Recreational Water Quality Research Articles

Environmental Factors Correlated with Culturable Enterococci Concentrations in Tropical Recreational Waters: A Case Study in Escambron Beach, San Juan, Puerto Rico.

Enterococci concentration variability at Escambron Beach, San Juan, Puerto Rico, was examined in the context of environmental conditions observed during 2005–2015. Satellite-derived sea surface temperature (SST), turbidity, direct normal irradiance, and dew point were combined with local precipitation, winds, and mean sea level (MSL) observations in a stepwise multiple regression analyses (Akaike Information Criteria model selection). Precipitation, MSL, irradiance, SST, and turbidity explained 20% of the variation in observed enterococci concentrations based upon these analyses. Changes in these parameters preceded increases in enterococci concentrations by 24 h up to 11 days, particularly during positive anomalies of turbidity, SST, and 480–960 mm of accumulated (4 days) precipitation, which relates to bacterial ecology. Weaker, yet still significant, increases in enterococci concentrations were also observed during positive dew point anomalies. Enterococci concentrations decreased with elevated irradiance and MSL anomalies. Unsafe enterococci concentrations per US EPA recreational water quality guidelines occurred when 4-day cumulative precipitation ranged 481–960 mm; irradiance < 667 W·m−2; daily average turbidity anomaly >0.005 sr−1; SST anomaly >0.8 °C; and 3-day average MSL anomaly <−18.8 cm. This case study shows that satellite-derived environmental data can be used to inform future water quality studies and protect human health.

Monitoring E. coli in a changing beachscape

Increased emphasis on protection of recreational water quality has led to extensive use of fecal indicator bacteria monitoring of coastal swimming waters in recent years, allowing for long-term, widespread retrospective studies. These studies are especially important for tracking environmental changes and perturbations in regional waters. We show that E. coli concentrations (EC) have decreased in Lake Michigan over the last 15years, coincident with the rapid invasion of Eurasian quagga mussels (Dreissenidae). While median water clarity in Lake Michigan increased by 32% from 2000 to 2014, median EC decreased by 34.9%. Of the 45 Lake Michigan beaches studied, 42 (93.3%) showed a relative decrease (76% significantly, p<0.05), in mean log E. coli between pre- and post-2007. As a result, Lake Michigan beach advisory frequency decreased by 40.0% (p<0.001) from 19.9% in 2000–2007 to 11.9% in 2008–2014. Finite Volume Coastal Ocean Model simulations at Ogden Dunes beach confirm that EC would decrease in response to the observed changes in water clarity (predicted=4.3%, actual=2.3%). In contrast, mean EC in western Lake Erie showed the opposite trend, with 17 of 19 (89.5%) beaches increasing in mean EC after 2007 (p<0.001). We explore plausible explanatory influences on lakewide EC and conclude that bacterial photoinactivation due to increased water clarity is an important contributing factor explaining the general decrease of E. coli densities in Lake Michigan. The trends and explanatory factors reported here may have important public health, management and ecological implications.

Hydrodynamic modelling of the influence of stormwater and combined sewer overflows on receiving water quality: Benzo(a)pyrene and copper risks to recreational water

The risk from chemical substances in surface waters is often increased during wet weather, due to surface runoff, combined sewer overflows (CSOs) and erosion of contaminated land. There are strong incentives to improve the quality of surface waters affected by human activities, not only from ecotoxicity and ecosystem health perspectives, but also for drinking water and recreational purposes. The aim of this study is to investigate the influence of urban stormwater discharges and CSOs on receiving water in the context of chemical health risks and recreational water quality. Transport of copper (Cu) and benzo[a]pyrene (BaP) in the Göta River (Sweden) was simulated using a hydrodynamic model. Within the 16 km modelled section, 35 CSO and 16 urban stormwater point discharges, as well as the effluent from a major wastewater treatment plant, were included. Pollutant concentrations in the river were simulated for two rain events and investigated at 13 suggested bathing sites. The simulations indicate that water quality guideline values for Cu are exceeded at several sites, and that stormwater discharges generally give rise to higher Cu and BaP concentrations than CSOs. Due to the location of point discharges and the river current inhibiting lateral mixing, the north shore of the river is better suited for bathing. Peak concentrations have a short duration; increased concentrations of the pollutants may however be present for several days after a rain event. Monitoring of river water quality indicates that simulated Cu and BaP concentrations are in the same order of magnitude as measured concentrations. It is concluded that hydrodynamic modelling is a useful tool for identifying suitable bathing sites in urban surface waters and areas of concern where mitigation measures should be implemented to improve water quality.

