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USGS2007

Interaction and influence of two creeks on Escherichia coli concentrations of nearby beaches: Exploration of predictability and mechanisms

The impact of river outfalls on beach water quality depends on numerous interacting factors. The delivery of contaminants by multiple creeks greatly complicates understanding of the source contributions, especially when pollution might originate up- or down-coast of beaches. We studied two beaches along Lake Michigan that are located between two creek outfalls to determine the hydrometeorologic factors influencing near-shore microbiologic water quality and the relative impact of the creeks. The creeks continuously delivered water with high concentrations of Escherichia coli to Lake Michigan, and the direction of transport of these bacteria was affected by current direction. Current direction reversals were associated with elevated E. coli concentrations at Central Avenue beach. Rainfall, barometric pressure, wave height, wave period, and creek specific conductance were significantly related to E. coli concentration at the beaches and were the parameters used in predictive models that best described E. coli variation at the two beaches. Multiple inputs to numerous beaches complicates the analysis and understanding of the relative relationship of sources but affords opportunities for showing how these complex creek inputs might interact to yield collective or individual effects on beach water quality.

Journal of Environmental Quality↗

USGS2002

Occurrence and distribution of microbiological contamination and enteric viruses in shallow ground water in Baltimore and Harford counties, Maryland

The U.S. Geological Survey, in cooperation with the Maryland Department of the Environment and the Wisconsin State Laboratory of Hygiene, conducted a study to characterize the occurrence and distribution of viral contamination in small (withdrawing less than 10,000 gallons per day) public water-supply wells screened in the shallow aquifer in the Piedmont Physiographic Province in Baltimore and Harford Counties, Maryland. Two hundred sixty-three small public water-supply wells were in operation in these counties during the spring of 2000. Ninety-one of these sites were selected for sampling using a methodology that distributed the samples evenly over the population and the spatial extent of the study area. Each site, and its potential susceptibility to microbiological contamination, was evaluated with regard to hole depth, casing interval, and open interval. Each site was evaluated using characteristics such as on-site geology and on-site land use.Samples were collected by pumping between 200 and 400 gallons of untreated well water through an electropositive cartridge filter. Water concentrates were subjected to cell-culture assay for the detection of culturable viruses and reverse-transcription polymerase chain reaction/gene probe assays to detect viral ribonucleic acid; grab samples were analyzed for somatic and male-specific coliphages, Bacteroides fragilis, Clostridium perfringens, enterococci, Escherichia coli, total coliforms, total oxidized nitrogen, nitrite, organic nitrogen, total phosphate, ortho-phosphate, calcium, magnesium, sodium, potas-sium, chloride, sulfate, iron, acid-neutralizing capacity, pH, specific conductance, temperature, and dissolved oxygen.One sample tested positive for the presence of the ribonucleic acid of rotavirus through poly-merase chain-reaction analysis. Twenty-nine per-cent of the samples (26 of 90) had bacterial con-tamination. About 7 percent of the samples (6 of 90) were contaminated with either male-specific coliphage, somatic coliphage, or bacteriophages of Bacteroides fragilis. About 3 percent of the sam-ples (3 of 87) had oxidized nitrogen concentra-tions that exceeded the U.S. Environmental Protection Agency?s Maximum Contaminant Level of 10.0 milligrams per liter. A statistical analysis showed that no significant relation exists between the presence of bacteria or coliphage and all variables, except the mean temperature of the water sample as measured in the field. Additionally, the concentration of total coliform bacteria had a statistically significant, moderately strong cor-relation with the concentration of sulfate and sample pH as measured at the U.S. Geological Survey National Water-Quality Laboratory in Denver, Colorado.

