Microbial load from animal feces at a recreational beach

Tracking the sources of Leptospira and nutrient flows in two urban watersheds of Puerto Rico

This study investigated the relationship between nutrient levels, source of fecal contamination, and pathogenic Leptospira in Puerto Rico's northern coast and San Juan Bay Estuary (SJBE) aquatic ecosystems. Microbial source tracking (MST) was also used to investigate the connections between sources of feces contamination and the presence of Leptospira. Eighty-seven water samples were collected during the June (n=44) and August (n=43) in 2020. To quantify phosphorus and nitrogen concentrations, standard USEPA protocols were utilized, specifically Methods 365.4 for total and dissolved phosphorus, 351.2 for total Kjeldahl nitrogen and ammonium, and 353.2 for nitrate. Lipl32 gene-specific quantitative polymerase chain reaction (qPCR) was used to detect the presence of Leptospira. Human (HF183), canine (BacCan-UCD), and equine (HoF597) MST assays were utilized to trace the origins of fecal contamination. Forty one percent of the locations exceeded Puerto Rico's authorized total phosphorus limit of 160 g L-1, while 34% exceeded the total nitrogen limit of 1700 g L-1. Nearly half of the streams examined are affected by eutrophication. The MST analysis identified human and canine feces as the most prevalent contaminants, affecting approximately 50% of the sites. In addition, Leptospira was detected in 32% of the June samples. There was a significant correlation (r = 0.79) between the incidence of pathogenic Leptospira and the human bacterial marker (HF183). This study illuminates the central role of anthropogenic inputs in nutrient enrichment and pathogen proliferation in Puerto Rico's aquatic ecosystems.

Integrating microbial source tracking with quantitative microbial risk assessment to evaluate site specific risk based thresholds at two South Florida beaches

Quantitative microbial risk assessment (QMRA) can be used to evaluate health risks associated with recreational beach use. This study developed a site-specific risk assessment using a novel approach that combined quantitative PCR-based measurement of microbial source tracking (MST) genetic markers (human, dog, and gull fecal bacteria) with a QMRA analysis of potential pathogen risk. Water samples (n = 24) from two recreational beaches were collected and analyzed for MST markers as part of a broader Beach Exposure And Child Health Study that examined child behavior interactions with the beach environment. We report here the measurements of fecal bacteria MST markers in the environmental DNA extracts of those samples and a QMRA analysis of potential health risks utilizing the results from the MST measurements in the water samples. Human-specific Bacteroides was enumerated by the HF183 Taqman qPCR assay, gull-specific Catellicoccus was enumerated by the Gull2 qPCR assay, and dog-specific Bacteroides was enumerated by the DogBact qPCR assay. Derived reference pathogen doses, calculated from the MST marker concentrations detected in recreational waters, were used to estimate the risk of gastrointestinal illness for both children and adults. Dose-response equations were used to estimate the probability of the risk of infection (Pinf) per a swimming exposure event. Based on the QMRA simulations presented in this study, the GI risk from swimming or playing in water containing a mixture of human and non-human fecal sources appear to be primarily driven by the human fecal source. However, the estimated median GI health risk for both beaches never exceeded the U.S. EPA risk threshold of 32 illnesses per 1,000 recreation events. Our research suggests that utilizing QMRA together with MST can further extend our understanding of potential recreational bather risk by identifying the source contributing the greatest risk in a particular location, therefore informing beach management responses and decision-making.

Environmental risk assessment for fecal contamination sources in urban and peri-urban estuaries, in Escambia and Santa Rosa counties, FL, USA

Fecal pollution of estuaries and adjacent creeks and streams is of significant concern along the Gulf of Mexico. The prospective threat to human life and water quality impairment via fecal pollution is a substantial danger to the strength and resistance of coastline areas. Pensacola, FL, has a prosperous coastal tourism industry that is utilized for numerous other uses, such as recreational watersports and boating, seafood, and shellfish harvesting. However, the frequency and severity of fecal contamination present possible socio-economic issues, specifically financial hardships. Therefore, understanding the source, abundance, and fate of fecal microbial pollutants in aquatic systems signifies an imperative initial stage for detecting the host sources and techniques to lessen their transport from the landscape. This research aimed to quantify the fecal indicator bacteria (FIB), Escherichia coli, and perform microbiological fecal source tracking to verify if the fecal inputs are of either animal or human host origin. Surface water samples were taken from urban and peri-urban creeks for two sampling periods (February 2021 and January 2022), and IDEXX Colilert-18 (USEPA Standard Method 9223) was used for E. coli enumeration. DNA extractions were obtained from each sample, and quantitative PCR was utilized for fecal microbial source tracking (MST) to detect human, dog, ruminant, and bird host-specific Bacteroides DNA. The result indicates elevated quantities of FIB, E. coli, that surpass the threshold considered safe regarding human health. E. coli at six sites over the two sampling periods exceeded the impairment threshold, reaching as high as 866.4 MPN/100 ml. Fecal source tracking identified human host fecal contamination at four of nine sites, dogs at three of nine, and birds at one site. However, those sites with sources identified via MST all had E. coli levels below impairment thresholds. No sites were determined to be positive for ruminant as a source or for the pathogen Helicobacter pylori. No canine host fecal inputs were found in January 2022, and only one site with human sewage. Our results highlight the utility of MST in assessing bacterial inputs to water bodies and the challenges.

Probabilistic fecal pollution source profiling and microbial source tracking for an urban river catchment

We developed an innovative approach to estimate the occurrence and extent of fecal pollution sources for urban river catchments. The methodology consists of 1) catchment surveys complemented by literature data where needed for probabilistic estimates of daily produced fecal indicator (FIBs, E. coli, enterococci) and zoonotic reference pathogen numbers (Campylobacter, Cryptosporidium and Giardia) excreted by human and animal sources in a river catchment, 2) generating a hypothesis about the dominant sources of fecal pollution and selecting a source targeted monitoring design, and 3) verifying the results by comparing measured concentrations of the informed choice of parameters (i.e. chemical tracers, C. perfringensspores, and host-associated genetic microbial source tracking (MST) markers) in the river, and by multi-parametric correlation analysis. We tested the approach at a study area in Vienna, Austria. The daily produced microbial particle numbers according to the probabilistic estimates indicated that, for the dry weather scenario, the discharge of treated wastewater (WWTP) was the primary contributor to fecal pollution. For the wet weather scenario, 80-99 % of the daily produced FIBs and pathogens resulted from combined sewer overflows (CSOs) according to the probabilistic estimates. When testing our hypothesis in the river, the measured concentrations of the human genetic fecal marker were log₁₀ 4 higher than for selected animal genetic fecal markers. Our analyses showed for the first-time statistical relationships between C. perfringens spores (used as conservative microbial tracer for communal sewage) and a human genetic fecal marker (i.e. HF183/BacR287) with the reference pathogen Giardia in river water (Spearman rank correlation: 0.78-0.83, p < 0.05. The developed approach facilitates urban water safety management and provides a robust basis for microbial fate and transport models and microbial infection risk assessment.

Fecal indicator bacteria levels at a marine beach before, during, and after the COVID-19 shutdown period and associations with decomposing seaweed and human presence

Studies are limited that evaluate seaweed as a source of bacteria to beach waters. The objective of the current study was to evaluate whether seaweed, along with humans and other animals, could be the cause of beach advisories due to elevated levels of enterococci. The monitoring period occurred a year prior to and through the COVID-19 beach shutdown period, which provided a unique opportunity to evaluate bacteria levels during prolonged periods without recreational activity. Samples of water, sediment, and seaweed were measured for enterococci by culture and qPCR, in addition to microbial source tracking by qPCR of fecal bacteria markers from humans, dogs, and birds. During periods of elevated enterococci levels in water, these analyses were supplemented by chemical source tracking of human-associated excretion markers (caffeine, sucralose, acetaminophen, ibuprofen, and naproxen). Results show that enterococci with elevated levels of human fecal markers persist in the seaweed and sediment and are the likely contributor to elevated levels of bacteria to the nearshore waters. During the shutdown period the elevated levels of enterococci in the sediment were isolated to the seaweed stranding areas. During periods when the beaches were open, enterococci were distributed more uniformly in sediment across the supratidal and intertidal zones. It is hypothesized from this study that human foot traffic may be responsible for the spread of enterococci throughout these areas. Overall, this study found high levels of enterococci in decomposing seaweed supporting the hypothesis that decomposing seaweed provides an additional substrate for enterococci to grow.

