A multi-marker assessment of sewage contamination in streams using human-associated indicator bacteria, human-specific viruses, and pharmaceuticals.

Human sewage contaminates waterways, delivering excess nutrients, pathogens, chemicals, and other toxic contaminants. Contaminants and various sewage indicators are measured to monitor and assess water quality, but these analytes vary in their representation of sewage contamination and the inferences about water quality they support. We measured the occurrence and concentration of multiple microbiological (n = 21) and chemical (n = 106) markers at two urban stream locations in Milwaukee, Wisconsin, USA over two years. Five-day composite water samples (n = 98) were collected biweekly, and sewage influent samples (n = 25) were collected monthly at a Milwaukee, WI water reclamation facility. We found the vast majority of markers were not sensitive enough to detect sewage contamination. To compare analytes for monitoring applications, five consistently detected human sewage indicators were used to evaluate temporal patterns of sewage contamination, including microbiological (pepper mild mottle virus, human Bacteroides, human Lachnospiraceae) and chemical (acetaminophen, metformin) markers. The proportion of human sewage in each stream was estimated using the mean influent concentration from the water reclamation facility and the mean concentration of all stream samples for each sewage indicator marker. Estimates of instream sewage pollution varied by marker, differing by up to two orders of magnitude, but four of the five sewage markers characterized Underwood Creek (mean proportions of human sewage ranged 0.0025 % - 0.075 %) as less polluted than Menomonee River (proportions ranged 0.013 % - 0.14 %) by an order of magnitude more. Chemical markers correlated with each other and yielded higher estimates of sewage pollution than microbial markers, which exhibited greater temporal variability. Transport, attenuation, and degradation processes can influence chemical and microbial markers differently and cause variation in human sewage estimates. Given the range of potential human and ecological health effects of human sewage contamination, robust characterization of sewage contamination that uses multiple lines of evidence supports monitoring and research applications.

Integrating quantitative microbiological risk assessment and disability-adjusted life years to evaluate the effects of urbanization on health risks for river recreationists.

Urban rivers provide an excellent opportunity for water recreation. This study probabilistically assessed health risks associated with water recreation in urban rivers in the Bitan Scenic Area, Taiwan, by employing quantitative microbial risk assessment and disability-adjusted life years (DALYs). Moreover, the effects of urbanization on the health risks of river recreation induced by waterborne pathogenic Escherichia coli (E. coli) were investigated. First, data on river E. coli levels were collected in both the Bitan Scenic Area and the upstream river section, and model parameters were obtained through a questionnaire administered to river recreationists. Monte Carlo simulation was then employed to address parameter uncertainty. Finally, DALYs were calculated to quantify the cumulative effects in terms of potential life lost and years lived with disability. The results indicated that the 90 % confidence intervals for the disease burden (DB) were 0.2-74.1 × 10-6, 0.01-94.0 × 10-6, and 0.3-128.9 × 10-6 DALY per person per year (pppy) for canoeing, swimming, and fishing, respectively, in the Bitan Scenic Area. Furthermore, urbanization near the Bitan Scenic Area approximately doubled the DB risks to river recreationists in upstream rural areas. At the 95th percentile, the DB risks exceeded the tolerances recommended by the World Health Organization (1 × 10-6) or U.S. Environmental Protection Agency (1 × 10-4). The findings suggest that the simultaneous implementation of effluent sewer systems and best management practices can reduce health risks to river recreationists by at least half, reducing the DALY levels below 1 × 10-4 or even 1 × 10-5 pppy.

Integrating global microbiome data into antibiotic resistance assessment in large rivers.