Water-Resources Investigations Report↗

USGS2002

Ground-water quality and discharge to Chincoteague and Sinepuxent Bays adjacent to Assateague Island National Seashore, Maryland

Water-Resources Investigations Report↗

USGS2004

Evaluation of Water Quality for Two St. Johns River Tributaries Receiving Septic Tank Effluent, Duval County, Florida

Tributary streamflow to the St. Johns River in Duval County is thought to be affected by septic tank leachate from residential areas adjacent to these tributaries. Water managers and the city of Jacksonville have committed to infrastructure improvements as part of a management plan to address the impairment of tributary water quality. In order to provide data to evaluate the effects of future remedial activities in selected tributaries, major ion and nutrient concentrations, fecal coliform concentrations, detection of wastewater compounds, and tracking of bacterial sources were used to document septic tank influences on the water quality of selected tributaries. The tributaries Fishing Creek and South Big Fishweir Creek were selected because they drain subdivisions identified as high priority locations for septic tank phase-out projects: the Pernecia and Murray Hill B subdivisions, respectively. Population, housing (number of residences), and septic tank densities for the Murray Hill B subdivision are greater than those for the Pernecia subdivision. Water-quality samples collected in the study basins indicate influences from ground water and septic tanks. Estimated concentrations of total nitrogen ranged from 0.33 to 2.86 milligrams per liter (mg/L), and ranged from less than laboratory reporting limit (0.02 mg/L) to 0.64 mg/L for total phosphorus. Major ion concentrations met the State of Florida Class III surface-water standards; total nitrogen and total phosphorus concentrations exceeded the U.S. Environmental Protection Agency Ecoregion XII nutrient criteria for rivers and streams 49 and 96 percent of the time, respectively. Organic wastewater compounds detected at study sites were categorized as detergents, antioxidants and flame retardants, manufactured polycarbonate resins, industrial solvents, and mosquito repellent. The most commonly detected compound was para-nonylphenol, a breakdown product of detergent. Results of wastewater sampling give evidence that stream water in the study basins is affected by septic tank effluent. Fecal coliform bacteria concentrations were measured on a monthly basis; of 115 samples, 63 percent exceeded the State of Florida fecal coliform bacteria standard for Class III surface waters of 800 colonies per 100 milliliters of water on any 1 day. Fecal coliform bacteria concentrations ranged from less than 20 colonies per 100 milliliters of sample to greater than or equal to 160,000 colonies per 100 milliliters of sample. Antibiotic resistance patterns of fecal coliform bacteria were used to identify the sources of fecal coliform bacteria. Significant sources of fecal coliform bacteria included wild animals, dogs, and humans. A majority of the fecal coliform bacteria were classified to be from human sources. Because the primary source of fecal coliform bacteria is from human sources, and most likely septic tank effluent, management of human sources may substantially improve microbiological water quality in both the Fishing Creek and South Branch Big Fishweir Creek basins.

Water-Resources Investigations Report↗

USGS2002

Practical application of disease resistance: A brook trout fishery selected for resistance to furunculosis

Selection is unwittingly influenced by nuances of fish culturists and adaptation of fish to intensive culture within artificial environments. When pathogens are present, susceptible individuals may be selectively eliminated from a population, accounting for inter-specific and intra-specific differences in susceptibility to disease. Biologists often intensify such selection to enhance resistance. Particularly important to this discourse is the selective breeding program initiated by the New York State Department of Environmental Conservation (Rome, NY, USA) to produce brown trout ( Salmo salar ) and brook trout ( Salvelinus fontinalis ) that are resistant to Aeromonas salmonicida . This program, specifically as it relates to brook trout, is reviewed throughout the current manuscript. In addition, we present a comparison between the performance of the Rome strain of brook trout to that of the Owhi strain of brook trout during a 17-month production cycle at the Ed Weed Fish Culture Station (Grand Isle, VT, USA) and after stocking into Vermont waters. The Owhi strain is used in recreational fisheries because it has good post-stocking survival, but these fish are sensitive to furunculosis. Our data indicated that the Rome strain had a food conversion rate of 1.3 that was slightly less than the 1.1 conversion rate of the Owhi brook trout. The growth rate measured as Monthly Temperature Units per inch (MTU/in.) among Rome brook trout (24.9 MTU/in.) was better than the Owhi brook trout (29.5 MTU/in.). Both the average length (23.6 cm) and weight (159.7 g) of individual Rome brook trout were superior to those of the Owhi strain (20.4 cm and 78.2 g, respectively). Just prior to stocking, survival within the hatchery was 84% among the Rome trout, but only 51% among the Owhi brook trout and mortality was attributed to a persistent epizootic of furunculosis. Microbiological assays indicated that the prevalence of A. salmonicida in dermal mucus attained equivalent levels within both strains of fish at different phases of the production cycle. The level of systemic infection, however, was regulated to a much greater extent by the Rome strain of brook trout throughout production. Our results indicated that the Rome brook trout strain satisfies management objectives for establishing an effective recreational brook trout fishery. Use of this strain also reduces management issues that complicate production when A. salmonicida is enzootic.

