Poster Abstracts

1

A multi-year study of Bay City State Recreation Area and inlets with microbial source tracking

Microbial Source Tracking (MST) was performed in an effort to determine the origin of fecal contamination in samples collected from Bay City State Recreation Area and its nearest inlets during the 2023-2026 beach seasons.  The beach had unprecedented levels of closure during this time. Our MST analysis relies on the methods of digital drop Polymerase Chain Reaction (ddPCR), with duplexed targets for Gull/Human, Ruminant/Bovine, and Canine/ND2(Canada Goose). The results indicate the high presence of both human and gull markers on days when the beach was closed, with strong contributions to the contamination from nearby Tobico Marsh.  By cross-referencing the Colilert and MST assays, main contender(s) for sources of fecal contamination can be inferred and communicated with our local health department and government partners.

Bloom season cyanobacteria biomass variability in Lake Erie is coupled with multiple environmental factors

Cyanobacteria densities are an indicator of harmful algal bloom intensity and potential for microcystin production and human exposure. Nearshore and offshore waters at Maumee Bay State Park Beach (Oregon, OH) were evaluated to determine mid- to late summer temporal patterns in cyanobacteria abundance, and relationships between abundance and meteorological , hydrodynamic, and water-quality conditions. Water samples (n = 147) were collected from seven locations, representing recreational beach waters (8 m from the shoreline) and offshore (1.0 km and 4.1 km) locations. Measurements included cyanobacteria biomass densities (inferred from chlorophyll-a mass), total chlorophyll, turbidity, nitrate/nitrite, specific conductance, dissolved oxygen, and pH. Meteorological and hydrodynamic variables included air and water temperature, previous 24 and 48 h precipitation, solar radiation, wind speed and direction, wave height, lake level, and Maumee River discharge. Each of the meteorological and hydrodynamic variables were also measured 24 and 48 hours before sampling occurred. Relationships between cyanobacteria and environmental variables were evaluated using spearman correlation and regression modelling.  On average, cyanobacteria abundance experienced an 11.5-fold increase from July to August across three summers.  The annual mean cyanobacteria biomass varied significantly, with average abundance among the three summers declining from 14.46 g/ml in mid-summer samples to 22.45 g/ml in late summer. Mean cyanobacteria biomass positively correlated with 24-h precipitation (r = 0.60) Maumee River discharge (r = −0.61) and Maumee River nitrate/nitrite concentrations recorded 24 hours before each sampling event (r = −0.58).  Overall, results showed that cyanobacteria biomass abundance increased throughout the summer and varied with solar irradiance and meteorological, hydrodynamic, and water quality conditions. 

Calibration and usability of Bactiquick for environmental endotoxin measurements 

Background: Bactiquick is a portable, rapid colorimetric endotoxin assay that provides results in <15 minutes, compared with culture-based methods that take at least 18 hours. Because its use for monitoring bacteria in recreational water is relatively new, Bactiquick needs to be evaluated under different testing conditions and calibrated to assess its accuracy.   Objective: This study aims to evaluate Bactiquick performance under laboratory and field conditions and to develop calibration methods for the instrument as well as assay reagent performance using an Escherichia coli culture as the endotoxin test sample.   Methods: Bactiquick measurements were conducted under laboratory and field conditions and resultant ERU (Endotoxin Risk Unit) values were compared. To evaluate the effect of testing Bactiquick while transporting in a vehicle, Bactiquick ERUs were compared between bench tests and incubations performed inside a moving car. For calibration, a tartrazine dye-based method was developed in which one vial containing water was used to start the test and then swapped with a vial containing tartrazine dye for the remainder of the test. This method allowed the Bactiquick instrument to be evaluated independently of the assay reagent. Multiple tartrazine tests were performed, including a linearity test using serial dilutions, a volume test, a vial-swap timing test, tests evaluating the effects of external light, a bubble test, and a vial-orientation test. An E. coli culture was evaluated over a series of dilutions to further evaluate the response range.   Results: Laboratory and field measurements showed no significant difference in Bactiquick ERU values, indicating comparable performance between field and laboratory conditions. Comparison of bench incubations with incubations during transport in a car showed no difference, suggesting that vibration or other effects associated with transport did not significantly influence results. Citizen scientists from the Friends of the Rouge were able to easily implement Bactiquick measurements at a Detroit River beach, with results generally agreeing with their low E. coli counts and the tartrazine calibration procedure. The tartrazine calibration method demonstrated a linear relationship between tartrazine concentration and Bactiquick ERU values in the range 0-100 ERU, supporting its potential use as an instrument calibration method. Vial-swap timing, light exposure, bubbles, and vial orientation showed insignificant differences in ERU values; volumes below 150 µL gave inaccurate results, while volumes above 200 µL produced uniform results. The E. coli cultures produced measurable ERU responses across the concentrations tested, providing evidence for evaluating assay reagent performance and establishing a linear response range up to ERU=120. E. coli cultures can be used as positive controls for evaluating Bactiquick reagents (see poster by Ghosh et al.).   Conclusions: The results indicate that Bactiquick is a robust instrument with measurements being relatively consistent across the laboratory, field, and calibration conditions tested. The tartrazine method shows promise as a simple approach for instrument calibration and quality control. Both the tartrazine calibration tests and the E. coli measurements indicate that the useful range of Bactiquick ERU values is between 1 and 120. 