Making a network of patches, gaps, and spaces: marine and coastal governance in Stilbaai, South Africa

Based on research conducted by myself and colleagues as part of the Southern Cape Interdisciplinary Fisheries Research Project, I present an overview of residents' perspectives on the Stilbaai Marine Protected Area, located on the Southern Cape coast of South Africa. Currently, South Africa's marine governance sector is often fraught with politicking, inefficiencies, and other effects that strain the social-ecological system. This research shows that despite some fragmentation of governance, there are opportunities, and a general willingness, to engage in activities that take care of the local environment on the behalf of residents, that serve to educate about ocean-positive behaviours and engage visitors more meaningfully on the benefits and value of the Stilbaai Marine Protected Area. Problems that residents perceive to be associated with the Marine Protected Area are noted, and suggestions are made to enhance a sense of caretaking, or sorgskap, within the community to fill the gaps of certain governance or regulation inadequacies. Indeed, I argue that in lieu of efficient formal governance structures and collaborations, it is the informal characteristic of caretaking activities by the community that renders these activities more sustainable, long term, and effective in building a "culture" of caretaking.

Quantitative Risk Assessment for the Introduction of Carbapenem-Resistant Enterobacteriaceae (CPE) into Dutch Livestock Farms

Early detection of emerging carbapenem-resistant Enterobacteriaceae (CPE) in food-producing animals is essential to control the spread of CPE. We assessed the risk of CPE introduction from imported livestock, livestock feed, companion animals, hospital patients, and returning travelers into livestock farms in The Netherlands, including (1) broiler, (2) broiler breeder, (3) fattening pig, (4) breeding pig, (5) farrow-to-finish pig, and (6) veal calf farms. The expected annual number of introductions was calculated from the number of farms exposed to each CPE source and the probability that at least one animal in an exposed farm is colonized. The total number of farms with CPE colonization was estimated to be the highest for fattening pig farms, whereas the probability of introduction for an individual farm was the highest for broiler farms. Livestock feed and imported livestock are the most likely sources of CPE introduction into Dutch livestock farms. Sensitivity analysis indicated that the number of fattening pig farms determined the number of high introductions in fattening pigs from feed, and that uncertainty on CPE prevalence impacted the absolute risk estimate for all farm types. The results of this study can be used to inform risk-based surveillance for CPE in livestock farms.

Comparison of three purse-string suture techniques for prevention of anal leakage during surgery

OBJECTIVE

To compare 3 anal purse-string suture techniques for resistance to leakage and to identify the suture technique requiring the fewest tissue bites to create a consistent leak-proof orifice closure.

ANIMALS

18 large-breed canine cadavers.

PROCEDURES

3 purse-string suture techniques (3 bites with 0.5 cm between bites [technique A], 5 bites with 0.5 cm between bites [technique B], and 3 bites with 1.0 cm between bites [technique C]) were evaluated. Each technique involved 2-0 monofilament nylon suture that was placed in the cutaneous tissue around the anus and knotted with 6 square throws. Standardized 2.0-cm-diameter circular templates with the designated bite number and spacing indicated were used for suture placement. Leak-pressure testing was performed, and the pressure at which saline was first observed leaking from the anus was recorded. The median and interquartile (25th to 75th percentile) range (IQR) were compared among 3 techniques.

RESULTS

Median leak pressure for technique A (101 mm Hg; IQR, 35 to 131.3 mm Hg) was significantly greater than that for technique C (19 mm Hg; IQR, 14.3 to 25.3 mm Hg). Median pressure did not differ between techniques A and B (50 mm Hg; IQR, 32.5 to 65 mm Hg) or between techniques B and C.

CLINICAL RELEVANCE

Placement of an anal purse-string suture prevented leakage at physiologic colonic and rectal pressures, regardless of technique. Placement of 3 bites 0.5 cm apart (technique A) is recommended because it used the fewest number of bites and had the highest resistance to leakage.

Quantitative detection of human- and canine-associated Bacteroides genetic markers from an urban coastal lagoon

The contamination of water catchments by nonpoint source faecal pollution is a major issue affecting the microbial quality of receiving waters and is associated with the occurrence of a range of enteric illnesses in humans. The potential sources of faecal pollution in surface waters are diverse, including urban sewage leaks, surface runoff and wildlife contamination originating from a range of hosts. The major contributing hosts require identification to allow targeted management of this public health concern. In this study, two high-performing Microbial Source Tracking (MST) assays, HF183/Bac242 and BacCan-UCDmodif, were used for their ability to detect host-specific Bacteroides 16Sr RNA markers for faecal pollution in a 12-month study on an urban coastal lagoon in Sydney, Australia. The lagoon was found to contain year-round high numbers of human and canine faecal markers, as well as faecal indicator bacteria counts, suggesting considerable human and animal faecal pollution. The high sensitivity and specificity of the HF183/Bac242 and BacCan-UCDmodif assays, together with the manageable levels of PCR inhibition and high level DNA extraction efficiency obtained from lagoon water samples make these markers candidates for inclusion in an MST 'toolbox' for investigating host origins of faecal pollution in urban surface waters.

Indexes for the assessment of bacterial pollution in bathing waters from point sources: The northern Adriatic Sea CADEAU service

This paper presents a novel set of water quality indexes to identify the area potentially affected by point sources of bacterial pollution in coastal bathing waters. The indexes, developed in the framework of the CADEAU service, are evaluated on the results of a modelling system based on the integration of a high-resolution ocean model, remote sensing observations and in situ monitoring data for the northern Adriatic Sea. In particular, the system is a downscaling of the Mediterranean Copernicus Marine Environment Monitoring Service and exploits data produced within the Bathing Waters Directive, the Water Framework Directive and the Urban Waste Water Treatment Directive to create added value products. The aim of the proposed indexes is to support the identification of areas of influence for bathing waters by identifying the potential threat from point sources of bacterial pollution, both in standard conditions and peculiar events such as a total bypass of wastewater treatment plants. The results for the Chioggia Municipality case study show the potential of the indexes to significantly improve the geographical identification and quantitative evaluation of the impacts of bacterial pollution sources on bathing waters, facilitating the design of mitigation measures. The proposed methodology represents a new management approach to support local authorities in defining the area of influence within the water bathing profile through the proper characterization of the point sources of bacterial pollution.

Sources of Low Level Human Fecal Markers in Recreational Waters of Two Santa Barbara, CA Beaches: Roles of WWTP Outfalls and Swimmers

Worldwide, fecal indicator bacteria (FIB) evidence coastal water contamination for which sources are unknown. Here, for two FIB-impacted Santa Barbara recreational beaches, hypothesized fecal sources were investigated over three dry seasons (summers) using nearly 2000 field samples of water (ocean, creek, groundwater), sand, sediments, effluent and fecal sources. In years 1 and 2, gull and dog feces were identified as the probable main FIB sources to surf zone waters, yet HF183 human fecal markers were consistently detected. Determining HF183 sources was therefore prioritized, via year 3 sub-studies. In lower watersheds, human and dog wastes were mobilized by small storms into creeks, but no storm drain outfalls or creeks discharged into surf zones. Beach area bathrooms, sewers, and a septic system were not sources: dye tracing discounted hydraulic connections, and shallow groundwater was uncontaminated. Sediments from coastal creeks and downstream scour ponds, nearshore marine sediments, and sands from inter- and supratidal zones contained neither HF183 nor pathogens. Two nearby wastewater treatment plant (WWTP) outfalls discharged HF183 into plumes that were either deep or distant with uncertain onshore transport. Regardless, local sources were evidenced, as surf zone HF183 detection rates mostly exceeded those offshore and nearshore (around boat anchorages). The presence of swimmers was associated with surf zone HF183, as swimmer counts (on weekdays, holidays, weekends, and during races) significantly correlated (p<0.05, n = 196) to HF183 detections. Besides comprehensively assessing all possible fecal sources, this study provides new explanations of chronic low-level human markers in recreational beach surf zones, suggesting likely lowest achievable HF183 thresholds.