Vermont↗

USGS2013

Variation in the hindgut microbial communities of the Florida manatee, Trichechus manatus latirostris over winter in Crystal River, Florida

The Florida manatee, Trichechus manatus latirostris, is a hindgut-fermenting herbivore. In winter, manatees migrate to warm water overwintering sites where they undergo dietary shifts and may suffer from cold-induced stress. Given these seasonally induced changes in diet, the present study aimed to examine variation in the hindgut bacterial communities of wild manatees overwintering at Crystal River, west Florida. Faeces were sampled from 36 manatees of known sex and body size in early winter when manatees were newly arrived and then in mid-winter and late winter when diet had probably changed and environmental stress may have increased. Concentrations of faecal cortisol metabolite, an indicator of a stress response, were measured by enzyme immunoassay. Using 454-pyrosequencing, 2027 bacterial operational taxonomic units were identified in manatee faeces following amplicon pyrosequencing of the 16S rRNA gene V3/V4 region. Classified sequences were assigned to eight previously described bacterial phyla; only 0.36% of sequences could not be classified to phylum level. Five core phyla were identified in all samples. The majority (96.8%) of sequences were classified as Firmicutes (77.3 ± 11.1% of total sequences) or Bacteroidetes (19.5 ± 10.6%). Alpha-diversity measures trended towards higher diversity of hindgut microbiota in manatees in mid-winter compared to early and late winter. Beta-diversity measures, analysed through permanova, also indicated significant differences in bacterial communities based on the season.

Florida↗

USGS2015

The effect of natural organic matter on mercury methylation by Desulfobulbus propionicus 1pr3

Methylation of tracer and ambient mercury ( 200 Hg and 202 Hg, respectively) equilibrated with four different natural organic matter (NOM) isolates was investigated in vivo using the Hg-methylating sulfate-reducing bacterium Desulfobulbus propionicus 1pr3. Desulfobulbus cultures grown fermentatively with environmentally representative concentrations of dissolved NOM isolates, Hg[II], and HS − were assayed for absolute methylmercury (MeHg) concentration and conversion of Hg(II) to MeHg relative to total unfiltered Hg(II). Results showed the 200 Hg tracer was methylated more efficiently in the presence of hydrophobic NOM isolates than in the presence of transphilic NOM, or in the absence of NOM. Different NOM isolates were associated with variable methylation efficiencies for either the 202 Hg tracer or ambient 200 Hg. One hydrophobic NOM, F1 HpoA derived from dissolved organic matter from the Florida Everglades, was equilibrated for different times with Hg tracer, which resulted in different methylation rates. A 5 day equilibration with F1 HpoA resulted in more MeHg production than either the 4 h or 30 day equilibration periods, suggesting a time dependence for NOM-enhanced Hg bioavailability for methylation.