Assessment of the microbiological quality of recreational waters: indicators and methods

The microbiological quality of recreational waters (RW) has been assessed through the use of microbial indicators. Usually, three typical fecal bacteria, namely fecal coliforms, Escherichia coli and Enterococcus spp., are deemed by legislation and regulatory agencies for routine monitoring of the fecal contamination in RW. However, these traditional indicators have some limitations, as they underestimate health risks and do not determine the sources of contamination. Currently, the increasing concern with the minimization of human health risks associated with recreational water use and the protection of water resources outweigh the actual normative perspective. The potentials and limitations of conventional and alternative fecal contamination detection systems must be carefully evaluated, taking into account the specificities of each recreational water body and the natural or anthropogenic sources of environmental variability. The careful choice of analysis for detection and quantification of indicators in the light of their potential and shortcomings is of major importance for the timely evaluation of risks and implementation of strategies that effectively protect users and preserve water quality. This paper presents a critical literature review of the traditional and innovative methodologies for the analysis of fecal indicators in recreational water and intends to discuss their contribution for the management of the microbiological quality and safety of leisure surface waters.

Identification of Factors Affecting Fecal Pollution in Beaver Lake Reservoir.

Standard methods for the evaluation of recreational water quality rely on generic bacterial indicators such as . However, does not provide enough information to determine fecal source or public health risk. The stsudy objective was to determine factors influencing the presence of and host-specific markers (HSM) from upstream to downstream in Beaver Lake Reservoir (BLR). From February 2014 to September 2015, 420 base flow and rain event samples were collected from seven sites-two sites from streams (White River [WR] and War Eagle Creek) draining into BLR and five sites from within BLR. Each sample was analyzed for and by quantitative polymerase chain reaction for HSM related to human, bovine, and poultry. The data indicate that overall levels of were significantly greater in the WR and significantly lower at the most downstream sampling location in BLR. is more likely present during spring (adjusted odds ratio [aOR] = 1.86), at the WR sampling site (aOR = 3.39), or during a rain event (aOR = 2.73). Moreover, the HSM HumM2 is more likely present (aOR = 1.99) when is present. These same factors were associated with concentrations >126 most probable number 100 mL (aOR = 2.76-12.48), except the poultry marker CL was more likely associated (aOR = 3.81) than HumM2. This study revealed that both seasonal and locational factors are important variables for fecal pollution in BLR. Moreover, these same factors may apply to fecal pollution in manmade reservoirs within similar types of watersheds across the United States, as well as internationally.

An integrated approach for the assessment of land-based pollution loads in the coastal zone

The identification and prioritization of pollution sources is essential to coastal zone management. This task is complicated when a variety of pollution sources are found and by limited data availability, which can result in an inconclusive assessment and differing public perceptions, ultimately hindering the progress of management actions. This is the case in Cartagena Bay (Colombia), a Caribbean hot-spot of pollution, which receives large freshwater discharges from the Magdalena River drained via the Dique Canal along with coastal industrial effluents and untreated domestic wastewater from parts of the coastal population. This study presents a methodology for the integrated assessment of anthropogenic pollution sources discharged into the coastal zone by estimating their loads and comparing their relative contributions to receiving coastal waters. Given the lack of available data on discharges and water quality, an integrated approach is applied by combining various methods of load estimation while emphasizing the importance of calculating confidence intervals for each load value. Pollution loads from nearby sources of domestic wastewater, coastal industrial effluents and continental runoff were assessed with respect to their contributions of coliforms, total suspended solids, nitrogen, phosphorus, and biological oxygen demand (BOD). Loads from the canal's surface runoff were calculated with monthly discharge and water quality data. Domestic loads were computed using GIS analyses of population and sewerage coverage in combination with export coefficients of daily load per capita. Industrial loads were estimated based on previous studies. Results show that each type of land-based source is responsible for different pollution impacts observed in Cartagena Bay. Occasionally, inadequate recreational water quality can be attributed to nearby sources of domestic wastewater, which contribute the highest coliform load (6.7 ± 3.9 × 1015 MPN/day). Continental runoff via the Dique Canal contributes the greatest sediment load (2.5 ± 1.9 × 103 t/day) causing the bay's turbid plumes and related ecosystem issues. Hypoxic conditions in the bay can be attributed to all three pollution sources which all discharge significant BOD loads (2–8 t/day), while the highest total phosphorus load comes from the Dique Canal (3.2 ± 2.4 t/day) and the highest nitrogen loads flow from the canal (3.7 ± 3.1 t·NO3-N/day) and the industrial sector (3.1 ± 4.1 t·N/day). Given that these loads are projected to increase in future years, this study highlights the importance of prioritization and mitigation in coastal pollution management and demonstrates a method that could be applied in other places with similar problems in the Wider Caribbean Region.