Bather Shedding as a Source of Human Fecal Markers to a Recreational Beach

Microbial source tracking (MST) can identify and locate surf zone fecal indicator bacteria (FIB) sources. However, DNA-based fecal marker results may raise new questions, since FIB and DNA marker sources can differ. Here, during 2 years of summertime (dry season) MST for a Goleta, California recreational beach, surf zone FIB were mainly from gulls, yet low level human-associated DNA-based fecal marker (HF183) was detected in 25 and 14% of surf zone water samples, respectively. Watershed sources were hypothesized because dry weather creek waters had elevated FIB, and runoff-generating rain events mobilized human (and dog) fecal markers and Salmonella spp. into creeks, with human marker HF183 detected in 40 and 50% of creek water samples, dog markers detected in 70 and 50% of samples, and Salmonella spp. in 40 and 33.3% of samples, respectively over 2 years. However, the dry weather estuary outlet was bermed in the first study year; simultaneously, creek fecal markers and pathogens were lower or similar to surf zone results. Although the berm breached in the second year, surf zone fecal markers stayed low. Watershed sediments, intertidal beach sands, and nearshore sediments were devoid of HF183 and dog-associated DNA markers. Based on dye tests and groundwater sampling, beach sanitary sewers were not leaking; groundwater was also devoid of HF183. Offshore sources appeared unlikely, since FIB and fecal markers decreased along a spatial gradient from the surf zone toward nearshore and offshore ocean waters. Further, like other regional beaches, surf zone HF183 corresponded significantly to bather counts, especially in the afternoons when there were more swimmers. However, morning detections of surf zone HF183 when there were few swimmers raised the possibility that the wastewater treatment plant (WWTP) offshore outfall discharged HF183 overnight which transported to the surf zone. These findings support that there may be lowest achievable limits of surf zone HF183 owing to several chronic and permanent, perhaps diurnal, low concentration sources.

Microbial Source Tracking of Fecal Indicating Bacteria in Coral Reef Waters, Recreational Waters, and Groundwater of Saipan by Real-Time Quantitative PCR

The Commonwealth of the Northern Mariana Islands (CNMI) recently identified the need to improve its capacity for detecting and tracking land-based sources of pollution (LBSP) in coastal waters, particularly microbial contaminants like fecal indicator bacteria (FIB). Reported here is a baseline study of a suite of host-specific FIB microbial source tracking (MST) markers in the coastal shoreline and reef waters around the island of Saipan. Three sampling campaigns were conducted in September 2017, March 2018, and August 2018. Samples were collected from the nearshore surface waters of Saipan, the reef waters of Saipan Lagoon, and groundwater from beaches along the Saipan Lagoon shoreline. Measurements of submarine groundwater discharge (SGD) into nearshore waters and isotopic source tracking of nitrogen inputs were conducted concurrently with MST. Environmental DNA was extracted from the samples and analyzed by quantitative polymerase chain reaction (qPCR) for MST gene markers of fecal Bacteroidales specifically associated with humans, dogs, cows, and pigs, and for an MST gene marker of Catellicoccus associated with seabirds. MST assessments were combined with local knowledge, assessments of sanitary infrastructure, and routine watershed surveys. This study identified hotspots of human FIB along the western Saipan Lagoon shoreline in both surface waters and groundwater, plus another hotspot of human FIB at a popular tourist bathing area known as the Grotto. FIB hotspots on the Lagoon shoreline coincided with areas of high SGD and nitrogen isotopic data indicating sewage-derived N inputs. It appears that faulty sanitary infrastructure may be contributing to inputs to Saipan Lagoon, while bather shedding is likely a primary input for the Grotto area. Moderate levels of dog fecal contamination were common and widespread across the island. High levels of seabird fecal contamination were more random, both spatially and temporally, and mostly concentrated along the less developed northeast region of Saipan. No significant levels of cow or pig fecal marker were detected in coastal water samples. This study provides demonstration and establishment of analytical capacity to resource management in CNMI for MST technology to aid in trouble-shooting water quality issues involving land-based sources of microbial contaminants to CNMI coastal waters.

Untreated sewage contamination of beach sand from a leaking underground sewage system

Thirty people (mostly children) experienced an episode of skin rash days after a sand sifting beach operation at Porto Pim Beach in Faial, Azores during June 2019. An environmental and epidemiologic investigation was conducted to identify the cause of the outbreak of skin rash. The epidemiologic investigation found that some of the patients experiencing symptoms had never entered the beach water. During the pollution period and throughout the epidemiologic investigation, faecal indicator bacteria levels (94 CFU/100 ml for intestinal enterococci and 61 CFU/100 ml for Escherichia coli) in water remained under the limits used for the ninety-five percentile calculation of an Excellent coastal and transitional bathing water defined in the Portuguese Legislation (100 CFU/100 ml for intestinal enterococci and 250 CFU/100 ml for Escherichia coli). Thus sand contact was considered as a likely primary exposure route. Sand microbiological analysis for faecal indicator organisms and electron microscopy strongly suggested faecal contamination. Chemical analysis of the sand also revealed a concomitant substance compatible with sodium-hypochlorite as analysed using gas chromatography and subsequently confirmed by free chlorine analysis. Inspection of the toilet facilities and sewage disposal system revealed a leaking sewage distribution box. Collectively, results suggest that the cause of the outbreak was the leaking underground sewage distribution box that serviced the beach toilet facilities (40 m from beach), where sodium-hypochlorite was used for cleaning and disinfection. This sewage then contaminated the surficial sands to which beach goers were exposed. Chlorine being an irritant substance, was believed to have been the cause of the symptoms given the sudden presentation and dissipation of skin rashes. No gastro-intestinal illness was reported during this episode and during the following 30 days. Like water, beach sand should also be monitored for safety, especially for areas serviced by aged infrastructure.

Fecal Indicator Bacteria Transport from Watersheds with Differing Wastewater Technologies and Septic System Densities

Wastewater contains elevated concentrations of fecal indicator bacteria (FIB). The type of wastewater treatment technology and septic system density may influence the FIB concentration and exports at the watershed scale. The goal of this study was to gain a better understanding of FIB concentrations and exports from watersheds served by conventional septic (CS) systems, sand filter (SF) septic systems, and a municipal sewer (SEW) system. Seven watersheds (3 CS, 3 SF, and 1 SEW) were monitored to quantify FIB concentration and export monthly from April 2015 to March 2016. The type of wastewater treatment did not yield significant differences in FIB concentration or exports when pooling watersheds using similar wastewater treatment. Watersheds with the highest septic densities (approximately 0.4 systems ha−1) contained greater FIB concentrations and exports than watersheds with the lowest (approximately 0.1–0.2 systems ha−1), but only FIB concentrations significantly differed. These findings suggest that when the septic system density exceeds 0.4 systems ha−1, water quality degradation from septic leachate may be observable at the watershed scale, especially in watersheds dominated by residential development. More research is recommended to determine if this density threshold is similar for other water pollutants and/or in watersheds with differing hydrogeological, land use, and wastewater characteristics.

Environmental and Adaptive Changes Necessitate a Paradigm Shift for Indicators of Fecal Contamination

Changes in the occurrence, distribution, and seasonal variation of waterborne pathogens due to global climate change may increase the risk of human exposure to these microorganisms, thus heightening the need for more reliable surveillance systems. Routine monitoring of drinking water supplies and recreational waters is performed using fecal indicator microorganisms, such as Escherichia coli , Enterococcus spp., and coliphages. However, the presence and numbers of these indicators, especially E. coli and Enterococcus spp., do not correlate well with those of other pathogens, especially enteric viruses, which are a major cause of waterborne outbreaks associated with contaminated water and food, and recreational use of lakes, ponds, rivers, and estuarine waters. For that reason, there is a growing need for a surveillance system that can detect and quantify viral pathogens directly in water sources to reduce transmission of pathogens associated with fecal transmission. In this review, we present an updated overview of relevant waterborne enteric viruses that we believe should be more commonly screened to better evaluate water quality and to determine the safety of water use and reuse and of epidemiological data on viral outbreaks. We also discuss current methodologies that are available to detect and quantify these viruses in water resources. Finally, we highlight challenges associated with virus monitoring. The information presented in this review is intended to aid in the assessment of human health risks due to contact with water sources, especially since current environmental and adaptive changes may be creating the need for a paradigm shift for indicators of fecal contamination.