Frontiers in Microbiology↗

USGS1973

Characteristics of water quality and streamflow, Passaic River basin above Little Falls, New Jersey

The findings of a problem-oriented river-system investigation of the water-quality and streamflow characteristics of the Passaic River above Little Falls, N.J. (drainage area 762 sq mi) are described. Information on streamflow duration, time-of-travel measurements, and analyses of chemical, biochemical, and physical water quality are summarized. This information is used to define relations between water quality, streamflow, geology, and environmental development in the basin's hydrologic system. The existence, nature, and magnitude of long-term trends in stream quality--as measured by dissolved solids, chloride, dissolved oxygen, biochemical oxygen demand, ammonia, nitrate, and turbidity--and in streamflow toward either improvement or deterioration are appraised at selected sites within the river system. The quality of streams in the upper Passaic River basin in northeastern New Jersey is shown to be deteriorating with time. For example, biochemical oxygen demand, an indirect measure of organic matter in a stream, is increasing at most stream-quality sampling sites. Similarly, the dissolved-solids content, a measure of inorganic matter, also is increasing. These observations suggest that the Passaic River system is being used more and more as a medium for the disposal of industrial and municipal waste waters. Dissolved oxygen, an essential ingredient for the natural purification of streams receiving waste discharges, is undersaturated (that is, below theoretical solubility levels) at all sampling sites and is decreasing with time at most sites. This is another indication of the general deterioration of stream quality in the upper basin. It also indicates that the ability of the river system to receive, transport, and assimilate wastes, although exceeded now only for short periods during the summer months, may be exceeded more continually in the future if present trends hold. Decreasing ratios of ammonia to nitrate in a downstream direction on the main stem Passaic River suggests that nitrification (the biochemical conversion of ammonia to nitrate) as well as microbiological decomposition of organic matter (waste waters) is contributing to the continued and increasing undersaturation of dissolved oxygen in the river system. Passaic River streams are grouped into five general regions of isochemical quality on the basis of predominant constituents and dissolved-solids content during low flows. The predominant cations in all but one region are calcium and magnesium (exceeding 50 percent of total cations) ; in that region, where man's activities probably have altered the natural stream waters, the percentage of sodium and potassium equals that of calcium and magnesium. In two of the five regions, the predominant anion is bicarbonate; a combination of sulfate, chloride, and nitrate is predominant in the other three regions. Dissolved-solids content during low flows generally ranges from 100 to 600 milligrams per liter. Several time-of-travel measurements within the basin are reported. These data provide reasonable estimates of the time required for soluble contaminants to pass through particular parts of the river system. For example, the peak concentration of a contaminant injected into the river system at Chatham during extreme low flow would be expected to travel to Little Falls, about 31 miles, in about 13 days; but at medium flow, in about 5 days.

Water Supply Paper↗

USGS2020

Water quality and ecological risk assessment of intermittent streamflow through mining and urban areas of San Marcos River sub-basin, Mexico

Intermittent rivers are becoming more ecologically stressed worldwide. Flow cessation occurs naturally and spatiotemporally in these systems and anthropogenic activities such as wastewater discharges can have considerable impacts. Public entities mostly monitor water quality in permanent streams, leading to insufficient monitoring of intermittent streams and consequently to their potentially inadequate management.. This study analyzed spatiotemporal patterns of water quality and associated ecological risk through the quantification of physicochemical and microbiological pollutants in the intermittent river system of El Novillo and San Marcos in Northeast Mexico. Results showed that water quality varied geographically and seasonally. Based on national and international criteria, annual averages of water quality parameters analyzed suggested that streamflow in these river systems is of poor quality and poses high ecological risk to aquatic life. In the urban area, annual mean concentrations of Cd and Pb (0.14 and 0.4 mg/L) were 77- and 10-fold higher than their respective water quality criteria (<0.0018 and 0.04 mg/L). Statistically significant (q < 0.05) correlations were identified in concentrations of cyanide, Cd, Cu and Pb between wastewater seeping into the river and streamflow within the urban area. These observations highlight the unique sensitivity of intermittent urban streams to anthropogenic activities and may provide useful information to enhance current water management plans for the El Novillo-San Marcos River system for the protection of ecosystem integrity and human health.