E. coli and endotoxin monitoring of inland lake beaches across Michigan DHD10

Inland lake water quality monitoring is conducted to help reduce the exposure of possible harmful pathogens to the general population. Over the course of the summer, thirteen beaches from eleven lakes across Wexford, Mecosta, Missaukee, Kalkaska, Crawford, and Antrim counties were monitored. Findings were reported to DHD10, the local health department for these counties. Using Bactiquick and/or Colilert, the E. coli and endotoxin levels were monitored at these beaches. Colilert is a reliable, accurate, established culture-based test used to measure the number of E. coli colony forming units (CFU). One colony is equal to one bacterium in the water. Michigan government standards regard water samples at or above 300 CFU/100 mL as hazardous to human health. The beaches that were tested have consistently shown safe levels of E. coli except on two different dates at two different beaches. Bactiquick is a relatively new portable system that can estimate the number of gram-negative bacteria (endotoxins) in the water in 13 minutes. Endotoxins are lipopolysaccharides found in the outer membrane of gram-negative bacteria. Only Kenwood Park (Lake Cadillac), Missaukee County Park Beach (Lake Missaukee), School Section Lake Veterans Park Beach, Lake Margrethe State Forest Campground, and Torch Lake Sand Bar Public Access Point were monitored with both Bactiquick and Colilert. Comparing results of both tests allows for the determination of the effectiveness of the Bactiquick system for public health water quality monitoring. This data, along with data from other labs, will be used by MI EGLE and the Rose Lab at MSU to make a broader comparison of the effectiveness of the Bactiquick system and its use to monitor water quality in the future. Of the two lakes with high levels of E. coli, only Lake Missaukee was monitored using both Bactiquick and Colilert. Samples with ≥300 CFU/100 mL were candidates for microbial source tracking or MST. MST uses PCR based methods to determine what possible species cause E. coli contamination. Only human DNA markers were used for these samples. Due to consumable error only one of the two samples above 300 CFU/100 mL was tested.

Enhancing community water safety with a unified MST database for Michigan

Water quality monitoring is essential for informing local health departments about contamination concerns affecting recreational waters. In Michigan, E. coli serves as the primary indicator, with 300 MPN/100 mL used as the threshold for issuing beach notifications. Although this test identifies exceedances in lakes and rivers, it does not reveal the origin of contamination. Microbial source tracking (MST) molecular tools provide additional insight by identifying host specific fecal pollution sources. Michigan’s beach water testing network (MiNET) incorporates MST during the swim season to evaluate spatial and temporal trends in water quality and fecal contamination across Michigan. This project focuses on utilizing a data pipeline to harmonize and aggregate MST results, creating a statewide database accessible to local health departments (LHDs) to support informed decision making. 
    The project began with designing a structured data template to compile quantitative MST target concentrations throughout the monitoring period. The template includes site-and sample specific metadata and dedicated fields for E. coli and MST marker results. Using this system, we compiled data from over 650 samples collected across multiple testing sites in Michigan between June 2017-September 2025. Samples were analyzed for Human (HF183) and (B.theta), Bovine (CowM2), Canine (DG3), Ruminant (Rum2Bac), Gull (Gull4), Porcine (Pig2Bac), and E. coli markers. The dataset captures both marker detection and quantitative concentrations, allowing evaluation of marker frequency and expression across sites. These concentration patterns will help identify dominant fecal contamination sources, particularly where specific markers recur at elevated levels, spatially and temporally. 
 The data pipeline supports consistent characterization and analysis of MST datasets and represents a promising foundation for county, state, or national level MST databases. Such characterization can guide testing priorities, highlight markers with historical contamination relevance, and ultimately provide targeted, cost effective insights and mitigation strategies that strengthen public communication, water quality awareness, and environmental stewardship.

Evaluation of a novel E.coli testing method for beach monitoring at select Wisconsin beaches

The standard testing methodologies for determining E.coli concentrations at swimming beaches include membrane filtration, defined substrate, and molecular methods.  By far, defined substrate methods are the most widely used and there are a number approved by US EPA and state regulatory agencies.  The most used method in Wisconsin is the Colilert/Colilert-18 method.  While it is state-approved and has a track record of use spanning over 20 years, it requires a minimum incubation time of 18 hours, and you must go to a laboratory to evaluate the results.  IDEXX laboratories recently brought a new technology called the Tecta to market and facilities have started to gain regulatory approval for its use.  However, the Tecta is only approved for use in presence/absence analysis even though it performs quantification of the samples analyzed.  The Tecta is automated and can provide results in less than 18 hours and does not require a lab technician to be at the lab to evaluate the sample after incubation.  The Tecta will email results immediately after reaching a certain threshold for positivity.  The automated results and ability to save trips to and from the laboratory could save hundreds of hours of staff time, significant travel reimbursement, and provide results in a timelier manner.  The goal of this project was to compare the Tecta quantification results for E.coli with those from the Colilert/Colilert-18 test.  Several beaches in northeastern Wisconsin were chosen for study where single samples were collected, split into separate 100 mL samples for simultaneous analysis by the Tecta and Colilert-18.  These split sample results were then compared over the 2025 and 2026 swimming season.  In addition to quantification comparisons the impact of the method on beach actions such as advisories and closures was also evaluated.