Host Specificity and Sensitivity of Established and Novel Sewage-Associated Marker Genes in Human and Nonhuman Fecal Samples

Microbial source tracking (MST) methods measure fecal contamination levels and identify possible sources using quantitative PCR (qPCR) that targets host-associated fecal microorganisms. To date, most established MST assays for human sources, especially bacterial markers, have shown some nonhuman host cross-reactions. Recently developed assays, such as the crAssphage CPQ_056, Lachnospiraceae Lachno3, and Bacteroides BacV6-21, have more limited information on host sensitivity and host specificity for human or sewage sources, particularly in countries other than the United States. In this study, we rigorously evaluated six sewage-associated MST assays (i.e., Bacteroides HF183, human adenovirus [HAdV], human polyomavirus [HPyV], crAssphage CPQ_056, Lachno3, and BacV6-21) to show advantages and disadvantages of their applications for MST. A total of 29 human and 3 sewage samples and 360 nonhuman fecal samples across 14 hosts collected from a subtropical region of Australia were tested for marker host specificity, host sensitivity, and concentrations. All sewage samples were positive for all six marker genes tested in this study. Bacterial markers were more prevalent than viral markers in human feces. Testing against animal hosts showed human feces (or sewage)-associated marker gene specificity was HAdV (1.00) > HPyV (0.99) > crAssphage CPQ_056 (0.98) > HF183 (0.96) > Lachno3 (0.95) > BacV6-21 (0.90), with marker concentrations in some animal fecal samples being 3 to 5 orders of magnitude lower than those in sewage. When considering host specificity, sensitivity, and concentrations in source samples, the HF183, Lachno3, and crAssphage CPQ_056 tests were the most suitable assays in this study for sewage contamination tracking in subtropical waters of Australia.IMPORTANCE Large financial investments are required to remediate fecal contamination sources in waterways, and accurate results from field studies are crucial to build confidence in MST approaches. Host specificity and sensitivity are two main performance characteristics for consideration when choosing MST assays. Ongoing efforts for marker assay validation will improve interpretation of results and could shed light on patterns of occurrence in nontarget hosts that might explain the underlying drivers of cross-reaction of certain markers. For field applications, caution should be taken to choose appropriate MST marker genes and assays based on available host specificity and sensitivity data and background knowledge of the contaminating sources in the study area. Since many waterborne pathogens are viruses, employing both viral and bacterial markers in investigations could provide insight into contamination dynamics and ecological behavior in the environment. Therefore, combined usage of marker assays is recommended for more accurate and informative sewage contamination detection and fecal source resolution.

Marker genes of fecal indicator bacteria and potential pathogens in animal feces in subtropical catchments

We investigated the abundance of marker genes of two fecal indicator bacteria (FIB) and eight potential pathogens in fecal samples of humans (n = 14) and 10 domestic and native wild animals (n = 134). For each target animal, between 10 and 14 individual fecal samples were collected (n = 148 individual fecal samples in total). The abundance of FIB and potential pathogens within each sample was determined using quantitative PCR (qPCR) assays. All animals tested were positive for Escherichia coli (EC) and the concentrations ranged from 6.13 (flying fox) to 8.87 (chicken) log₁₀ GC/g of feces. These values for Enterococcus spp. (ENT) were 5.25 log₁₀ GC/g for flying fox and 8.12 log₁₀ GC/g of feces for chicken. Moderate correlations were observed between EC with P. aeruginosa, EC O157 and Cryptosporidium parvum, whereas weak correlations were observed between EC and Salmonella spp. and Giardia lamblia, Mycobacterium avium complex (MAC) and Campylobacter spp. The prevalence of MAC and P. aeruginosa were low in dog (14.3% each) and moderate (57.2%, MAC; 42.9% P. aeruginosa) in Eastern grey kangaroo fecal samples. Cryptosporidium parvum was detected in one cattle and one human fecal sample, while G. lamblia was detected in one dog, one flying fox, and one pig fecal samples. Among the eight potential pathogens tested, five pathogens were detected in chicken and dog fecal samples. The remaining animal species contained up to three potential pathogens in their feces. The data generated in this study may aid in the calculation of pathogen loads in the environment, and hence to assess the risks from human and animal fecal contamination of source waters.

To clean or not to clean? A critical review of beach cleaning methods and impacts

Cleaning is a fundamental concern of beach managers in many destinations as well as an important requirement in beach quality awards. However, it has been largely neglected in the literature. This paper provides an overview of empirical studies on beach cleaning and analyzes cleaning-related requirements of 11 beach awards that generate controversy in the literature. This study comments on key aspects of beach cleaning, resolves various misconceptions, and provides new perspectives by integrating related topics drawn from a wide range of literature. The arguments based on both the ecological and tourism managerial perspectives are presented, indicating the gaps and proposing research solutions. The paper calls for empirical studies with regard to the efficiency of different cleaning approaches on beaches with varying levels of use intensity and for methodological designs that separate the impacts of mechanical grooming from those of trampling, dune destruction, shore armoring, artificial lighting, among others.

Fecal indicator bacteria levels at beaches in the Florida Keys after Hurricane Irma

Hurricanes cause infrastructure failures which can lead to contamination of impacted areas. The objective of the current study was to evaluate whether Hurricane Irma contributed towards sewage contamination of coastal beaches. Through this study we evaluated indicators of fecal pollution (fecal indicator bacteria [FIB], enterococci and fecal coliform) and physico-chemical parameters (salinity, pH, turbidity, and temperature) in coastal waters of the Florida Keys shortly after the hurricane. To augment available county sampling data, two sets of sampling efforts were conducted; one focused on collecting samples spatially throughout the Keys to assess whether areas closer to hurricane landfall were more highly impacted. The second was to collect temporally intensive samples at one location during falling tide to evaluate the hypothesis of groundwater contamination. Samples were analyzed for FIB using a new method called timed appearance of culture signal (TACS), which was subsequently calibrated using traditional membrane filter and chromogenic substrate methods. Results showed that coastal beach waters were characterized by elevated but sporadic levels of fecal indicator bacteria up to two months after the hurricane. Spikes were not correlated with physico-chemical characteristics of the water. Our temporally intensive sampling effort did not support the hypothesis that groundwater was a source of elevated FIB. Competing factors could have played a role in the sporadic nature of the FIB levels after the hurricane. We suggest that beach erosion may have flushed out sediments at beaches closer to the hurricane landfall location thereby improving water quality during dry conditions. We also suggest that during wet conditions a source of FIB could include runoff from debris staging areas. Preemptive beach closures immediately after the hurricane were justified due to the sporadic nature of FIB contamination.

Assessment of local and regional strategies to control bacteria levels at beaches with consideration of impacts from climate change

The objective of this study was to evaluate relationships between local factors (beach geomorphology and management) and regional factors (infrastructure improvements and temperature changes) against levels of fecal indicator bacteria (FIB) at recreational beaches. Data were evaluated for 17 beaches located in Monroe County, Florida (Florida Keys), USA, including an assessment of sanitary infrastructure improvements using equivalent dwelling unit (EDU) connections. Results show that elevated FIB levels were associated with beach geomorphologies characterized by impeded flow and by beaches with lax management policies. The decrease in EDUs not connected coincided with a decrease in the fraction of days when bacteria levels were out of compliance. Multivariate factor analysis also identified beach management practices (presence of homeless and concession stands) as being associated with elevated FIB. Overall, results suggest that communities can utilize beach management strategies and infrastructure improvements to overcome the negative water quality impacts anticipated with climate change.