River Water Quality: Who Cares, How Much and Why?

An important motivation for the implementation of the Water Framework Directive is the creation of non-market environmental benefits, such as improved ecological quality, or greater opportunities for open-access river recreation via microbial pollution remediation. Pollution sources impacting on ecological or recreational water quality may be uncorrelated, but non-market benefits arising from riverine improvements are typically conflated within benefit valuation studies. Using stated preference choice experiments embedded within a survey that also collected respondents’ socio-economic characteristics, we aimed to disaggregate these sources of value for different river users, thereby allowing decision makers to understand the consequences of adopting alternative investment strategies. Our results suggested that anglers derived greater value from improvements to the ecological quality of river water, in contrast to swimmers and rowers, for whom greater value is gained from improvements to recreational quality. More generally, we found three distinct groups of respondents: a majority preferring ecological over recreational improvements, a substantial minority holding opposing preference orderings, and a yet smaller proportion expressing relatively low values for either form of river quality enhancement. As such, this research demonstrates that the non-market benefits that may accrue from different types of water quality improvements are nuanced in terms of their potential beneficiaries and, by inference, their overall value and policy implications.

Determination of Bacterial Quality of Water in Randomly Selected Swimming Pools in Kampala City, Uganda

Swimming pools have become major recreation facilities for leisure and sports in cities across the world, but the standard guidelines, particularly in developing countries, are not adhered to because little is known about the contaminants in the pools and the possible health risks involved. This study provides a survey of bacterial quality of water from swimming pools in Kampala. A total of 26 water samples were collected from 13 outdoor swimming pools in Kampala between January and June 2016 and analysed for total aerobic plate count (TPC), Escherichia coli, coliforms, and Salmonella. The heterotrophic bacterial load ranged between 0 and 6.35 × 105 cfu/ml, where 6.35 × 105 cfu/ml was the highest load and 3 × 101 cfu/ml the least. The highest average TPC was 6.19 × 105 cfu/ml and the lowest 5.07 × 103 cfu/ml. 30.8% of the pools had TPC within acceptable limits (≤5 × 102 cfu/ml), whereas 69.2% were highly contaminated and did not conform to the Uganda National Water and Sewerage Corporation standards of recreational water quality for both treated (0 cfu/100 mls) water and untreated (10 cfu/100 mls) water. Although no positive results were yielded for E. coli, coliforms, and Salmonella, TPC represented the presence of heterotrophic bacteria which are often indicated in opportunistic infections.

Multiple lines of evidence to identify sewage as the cause of water quality impairment in an urbanized tropical watershed