Rivers are important in spreading antimicrobial resistance (AMR). Assessing AMR risk in large rivers is challenged by large spatial scale and numerous contamination sources. Integrating river resistome data into a global framework may help addressing this difficulty. Here, we conducted an omics-based assessment of AMR in a large river (i.e. the Pearl River in China) with global microbiome data. Results showed that antibiotic resistome in river water and sediment was more diversified than that in other rivers, with contamination levels in some river reaches higher than global baselines. Discharge of WWTP effluent and landfill waste drove AMR prevalence in the river, and the resistome level was highly associated with human and animal sources. Detection of 54 risk rank I ARGs and emerging mobilizable mcr and tet(X) highlighted AMR risk in the river reaches with high human population density and livestock pollution. Florfenicol-resistant floR therein deserved priority concerns due to its high detection frequency, dissimilar phylogenetic distance, mobilizable potential, and presence in multiple pathogens. Co-sharing of ARGs across taxonomic ranks implied their transfer potentials in the community. By comparing with global genomic data, we found that Burkholderiaceae, Enterobacteriaceae, Moraxellaceae and Pseudomonadaceae were important potential ARG-carrying bacteria in the river, and WHO priority carbapenem-resistant Enterobacteriaceae, A. baumannii and P. aeruginosa should be included in future surveillance. Collectively, the findings from this study provide an omics-benchmarked assessment strategy for public risk associated with AMR in large rivers.

Uncertainty assessment for three-dimensional hydrodynamic and fecal coliform modeling in the Danshuei River estuarine system: The influence of first-order parametric decay reaction.

Modeling fecal contamination in water bodies is of importance for microbiological risk assessment and management. This study investigated the transport of fecal coliform (e.g., up to 2.1 × 106 CFU/100 ml at the Zhongshan Bridge due to the main point source from the Xinhai Bridge) in the Danshuei River estuarine system, Taiwan with the main focus on assessing model uncertainty due to three relevant parameters for the microbial decay process. First, a 3D hydrodynamic-fecal coliform model (i.e., SCHISM-FC) was developed and rigorously validated against the available data of water level, velocity, salinity, suspended sediment and fecal coliform measured in 2019. Subsequently, the variation ranges of decay reaction parameters were considered from several previous studies and properly determined using the Monte Carlo simulations. Our analysis showed that the constant ratio of solar radiation (α) as well as the settling velocity (vs) had the normally-distributed variations while the attachment fraction of fecal coliform bacteria (Fp) was best fitted by the Weibull distribution. The modeled fecal coliform concentrations near the upstream (or downstream) stations were less sensitive to those parameter variations (see the smallest width of confidence interval about 1660 CFU/100 ml at the Zhongzheng Bridge station) due to the dominant effects of inflow discharge (or tides). On the other hand, for the middle parts of Danshuei River where complicated hydrodynamic circulation and decay reaction occurred, the variations of parameters led to much larger uncertainty in modeled fecal coliform concentration (see a wider confidence interval about 117,000 CFU/100 ml at the Bailing Bridge station). Overall, more detailed information revealed in this study would be helpful while the environmental authority needs to develop a proper strategy for water quality assessment and management. Owing to the uncertain decay parameters, for instance, the modeled fecal coliform impacts at Bailing Bridge over the study period showed a 25 % difference between the lowest and highest concentrations at several moments. For the detection of pollution occurrence, the highest to lowest probabilities for a required fecal coliform concentration (e.g., 260,000 CFU/100 ml over the environmental regulation) at Bailing Bridge was possibly greater than three.

Predicting Fecal Indicator Bacteria Using Spatial Stream Network Models in A Mixed-Land-Use Suburban Watershed in New Jersey, USA.

Good water quality safeguards public health and provides economic benefits through recreational opportunities for people in urban and suburban environments. However, expanding impervious areas and poorly managed sanitary infrastructures result in elevated concentrations of fecal indicator bacteria and waterborne pathogens in adjacent waterways and increased waterborne illness risk. Watershed characteristics, such as urban land, are often associated with impaired microbial water quality. Within the proximity of the New York-New Jersey-Pennsylvania metropolitan area, the Musconetcong River has been listed in the Clean Water Act's 303 (d) List of Water Quality-Limited Waters due to high concentrations of fecal indicator bacteria (FIB). In this study, we aimed to apply spatial stream network (SSN) models to associate key land use variables with E. coli as an FIB in the suburban mixed-land-use Musconetcong River watershed in the northwestern New Jersey. The SSN models explicitly account for spatial autocorrelation in stream networks and have been widely utilized to identify watershed attributes linked to deteriorated water quality indicators. Surface water samples were collected from the five mainstem and six tributary sites along the middle section of the Musconetcong River from May to October 2018. The log10 geometric means of E. coli concentrations for all sampling dates and during storm events were derived as response variables for the SSN modeling, respectively. A nonspatial model based on an ordinary least square regression and two spatial models based on Euclidean and stream distance were constructed to incorporate four upstream watershed attributes as explanatory variables, including urban, pasture, forest, and wetland. The results indicate that upstream urban land was positively and significantly associated with the log10 geometric mean concentrations of E. coli for all sampling cases and during storm events, respectively (p < 0.05). Prediction of E. coli concentrations by SSN models identified potential hot spots prone to water quality deterioration. The results emphasize that anthropogenic sources were the main threats to microbial water quality in the suburban Musconetcong River watershed. The SSN modeling approaches from this study can serve as a novel microbial water quality modeling framework for other watersheds to identify key land use stressors to guide future urban and suburban water quality restoration directions in the USA and beyond.