From bacteria to beach flags: Understanding Chicago beachgoers' water quality perceptions

Background: Recreational water quality monitoring is an important part of protecting beachgoers from exposure to bacterial contamination. However, the effectiveness of monitoring and advisory systems depends on whether beachgoers understand water quality information and use it when making decisions about swimming. The Chicago Park District has partnered with the University of Illinois Chicago School of Public Health since 2017 to monitor its beaches seven days a week throughout the summer season using rapid methods, but less is known about beachgoers’ perceptions of bacterial water quality, understanding of beach notification systems, and trust in public health advisories. Objective: To characterize Chicago beachgoers’ perceptions and knowledge of recreational water quality, their trust in water quality advisories, and their reported responses to bacterial swimming advisories. Methods: From August to early September of the 2026 beach season, an in-person intercept survey was administered to random adult beachgoers at 17 Chicago Park District beaches. The bilingual English/Spanish survey assessed perceptions of Lake Michigan water quality, awareness of beach flag meanings and bacterial monitoring, trust in public health advisories, previous responses to beach advisories, and preferred methods for receiving water quality information. Descriptive statistics were calculated for 334 completed responses collected across Chicago beaches. Results: Most respondents reported trusting public health water quality advisories at least somewhat (77.4%), and 77.4% reported that they would probably or definitely avoid entering the water if a bacterial advisory was issued. Similarly, 72.2% reported having previously decided not to enter the water due to a beach advisory or closure. However, the understanding of the relationship between beach notification systems and bacterial water quality appeared limited. While 77.2% of respondents identified waves or currents as something represented by the beach flag system, only 8.4% selected water quality or bacteria levels. Weather forecasts were the most commonly used resource before visiting a beach (89.2%), while 23% reported using the Chicago Park District website. Beach signs were the most preferred method for receiving water quality information (66%), followed by text message alerts (12%) and beach warning flags (7.8%). More than half of respondents rated Lake Michigan water quality as good or very good (55.7%), while 20.4% were unsure about recent trends and 18.3% perceived water quality as worsening. Conclusions: Chicago beachgoers reported substantial trust in public health water quality advisories and indicated that bacterial advisories could influence their decisions to enter the water. However, the relatively small proportion identifying bacterial water quality as a meaning of the beach flag system suggests an opportunity to strengthen communication about bacterial monitoring and recreational water quality risks. Clear and prominent information at beaches, particularly through signs and additional communication channels, may help beachgoers better understand monitoring results to make informed decisions about recreational water use.

8

Improving beach monitoring through detection of potential increased pathogens and AMR-linked signals 

Recreational beaches remain a significant public health concern due to potential exposure to waterborne pathogens and fecal contamination. Current monitoring approaches rely on culture-based methods targeting fecal indicator bacteria such as Escherichia coli, which requires 18-24 hours to obtain results.This delay can result in missed short-term contamination events and can prolong public exposure, limiting the ability to implement timely and protective beach closures. Additionally, reliance on indicator organisms provides limited insight into other microbial hazards such as pathogens present in recreational waters. To address these limitations, a statewide collaboration among Michigan Technological University, Michigan State University, University of Michigan, Wayne State University, and Michigan Department of Environment, Great Lakes, and Energy has been established to evaluate the broader capabilities of an emerging monitoring technology called Bactiquick. While previous studies have focused on the technology's effectiveness, this study aims to assess its ability to capture additional Gram-negative bacterial signals that may pose a risk to public health. This study specifically investigates instances in which Bactiquick yields positive (yellow or red)  results while IDEXX Colilert methods are below the beach closure threshold (300 MPN). These discrepancies suggest the presence of alternative bacterial sources or other biologically active endotoxins not captured by standard fecal indicator testing. Through this targeted analysis, this work aims to evaluate whether these signals are associated with antimicrobial resistance (AMR) markers or other waterborne based pathogens, contributing to a more comprehensive understanding of microbial risk in recreational waters. By enabling rapid, field-based detection, Bactiquick can capture transient contamination events that are often missed by traditional monitoring methods, directly reducing the risk of public health exposure to concerning water pollutants. Its ability to produce results within 15 minutes can greatly improve public health responses, allowing for faster advisory and mitigation efforts at recreational sites. In addition, its low cost and ease of use makes it a practical solution for expanding monitoring efforts in rural, underserved, and indigenous communities where delayed detection can lead to higher risk of exposure. Ultimately, increasing testing frequency enabled by this technology strengthens public health protection. 

Investigating drivers of high Bactiquick bacground signal not associated with E. coli

