Interaction and Influence of Two Creeks on <i>Escherichia coli</i> Concentrations of Nearby Beaches: Exploration of Predictability and Mechanisms

Nevers, Meredith B.; Whitman, Richard L.; Frick, Walter E.; Ge, Zhongfu

doi:10.2134/jeq2007.0025

Cited by 36 publications

(37 citation statements)

References 26 publications

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“…coli concentrations (geometric mean of 1.4 log 10 MPN·100 mL −1 ) were generally below USEPA recreational water quality criteria and consistent with previously measured ranges in Great Lakes tributary rivers (30)(31)(32). A comprehensive review (33) found that E. coli levels in freshwater below 2.23 log 10 MPN·100 mL −1 were associated with low relative risks of gastrointestinal illness for swimmers compared with nonswimmers.…”

Section: −1supporting

confidence: 76%

Linking fecal bacteria in rivers to landscape, geochemical, and hydrologic factors and sources at the basin scale

Verhougstraete

Martin

Kendall

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

110

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Linking fecal indicator bacteria concentrations in large mixed-use watersheds back to diffuse human sources, such as septic systems, has met limited success. In this study, 64 rivers that drain 84% of Michigan's Lower Peninsula were sampled under baseflow conditions for Escherichia coli, Bacteroides thetaiotaomicron (a human source-tracking marker), landscape characteristics, and geochemical and hydrologic variables. E. coli and B. thetaiotaomicron were routinely detected in sampled rivers and an E. coli reference level was defined (1.4 log 10 most probable number·100 mL −1). Using classification and regression tree analysis and demographic estimates of wastewater treatments per watershed, septic systems seem to be the primary driver of fecal bacteria levels. In particular, watersheds with more than 1,621 septic systems exhibited significantly higher concentrations of B. thetaiotaomicron. This information is vital for evaluating water quality and health implications, determining the impacts of septic systems on watersheds, and improving management decisions for locating, constructing, and maintaining on-site wastewater treatment systems.Escherichia coli | Bacteroides thetaiotaomicron | baseflow | reference conditions | septic system W ater quality degradation influenced by diffuse sources at large watershed scales has been difficult to describe. Human modifications of natural landscapes can permanently alter hydrologic cycles and affect water quality (1, 2). Deforestation (3) and increased impervious surface area (4) have been linked with decreased infiltration and thus increased surface runoff. Overland flows concentrate pollutants and rapidly transport them down gradient where they eventually enter surface water systems and affect water quality (5, 6). A number of models have been developed to calculate overland and surface water flows (7,8) and nutrient/chemical transport (9), but few studies have focused on microbial movement from land to water, particularly nontraditional fecal indicator bacteria that can be used to track human sources of pollution.Microbial contamination poses one of the greatest health risks to swimming areas, drinking water intakes, and fishing/shellfish harvesting zones where human exposures are highest (10-12). These highly visible areas often receive more attention than sources of contamination because identifying the origin of pollution in complex watersheds requires costly comprehensive investigation of environmental and hydrologic conditions across temporal and spatial scales (13). Grayson et al. (14) suggest using a "snapshot" approach that captures water quality characteristics at a single point in time across broad areas to provide information frequently missed during routine monitoring. Compared with long-term comprehensive investigations, the snapshot approach reduces the number of samples, cost, and personnel required to examine pollution sources.Escherichia coli concentrations are commonly used to describe the relative human health risk during water quality monitoring in li...