Dam construction alters planktonic microbial predator‒prey communities in the urban reaches of the Yangtze River.

While dam construction supports social and economic development, changes in hydraulic conditions can also affect natural aquatic ecosystems, especially microbial ecosystems. The compositional and functional traits of multi-trophic microbiota can be altered by dam construction, which may result in changes in aquatic predator-prey interactions. To understand this process, we performed a large-scale sampling campaign in the urban reaches of the dam-impacted Yangtze River (1 995 km) and obtained 211 metagenomic datasets and water quality data. We first compared the compositional traits of planktonic microbial communities upstream, downstream, and in a dam reservoir. Results showed that Bacteroidetes (R-strategy) bacteria were more likely to survive upstream, whilst the reservoir and downstream regions were more conducive to the survival of K-strategy bacteria such as Actinobacteria. Eukaryotic predators tended to be enriched upstream, whilst phototrophs tended to be enriched in the reservoir and downstream regions. Based on bipartite networks, we inferred that the potential microbial predator-prey interactions gradually and significantly decreased from upstream to the downstream and dam regions, affecting 56% of keystone microbial species. Remarkably, functional analysis showed that the abundance of the photosynthetic gene psbO was higher in the reservoir and downstream regions, whilst the abundance of the KEGG carbohydrate metabolic pathway was higher upstream. These results indicate that dam construction in the Yangtze River induced planktonic microbial ecosystem transformation from detritus-based food webs to autotroph-based food webs.

Assessment of the Appearance and Toxin Production Potential of Invasive Nostocalean Cyanobacteria Using Quantitative Gene Analysis in Nakdong River, Korea.

Invasive nostocalean cyanobacteria (INC) were first reported in tropical regions and are now globally spreading rapidly due to climate change, appearing in temperate regions. INC require continuous monitoring for water resource management because of their high toxin production potential. However, it is difficult to analyze INC under a microscope because of their morphological similarity to nostocalean cyanobacteria such as the genus Aphanizomenon. This study calculates the gene copy number per cell for each target gene through quantitative gene analysis on the basis of genus-specific primers of genera Cylindrospermopsis, Sphaerospermopsis, and Cuspidothrix, and the toxin primers of anatoxin-a, saxitoxin, and cylindrospermopsin. In addition, quantitative gene analysis was performed at eight sites in the Nakdong River to assess the appearance of INC and their toxin production potential. Genera Cylindrospermopsis and Sphaerospermopsis did not exceed 100 cells mL-1 at the maximum, with a low likelihood of related toxin occurrence. The genus Cuspidothrix showed the highest cell density (1759 cells mL-1) among the INC. Nakdong River has potential for the occurrence of anatoxin-a through biosynthesis by genus Cuspidothrix because the appearance of this genus coincided with that of the anatoxin-a synthesis gene (anaF) and the detection of the toxin by ELISA.

Exposure Assessment of Multiple Mycotoxins and Cumulative Health Risk Assessment: A Biomonitoring-Based Study in the Yangtze River Delta, China.