Indicator bacteria, which are conventionally used to evaluate recreational water quality, can originate from various non-human enteric and extra-enteric sources, hence they may not be indicative of human health risk nor do they provide information on the sources of contamination. In this study we utilized traditional (enterococci and Escherichia coli) and alternative (Clostridium perfringens) indicator bacteria, F+-specific coliphage, molecular markers for microorganisms associated with human sewage (human-associated Bacteroides and polyomaviruses), and microbial community analysis tools (16S rRNA gene fragment amplicon sequencing), to identify and evaluate human sewage-related impact in the Manoa watershed in Honolulu, Hawaii. Elevated concentrations of enterococci (geometric mean ranging from 1604 to 2575 CFU 100 mL−1) and C. perfringens (45–77 CFU 100 mL−1) indicated impairment of the urbanized section of the stream, while indicator bacteria concentrations decreased downstream in the tidally influenced Ala Wai Canal. The threshold values triggering water quality violation notifications in Hawaii were exceeded in 33.3–75.0% of samples collected at sites in the urbanized section of Manoa Stream, but were not exceeded in any of the samples collected at an upstream site located in a forested area. Correlation between indicator bacteria concentrations and rainfall amounts was weak to moderate but significant (E. coli R = 0.251, P = 0.009; enterococci R = 0.369, P < 0.001; C. perfringens R = 0.343, P < 0.001), while concentrations of human fecal-associated molecular markers were not significantly correlated with rainfall (human-associated Bacteroides, R = 0.131, P = 0.256; human-associated polyomaviruses, R = 0.213, P = 0.464). Presence of human sewage was confirmed by detection of human-associated Bacteroides and human polyomavirus in the urbanized section of Manoa Stream (83.3–100% and 41.7–66.7% positive samples respectively). It was further confirmed by microbial community analyses which suggested that an average 2.4–3.4% of the total bacterial population in this section was associated with sewage. Microbial community profiles were significantly influenced by rainfall (R2 = 0.4390, P < 0.001), pH (R2 = 0.3077, P = 0.006), salinity (R2 = 0.2614, P = 0.038), and conductivity (R2 = 0.2676, P = 0.031). Although microbial diversity fluctuated throughout the watershed, it was lower in the impaired section. Leaking sewer systems and illegal cross-connections are implicated in the impairment of the watershed, hence both the sewer and the storm water lines should be routinely inspected. Collectively, our data suggest that information derived from the analysis of microbial communities complements current marker-based microbial source tracking techniques and environmental monitoring programs.

Effects of submerged zone, media aging, and antecedent dry period on the performance of biochar-amended biofilters in removing fecal indicators and nutrients from natural stormwater

Biochar has demonstrated promising performance as an amendment to biofilter soil media in removing fecal indicator bacteria (FIB) from simulated stormwater. However, there is no study that investigates its efficacy in treating natural stormwater runoff. Additional information, including the effects of antecedent dry period, microbial biofilm, and presence of a saturation zone on the performance of biochar-augmented biofilters are needed to inform their field implementation. This study uses laboratory column experiments to monitor FIB (enterococci and Escherichia coli) and nutrient removal capacity of biochar-amended biofilters for 140days using natural stormwater. Our study also investigates the effects of antecedent dry days (ADD) and the presence of a saturation zone (SZ) on the performance of lab-scale biochar-amended biofilters. The results suggest insignificant influence of the ADD and SZ on FIB removal performance, however biofilters with a SZ perform significantly better in removing nitrate-nitrogen compared to those without a SZ. In addition, it appears that the presence of biofilm augments nutrient removal capacity but reduces FIB removal capacity. Our observations indicate that biochar-amended biofilters are able to treat (to comply with recreational water quality standard for FIB) urban stormwater runoff for the duration of the experiment. Nitrate- and ammonium-nitrogen removal in the biologically aged biofilters is found to be 50–60% while the total dissolved phosphorus and the organic nitrogen removal is 20–30%. Our results inform full-scale design of biochar-amended biofilters in order to meet the total maximum daily load (TMDL) and municipal separate storm sewer system (MS4) permitting requirement for FIB and nutrients.

Microbial pollution characterization of water and sediment at two beaches in Saginaw Bay, Michigan

Abstract Singing Bridge Beach and Whites Beach in Saginaw Bay have been designated as impaired water bodies by the Michigan Department of Environmental Quality (MDEQ). To quantify microbial loads and to determine probable sources of elevated E. coli levels, water and sediment samples were collected from both beaches during swimming season 2011. Sources of fecal pollution were assessed using multiple molecular markers: human-associated Bacteroides thetaiotaomicron α 1–6 mannanase (B. theta), bovine-associated Bacteroides (BoBac), human adenoviruses (HAdVs), and bovine adenoviruses (BAdVs). Fecal indicator bacteria (E. coli and enterococci) were also monitored. In Singing Bridge Beach, 50% of water samples (n = 78) exceeded the recreational water quality guidelines for E. coli, while in Whites Beach all water samples met the E. coli standard. B. theta, BoBac, HAdVs, and BAdVs were detected in both beaches indicating influence of multiple sources of contamination. Cell culture assays indicated six water samples from Singing Bridge Beach and seven water samples from Whites Beach contained infectious viruses. Both frequency and concentrations of B. theta and BoBac were higher in sediment samples than in water samples. Elevated BoBac as compared with B. theta in water and sediment samples in both beaches, which are located in a watershed characterized as intensely farmed, suggest that runoff from agricultural areas was one of the probable dominant pollution sources. This study demonstrates that Bacteroides markers used in combination with land use information may help to characterize impacted beaches in mixed watersheds and design management plans.