Periodic fecal contamination at public beaches can cause illnesses that require medical treatment or hospitalization, necessitating routine monitoring of recreational waters in the state of Michigan. The most widely used method to determine beach safety is Colilert-18, a culture-based analytical method that targets actively growing Escherichia coli (E. coli), a fecal indicator bacteria. However, the eighteen-hour timeframe creates a lag between sample collection and test result. Bactiquick real-time water testing kits are a new technology that uses a colorimetric indicator of endotoxin concentrations (a molecule found in all Gram-negative bacteria) that can generate results in 15 minutes. Although some validation data for the Bactiquick method exists, it remains unclear whether the Bactiquick measure is strongly correlated with E. coli abundance across diverse environmental settings. Our study aims to evaluate when and where Bactiquick does or does not match Colilert-18 results, and whether any environmental conditions generate systematic differences between the two tests. We hypothesized that terrestrial dissolved organic matter and algal abundance (measured as chlorophyll concentration) amongst sites would influence how Bactiquick results should be interpreted across sites. We sampled 25 sites across Muskegon County, Michigan each week for ten weeks. Composite samples from each site visit were analyzed using Bactiquick and Colilert-18, as well as chlorophyll concentrations and water color (a proxy for terrestrial dissolved organic matter concentration). Bactiquick high risk readings (>57 ERU) only matched with Colilert-18 results (>300 MPN) for ~6% of samples in this study. For ~50% of our samples, Bactiquick indicated high risk that did not match with Colilert-18 results (“false positives”). Since Colilert-18 targets E.coli, false positives by Bactiquick indicate the absence of E. coli in those samples and suggest other factors are driving high signals. High water color and chlorophyll values in samples with false positives suggest water conditions across sites may produce high background Bactiquick signals. Site-specific estimation or statistical-model-based predictions of site-specific background Bactiquick levels could increase the number of beaches for which Bactiquick can be used reliably.

10

Predict beach closure probability using Escherichia coli levels in surrounding water body

Background: Fecal contamination in recreational water bodies poses serious public health threat to swimmers and coliphage including Escherichia coli is used as a bacterial indicator of such contamination. Local warnings against water contact including swim closure and contamination advisory at beach sites with bacterial level exceedance are implemented in Michigan and nationwide. Monitoring more than two thousand beach sites’ water quality in real time could be challenging and predicative modeling of high-risk regions for priority testing helps preventative efforts. In this study, we aim to identify beach sites with high probability of closure through historical data and predicative modeling within Michigan. Methods: We used MiEnviro BeachGuard historical sampling and testing results to generate weekly mean E. coli levels from 2010 to 2025. Given the samplings were concentrated from May to October, we censored the study timeframe to this period seasonally. Weekly closure probability was calculated as the percentage of a week being closed or having contamination warning due to high bacterial level for a beach site according to EGLE for exploratory analyses. Climate data including precipitation, air temperature, and snowfall were obtained from NOAA weather station records and kriging was used to interpolate each measure for each beach site. The seasonality of closure was examined using wavelet analysis and county-level spatiotemporal clusters with high closure probability were generated using scan statistics. To predict closure probability, weekly binary closure status was created and any week with mean E. coli level exceeding 300 units/100 ml was marked as closed. A hierarchical Bayesian model was trained on 2010-2023 climate data and predicted site-specific weekly closure status for 2024-2025.  Results: Overall closure probability and bacterial level in Michigan peak in June, July and August but diverse local patterns with different peak timing and seasonality are present for 2020-2025 period. Sites in upper peninsula have lower mean E. coli level and delayed peak timing overall compared to lower peninsular sites.  Counties and beach sites with high historical mean seasonal closure probability and bacterial level were identified. The prediction model has 0.745 prediction accuracy on the weekly closure status for 892 beach sites.  Conclusion: Prediction model can reasonably identify sites at high-risk of elevated bacterial levels, which can provide real-time estimates using updated climate data and insights on high-priority sampling sites for lab testing. For future steps, we aim to integrate more streams of climate data and provide an interactive dashboard with real-time forecasting capabilities for bacterial levels. 

11

Tiny Terrors: Microplastics and their impact on bacterial communities on Muskegon County beaches

Microplastics are an emerging and still poorly understood pollutant in the Great Lakes. As these particles become increasingly ubiquitous in aquatic environments, concerns are growing about their ecological and public-health impacts. Although the microplastics literature is expanding rapidly, important knowledge gaps remain, particularly regarding their role as substrates for microbial biofilm formation in nearshore freshwater systems.  This study will investigate the potential impacts of microplastics on bacterial communities associated with Lake Michigan beaches in Muskegon County, Michigan. Specifically, we aim to identify which bacterial taxa colonize microplastic surfaces, determine which taxa dominate microplastic-associated biofilms, assess how these communities vary across space and time, and evaluate whether microplastic-associated bacteria may pose potential human-health concerns, including skin irritation, infection risk, or contact-related allergic responses.  By addressing these questions, this study will improve understanding of how microplastics influence microbial communities on Muskegon County beaches and help establish a framework for monitoring and managing microplastic pollution along Great Lakes shorelines.

 Christopher Kotkowicz, Annis Water Resources Institute - Grand Valley State University

12

Unbound phycocyanin as a rapid indicator of toxin risk across nearshore–offshore gradients

Cyanobacterial harmful algal blooms (HABs) in western Lake Erie pose persistent risks to ecosystem integrity and human health, particularly in nearshore recreational waters where human exposure is greatest. While monitoring efforts typically focus on biomass and toxin concentrations, less is known about how cyanobacterial physiological stress and toxin release vary across the nearshore–offshore gradient. This study investigates unbound phycocyanin (uPC), a fluorescence-based indicator of cyanobacterial stress and cell lysis, as a mechanistic and potentially rapid proxy for microcystin bioavailability. During the 2025 bloom season, uPC concentrations and detection frequency were highest at the beach and declined offshore, indicating enhanced cellular destabilization at the land–water interface. Short-term (0–72 h) incubation experiments revealed that increases in uPC frequently coincided with declining cyanobacterial biomass and were amplified under nutrient enrichment and low-light conditions, consistent with stress-induced cell lysis rather than simple biomass accumulation. These results provide mechanistic support for interpreting elevated nearshore uPC as a signal of active toxin release. Ongoing work extends this framework by directly pairing uPC with microcystin measurements partitioned into intracellular and extracellular fractions along a high-resolution transect from the beach to offshore waters. We expect nearshore environments to exhibit a shift toward extracellular toxin dominance, reflecting enhanced lysis and increased exposure risk for recreational users. Together, these findings position uPC as a rapid, field-deployable indicator linking cyanobacterial physiological stress to toxin release, offering a new approach for assessing HAB risk in dynamic nearshore environments where current monitoring strategies may underestimate exposure.