The extensive exposure to multiple mycotoxins has been demonstrated in many countries; however, realistic assessments of the risks related to cumulative exposure are limited. This biomonitoring study was conducted to investigate exposure to 23 mycotoxins/metabolites and their determinants in 227 adults (aged 20-88 years) in the Yangtze River Delta, China. Eight mycotoxins were detected in 110 urine samples, and multiple mycotoxins co-occurred in 51/227 (22.47%) of urine samples, with deoxynivalenol (DON), fumonisin B1 (FB1), and zearalenone (ZEN) being the most frequently occurring. For single mycotoxin risk assessment, FB1, ZEN, aflatoxin B1 (AFB1), and ochratoxin A (OTA) all showed potential adverse effects. However, for the 12 samples containing DON and ZEN, in which none had a hazard risk, the combination of both mycotoxins in two samples was considered to pose potential endocrine disrupting risks to humans by hazard index (HI) method. The combined margin of exposure (MOET) for AFB1 and FB1 could constitute a potential health concern, and AFB1 was the main contributor. Our approach provides a blueprint for evaluating the cumulative risks related to different types of mycotoxins and opens a new horizon for the accurate interpretation of epidemiological health outcomes related to multi-mycotoxin exposure.

Quantitative microbial risk assessment for waterborne pathogens in a wastewater treatment plant and its receiving surface water body.

BACKGROUND: Access to safe water for drinking and domestic activities remains a challenge in emerging economies like South Africa, forcing resource-limited communities to use microbiologically polluted river water for personal and household purposes, posing a public health risk. This study quantified bacterial contamination and the potential health hazards that wastewater treatment plant (WWTP) workers and communities may face after exposure to waterborne pathogenic bacteria in a WWTP and its associated surface water, respectively. RESULTS: Escherichia coli (Colilert®-18/ Quanti-Tray® 2000) and enterococci (Enterolert®/ Quanti-Tray® 2000) were quantified and definitively identified by real-time polymerase chain reaction targeting the uidA and tuf genes, respectively. An approximate beta-Poisson dose-response model was used to estimate the probability of infection (Pi) with pathogenic E. coli. Mean E. coli concentration ranged from 2.60E+ 02/100 mL to 4.84E+ 06/100 mL; enterococci ranged from 2.60E+ 02/100 mL to 3.19E+ 06/100 mL across all sampled sites. Of the 580 E. coli isolates obtained from this study, 89.1% were intestinal, and 7.6% were extraintestinal pathogenic E. coli. The 579 enterococci obtained were 50.4% E. faecalis (50.4%), 31.4% E. faecium, 3.5%, E. casseliflavus and 0.7% E. gallinarum. The community health risk stemming from the use of the water for recreational and domestic purposes revealed a greater health risk (Pi) from the ingestion of 1 mL of river water from upstream (range, 55.1-92.9%) than downstream (range, 26.8-65.3%) sites. The occupational risk of infection with pathogenic E. coli for workers resulting from a once-off unintentional consumption of 1 mL of water was 0% (effluent) and 23.8% (raw influent). Multiple weekly exposures of 1 mL over a year could result in a Pi of 1.2 and 100% for the effluent and influent, respectively. CONCLUSION: Our findings reveal that there is a potentially high risk of infection for WWTP workers and communities that use river water upstream and downstream of the investigated WWTP.

Longitudinal Assessment of the Dynamics of Escherichia coli, Total Coliforms, Enterococcus spp., and Aeromonas spp. in Alternative Irrigation Water Sources: a CONSERVE Study.