Determination of wild animal sources of fecal indicator bacteria by microbial source tracking (MST) influences regulatory decisions

Fecal indicator bacteria (FIB) are used to assess fecal pollution levels in surface water and are among the criteria used by regulatory agencies to determine water body impairment status. While FIB provide no information about pollution source, microbial source tracking (MST) does, which contributes to more direct and cost effective remediation efforts. We studied a watershed in Florida managed for wildlife conservation that historically exceeded the state regulatory guideline for fecal coliforms. We measured fecal coliforms, enterococci, a marker gene for avian feces (GFD), and a marker gene for human-associated Bacteroides (HF183) in sediment, vegetation, and water samples collected monthly from six sites over two years to: 1) assess the influence of site, temporal factors, and habitat (sediment, vegetation, and water) on FIB and MST marker concentrations, 2) test for correlations among FIB and MST markers, and 3) determine if avian feces and/or human sewage contributed to FIB levels. Sediment and vegetation had significantly higher concentrations of FIB and GFD compared to water and thus may serve as microbial reservoirs, providing unreliable indications of recent contamination. HF183 concentrations were greatest in water samples but were generally near the assay limit of detection. HF183-positive results were attributed to white-tailed deer (Odocoileus virginianus) feces, which provided a false indication of human sewage in this water body. FIB and GFD were positively correlated while FIB and HF183 were negatively correlated. We demonstrated that birds, not sewage, were the main source of FIB, thus avoiding implementation of a total maximum daily load program (TMDL). Our results demonstrate that the concomitant use of FIB and MST can improve decision-making and provide direction when water bodies are impaired, and provides a strategy for natural source exclusion in water bodies impacted by wild animal feces.

A Non-invasive Method to Collect Fecal Samples from Wild Birds for Microbiome Studies

Over the past few decades, studies have demonstrated that the gut microbiota strongly influences the physiology, behavior, and fitness of its host. Such studies have been conducted primarily in humans and model organisms under controlled laboratory conditions. More recently, researchers have realized the importance of placing host-associated microbiota studies into a more ecological context; however, few non-destructive methods have been established to collect fecal samples from wild birds. Here, we present an inexpensive and easy-to-use kit for the non-invasive collection of feces from small birds. The portability of the collection kit makes this method amenable to field studies, especially those in remote areas. The main components of the collection kit include a flat-bottomed paper bag, a large modified weigh boat (tray), vinyl-coated hardware cloth fencing (grate), a clothespin, and a 10% bleach solution (to sterilize the tray and grate). In the paper bag, a sterile tray is placed under a small grate, which prevents the birds from contacting the feces and reduces the risk of contamination. After capture, the bird is placed in the bag for 3-5 min until it defecates. After the bird is removed from the bag, the tray is extracted and the fecal sample is moved to a collection tube and frozen or preserved. We believe that our method is an affordable and easy option for researchers studying the gut microbiota of wild birds.

Effects of urban stormwater and iron-enhanced sand filtration on Daphnia magna and Pimephales promelas

Urban stormwater is an important but incompletely characterized contributor to surface-water toxicity. The present study used 5 bioassays of 2 model organisms (Daphnia magna and fathead minnow, Pimephales promelas) to investigate stormwater toxicity and mitigation by full-scale iron-enhanced sand filters (IESFs). Stormwater samples were collected from major stormwater conveyances and full-scale IESFs during 4 seasonal events (winter snowmelt and spring, early summer, and late summer rainfalls) and analyzed for a diverse range of contaminants of emerging concern including pharmaceuticals, personal care products, industrial chemicals, and pesticides. Concurrently, stormwater samples were collected for toxicity testing. Seasonality appeared more influential and consistent than site type for most bioassays. Typically, biological consequences were least in early summer and greatest in late summer and winter. In contrast with the unimproved and occasionally reduced biological outcomes in IESF-treated and late summer samples, water chemistry indicated that numbers and total concentrations of detected organic chemicals, metals, and nutrients were reduced in late summer and in IESF-treated stormwater samples. Some potent toxicants showed more specific seasonality (e.g., high concentrations of polycyclic aromatic hydrocarbons and industrial compounds in winter, pesticides in early summer and spring, flame retardants in late summer), which may have influenced outcomes. Potential explanations for insignificant or unexpected stormwater treatment outcomes include confounding effects of complex stormwater matrices, IESF nutrient removal, and, less likely, unmonitored toxicants. Environ Toxicol Chem 2018;37:2645-2659. © 2018 SETAC.

The Impact of Tides on Microbial Water Quality at an Inland River Beach

Most coastal freshwater ecosystems in the United States have semi-tidal movements during the day. Routine monitoring of these environments is conducted once during the day when tides can be at either ebb or flood conditions, causing a variability in bacterial concentrations and misinterpretation of the illness risk associated with human activities. The occurrence and levels of enterococci (enterococci 23S rDNA [Ent23S]) and human- (HF183) and avian- (GFD) associated microbial source tracking (MST) markers were investigated using quantitative polymerase chain reaction (qPCR) along with detection of culturable enterococci and environmental parameters. Samples were collected during flood and ebb tide conditions (May-September) from a tidal river used for recreational activities. Culturable enterococci [(420) = 2.093, = 0.040] and Ent23S [(420) = 2.243, = 0.028] controlled for tide type were significantly different; higher enterococci concentrations were detected during the flood tide. Among all samples, 6% were positive for HF183, and GFD was positively correlated with Ent23S ( = 0.92, = 0.029) and conductivity ( = 0.93, = 0.023) during flood tide. Unlike the general assumption that ebb tide flow in a river would likely carry runoff from the land, the microbial contaminants in this case were transported from upstream via ocean water to the river during the flood tide. These results suggest that hydrology and land use patterns must be considered in sampling design when conducting future microbial water quality monitoring programs to better characterize recreational water safety in tidal rivers.

Poikilothermic Animals as a Previously Unrecognized Source of Fecal Indicator Bacteria in a Backwater Ecosystem of a Large River

Quantitative information regarding the presence of Escherichia coli, intestinal enterococci, and Clostridium perfringens in poikilotherms is notably scarce. Therefore, this study was designed to allow a systematic comparison of the occurrence of these standard fecal indicator bacteria (SFIB) in the excreta of wild homeothermic (ruminants, boars, carnivores, and birds) and poikilothermic (earthworms, gastropods, frogs, and fish) animals inhabiting an alluvial backwater area in eastern Austria. With the exception of earthworms, the average concentrations of E. coli and enterococci in the excreta of poikilotherms were equal to or only slightly lower than those observed in homeothermic excreta and were 1 to 4 orders of magnitude higher than the levels observed in the ambient soils and sediments. Enterococci reached extraordinarily high concentrations in gastropods. Additional estimates of the daily excreted SFIB (E. coli and enterococcus) loads (DESL) further supported the importance of poikilotherms as potential pollution sources. The newly established DESL metric also allowed comparison to the standing stock of SFIB in the sediment and soil of the investigated area. In agreement with its biological characteristics, the highest concentrations of C. perfringens were observed in carnivores. In conclusion, the long-standing hypothesis that only humans and homeothermic animals are primary sources of SFIB is challenged by the results of this study. It may be necessary to extend the fecal indicator concept by additionally considering poikilotherms as potential important primary habitats of SFIB. Further studies in other geographical areas are needed to evaluate the general significance of our results. We hypothesize that the importance of poikilotherms as sources of SFIB is strongly correlated with the ambient temperature and would therefore be of increased significance in subtropical and tropical habitats and water resources.IMPORTANCE The current fecal indicator concept is based on the assumption that the standard fecal indicator bacteria (SFIB) Escherichia coli, intestinal enterococci, and Clostridium perfringens multiply significantly only in the guts of humans and other homeothermic animals and can therefore indicate fecal pollution and the potential presence of pathogens from those groups. The findings of the present study showed that SFIB can also occur in high concentrations in poikilothermic animals (i.e., animals with body temperatures that vary with the ambient environmental temperature, such as fish, frogs, and snails) in an alluvial backwater area in a temperate region, indicating that a reconsideration of this long-standing indicator paradigm is needed. This study suggests that poikilotherms must be considered to be potential primary sources of SFIB in future studies.