Evaluation of the dry and wet weather recreational health risks in a semi-enclosed marine embayment in Southern California

For many coastal regions around the world, recreational beach water quality is assessed using fecal indicator bacteria (FIB). However, the utility of FIB as indicators of recreational water illness (RWI) risk has been questioned, particularly in coastal settings with no obvious sources of human sewage. In this study we employed a source-apportionment quantitative microbial risk assessment (SA-QMRA) to assess RWI risk at a popular semi-enclosed recreational beach in Southern California (Baby Beach, City of Dana Point) with no obvious point sources of human sewage. Our SA-QMRA results suggest that, during dry weather, the median RWI risk at this beach is below the U.S. EPA recreational water quality criteria (RWQC) of 36 illness cases per 1000 bathers. During wet weather, the median RWI risk predicted by SA-QMRA depends on the assumed level of human waste associated with stormwater; the RWI risk is below the EPA RWQC illness risk benchmark 100% of the time provided that <2% of the FIB in stormwater are of human origin. However, these QMRA outcomes contrast strongly with the EPA RWQC for 30-day geometric mean of enterococci bacteria. Our results suggest that SA-QMRA is a useful framework for estimating robust RWI risk that takes into account local information about possible human and non-human sources of FIB.

Summer Recreational Water Tourism: A Deadly Human Encounter with Naegleria fowleri

This paper reports about a pathogenic free-living organism that’s affecting the quality of recreational waters in the three states. Naegleria fowleri, multiplies in fresh water during warm seasons which coincides with peak outdoor tourism activities. The deadly organism is acquired while swimming, during which it easily enters the nostrils and reaches the brain. If the recreational water supply of a destination were to be compromised, the whole tourism cycle may be at risk. Swimming in freshwater and untreated pools increases the threat. There are no established standards for controlling the occurrence of Naegleria fowleri in fresh water. The ideal method of preventing infection is by refraining from engaging in recreational activities in fresh bodies of water during summer months.

Longitudinal assessment of rainwater quality under tropical climatic conditions in enabling effective rainwater harvesting and reuse schemes

A longitudinal harvested rainwater quality monitoring study was undertaken at 6 sites within Selangor, Malaysia over a period of 8 months. Overall, harvested rainwater is of good quality, falling within the Malaysian recreational water quality Class IIB standards with exceptions for pH (18/92), ammonia (1/92), phosphates (3/92), and total coliforms (8/92). A large number of samples tested positive for Escherichia coli (22/92), total coliforms (64/92) and Chromobacterium violaceum (7/92), showing that disinfection of harvested rainwater is mandatory prior to reuse. 2/37 harvested rainwater samples exceeded lead limits in Malaysian drinking water standards, showing that consuming rainwater without additional treatment may pose a health risk. Mixing harvested rainwater with groundwater resulted in higher phosphates and total coliforms. Rainwater collected during the wet seasons have higher concentrations of suspended solids, turbidity, and Escherichia coli than dry seasons due to the antecedent dry period. Last but not least, both principal component analysis and positive matrix factorisation were conducted on 37 samples to apportion pollutant sources in harvested rainwater. 7 principal components were identified, namely: industrial dust, steel, roadside dust, faeces, organic decay, fertilisers, and plumbing. The results from principal component analysis and positive matrix factorisation were in agreement, although the latter identified mains water top-up as an additional factor responsible for dissolved solids. Both techniques are effective at apportioning pollutant sources in harvested rainwater, and show that a rainwater harvesting system should be designed carefully to reduce contributions from steel, plumbing, organic decay, bird faeces, industrial dust and roadside dust.