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Section: −1supporting

confidence: 76%

Linking fecal bacteria in rivers to landscape, geochemical, and hydrologic factors and sources at the basin scale

Verhougstraete

Martin

Kendall

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

110

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“…Overall, the levels of fecal indicators were found to be higher in Wisconsin than in Michigan beaches. Water quality was correlated to proximity to a river mouth, a result that has been documented by others at freshwater beaches (43,(48)(49)(50)(51). Sand samples collected within the berm zone were consistently found to have high levels of FIB compared to concentrations within water grab samples collected in the same transect.…”

Section: Discussionsupporting

confidence: 65%

Influence of Land Use, Nutrients, and Geography on Microbial Communities and Fecal Indicator Abundance at Lake Michigan Beaches

Cloutier

Alm

McLellan

2015

Appl Environ Microbiol

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bMicrobial communities within beach sand play a key role in nutrient cycling and are important to the nearshore ecosystem function. Escherichia coli and enterococci, two common indicators of fecal pollution, have been shown to persist in the beach sand, but little is known about how microbial community assemblages are related to these fecal indicator bacteria (FIB) reservoirs. We examined eight beaches across a geographic gradient and range of land use types and characterized the indigenous community structure in the water and the backshore, berm, and submerged sands. FIB were found at similar levels in sand at beaches adjacent to urban, forested, and agricultural land and in both the berm and backshore. However, there were striking differences in the berm and backshore microbial communities, even within the same beach, reflecting the very different environmental conditions in these beach zones in which FIB can survive. In contrast, the microbial communities in a particular beach zone were similar among beaches, including at beaches on opposite shores of Lake Michigan. The differences in the microbial communities that did exist within a beach zone correlated to nutrient levels, which varied among geographic locations. Total organic carbon and total phosphorus were higher in Wisconsin beach sand than in beach sand from Michigan. Within predominate genera, finescale sequence differences could be found that distinguished the populations from the two states, suggesting a biogeographic effect. This work demonstrates that microbial communities are reflective of environmental conditions at freshwater beaches and are able to provide useful information regarding long-term anthropogenic stress. Since the creation of the Federal Beach Environmental Assessment and Coastal Health (BEACH) Act of 2000, coastal communities have been challenged with implementing programs for the monitoring of recreational waters. Water quality monitoring relies on fecal indicator bacteria (FIB), such as Escherichia coli and enterococci, and the assumption that both are fecal in origin. In recent years, many Great Lakes coastal recreational waters were monitored for the first time and subsequently were found to have unacceptable levels of E. coli, indicating the presence of contamination from sources such as sewage, stormwater, or agricultural runoff. However, recent studies have detected high concentrations of FIB in recreational beach sands compared to the concentrations in the nearby monitored waters (1-4). Importantly, several studies have documented that sand reservoirs of FIB play a large role in beach water samples exceeding regulatory limits (1, 3, 5-7).Persistent FIB in the beach environment is of great concern. The presence of FIB in either recreational waters or sand is assumed to indicate a recent pollution event. However, the persistence and possible proliferation of FIB in the beach environment can confound beach-monitoring efforts and poses additional challenges for beach managers. In addition, there is mounting evidence that E. co...

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“…Although log culturable E. coli and enterococci CCE were significantly higher than log enterococci CFU (F 2 , 92 = 11.856, P b 0.0001), they were not different from one another. Mean E. coli densities at Jeorse Park were generally higher than historic E. coli levels at other beaches along southern Lake Michigan (Nevers and Whitman, 2005;Nevers et al, 2007).…”

Section: E Coli and Enterococci Densitiesmentioning

confidence: 71%

Wildlife, urban inputs, and landscape configuration are responsible for degraded swimming water quality at an embayed beach

Byappanahalli

Nevers

Whitman

et al. 2015

Journal of Great Lakes Research

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Interaction and Influence of Two Creeks on Escherichia coli Concentrations of Nearby Beaches: Exploration of Predictability and Mechanisms

Cited by 36 publications

References 26 publications

Linking fecal bacteria in rivers to landscape, geochemical, and hydrologic factors and sources at the basin scale

Linking fecal bacteria in rivers to landscape, geochemical, and hydrologic factors and sources at the basin scale

Influence of Land Use, Nutrients, and Geography on Microbial Communities and Fecal Indicator Abundance at Lake Michigan Beaches

Wildlife, urban inputs, and landscape configuration are responsible for degraded swimming water quality at an embayed beach

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