As climate change continues to stress freshwater resources, we have a pressing need to identify alternative (nontraditional) sources of microbially safe water for irrigation of fresh produce. This study is part of the center CONSERVE, which aims to facilitate the adoption of adequate agricultural water sources. A 26-month longitudinal study was conducted at 11 sites to assess the prevalence of bacteria indicating water quality, fecal contamination, and crop contamination risk (Escherichia coli, total coliforms [TC], Enterococcus, and Aeromonas). Sites included nontidal freshwater rivers/creeks (NF), a tidal brackish river (TB), irrigation ponds (PW), and reclaimed water sites (RW). Water samples were filtered for bacterial quantification. E. coli, TC, enterococci (∼86%, 98%, and 90% positive, respectively; n = 333), and Aeromonas (∼98% positive; n = 133) were widespread in water samples tested. Highest E. coli counts were in rivers, TC counts in TB, and enterococci in rivers and ponds (P < 0.001 in all cases) compared to other water types. Aeromonas counts were consistent across sites. Seasonal dynamics were detected in NF and PW samples only. E. coli counts were higher in the vegetable crop-growing (May-October) than nongrowing (November-April) season in all water types (P < 0.05). Only one RW and both PW sites met the U.S. Food Safety Modernization Act water standards. However, implementation of recommended mitigation measures of allowing time for microbial die-off between irrigation and harvest would bring all other sites into compliance within 2 days. This study provides comprehensive microbial data on alternative irrigation water and serves as an important resource for food safety planning and policy setting.IMPORTANCE Increasing demands for fresh fruit and vegetables, a variable climate affecting agricultural water availability, and microbial food safety goals are pressing the need to identify new, safe, alternative sources of irrigation water. Our study generated microbial data collected over a 2-year period from potential sources of irrigation (rivers, ponds, and reclaimed water sites). Pond water was found to comply with Food Safety Modernization Act (FSMA) microbial standards for irrigation of fruit and vegetables. Bacterial counts in reclaimed water, a resource that is not universally allowed on fresh produce in the United States, generally met microbial standards or needed minimal mitigation. We detected the most seasonality and the highest microbial loads in river water, which emerged as the water type that would require the most mitigation to be compliant with established FSMA standards. This data set represents one of the most comprehensive, longitudinal analyses of alternative irrigation water sources in the United States.

Impact assessment of bioaugmented tannery effluent discharge on the microbiota of water bodies.

Effluents are commonly discharged into water bodies, and in order for the process to be as environmentally sound as possible, the potential effects on native water communities must be assessed alongside the quality parameters of the effluents themselves. In the present work, changes in the bacterial diversity of streamwater receiving a tannery effluent were monitored by high-throughput MiSeq sequencing. Physico-chemical and microbiological parameters and acute toxicity were also evaluated through different bioassays. After the discharge of treated effluents that had been either naturally attenuated or bioaugmented, bacterial diversity decreased immediately in the streamwater samples, as evidenced by the over-representation of taxa such as Brachymonas, Arcobacter, Marinobacterium, Myroides, Paludibacter and Acinetobacter, typically found in tannery effluents. However, there were no remarkable changes in diversity over time (after 1 day). In terms of the physico-chemical and microbiological parameters analyzed, chemical oxygen demand and total bacterial count increased in response to discharge of the treated effluents. No lethal effects were observed in Lactuca sativa L. seeds or Rhinella arenarum embryos exposed to the streamwater that had received the treated effluents. All of these results contribute to the growing knowledge about the environmental safety of effluent discharge procedures.

Assessment of antibiotic resistant coliforms from bioaerosol samples collected above a sewage-polluted river in La Paz, Bolivia.

Antimicrobial resistance is a global health risk, and the presence of resistant bacteria in the environment may be an indicative of fecal pollution. The objective of this study has been to assess the antibiotic resistance of airborne coliforms near a highly impacted urban river that may contain high levels of fecal waste. The pilot study has been located within an Andean river basin, the Choqueyapu River basin, which flows through La Paz city in Bolivia. Bioaerosol samples have been collected using liquid impingement and plated on mTEC agar. Coliforms have been detected within 80% of the air samples. The resistance profiles of coliforms present in 20 air samples have been determined by using a modified Kirby-Bauer disk diffusion test against amoxicillin-clavulanic acid, ciprofloxacin, gentamicin, meropenem, sulfamethoxazole-trimethoprim, and tetracycline, antibiotics commonly used to treat gram-negative infection. Broad patterns of antibiotic resistance have been observed throughout the study, with coliforms from at least one sample exhibiting resistance to each of the tested antibiotics. Resistance to sulfamethoxazole and amoxicillin-clavulanic acid has been the most commonly observed, with coliforms in 73% and 60% of samples which helps to demonstrate resistance to these antibiotics, respectively. This study provides insight into the prevalence of airborne, antibiotic resistant coliforms near concentrated fecal waste streams and this highlights an underappreciated hazard and the potential exposure risk in areas where fecal waste may become aerosolized at any given time.