El Novillo Canyon↗

USGS2013

Geographic setting influences Great Lakes beach microbiological water quality

Understanding of factors that influence Escherichia coli (EC) and enterococci (ENT) concentrations, pathogen occurrence, and microbial sources at Great Lakes beaches comes largely from individual beach studies. Using 12 representative beaches, we tested enrichment cultures from 273 beach water and 22 tributary samples for EC, ENT, and genes indicating the bacterial pathogens Shiga-toxin producing E. coli (STEC), Shigella spp., Salmonella spp, Campylobacter jejuni/coli, and methicillin-resistant Staphylococcus aureus, and 108–145 samples for Bacteroides human, ruminant, and gull source-marker genes. EC/ENT temporal patterns, general Bacteroides concentration, and pathogen types and occurrence were regionally consistent (up to 40 km), but beach catchment variables (drains/creeks, impervious surface, urban land cover) influenced exceedances of EC/ENT standards and detections of Salmonella and STEC. Pathogen detections were more numerous when the EC/ENT Beach Action Value (but not when the Geometric Mean and Statistical Threshold Value) was exceeded. EC, ENT, and pathogens were not necessarily influenced by the same variables. Multiple Bacteroides sources, varying by date, occurred at every beach. Study of multiple beaches in different geographic settings provided new insights on the contrasting influences of regional and local variables, and a broader-scale perspective, on significance of EC/ENT exceedances, bacterial sources, and pathogen occurrence.

Great Lakes↗

USGS1996

Hydrologic and microbiological factors affecting persistence and migration of petroleum hydrocarbons spilled in a continuous-permafrost region

Fuel spills, totaling about 1300 m3, occurred between 1976 and 1978 adjacent to Imikpuk Lake, a drinking water source near Barrow, AK. Substantial contamination of soils and groundwater near the lake persists. We examined the magnitude and direction of groundwater flux and the microbial activity at this site to understand the persistence of contamination and its effect on the lake. We found that groundwater flux is small due to shallow permafrost, which restricts the cross-sectional area available for flow, and to the short annual thaw season (ca. 90 days). The small flux and limited depth also constrain contaminant transport and dispersion, resulting in persistent, shallow contamination. The numbers of hydrocarbon-oxidizing microorganisms and their laboratory mineralization potentials for benzene (at 10 ??C) were higher in samples from contaminated areas than in reference samples. Benzene mineralization potentials in groundwater samples were comparable to more temperate systems (0.1-0.5 mg of benzene mineralized L-1 day-1) and were stimulated by nutrient additions. Field measurements of dissolved oxygen, nitrate, ferrous iron, and sulfide in groundwater provided evidence that biodegradation of petroleum hydrocarbons is occurring in situ. Despite evidence of an active microbial population, microbial processes, like contaminant transport, are likely limited at this site by the short annual thaw season.

Environmental Science & Technology↗

USGS2023

The persistence of time: The lifespan of Bacillus anthracis spores in environmental reservoirs

Anthrax is a lethal bacterial zoonosis primarily affecting herbivorous wildlife and livestock. Upon host death Bacillus anthracis vegetative cells form spores capable of surviving for years in soil. Anthrax transmission requires host exposure to large spore doses. Thus, conditions that facilitate higher spore concentrations or promote spore survival will increase the probability that a pathogen reservoir infects future hosts. We investigated abiotic and pathogen genomic variation in relation to spore concentrations in surface soils (0e1 cm depth) at 40 plains zebra (Equus quagga) anthrax carcass sites in Namibia. Specifically, how initial spore concentrations and spore survival were affected by seasonality associated with the timing of host mortality, local soil characteristics, and pathogen genomic variation. Zebras dying of anthrax in wet seasons-the peak season for anthrax in Etosha National Park-had soil spore concentrations 1.36 orders of magnitude higher than those that died in dry seasons. No other variables considered affected spore concentrations, and spore survival rates did not differ among sites. Surface soils at these pathogen reservoirs remained culture positive for a range of 3.8e10.4 years after host death. Future research could evaluate if seasonal patterns in spore concentrations are driven by differences in sporulation success or levels of terminal bacteremia.