 Odiljon Eshmatov, University of Toledo

Application of multiplex dPCR for fecal source tracking in an Allegan County inland lake    

Fecal contamination in recreational waters represents a possible public health threat to humans using these impacted resources for swimming, fishing, boating, and the like. Identifying the source of contamination can help, first, to stratify the degree of risk, and second, to aid in  mitigating the effects of the pollution or preventing it from initially entering the water. Microbial source tracking (MST) is employed to quantify the dominant sources of fecal contamination.  We report on the outcomes of a two year MST study of Dumont Lake, a small lake in west Michigan utilized by residents and visitors for recreation. Since its inclusion in Allegan County Health Department’s inland lake beach monitoring program in 2023, swim advisories have been issued for Dumont Lake each year due to high E. coli levels from previously unidentified sources. In the summers of 2025 and 2026, an MST protocol was utilized alongside ongoing E. coli counts in order to identify origins of fecal contamination at this site. We have implemented a multiplex primer/probe approach, for the majority of the targets, designed by GT Molecular (GT-Digital™ Microbial Source Tracking Human;E.coli;Cow;Gull;Dog Panel v1.0). As well as, a singleplex Canadian goose target (GT-DigitalTM Microbial Source Tracking Goose CGOF1 Assay Kit v1.0 for the QIAGEN® QIAcuity® Digital PCR System ALPHA). Produced for use with the QIAGEN QIAcuity digital PCR system, the GT kit targets 16S ribosomal DNA sequences from host animal specific bacterial strains from HF183 human Bacteroides, Gull4 Catellicoccus marimallium, BacCan dog Bacteroides, CowM2 bovine Bacteroides, CGOF1 Canadian goose Bacteroides, and a non-specific E. coli general fecal marker.      In these studies, low probe target levels were found in the majority of Dumont Lake samples. However, given that the sampling events we examined displayed correspondingly low detectable E. coli counts, this was not surprising. Almost all of the samples tested had the dog (BacCan) target. These samples were found to have a concentration of between 32 and 3,500  gene copies/100mL of water. About half of the samples were found to have hits of the human (HF183 target), with concentrations ranging from 31 to 700 gene copies/100mL of water. And one sample, taken from an unnamed stream inlet, had a very large number of Canadian goose (CGOF1) hits at  a concentration of around 6,100 gene copies/100mL of water.  To give context for the dPCR results from Dumont Lake, we tested archived watershed samples from Allegan and Ottawa counties that were known to carry high E. coli counts. These samples showed high dPCR MST levels (mostly dog and human in origin). These results suggest that the GT MST primer/probe set in combination with the QIAcuity dPCR instrument provides a cost- and time-efficient MST workflow and that the primary source of fecal contamination in Dumont Lake is associated with dogs.

15

Determining the Impact of Holding Times on Microbial Source Tracking Results

The standard method for beach water samples that are to be run on MST indicates that samples should be filtered within 6 hours of collection (EPA 821-R-19-002). We hypothesize that increasing the time between sample collection and filtration will lead to more DNA degradation, and a measurable decline in gene copy numbers for each MST marker. We will homogenize and divide beach water samples to create subsamples of the same concentration. We will then reproduce the scenario of samples being held for each respective amount of time by filtering each subsample at 8 hours, 36 hours, and 72 hours after collection. Then, we can extract and test each filter on common source tracking targets (such as HF183 and gull4) to determine the relative levels of DNA in each . By comparing the results from different filtration times, we can get an idea of how soon after collection degradation begins . By conducting this experiment, we hope to create a more efficient workflow. If longer hold times show comparable positive results to shorter hold times, we could potentially keep samples for an extended amount of time before filtering. This would decrease the pressure for quick sample processing by increasing the window for filtration after sample collection.

Evaluation of Bactiquick Sensitivity to Multiple Bacterial Species and potential interfering chemicals