One Health approach to Clostridioides difficile in Japan.

Clostridioides difficile infections (CDIs) are predominantly a healthcare-associated illness in developed countries, with the majority of cases being elderly and hospitalize patients who used antibiotic therapy. Recently, the incidence of community-associated CDIs (CA-CDIs) in younger patients without a previous history of hospitalization or antibiotic treatment has been increasing globally. C. difficile is sometimes found in the intestine of many animals, such as pigs, calves, and dogs. Food products such as retail meat products and vegetables sometimes contain C. difficile. C. difficile has also been isolated from several environments such as compost manure, rivers, and soils. Yet, direct transmission of C. difficile from animals, food products, and environments to humans has not been proven, although these strains have similar molecular characteristics. Therefore, it has been suggested that there is a relationship between CA-CDIs and C. difficile from animals, food products, and the environment. To clarify the importance of the presence of C. difficile in several sources, characterization of C. difficile in these sources is required. However, the epidemiology of C. difficile in animals, food products, and the environment is not well studied in Japan. This review summarizes recent trends of CDIs and compares the molecular characteristics of C. difficile in Japanese animals, food products, and the environment. The prevalence trends of C. difficile in Japan are similar to those in the rest of the world. Therefore, I recommend using a One Health approach to CDI surveillance, monitoring, and control.

Multi-model assessment of hydrological and environmental impacts on streambed microbes in Mediterranean catchments.

Microbes inhabiting intermittent streambeds are responsible for controlling and developing many biogeochemical processes essential for the ecosystem functions. Although streambed microbiota is adapted to intermittency the intensification of water scarcity and prolonged dry periods may jeopardise their capacity to cope with hydrological changes. This study aims to evaluate whether, and to what extent, the duration of dry periods affects streambed microbial density, diversity, composition (16S rRNA gene diversity) and functions (extracellular enzyme activities and respiration). Our results highlight the fact that hydrology modulates the community composition and, to some extent, the functions carried out under different environmental conditions. The relative abundance of certain taxa inhabiting the driest intermittent communities differs significantly from those found at sites with continuous flow. Microbial functional metrics revealed a progressive increase in recalcitrant carbon degradation activity at sites with an extended dry phase. In contrast, bacterial density and diversity were mainly influenced by the catchment land use, agriculture enhanced density but reduced diversity, and the presence of riparian vegetation supported greater streambed bacterial diversity. From this perspective, a combination of prolonged dryness with reduced riparian vegetation and increased agricultural land cover could compromise the ecosystem functioning by threaten microbially mediated processes linked to the carbon cycle.

Metagenomics as a Public Health Risk Assessment Tool in a Study of Natural Creek Sediments Influenced by Agricultural and Livestock Runoff: Potential and Limitations.

Little is known about the public health risks associated with natural creek sediments that are affected by runoff and fecal pollution from agricultural and livestock practices. For instance, the persistence of foodborne pathogens such as Shiga toxin-producing Escherichia coli (STEC) originating from these practices remains poorly quantified. Towards closing these knowledge gaps, the water-sediment interface of two creeks in the Salinas River Valley of California was sampled over a 9-month period using metagenomics and traditional culture-based tests for STEC. Our results revealed that these sediment communities are extremely diverse and have functional and taxonomic diversity comparable to that observed in soils. With our sequencing effort (∼4 Gbp per library), we were unable to detect any pathogenic E. coli in the metagenomes of 11 samples that had tested positive using culture-based methods, apparently due to relatively low abundance. Furthermore, there were no significant differences in the abundance of human- or cow-specific gut microbiome sequences in the downstream impacted sites compared to that in upstream more pristine (control) sites, indicating natural dilution of anthropogenic inputs. Notably, the high number of metagenomic reads carrying antibiotic resistance genes (ARGs) found in all samples was significantly higher than ARG reads in other available freshwater and soil metagenomes, suggesting that these communities may be natural reservoirs of ARGs. The work presented here should serve as a guide for sampling volumes, amount of sequencing to apply, and what bioinformatics analyses to perform when using metagenomics for public health risk studies of environmental samples such as sediments.IMPORTANCE Current agricultural and livestock practices contribute to fecal contamination in the environment and the spread of food- and waterborne disease and antibiotic resistance genes (ARGs). Traditionally, the level of pollution and risk to public health are assessed by culture-based tests for the intestinal bacterium Escherichia coli However, the accuracy of these traditional methods (e.g., low accuracy in quantification, and false-positive signal when PCR based) and their suitability for sediments remain unclear. We collected sediments for a time series metagenomics study from one of the most highly productive agricultural regions in the United States in order to assess how agricultural runoff affects the native microbial communities and if the presence of Shiga toxin-producing Escherichia coli (STEC) in sediment samples can be detected directly by sequencing. Our study provided important information on the potential for using metagenomics as a tool for assessment of public health risk in natural environments.