Citizen science-based water quality monitoring: Constructing a large database to characterize the impacts of combined sewer overflow in New York City.

To protect recreational water users from waterborne pathogen exposure, it is crucial that waterways are monitored for the presence of harmful bacteria. In NYC, a citizen science campaign is monitoring waterways impacted by inputs of storm water and untreated sewage during periods of rainfall. However, the spatial and temporal scales over which the monitoring program can sample are constrained by cost and time, thus hindering the construction of databases that benefit both scientists and citizens. In this study, we first illustrate the scientific value of a citizen scientist monitoring campaign by using the data collected through the campaign to characterize the seasonal variability of sampled bacterial concentration as well as its response to antecedent rainfall. Second, we examine the efficacy of the HyServe Compact Dry ETC method, a lower cost and time-efficient alternative to the EPA-approved IDEXX Enterolert method for fecal indicator monitoring, through a paired sample comparison of IDEXX and HyServe (total of 424 paired samples). The HyServe and IDEXX methods return the same result for over 80% of the samples with regard to whether a water sample is above or below the EPA's recreational water quality criteria for a single sample of 110 enterococci per 100mL. The HyServe method classified as unsafe 90% of the 119 water samples that were classified as having unsafe enterococci concentrations by the more established IDEXX method. This study seeks to encourage other scientists to engage with citizen scientist communities and to also pursue the development of cost- and time-efficient methodologies to sample environmental variables that are not easily collected or analyzed in an automated manner.

Effect of Rainfall Events on the Microbial Quality of Recreational Water in the Swan and Canning Rivers in Western Australia

Background: Rainfall events are known to be associated with the health of recreational water. Pathogens in recreational water may pose a risk to bathers and water users, including naturally occurring microorganisms as well as those that are present as a result of faecal pollution. This study aims to investigate whether rainfall events impact on the microbial quality of recreational water in Swan Canning estuary in Western Australia (WA) and to identify and propose effective management interventions. Methods: Compliance of water quality in recreational waters is assessed according to microbial water quality assessment categories (MACs) based on the 95th percentile of enterococci counts with the use of Enterotester TemplateTM. Results: Results indicate that the number of enterococci in the water rises along with increasing volumes of rainfall. Enterococci levels between 201 to 500 MPN/100ml are associated with rainfall ranging from 3-21mm and elevated enterococci levels over 700 MPN/100ml are associated with rainfall ranging from 12-35mm. Conclusion: A causal relationship between enterococci levels in recreational waters and rainfall events exists. Enterococci levels increase following rainfall events of 5mm and over in the majority of sampling sites along the Swan and Canning Rivers during five consecutive bathing seasons. Although environmental and faecal pol- lutions also contribute to recreational water quality, summer rainfall data has indicated that recreational water bodies experience periods of increased enterococci levels as rainfall volumes increase. Keywords: Enterococci level, microbial assessment category, NHMRC guidelines, rainfall, recreational water, water quality.

O desenvolvimento de ferramentas de predição de balneabilidade baseadas em níveis de precipitação: estudo de caso da praia de Cachoeira das Emas (SP)

RESUMO Este artigo apresenta resultados de um estudo realizado na praia Cachoeira das Emas, Rio Mogi-Guaçu, Pirassununga (SP), onde foram desenvolvidos modelos estatísticos simples de regressão linear utilizando níveis de precipitação como variáveis explanatórias, por meio da correlação positiva observada entre concentração de indicadores fecais na água e precipitação acumulada em 24, 48 e 72 horas anteriores à amostragem no rio. Os dados aplicados na calibração (período de 2009 a 2011) e validação (período de 2012) das ferramentas obtidas são oriundos das redes de monitoramento pluviométrico do Departamento de Águas e Energia Elétrica (DAEE) e de balneabilidade de água doce da Companhia Ambiental do Estado de São Paulo (Cetesb). Como essas redes possuem objetivos distintos, nem todos os eventos de precipitação que ocorreram durante o período de estudo foram relacionados com um valor de concentração de indicador fecal na água, e vice-versa. Logo, as equações de regressão obtidas ficaram baseadas em um baixo número de observações. Os resultados sugerem que há potencial de aplicação prática desse tipo de ferramenta, porém requer-se monitoramento específico e conjunto dos parâmetros do modelo a fim de obter uma quantidade significante de dados para a calibração e a validação da ferramenta. A aplicação desse recurso de gerenciamento de balneabilidade seria ideal para um período específico do ano com maior afluência de pessoas, em praias cuja principal fonte de poluição seja difusa e consequente do escoamento de drenagem. Teoricamente, seria possível empregar outras variáveis ambientais ao modelo além dos níveis de precipitação, tais como turbidez e vazão, desde que os parâmetros fossem monitorados com a qualidade da água.