Possible impacts of sea level rise on disease transmission and potential adaptation strategies, a review

Sea levels are projected to rise in response to climate change, causing the intrusion of sea water into land. In flat coastal regions, this would generate an increase in shallow water covered areas with limited circulation. This scenario raises a concern about the consequences it could have on human health, specifically the possible impacts on disease transmission. In this review paper we identified three categories of diseases which are associated with water and whose transmission can be affected by sea level rise. These categories include: mosquitoborne diseases, naturalized organisms (Vibrio spp. and toxic algae), and fecal-oral diseases. For each disease category, we propose comprehensive adaptation strategies that would help minimize possible health risks. Finally, the City of Key West, Florida is analyzed as a case study, due to its inherent vulnerability to sea level rise. Current and projected adaptation techniques are discussed as well as the integration of additional recommendations, focused on disease transmission control. Given that sea level rise will likely continue into the future, the promotion and implementation of positive adaptation strategies is necessary to ensure community resilience.

Effect of beach management policies on recreational water quality

When beach water monitoring programs identify poor water quality, the causes are frequently unknown. We hypothesize that management policies play an important role in the frequency of fecal indicator bacteria (FIB) exceedances (enterococci and fecal coliform) at recreational beaches. To test this hypothesis we implemented an innovative approach utilizing large amounts of monitoring data (n > 150,000 measurements per FIB) to determine associations between the frequency of contaminant exceedances and beach management practices. The large FIB database was augmented with results from a survey designed to assess management policies for 316 beaches throughout the state of Florida. The FIB and survey data were analyzed using t-tests, ANOVA, factor analysis, and linear regression. Results show that beach geomorphology (beach type) was highly associated with exceedance of regulatory standards. Low enterococci exceedances were associated with open coast beaches (n = 211) that have sparse human densities, no homeless populations, low densities of dogs and birds, bird management policies, low densities of seaweed, beach renourishment, charge access fees, employ lifeguards, without nearby marinas, and those that manage storm water. Factor analysis and a linear regression confirmed beach type as the predominant factor with secondary influences from grooming activities (including seaweed densities and beach renourishment) and beach access (including charging fees, employing lifeguards, and without nearby marinas). Our results were observable primarily because of the very large public FIB database available for analyses; similar approaches can be adopted at other beaches. The findings of this research have important policy implications because the selected beach management practices that were associated with low levels of FIB can be implemented in other parts of the US and around the world to improve recreational beach water quality.

Daily relative dog abundance, fecal density, and loading rates on intensively and minimally managed dog-friendly beaches in central California

Due to increased concerns regarding fecal pollution at marine recreational beaches, daily relative dog abundance and fecal density were estimated on an intensively managed (Beach 1) and a minimally managed (Beach 2) dog beach in Monterey County, California. Fecal loading and factors predictive of fecal deposition also were assessed. After standardizing for beach area, daily beach use and fecal densities did not differ between beaches and yearly fecal loading estimates revealed that unrecovered dog feces likely contributes significantly to fecal contamination (1.4 and 0.2metrictonnes/beach). Detection of feces was significantly associated with beach management type, transect position relative to mean low tideline, presence of beach wrack, distance to the nearest beach entrance, and season. Methodologies outlined in this study can augment monitoring programs at coastal beaches to optimize management, assess visitor compliance, and improve coastal water quality.

Shotgun metagenomic sequencing reveals freshwater beach sands as reservoir of bacterial pathogens

Recreational waters and adjacent beach sands harbor complex microbial communities which may contain human pathogens that cannot be detected by conventional methods. Here, we investigate the diversity of bacterial populations inhabiting four freshwater beaches of the Great Lakes region using shotgun metagenomic sequencing approach. Our analysis suggests that average taxonomic richness and alpha diversity are significantly higher (P < 0.001) in beach sands compared to the corresponding water environments. Compared to the water environments, beach sands harbored taxa from a more diverse range of phyla, including a higher proportion of sequences from unclassified phyla. Unique phyla were also identified in sand which included species from Aquificae, Candidatus Microgenomates, Latescibacteria, and Candidatus Aminicenantes. Sequences originating from pathogens were detected in both sand and water, with some pathogens enriched in both environments. Both lakes exhibited similar community composition suggesting that geographic location did not appear to have any major impact on bacterial diversity. These findings reveal the diversity of bacterial communities of freshwater beaches and highlight the importance of monitoring pathogens in recreational beaches, especially in the sand environment of these beaches.

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.

Distribution and Differential Survival of Traditional and Alternative Indicators of Fecal Pollution at Freshwater Beaches

Alternative indicators have been developed that can be used to identify host sources of fecal pollution, yet little is known about how their distribution and fate compare to traditional indicators. Escherichia coli and enterococci were widely distributed at the six beaches studied and were detected in almost 95% of water samples (n = 422) and 100% of sand samples (n = 400). Berm sand contained the largest amount of E. coli (P < 0.01), whereas levels of enterococci were highest in the backshore (P < 0.01). E. coli and enterococci were the lowest in water, using a weight-to-volume comparison. The gull-associated Catellicoccus marimammalium (Gull2) marker was found in over 80% of water samples, regardless of E. coli levels, and in 25% of sand samples. Human-associated Bacteroides (HB) and Lachnospiraceae (Lachno2) were detected in only 2.4% of water samples collected under baseflow and post-rain conditions but produced a robust signal after a combined sewage overflow, despite low E. coli concentrations. Burdens of E. coli and enterococci in water and sand were disproportionately high in relation to alternative indicators when comparing environmental samples to source material. In microcosm studies, Gull2, HB, and Lachno2 quantitative PCR (qPCR) signals were reduced twice as quickly as those from E. coli and enterococci and approximately 20% faster than signals from culturable E. coli High concentrations of alternative indicators in source material illustrated their high sensitivity for the identification of fecal sources; however, differential survival and the potential for long-term persistence of traditional fecal indicators complicate the use of alternative indicator data to account for the levels of E. coli and enterococci in environmental samples.

IMPORTANCE

E. coli and enterococci are general indicators of fecal pollution and may persist in beach sand, making their use problematic for many applications. This study demonstrates that gull fecal pollution is widespread at Great Lakes beaches, whereas human and ruminant contamination is evident only after major rain events. An exploration of sand as a reservoir for indicators found that E. coli was ubiquitous, while gull host markers were detected in only 25% of samples. In situ sand beach microcosms provided decay rate constants for E. coli and enterococci relative to alternative indicators, which establish comparative benchmarks that would be helpful to distinguish recent from past pollution. Overall, alternative indicators are useful for identifying sources and assessing potentially high health risk contamination events; however, beach managers should be cautious in attempting to directly link their detection to the levels of E. coli or enterococci.

Sources of bathing water pollution in northern Tuscany (Italy): Effects of meteorological variables

This study was carried out in a popular tourist destination located in Italy, where short-term pollution posed the problem of low quality status of bathing waters (according to European Directive) owing to the fecal contamination caused by drainage ditches. Our goal was to understand the role of meteorological conditions on freshwater and seawater bacterial indicator levels, and the impact of polluted streams on seawater contamination. To this aim, results from surface waters were analyzed during five bathing seasons, from 2011 to 2015. Our results demonstrated a relationship between bacterial densities and rainfall amount and a time-dependent dilution effect of the sea between the two halves of each bathing season. This analytical survey confirmed the strategic role of meteorological variables in bathing waters quality, and it could be a support for generation and development of predicting models of indicator levels for bathing area.

Sediment characteristics and microbiological contamination of beach sand - A case-study in the archipelago of Madeira

Beach sand can harbour pathogenic and opportunistic microorganisms, as well as faecal indicator bacteria that influence directly the bathing water quality. Pathogenic and opportunistic microorganisms often raise concern of exposure during beach related recreational activities. In this work, three different types of sandy beaches (natural basaltic, natural calcareous and artificial calcareous) of the Archipelago of Madeira (Portugal) were sampled for bacterial and fungal contaminants and grain size distribution, during four years (2010-2013). Following an extreme weather event in 2010, the faecal indicator bacteria levels spiked, returning to base levels shortly thereafter. The same phenomenon occurred with fungi, where potentially pathogenic fungi were the dominant group. Yeast-like fungi and dermatophytes were, however, mainly associated to months of higher usage by recreational users. Statistical analysis showed higher contamination of sediment in artificial beaches compared to natural beaches and granulometry and chemical composition of sand did not influence in the microbial loads. Instead, bather density and the influence of coastal protection structures needed to maintain the volume of artificial beach sand regarding the removal potential of wave induced currents are obvious influencing factors.