Background: Endotoxins are lipopolysaccharide components of the outer membrane of gram-negative bacteria that can be released into aquatic environments. Rapid and reliable detection of endotoxin can provide valuable information for assessing microbial contamination and water quality in recreational waters. Bactiquick is a rapid endotoxin detection platform recently introduced for water monitoring, based on the well-known Limulus amebocyte lysate (LAL)-based endotoxin assay method. This study evaluated the analytical specificity and breadth of endotoxin detection. Methods: Bactiquick performance was evaluated using three experimental approaches. First, the ability of Bactiquick to detect endotoxin from gram-negative bacterial species was evaluated using various dilutions of cultures of Escherichia coli, Escherichia marmotae, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Second, potential cross reactivity or interference by various chemicals was tested, including β-glucans (a known source of interference in some LAL-based assays), β-glucan blockers (Glucashield and Pierce β-glucan blockers), NaCl, and several buffers (Tris, HEPES). Solutions were tested at various concentrations in two ways: 1) directly added to the LAL assay tube or 2) used in place of the dilution solution of the Bactiquick assay and compared to the standard assay, for both environmental samples and standardized E. coli cultures. Third, Bactiquick was compared with a commercially available lab-based LAL endotoxin assay (Qubit Endotoxin Detection Assay Kit) designed for the Qubit Flex platform. Environmental and endotoxin calibration assay reactions were incubated at 37 oC on a dry block, stopped with acetic acid, and fluorescence was read on the Qubit Flex. Results: Bactiquick successfully detected endotoxin associated with E. coli, E. marmotae, P. aeruginosa, and K. pneumoniae, demonstrating broad endotoxin detection across distinct bacterial sources. Freeze-dried E. coli cultures yield positive responses even several weeks after storage at 4oC.No detectable Bactiquick response was observed with β-glucan across the tested dilutions, indicating no β-glucan cross reactivity under the experimental conditions, nor did the addition of the Pierce beta glucan blocker significantly change the response to a Bactiquick-positive result; however, Glucashield reduced Bactiquick responses by half. In tests to determine the inhibitor in Glucashield, we found that NaCl did not interfere with the assay but Tris (the buffer in Glucashield) and HEPES at a range of concentrations and pH values inhibited the assay.  Compared to the Qubit Flex LAL-based endotoxin assay, Bactiquick produced more consistent and reliable results. Despite its higher cost per assay, the Bactiquick workflow was more rapid and straightforward to perform and, as shown elsewhere (Thurston et al poster), portable and robust to use. Conclusion: Bactiquick demonstrated analytical specificity for endotoxin, successfully detecting four species of gram-negative bacterial species, with no detectable interference from or sensitivity to β-glucans; however, addition of some chemicals, such as Tris and HEPES, can interfere with the assay. Its broad detection capability, rapid and simple workflow, and favorable performance relative to an alternative LAL-based assay support its potential utility as a practical tool for rapid endotoxin monitoring in recreational beach water.

 Sneha Ghosh, Wayne State University

From Funding to Impact: How Cross-Sector Partnerships Power Cleaner Beaches

Plastic pollution remains a persistent and highly visible challenge on beaches and shorelines across the Great Lakes, requiring scalable, collaborative solutions that bridge technology, community engagement, and sustainable funding. The Great Lakes Plastic Cleanup (GLPC) offers a first-of-its-kind, binational model that combines innovative litter capture technologies with robust data collection and cross-sector partnerships to address litter in the Great Lakes Region at its source. This session will highlight how corporate partnerships have played a critical role in advancing on-the-ground impact, featuring perspectives from the Council of the Great Lakes Region (CGLR) as the project administrator, Meijer as a lead corporate funding partner, and Grand Valley State University’s Annis Water Resources Institute (GVSU) as a key implementation partner. Together, presenters will share how this partnership model enables deployment of technologies such as beach-cleaning Bebots and water-skimming Pixie Drones, supports consistent data collection and waste characterization, and expands reach and drives deeper community engagement. Attendees will gain insight into how corporate investment not only accelerates environmental outcomes, but also strengthens local capacity, supports education and outreach, and builds long-term project sustainability. The session will include real-world examples from beach sites in Michigan and the greater Great Lakes region, demonstrating how coordinated efforts between funders, nonprofit conveners, and local operators can scale impact while maintaining data integrity and community relevance. By showcasing lessons learned from GLPC’s multi-year implementation, this presentation will provide a replicable framework for leveraging corporate partnerships to advance litter mitigation strategies, enhance public engagement, and deliver measurable improvements to the health of the Great Lakes.

Implementing the Great Lakes Microbial Water Quality Assessment    

The International Joint Commission (IJC) is responsible for regular reporting on the status of the Great Lakes and other boundary waters and for investigating the risk to ecosystems and human health that may result from current or future stressors. In 1913, the IJC conducted a detailed microbial water quality study (over 19,000 samples) of the fecal-related pollution of the boundary waters of the Great Lakes, and the potential link between disease and sewage pollution (IJC 1918). Today, over 100 years later, despite the advances in drinking water treatment technology and source water control measures, microbial water quality concerns remain and range from beach closures, waterborne pathogen outbreaks in recreational waters, harmful algal blooms, impairment of water for domestic use, boil water advisories, taste and odor issues and the spread of antimicrobial resistance. New challenges, emerging contaminants and climate change are also threatening the Great Lakes water quality and health. A recent IJC Health Professionals Advisory Board (HPAB) study concluded that advanced molecular and genomic tools (e.g. PCR techniques and metagenomics) are sufficiently developed and are available for improving water quality assessment throughout the Great Lakes. However, a concerted effort is needed to build out a system of monitoring, data management, data interpretation, and sharing of data and analyses, to comprehensively define source water quality, degradation, impacts and restoration goals for a sustainable future.    The HPAB’s Great Lakes Microbial Water Quality Assessment (GL-MWQA) study is building out plans to implement molecular methods in long-term water quality monitoring programs in the Great Lakes.  The GL-MWQA study is focused on planning a large-scale basin-wide study to develop monitoring strategies identified by the IJC’s Large Basin Microbial Water Quality Study project. These molecular and genomics tools can be used to modernize and strategically plan for advancing microbial water quality assessment in three areas: 1) microbial source tracking (MST); 2) harmful algal blooms (HABs); and 3) ecosystem/human health assessment (metagenomics/pathogen detection). Study outcomes include:  1) Establishing a Great Lakes Community of Practice (CoP) for harmonizing the use of molecular tools and selecting appropriate microbial targets for study in microbiology labs across the basin;  2)   Developing an inter-Lab Round-Robin plan to validate molecular methods for use binationally across the Great Lakes for MST (potentially including pathogens of interest), HABs detection, and metagenomics characterization of water samples;  3) Developing a pilot study plan that engages stakeholders and includes coordination of field work and lab analyses and mapping of microbial water quality and health risks, and addresses data management; and,  4) Developing a plan for eventual multi-year rollout of the GL-MWQA across the basin. The IJC HPAB bi-national project team has been advancing the GL-MWQA study design for the last two years, working with technical experts and a contractor team. The poster will present the historical context for the GL-MWQA, and summarize the accomplishments of the study planning effort, including the development of a CoP, the laboratory round robin study design, and the pilot study components.