Etosha National Park↗

USGS2021

Resistance, resilience, and recovery of dryland soil bacterial communities across multiple disturbances

Dryland ecosystems are sensitive to perturbations and generally slow to recover post disturbance. The microorganisms residing in dryland soils are especially important as they contribute to soil structure and nutrient cycling. Disturbance can have particularly strong effects on dryland soil structure and function, yet the natural resistance and recovery of the microbial components of dryland soils has not been well documented. In this study, the recovery of surface soil bacterial communities from multiple physical and environmental disturbances is assessed. Samples were collected from three field sites in the vicinity of Moab, UT, United States, 6 to 7 years after physical and climate disturbance manipulations had been terminated, allowing for the assessment of community recovery. Additionally, samples were collected in a transect that included three habitat patches: the canopy zone soils under the dominant shrubs, the interspace soils that are colonized by biological soil crusts, and edge soils at the plot borders. Field site and habitat patch were significant factors structuring the bacterial communities, illustrating that sites and habitats harbored unique soil microbiomes. Across the different sites and disturbance treatments, there was evidence of significant bacterial community recovery, as bacterial biomass and diversity were not significantly different than control plots. There was, however, a small number of 16S rRNA gene amplicon sequence variants that distinguished particular treatments, suggesting that legacy effects of the disturbances still remained. Taken together, these data suggest that dryland bacterial communities may possess a previously unappreciated potential to recover within years of the original disturbance.

Frontiers in Microbiology↗

USGS2025

STREAMS guidelines: Standards for technical reporting in environmental and host-associated microbiome studies

The interdisciplinary nature of microbiome research, coupled with the generation of complex multi-omics data, makes knowledge sharing challenging. The Strengthening the Organization and Reporting of Microbiome Studies (STORMS) guidelines provide a checklist for the reporting of study information, experimental design and analytical methods within a scientific manuscript on human microbiome research. Here, in this Consensus Statement, we present the standards for technical reporting in environmental and host-associated microbiome studies (STREAMS) guidelines. The guidelines expand on STORMS and include 67 items to support the reporting and review of environmental (for example, terrestrial, aquatic, atmospheric and engineered), synthetic and non-human host-associated microbiome studies in a standardized and machine-actionable manner. Based on input from 248 researchers spanning 28 countries, we provide detailed guidance, including comparisons with STORMS, and case studies that demonstrate the usage of the STREAMS guidelines. STREAMS, like STORMS, will be a living community resource updated by the Consortium with consensus-building input of the broader community.

Nature Microbiology↗

USGS2024

A conserved interdomain microbial network underpins cadaver decomposition despite environmental variables

Microbial breakdown of organic matter is one of the most important processes on Earth, yet the controls of decomposition are poorly understood. Here we track 36 terrestrial human cadavers in three locations and show that a phylogenetically distinct, interdomain microbial network assembles during decomposition despite selection effects of location, climate and season. We generated a metagenome-assembled genome library from cadaver-associated soils and integrated it with metabolomics data to identify links between taxonomy and function. This universal network of microbial decomposers is characterized by cross-feeding to metabolize labile decomposition products. The key bacterial and fungal decomposers are rare across non-decomposition environments and appear unique to the breakdown of terrestrial decaying flesh, including humans, swine, mice and cattle, with insects as likely important vectors for dispersal. The observed lockstep of microbial interactions further underlies a robust microbial forensic tool with the potential to aid predictions of the time since death.