Evaluation of bacterial pathogen diversity, abundance and health risks in urban recreational water by amplicon next-generation sequencing and quantitative PCR

The microbial quality of urban recreational water is of great concern to public health. The monitoring of indicator organisms and several pathogens alone is not sufficient to accurately and comprehensively identify microbial risks. To assess the levels of bacterial pathogens and health risks in urban recreational water, we analyzed pathogen diversity and quantified four pathogens in 46 water samples collected from waterbodies in Beijing Olympic Forest Park in one year. The pathogen diversity revealed by 16S rRNA gene targeted next-generation sequencing (NGS) showed that 16 of 40 genera and 13 of 76 reference species were present. The most abundant species were Acinetobacter johnsonii, Mycobacterium avium and Aeromonas spp. Quantitative polymerase chain reaction (qPCR) of Escherichia coli (uidA), Aeromonas (aerA), M. avium (16S rRNA), Pseudomonas aeruginosa (oaa) and Salmonella (invA) showed that the aerA genes were the most abundant, occurring in all samples with concentrations of 104–6 genome copies/100mL, followed by oaa, invA and M. avium. In total, 34.8% of the samples harbored all genes, indicating the prevalence of these pathogens in this recreational waterbody. Based on the qPCR results, a quantitative microbial risk assessment (QMRA) showed that the annual infection risks of Salmonella, M. avium and P. aeruginosa in five activities were mostly greater than the U.S. EPA risk limit for recreational contacts, and children playing with water may be exposed to the greatest infection risk. Our findings provide a comprehensive understanding of bacterial pathogen diversity and pathogen abundance in urban recreational water by applying both NGS and qPCR.

Human-Associated Bacteroides spp. and Human Polyomaviruses as Microbial Source Tracking Markers in Hawaii.

This study represents an in-depth characterization of microbial source tracking (MST) markers in Hawaii. The distribution and concentrations of HF183TaqMan and HPyV markers in human and animal fecal samples and in wastewater, coupled with decay data obtained from sunlight-exposed and unexposed microcosms, support the concurrent application of HF183TaqMan and HPyV markers for sewage contamination detection in Hawaii waters. Both markers are more conservative and more specific markers of sewage than fecal indicator bacteria (enterococci and Escherichia coli). Analysis of HF183TaqMan (or newer derivatives) is recommended for inclusion in future epidemiological studies concerned with beach water quality, while better concentration techniques are needed for HPyV. Such epidemiological studies can be used to develop new recreational water quality criteria, which will provide direct information on the absence or presence of sewage contamination in water samples as well as reliable measurements of the risk of waterborne disease transmission to swimmers.

Acute Gastroenteritis and Recreational Water: Highest Burden Among Young US Children.

To provide summary estimates of gastroenteritis risks and illness burden associated with recreational water exposure and determine whether children have higher risks and burden. We combined individual participant data from 13 prospective cohorts at marine and freshwater beaches throughout the United States (n = 84 411). We measured incident outcomes within 10 days of exposure: diarrhea, gastrointestinal illness, missed daily activity (work, school, vacation), and medical visits. We estimated the relationship between outcomes and 2 exposures: body immersion swimming and Enterococcus spp. fecal indicator bacteria levels in the water. We also estimated the population-attributable risk associated with these exposures. Water exposure accounted for 21% of diarrhea episodes and 9% of missed daily activities but was unassociated with gastroenteritis leading to medical consultation. Children aged 0 to 4 and 5 to 10 years had the most water exposure, exhibited stronger associations between levels of water quality and illness, and accounted for the largest attributable illness burden. The higher gastroenteritis risk and associated burden in young children presents important new information to inform future recreational water quality guidelines designed to protect public health.