Quality assessment of water intended for human consumption from Kwanza, Dande and Bengo rivers (Angola).

Angola is one of the countries with a high rate of waterborne diseases, due to the scarcity and poor quality of water for human consumption. The watercourses are receptors of many effluents, mainly domestic sewage, due to a precarious or inexistent sanitation system and a small number of wastewater treatment plants. Therefore, this study aims: (i) to evaluate the water quality (physicochemical and microbiological parameters) of three Angolan rivers (Kwanza, Bengo and Dande) in locations where water is used as drinking water or abstracted for human consumption; (ii) to develop a new water quality index able to quantitatively express the water quality in those sites; and (iii) to assess the spatial distribution of water pollution through principal component analysis (PCA). Water quality assessment was performed by conducting four field surveys (campaigns I to IV); the first two campaigns took place in the dry season, while the last two ones took place in the rainy season. In the first two campaigns, the water quality was suitable to be treated for the production of drinking water, while in the last two campaigns, the water was unsuitable for that purpose (high levels of faecal coliforms were detected). The water quality index allowed to classify the water as generally excellent (campaigns I and II) and poor (campaigns III and IV). The rudimentary disinfection usually performed by individual water suppliers may improve the water quality, but it was not enough to achieve the parametric values required for human consumption in the rainy season (campaigns III and IV) except for Bengo sites. PCA identified sampling sites with the same water quality patterns, grouping into four groups (Kwanza sites) and two groups (Dande and Bengo sites). Therefore, the results of this study may support decision-makers as regards water supply management in the river stretches under study. The new developed Water Quality Index can support decision-makers in terms of water supply management, especially in countries with a high rate of waterborne diseases (e.g. Angola).

Validity of a single antibody-based lateral flow immunoassay depending on graphene oxide for highly sensitive determination of E. coli O157:H7 in minced beef and river water.

Considering the health risks of E. coli O157:H7 presence in food and water, an affordable and highly sensitive detection method is crucial. Herein, we report the first use of a single antibody-based fluorescent lateral flow immunoassay (FLFIA) depending on non-radiative energy transfer between graphene oxide and quantum dots for determination of E. coli O157:H7 in beef and river water. FLFIA showed a high sensitivity rate thousand-fold better than the conventional lateral flow (LF). In inoculated minced beef and river water samples, the limits of detection were 178 and 133 CFU g-1 or mL-1, respectively. Besides, it presented a high selectivity in the presence of other possible interfering bacteria. The single antibody approach reduced the assay cost to 60% less than the conventional LF. Alongside, the results could be read by portable LF readers or smartphones. These advantages offer FLFIA as a promising technology for pathogen detection in food and water.

Chemical and microbiological risk assessment of urban river water quality in Vietnam.