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Investigating the Impacts of Harmful Algal Blooms (HABs) on Lake Superior Tourism

The presence of harmful algal blooms (HABs) in Lake Superior has become more common since they were first detected in 2012. This study aims to understand how the presence of algal blooms, both harmful and not, are impacting tourism and outdoor recreation in the region. This study is specifically focused on answering four research questions: (1) How are Lake Superior coastal counties thinking about HABs from a tourism/outdoor recreation perspective? (2) How are HABs impacting Lake Superior tourism? (3) How are county/tourism staff communicating about algal blooms with beach/waterway users? (4) What additional resources are needed to help tourism & beach managers communicate about HABs?  Currently, there is little research focused on understanding how algal blooms are impacting Lake Superior tourism and outdoor recreation given that they are a relatively new phenomenon. Most existing research is focused on monitoring the occurrence of algal blooms and trying to identify why they are occurring. This poster presentation will share findings from a series of semi-structured interviews with public health and tourism professionals who work in Lake Superior coastal areas. Interviews are currently ongoing as of April 2026 with a goal for completion in the summer of 2026, so details are limited at this point. Preliminary findings from the interviews will be shared in this poster at the National Beach Summit.

Michigan microplastics policy to protect the Great Lakes and Human Health

Microplastics are increasingly detected in human tissues, including placenta and breast milk, raising significant concerns about exposure pathways and impacts on children and families. Michigan, home to the Great Lakes, the world’s largest source of surface freshwater, relies on this ecosystem as a primary source of drinking water, making the state an important focal point for microplastics research and prevention. A package of proposed legislation in Michigan addresses microplastics through two strategies: (1) Prevention, by expanding the federal ban on microbeads to further reduce preventable sources of pollution, and (2) Research, by directing systematic studies on the prevalence of microplastics in drinking water systems and the Great Lakes. This approach links immediate protective measures with evidence generation to inform future policy. The public health emphasis is clear: reducing inputs of microplastics into freshwater ecosystems while assessing existing contamination provides a foundation for protecting vulnerable populations, particularly children. By integrating prevention with research, Michigan’s legislative model demonstrates how state-level policy can complement federal action, generate critical data, and translate emerging science into population-level protections.

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Micro- and Nanoplastics in the Water Cycle: Impacts on Beaches and Health

Since the mid-20th century, global plastic production has surpassed 9 billion metric tons cumulatively, with annual output now exceeding 400 million tons. Approximately 9% has been recycled; the remainder accumulates in the environment, fragmenting continuously into micro- and nanoplastics (MNPs) — particles smaller than 5 millimeters and 1 micrometer, respectively. Once at this scale, MNPs integrate into the hydrological cycle, moving through ocean waters, river systems, atmospheric moisture, precipitation, and cloud formation. This presentation examines how four intrinsic properties of MNPs — persistence, size, chemical composition, and electrostatic charge — govern their behavior and distribution across aquatic and atmospheric systems, and proposes targeted strategies to address their growing influence on the water cycle and climate, with systematic relevance to the Great Lakes basin.

Testing the Waters Faster: A Comprehensive Evaluation of Bactiquick for Beach Monitoring 

Beach monitoring for biological risk is critical for protecting public health and ensuring resident safety during the summer months. Historically, the Milwaukee Health Department Laboratory (MHDL) relied on culture based Escherichia coli methods to generate results and guide beach action decisions. Although accurate in quantifying viable E. coli, these methods delayed our ability to respond to the current beach conditions by a full day – often leading to recreation in hazardous conditions. In recent years, MHDL has transitioned to molecular methods, specifically qPCR and dPCR, in conjunction with EPA standards for same day reporting of beach samplings. This shift has allowed us to make decisions based on the condition of the beach on the day of testing. Beginning in the summer of 2026, MHDL will further advance its testing approach by implementing a validated digital PCR method for beach monitoring. This change will enable not only sensitive detection of E. coli for determining beach action values, but also microbial source tracking to better identify trends in common sources of fecal contamination and to support the potential development of an action plan using these targets.  While enhanced molecular testing will improve contamination source tracking, alternative technologies may further reduce beach action response times. One promising tool is the new Bactiquick real time water testing device, which provides rapid, in field analysis of water samples. Producing results in 15 minutes, the device quantifies an approximate concentration of Gram-negative bacteria through endotoxin signal. Although Bactiquick is not currently an EPA-approved replacement for culture or molecular testing for E. coli due to its inability to differentiate E. coli endotoxin signal, it shows strong potential as a rapid preliminary screening tool or as a quick retesting method to support timely beach reopenings. Due to the potential for off-target high values, we anticipate its primary utility for MHDL will be rapid reopening of closed beaches. Throughout the summer of 2026, MHDL will conduct a comprehensive comparison of traditional culture-based and molecular methods against Bactiquick field results to evaluate its suitability for future beach seasons. Our poster will comprise of a statistical analysis of endotoxin risk units (the output of Bactiquick) and MPN/ 100 mL values generated by both Colilert-18 and our dPCR conversion calculation.

