIB), naturally thriving cyanobacteria, and Vibrio bacteria in the Lithuanian coastal Baltic Sea and Curonian Lagoon bathing sites, combining information into an integrated microbial risk assessment scheme. The results show that officially monitored indicators, such as FIB, do not exceed the acceptable ‘low’ risk threshold. Simultaneously, cyanobacteria and Vibrio cholerae abundance in the Curonian Lagoon sites reveal a ‘high’ probability of adverse health effects. In coastal bathing sites, a positive correlation was found between Escherichia coli, cyanobacterial harmful algae bloom (cHAB), and V. cholerae, indicating that all target microorganisms may occur at the same time, with consequently high risks for the health of bathers. Therefore, implementing new target organisms in national or even regional bathing water monitoring programs is recommended, in order to safeguard the health of beachgoers.

Avaliação microbiológica de amostras de água e leite provenientes de propriedades de base agroecológica e convencional no oeste do Paraná

Objetivou-se avaliar a qualidade microbiológica da água e do leite provenientes de propriedades de base agroecológica e convencional no Oeste do Paraná. As coletas foram realizadas em 20 propriedades convencionais no município de Santa Helena – PR, e em 27 de base agroecológica em Diamante d’Oeste e Ramilândia – PR. Foram realizadas coletas de leite nos diferentes sistemas de produção e estações do ano. Foram analisadas a contaminação por coliformes termotolerantes (CTerm), coliformes totais (CT), enterobactérias, aeróbios mesófilos (AM), a determinação da composição química, contagem de células somáticas (CCS) e contagem bacteriana total (CBT). Não houve diferença para a composição do leite entre os sistemas de produção no verão. Em relação a CCS durante o inverno, 44,4% e 55,0% das propriedades apresentaram valores acima de 600 mil céls mL-1, nos sistemas agroecológico e convencional, respectivamente. Em ambas as estações, a maioria das propriedades agroecológicas encontram-se acima de 600 mil UFC mL-1 de CBT. Em ambos os sistemas de produção e estações, os valores de AM apresentaram valores inferiores ao permitido pela IN76, e não houve diferença para as enterobactérias no leite. A contagem de CT no leite no inverno foi semelhante entre os dois sistemas de produção. Para as amostras da água para limpeza dos equipamentos de ordenha, os valores de CT e CTerm foram superiores no sistema agroecológico. Recomenda-se a utilização de práticas de manejo visando a redução dos valores de CCS e CBT do leite produzido no Oeste do Paraná para adequarem-se aos valores exigidos pela IN76.

Studi Higiene Sanitasi Makanan Dengan Pemeriksaan Escherichia coli Air Pencucian dan Peralatan Makan Di Pujasera X

Food sanitation is one of the methods used to protect food from contamination, maintain quality, and prevent potential bacterial transmission. This research was conducted to observe potential diseases caused by the microbiological quality of clean water for household use. MPN method was used to compare the quality of clean water based on the Peraturan Menteri Kesehatan Nomor 416 Tahun 1990. Swab method was implemented to observe the hygiene level of the cutlery to compare with the Peraturan Menteri Kesehatan Nomor 1098 Tahun 2003. 79/100 ml of total coliform found in tenant 1 and tenant 2 which means it did not meet the standards. Escherichia coli were found absent in both clean water sources. The same result comes from 2 samples of plates and spoons before and after the first usage and second usage. In tenant 2, Escherichia coli were found in plate sample no.1 before usage and the clerk’s hands before serving the food. Hence, it did not meet the standards. Based on the interviews and observations, the sanitation hygiene of the clerks and the physical hygiene of tenant 1 and tenant 2 had only fulfilled 61.9% and 57.1% of proper hygiene, so it needed to be improved.

Assessment of potential reference sites for evaluating the ecological status of subtropical and temperate Brazilian lotic systems using the epilithic diatom community.