The contamination and risk by nutrients (NH4+, NO2-, NO3- and PO43-), COD, BOD5, coliform and potentially toxic elements (PTEs) of As, Cd, Ni, Hg, Cu, Pb, Zn and Cr were investigated in urban river (Nhue River), Vietnam during 2010-2017. The extensive results demonstrated that concentrations of these contaminants showed significant spatial and temporal variations. The Nhue River was seriously polluted by NH4+ (0.025-11.28 mg/L), PO43- (0.17-1.72 mg/L), BOD5 (5.8-179.6 mg/L), COD (1.4-239.8 mg/L) and coliform (1540-326,470 CFU/100 mL); moderately polluted by As (0.2-131.15 µg/L) and Hg (0.11-4.1 µg/L); and slightly polluted by NO2- (0.003-0.33 mg/L) and Cd (2.1-18.2 µg/L). The concentrations of NH4+, PO43-, COD, BOD5 and coliform frequently exceeded both drinking water guidelines and irrigation water standards. Regarding PTEs, As, Cd and Hg concentrations were frequently higher than the regulatory limits. Human health risks of PTEs were evaluated by estimating hazard index (HI) and cancer risk through ingestion and dermal contacts for adults and children. The findings indicated that As was the most important pollutant causing both non-carcinogenic and carcinogenic concerns. The non-carcinogenic risks of As were higher than 1.0 at all sites for both adults (HI = 1.83-7.4) and children (HI = 2.6-10.5), while As posed significant carcinogenic risks for adults (1 × 10-4-4.96 × 10-4). A management strategy for controlling wastewater discharge and protecting human health is urgently needed.

[Assessment of Ecosystem Health of an Urban River Based on the Microbe Index of Biotic Integrity (M-IBI)].

The index of biotic integrity (IBI) has been widely used in river ecosystem health assessment. However, few studies have reported the application of microbial communities in ecosystem health assessment so far, especially for urban rivers. In this study, the Illumina high-throughput sequencing technique was applied to analyze the microbial community diversity and composition of five urban rivers selected in Zhejiang Province. Canonical correlation analyses (CCA) and Spearman correlation analysis were used to evaluate the relationship between each taxonomic group and the water quality properties to select the most sensitive taxonomic groups as candidate indexes. The functional metrics, including the relative abundance of pathogenic bacteria, pollutant-degrading bacteria, and nutrient cycling bacteria were also selected as candidate indexes. Based on the distribution range, discriminatory power, and Pearson's correlation analysis for candidate indexes, five metrics, including the Shannon-index, the number of microbial phyla, the relative abundance of Verrucomicrobia, Chlorobi, and Mycobacterium were selected to establish a biotic integrity index of microbes (M-IBI) evaluation system. A ratio score system was used to get metrics into a uniform score for all sampling points, and the results showed that among the urban river samples studied, most of them (40.9%) were at "Great" level, 45.5% were at "Good" level, 9.1% were at "Moderate" level, and 4.5% were at "Bad" level. The index of M-IBI effectively discriminated the least, medium, and highly impaired sampling points and provided a good match with the water quality (R=0.753, P<0.01), indicating that the M-IBI has potential as an index to evaluate the health of urban river ecosystems.

Assessment of chemical and microbiological parameters on the Leite River Lithuania.

The most common source of pollution is wastewater that comes from the industrial, agricultural, and household sectors. The aim of this work is to evaluate the impact of a new innovative wastewater treatment technology on the water quality of the Leite River, Lithuania. The Leite River basin receives wastewater from the Leitgiriai agglomeration; it is then released into a channel, which is 73 m away from the river. During the implementation of the BSR Interreg project "Water emissions and their reduction in village communities in the Baltic Sea Region as pilots (VillageWater)," the ineffective Leitgiriai wastewater treatment plant (WWTP) was reconstructed in September and October of 2017. Water samples from Leite River were collected in 2010-2018 in three locations: near the Kulynai, Leitgiriai, and Sausgalviai villages in Lithuania. The results show that the wastewater treatment efficiency is statistically higher than that before the reconstruction of the WWTP. The treated wastewater (before and after reconstruction) is released from the Leitgiriai WWTP into the surface water (channel), which flows into the Leite River. The highest concentrations (according to all examined indicators) have been observed in the channel and in the Leite River 500 m after the release point before the reconstruction. All differences are statistically significant (p < 0.05). According to the 2018 values, the water quality of the Leite River did comply with the good ecological status/potential class indicators near the Leitgiriai village. After the Leitgiriai WWTP reconstruction, the wastewater treatment efficiency increased two times on average. Therefore, the Leite River water quality near Leitgiriai improved.