Nature Microbiology↗

USGS2011

Microbial water quality before and after the repair of a failing onsite wastewater treatment system adjacent to coastal waters

Aims: The objective was to assess the impacts of repairing a failing onsite wastewater treatment system (OWTS, i.e., septic system) as related to coastal microbial water quality. Methods and Results: Wastewater, groundwater and surface water were monitored for environmental parameters, faecal indicator bacteria (total coliforms, Escherichia coli, enterococci) and the viral tracer MS2 before and after repairing a failing OWTS. MS2 results using plaque enumeration and quantitative reverse transcriptase polymerase chain reaction (qRT‐PCR) often agreed, but inhibition limited the qRT‐PCR assay sensitivity. Prerepair, MS2 persisted in groundwater and was detected in the nearby creek; postrepair, it was not detected. In groundwater, total coliform concentrations were lower and E. coli was not detected, while enterococci concentrations were similar to prerepair levels. E. coli and enterococci surface water concentrations were elevated both before and after the repair. Conclusions: Repairing the failing OWTS improved groundwater microbial water quality, although persistence of bacteria in surface water suggests that the OWTS was not the singular faecal contributor to adjacent coastal waters. A suite of tracers is needed to fully assess OWTS performance in treating microbial contaminants and related impacts on receiving waters. Molecular methods like qRT‐PCR have potential but require optimization. Significance and Impact of Study: This is the first before and after study of a failing OWTS and provides guidance on selection of microbial tracers and methods.

North Carolina↗

USGS2012

Comparison of DNA preservation methods for environmental bacterial community samples

Field collections of environmental samples, for example corals, for molecular microbial analyses present distinct challenges. The lack of laboratory facilities in remote locations is common, and preservation of microbial community DNA for later study is critical. A particular challenge is keeping samples frozen in transit. Five nucleic acid preservation methods that do not require cold storage were compared for effectiveness over time and ease of use. Mixed microbial communities of known composition were created and preserved by DNAgard™, RNAlater ® , DMSO–EDTA–salt (DESS), FTA ® cards, and FTA Elute ® cards. Automated ribosomal intergenic spacer analysis and clone libraries were used to detect specific changes in the faux communities over weeks and months of storage. A previously known bias in FTA ® cards that results in lower recovery of pure cultures of Gram-positive bacteria was also detected in mixed community samples. There appears to be a uniform bias across all five preservation methods against microorganisms with high G + C DNA. Overall, the liquid-based preservatives (DNAgard™, RNAlater ® , and DESS) outperformed the card-based methods. No single liquid method clearly outperformed the others, leaving method choice to be based on experimental design, field facilities, shipping constraints, and allowable cost.

FEMS Microbiology Ecology↗

USGS2011

Beach monitoring criteria: reading the fine print

Beach monitoring programs aim to decrease swimming-related illnesses resulting from exposure to harmful microbes in recreational waters, while providing maximum beach access. Managers are advised by the U.S. EPA to estimate microbiological water quality based on a 5-day geometric mean of fecal indicator bacteria (FIB) concentrations or on a jurisdiction-specific single-sample maximum; however, most opt instead to apply a default single-sample maximum to ease application. We examined whether re-evaluation of the U.S. EPA ambient water quality criteria (AWQC) and the epidemiological studies on which they are based could increase public beach access without affecting presumed health risk. Single-sample maxima were calculated using historic monitoring data for 50 beaches along coastal Lake Michigan on various temporal and spatial groupings to assess flexibility in the application of the AWQC. No calculation on either scale was as low as the default maximum (235 CFU/100 mL) that managers typically use, indicating that current applications may be more conservative than the outlined AWQC. It was notable that beaches subject to point source FIB contamination had lower variation, highlighting the bias in the standards for these beaches. Until new water quality standards are promulgated, more site-specific application of the AWQC may benefit beach managers by allowing swimmers greater access to beaches. This issue will be an important consideration in addressing the forthcoming beach monitoring standards.

Environmental Science & Technology↗