This research aimed at determining reference sites in southern Brazilian lotic systems, using the Water Quality Trophic Index (WQTI), based on epilithic diatom communities. Within the period of 2012 and 2016, 140 epilithic diatom samples from seven sampling sites within the spring area of the Andreas Stream Hydrographic Basin, Vera Cruz County, RS, Brazil, were analyzed quarterly. Similarly, from 2012 and 2014, water samples in these sampling sites were collected for determination of physicochemical and microbiological parameters, such as water temperature, pH, turbidity, dissolved oxygen, biochemical oxygen demand, nitrate, phosphate, total dissolved solids, and fecal coliforms. The results indicated the occurrence of two diatom samples groups with significant differences (p < 0.05). Group 1 (sampling sites P1, P4, and P5) was classified in the oligotrophic category with an average WQTI of 1.3 ± 0.2, while group 2 (sampling sites P2, P3, P6, and P7) was classified in the β-mesotrophic category with an average value of 2.0 ± 0.4). Achnanthidium minutissimum and Platessa hustedtii the dominant species were classified as oligotrophic taxa. Thus, we proposed the upper limit of the first interval of the WQTI score scale, equal to 1.5, as a reference value to differentiate the limits between the "high" and "good" ecological status to determine "reference sites" for subtropical and temperate Brazilian aquatic systems. The physical, chemical, and microbiological water quality evaluation gives support to this proposal, as far as the results indicated a significant improvement in the water quality, classifying sampling sites P1, P4, and P5 as having good quality appropriate for multiple uses.

Occurrence of indicator bacteria and pathogens in the waters of the noyyal river near its source and downstream in coimbatore district

Water, the bloodstream of the biosphere, also acts as a sink, solvent and transport vehicle for domestic, agricultural and industrial waste, causing pollution. The Noyyal River, a tributary of the River Cauvery, was once the lifeline of Coimbatore, but is now being threatened by pollution from various sources. Assessments of microbiological water quality have focused on the presence of Fecal Indicator Bacteria, which indicate that a contamination pathway exists between a bacterial source and the water supply, serving as a route for pathogen entry. Water samples from seven sites (Kooduthurai, Madakkadu,Thombilipalayam, Alandurai, Mathampatti, Perur and Aathuppalam) along the Noyyal, were analyzed for various microbiological characteristics. The results indicated that the river was relatively unpolluted upstream near its sources, but is progressively polluted on moving further downstream towardsCoimbatore city. Levels of Total Heterotrophic Bacteria, indicators such as Enterobacteriaceae, Total Coliforms, Fecal Coliforms (FC), Fecal Streptococci (FS), pathogens like Salmonella sp., Shigella sp., and Vibrio sp. were elevated at downstream sampling sites. Evaluation of the FC:FS ratio revealed that, the water was unfit for drinking at almost all the downstream sampling stations, and could have limited use for irrigation. The release of fecal microorganisms and pathogens from the sediments to the water column could be a major source of bacterial loading. Non-point sources were identified as the major contributors of contaminants. Regular monitoring of the river water and sediment, amelioration of point / non-pointsources of pollution, and speedy implementation of remedial measures, may restore this stretch of the Noyyal River to its former pristine state.

Antimicrobial peptide-functionalized magnetic nanoparticles for rapid capture and removal of pathogenic bacteria

A method that can rapidly and effectively capture and separate pathogenic bacteria, which remain viable even after capture for subsequent analysis, is potential future tool for medicine, water and food safety. In this study, novel antimicrobial peptide-based magnetic nanoparticles with neutralized bactericidal effects are developed for rapid and efficient capture and removal of pathogenic bacteria in water samples. The antimicrobial peptide-functionalized magnetic nanoparticles (AMP-MNPs) consist of magnetic core (Fe3O4), polydopamine (PDA) as an intermediate layer and antimicrobial peptide (Magainin I) as an outer layer (PDA@Fe3O4-AMP). The unique structure of AMP-MNPs allows retaining their capture ability via strong electrostatic interactions, while eliminating their bactericidal actions during interactions with bacteria’s outer membrane. The results of fluorescent microscopy indicate that the AMP-MNPs has no bactericidal effect, but only the binding ability towards bacteria. Factors such as concentration of AMP-MNPs, pH of the medium and ionic strength are crucial in mediating rapid and efficient bacterial capture. Higher concentration of AMP-MNPs (0.5 mg/mL) results in a high sensitive capture effect on 5 × 106–5 × 101 cfu/mL E. coli O157:H7, and a broad spectrum of capture ability towards various bacterial strains (1.5 × 107 cfu/mL) and allow rapid and efficient capture and magnetic-separation of pathogenic bacteria from tap and recreational water samples with capture efficiency greater than 97% and incubation time as short as 5 s. Whereas semi-selective capture of pathogenic and Gram-negative bacteria is achieved at lower concentration of AMP-MNPs (0.1 mg/mL). The developed AMP-MNPs may find great potential in microbiological applications and water quality analyses.