The impact of urban areas on the water quality gradient along a lowland river

The effects of five towns on river water pollution were examined along the Łyna River (southern watershed of the Baltic Sea, northern Poland). The relationships among the spatially derived indicators of urbanization, environmental variables, and physico-chemical and microbiological data (heterotrophic plate count at 22 and 37 °C, and fecal coli) obtained from longitudinal river profiling have been examined with the use of multivariate analyses such as principal component analysis with factor analysis (PCA/FA) and hierarchical cluster analysis (HCA). We recognized the river channel as an environmental path that links serial urban areas into an "urban river continuum." An overall increasing trend in nutrients and indicator bacteria from suburban headwaters to urbanized sections of the river was detected despite a significant decrease in those between the towns. We concluded that the role of a multicity is equally as important as a single urban area in predicting the impacts of man-made pollutants on river water quality.

Watershed Assessment with Beach Microbial Source Tracking and Outcomes of Resulting Gull Management

Total maximum daily load (TMDL) implementation at a southern California beach involved ultraviolet treatment of watershed drainage that provided >97% reduction in fecal indicator bacteria (FIB) concentrations. However, this pollutant control measure did not provide sufficient improvement of beach water quality, prompting further assessment. Investigation included microbial source tracking (MST) for human, gull, and canine fecal sources, monitoring of enterococci and fecal coliform, and measurement of chemical and physical water quality parameters for samples collected from watershed, groundwater, and beach sites, including a beach scour pond and tidal creek. FIB variability remained poorly modeled in regression analysis. However, MST revealed correlations between FIB and gull source tracking markers, leading to recommendations to manage gulls as a pollutant source. Beach conditions were followed for three years after implementation of a best management practice (BMP) to abate gulls using a falconry program for the beach and an upland landfill. The gull abatement BMP was associated with improved beach water quality, and this appears to be the first report of falconry in the context of TMDL implementation. Overall, MST data enabled management action despite an inability to fully model FIB dynamics in the coupled watershed-beach system.

Evaluating exposure of pedestrians to airborne contaminants associated with non-potable water use for pavement cleaning

Climate change and increasing demography press local authorities to look after affordable water resources and replacement of drinking water for city necessities like street and pavement cleaning by more available raw water. Though, the substitution of drinking by non-drinking resources demands the evaluation of sanitary hazards. This article aims therefore to evaluate the contribution of cleaning water to the overall exposure of city dwellers in case of wet pavement cleaning using crossed physical, chemical and biological approaches. The result of tracer experiments with fluorescein show that liquid water content of the cleaning aerosol produced is about 0.24 g m(-3), rending possible a fast estimation of exposure levels. In situ analysis of the aerosol particles indicates a significant increase in particle number concentration and particle diameter, though without change in particle composition. The conventional bacterial analysis using total coliforms as tracer suggests that an important part of the contamination is issued from the pavement. The qPCR results show a more than 20-fold increase of background genome concentration for Escherichia coli and 10-fold increase for Enterococcus but a negligible contribution of the cleaning water. The fluorescence analysis of the cleaning aerosol confirms the above findings identifying pavement surface as the major contributor to aerosol organic load. The physical, chemical and microbiological approaches used make it possible to describe accurately the cleaning bioaerosol and to identify the existence of significantly higher levels of all parameters studied during the wet pavement cleaning. Though, the low level of contamination and the very short time of passage of pedestrian in the zone do not suggest a significant risk for the city dwellers. As the cleaning workers remain much longer in the impacted area, more attention should be paid to their chronic exposure.

Activity of extracellular enzymes on the marine beach differing in the level of antropopressure

The level of activity of extracellular enzymes was determined on two transects characterised by different anthropic pressure on a sandy beach in Ustka, the southern coast of the Baltic Sea. Generally, the level of activity of the studied enzymes was higher on the transect characterised by high anthropic pressure. The ranking order of the mean enzyme activity rates in the sand was as follows: lipase > phosphatase > aminopeptidase > β-glucosidase > α-glucosidase > chitinase. Each enzyme had its characteristic horizontal profile of activity. The levels of activity of the studied enzymes were slightly higher in the surface than subsurface sand layer. Extracellular enzymatic activities were strongly influenced by the season.

Using probabilities of enterococci exceedance and logistic regression to evaluate long term weekly beach monitoring data

Recreational water quality surveillance involves comparing bacterial levels to set threshold values to determine beach closure. Bacterial levels can be predicted through models which are traditionally based upon multiple linear regression. The objective of this study was to evaluate exceedance probabilities, as opposed to bacterial levels, as an alternate method to express beach risk. Data were incorporated into a logistic regression for the purpose of identifying environmental parameters most closely correlated with exceedance probabilities. The analysis was based on 7,422 historical sample data points from the years 2000-2010 for 15 South Florida beach sample sites. Probability analyses showed which beaches in the dataset were most susceptible to exceedances. No yearly trends were observed nor were any relationships apparent with monthly rainfall or hurricanes. Results from logistic regression analyses found that among the environmental parameters evaluated, tide was most closely associated with exceedances, with exceedances 2.475 times more likely to occur at high tide compared to low tide. The logistic regression methodology proved useful for predicting future exceedances at a beach location in terms of probability and modeling water quality environmental parameters with dependence on a binary response. This methodology can be used by beach managers for allocating resources when sampling more than one beach.

Number of bacteria decomposing organic phosphorus compounds and phosphatase activity in the sand of two marine beaches differing in the level of anthropopressure

Number of heterotrophic bacteria ability to decompose organic phosphorus compounds and the level of phosphatase activity in the sand of two marine beaches (southern coast of the Baltic Sea) differing in the level of anthropopressure were studied. The study showed that the number of bacteria and level phosphatase activity were higher in the sand of the beach subjected to stronger anthropopressure. In both studied beaches bacteria hydrolysing DNA were the most numerous (92.7-302.8 CFU·g(-1) d.w.). The least numerous were phytin (26.0·10(3) CFU·g(-1) d.w.) and phenolphthalein diphosphate (11.1·10(3) CFU·g(-1) d.w.) decomposing bacteria. Number of bacteria able to attack tested organic phosphorus compounds were the most numerous in dry zones (10.77-739.92 CFU·g(-1) d.w.) then wet zones (3.34-218.15 CFU·g(-1) d.w.). In both studied beaches bacteria hydrolysing organic phosphorus compounds and phosphatase activity generally were more numerous in surface sand layer. Seasonal variation in the occurrence of bacteria in both studied beaches was observed.

Resolving conflicts in public health protection and ecosystem service provision at designated bathing waters

Understanding and quantifying the trade-off between the requirement for clean safe bathing water and beaches and their wider ecosystem services is central to the aims of the European Union (EU) Marine Strategy Framework Directive (MSFD), and vital for the sustainability and economic viability of designated bathing waters. Uncertainty surrounding the impacts of ensuing bathing water policy transitions, e.g. the EU revised Bathing Waters Directive (rBWD), puts new urgency on our need to understand the importance of natural beach assets for human recreation, wildlife habitat and for protection from flooding and erosion. However, managing coastal zones solely in terms of public health could have potentially negative consequences on a range of other social and cultural ecosystem services, e.g. recreation. Improving our knowledge of how bathing waters, surrounding beach environments and local economies might respond to shifts in management decisions is critical in order to inform reliable decision-making, and to evaluate future implications for human health. In this paper we explore the conflicts and trade-offs that emerge at public beach environments, and propose the development of an evaluative framework of viable alternatives in environmental management whereby bathing waters are managed for their greatest utility, driven by identifying the optimal ecosystem service provision at any particular site.

Dynamics of marine bacterial community diversity of the coastal waters of the reefs, inlets, and wastewater outfalls of southeast Florida

Coastal waters adjacent to populated southeast Florida possess different habitats (reefs, oceanic inlets, sewage outfalls) that may affect the composition of their inherent microbiomes. To determine variation according to site, season, and depth, over the course of 1 year, we characterized the bacterioplankton communities within 38 nearshore seawater samples derived from the Florida Area Coastal Environment (FACE) water quality survey. Six distinct coastal locales were profiled – the Port Everglades and Hillsboro Inlets, Hollywood and Broward wastewater outfalls, and associated reef sites using culture-independent, high-throughput pyrosequencing of the 16S rRNA V4 region. More than 227,000 sequences helped describe longitudinal taxonomic profiles of marine bacteria and archaea. There were 4447 unique operational taxonomic units (OTUs) identified with a mean OTU count of 5986 OTUs across all sites. Bacterial taxa varied significantly by season and by site using weighted and unweighted Unifrac, but depth was only supported by weighted Unifrac, suggesting a change due to presence/absence of certain OTUs. Abundant microbial taxa across all samples included Synechococcus, Pelagibacteraceae, Bacteroidetes, and various Proteobacteria. Unifrac analysis confirmed significant differences at inlet sites relative to reef and outfalls. Inlet-based bacterioplankton significantly differed in greater abundances of Rhodobacteraceae and Cryomorphaceae, and depletion of SAR406 sequences. This study also found higher counts of Firmicutes, Chloroflexi, and wastewater associated SBR1093 bacteria at the outfall and reef sites compared to inlet sites. This study profiles local bacterioplankton populations in a much broader context, beyond culturing and quantitative PCR, and expands upon the work completed by the National Oceanic and Atmospheric Administration FACE program.

Quantitative PCR measurements of Escherichia coli including shiga toxin-producing E. coli (STEC) in animal feces and environmental waters

Quantitative PCR (qPCR) assays were used to determine the concentrations of E. coli including shiga toxin-producing E. coli (STEC) associated virulence genes (eaeA, stx1, stx2, and hlyA) in ten animal species (fecal sources) and environmental water samples in Southeast Queensland, Australia. The mean Log10 concentrations and standard deviations of E. coli 23S rRNA across fecal sources ranged from 1.3 ± 0.1 (horse) to 6.3 ± 0.4 (cattle wastewater) gene copies at a test concentration of 10 ng of DNA. The differences in mean concentrations of E. coli 23S rRNA gene copies among fecal source samples were significantly different from each other (P < 0.0001). Among the virulence genes, stx2 (25%, 95% CI, 17-33%) was most prevalent among fecal sources, followed by eaeA (19%, 95% CI, 12-27%), stx1 (11%, 95% CI, 5%-17%) and hlyA (8%, 95% CI, 3-13%). The Log10 concentrations of STEC virulence genes in cattle wastewater samples ranged from 3.8 to 5.0 gene copies at a test concentration of 10 ng of DNA. Of the 18 environmental water samples tested, three (17%) were positive for eaeA and two (11%) samples were also positive for the stx2 virulence genes. The data presented in this study will aid in the estimation of quantitative microbial risk assessment (QMRA) from fecal pollution of domestic and wild animals in drinking/recreational water catchments.

Microbial evaluation of sandboxes located in urban area

This paper presents the results of a study on the degree of bacteriological pollution of sandboxes situated in fenced and unfenced housing estates located in an urban area in Olsztyn, Poland. Heterotrophic plate counts (HPC22, HPC37), Enterobacteriaceae, Escherichia coli, Enterococcus spp., Staphylococcus spp. and Clostridium perfringens determined by cultivation and fluorescence in situ hybridization (FISH) methods were used as indicators of the sanitary state. Their maximum number in the sand samples reached values of up to 5.4×10(7), 2.6×10(6), 3.3×10(4), 2.1×10(3), 1.8×10(4), 1.9×10(1) and 1.2×10(4)CFU/g, respectively. It was found that values of culture-independent method were two-four orders greater than those obtained by the cultivation method. Among identified Enterobacteriaceae, Pantoea spp. and Enterobacter cloacae were the most numerous, whereas Escherichia cells were detected only occasionally. Pathogenic bacteria of the genus Salmonella sp. were isolated from sandboxes also when E. coli were absent. Bacteria from Staphylococcus genus were isolated irrespective of the site and time of sampling. Additionally, the presence of molds and yeasts was studied. Maximum counts of these microorganisms amounted to 1.0×10(5) and to 3.5×10(4)CFU/g. Aspergillus, Penicillium, Alternaria and Trichoderma genera were most numerous among molds, whereas Trichosporon was detected most frequently among yeasts. Sandboxes in the fenced housing estate and those located in the area which is not close to trees were less polluted than the sand collected from sandboxes in the unfenced housing estate. Potentially pathogenic bacteria of the genus Salmonella spp. were identified in analyzed sandboxes, also when Toxocara and E. coli were absent. It seems that assessing the contamination of children's play areas basing only on fecal bacteria counts and by monitoring number of parasites' eggs may be insufficient to evaluate microbial pollution of sandboxes and may not fully reflect their safety for children.

Groundwater and stream E. coli concentrations in coastal plain watersheds served by onsite wastewater and a municipal sewer treatment system

The goal of this study was to determine if onsite wastewater treatment systems (OWS) were influencing groundwater and surface water Escherichia coli concentrations in a coastal plain watershed. Piezometers for groundwater monitoring were installed at four residences served by OWS and five residences served by a municipal wastewater treatment system (MWS). The residences were located in two different, but nearby (<3 km), watersheds. Effluent from the four septic tanks, groundwater from piezometers, and the streams draining the OWS and MWS watersheds were sampled on five dates between September 2011 and May 2012. Groundwater E. coli concentrations and specific conductivity were elevated within the flow path of the OWS and near the stream, relative to other groundwater sampling locations in the two watersheds. Groundwater discharge in the OWS watershed could be a contributor of E. coli to the stream because E. coli concentrations in groundwater at the stream bank and in the stream were similar. Stream E. coli concentrations were higher for the OWS in relation to MWS watersheds on each sampling date. Water quality could be improved by ensuring OWS are installed and operated to maintain adequate separation distances to water resources.

Microbes in Beach Sands: Integrating Environment, Ecology and Public Health

Beach sand is a habitat that supports many microbes, including viruses, bacteria, fungi and protozoa (micropsammon). The apparently inhospitable conditions of beach sand environments belie the thriving communities found there. Physical factors, such as water availability and protection from insolation; biological factors, such as competition, predation, and biofilm formation; and nutrient availability all contribute to the characteristics of the micropsammon. Sand microbial communities include autochthonous species/phylotypes indigenous to the environment. Allochthonous microbes, including fecal indicator bacteria (FIB) and waterborne pathogens, are deposited via waves, runoff, air, or animals. The fate of these microbes ranges from death, to transient persistence and/or replication, to establishment of thriving populations (naturalization) and integration in the autochthonous community. Transport of the micropsammon within the habitat occurs both horizontally across the beach, and vertically from the sand surface and ground water table, as well as at various scales including interstitial flow within sand pores, sediment transport for particle-associated microbes, and the large-scale processes of wave action and terrestrial runoff. The concept of beach sand as a microbial habitat and reservoir of FIB and pathogens has begun to influence our thinking about human health effects associated with sand exposure and recreational water use. A variety of pathogens have been reported from beach sands, and recent epidemiology studies have found some evidence of health risks associated with sand exposure. Persistent or replicating populations of FIB and enteric pathogens have consequences for watershed/beach management strategies and regulatory standards for safe beaches. This review summarizes our understanding of the community structure, ecology, fate, transport, and public health implications of microbes in beach sand. It concludes with recommendations for future work in this vastly under-studied area.

Microbial source tracking in a coastal California watershed reveals canines as controllable sources of fecal contamination

Elevated levels of fecal indicator bacteria (FIB), including Escherichia coli and enterococci, trigger coastal beach advisories and signal public health risks. Solving FIB pollution in suburban coastal watersheds is challenging, as there are many potential sources. The Arroyo Burro watershed in Santa Barbara, CA is an example, with its popular, but chronically FIB-contaminated beach. To address, a microbial source tracking study was performed. Surface waters were sampled over 2 years, FIB were quantified, and DNA was analyzed for host-associated fecal markers. Surf zone FIB were only elevated when the coastal lagoon was discharging. Among the fecal sources into the lagoon, including upstream human sources and coastal birds, canines were the most important. Canine sources included input via upstream creek water, which decreased after creek-side residences were educated about proper pet waste disposal, and direct inputs to the lagoon and surf zone, where dog waste could have been tidally exchanged with the lagoon. Based on this study, canine waste can be an influential, yet controllable, fecal source to suburban coastal beaches.