Trash Removal Technologies Education and Research Program for the Great Lakes

Started in 2022, with funding support from Meijer Incorporated and The Council of the Great Lakes Region, Ohio Sea Grant received two trash removal devices. One focused on removing trash from beaches and the other targeted to skim the water’s surface to remove trash. With the equipment being newer technology, project partners developed data collection methods, best management practices for equipment operations, transport, and maintenance as well as developed education and outreach initiatives for the highly visible equipment. In this presentation we will discuss the effectiveness and feasibility of using remote-controlled robotics technology to remove trash from beaches and waterways. To better support Ohio Sea Grant’s efforts in this project, the Beach and On-water Trash Trapping Tech Team for Lake Erie (BOTtttle) was developed. A partnership between Ohio Sea Grant and Cuyahoga Community College’s Youth Technology Academy (YTA), the program, supported with funding from the National Oceanic and Atmospheric Administration Climate-Ready Coasts Program, Bipartisan Infrastructure Law, works with underserved and underrepresented high school students in the Cleveland area to offer educational programming and workforce development opportunities in the STEM disciplines. We are working together to engage Cleveland youth in Lake Erie stewardship activities, introduce them to the water quality issue of marine debris in their local community, and utilize their expertise with robotics to effectively operate and manage trash removal technologies. Students receive relevant job training and field experience in the rapidly growing blue/water economy and marine debris removal technologies sector. In addition to robotics care, operation, and maintenance, students support waste characterization efforts to learn more about data collection, monitoring, and management protocols. Interactive programming engages youth with their coastal environment empowering them to care for their coastal areas and drinking water sources.

Use Case for BactiQuick: Detection of Agricultural Impacts on Watershed Water Quality  

Background: Agricultural livestock operations can contribute to microbial contamination in surface waters that ultimately affect downstream recreational beaches. Rapid detection methods have the potential to provide earlier indications of poor water quality than conventional laboratory approaches, supporting more timely public health decisions. Building upon ongoing beach monitoring efforts in Wayne County, Michigan, this project evaluates microbial water quality in tributaries located upstream and downstream of agricultural livestock operations within watersheds that discharge into recreational waters.  

Objectives: Determine whether rapid endotoxin screening can detect microbial contamination gradients associated with agricultural land use and prioritize locations for subsequent microbial source tracking and sequencing analyses.  

Methods: During Summer 2026, water samples were collected upstream and downstream from multiple agricultural sites in the Rouge River Watershed. Three sites within the Huron Watershed were also sampled for comparison. Water samples were analyzed using BactiQuick as a rapid screening tool for bacterial endotoxin contamination. To analyze samples in the linear range of BactiQuick measurements (ERU = 0 – 120; see poster by Thurston et al.), samples were tested at one-fifth full strength. Samples were also enumerated for Escherichia coli using Colilert and Petrifilm methods.  

Results/Conclusions: There is substantial spatial variability in microbial contamination. Two downstream locations exhibited higher bacterial indicators than paired upstream sites. BactiQuick measurements generally reflect patterns observed with lab-based methods, suggesting its potential utility as a rapid screening approach for identifying contamination hotspots.  

Future Direction: Future work will incorporate microbial source tracking and next-generation sequencing to identify contamination sources, characterize bacterial communities, and evaluate antimicrobial resistance markers. These efforts will provide a more comprehensive understanding of agricultural influences on watershed health and support risk-based decision making for recreational water management. 

Wastewater Persistence and Partitioning of Mycobacterium tuberculosis, Neisseria meningitidis, and Bordetella pertussis

Globally, cases of bacterial respiratory pathogens caused by Mycobacterium tuberculosis, Bordetella pertussis, and Neisseria meningitidis have surged since the COVID-19 pandemic. Wastewater monitoring has emerged as a powerful tool to track trends and identify hotspots of infectious diseases, yet has rarely been applied to bacterial respiratory pathogens, and we have limited understanding of how these bacterial pathogens partition between solid and liquids phases or persist in wastewater. In this study, we investigated the persistence and partitioning of M. tuberculosis, N. meningitidis, and B. pertussis in wastewater sludge across 5 days at multiple temperatures: 4°C, 22°C, and 35°C. The three bacteria were cultured for 18h to 3 weeks until reaching log-phase growth, then harvested and combined into a live bacterial cocktail targeting 10^4 gc/µL for each organism. Bacterial growth and concentrations were estimated by optical density measurements and ddPCR, respectively. We also designed a novel assay for B. pertussis detection and report the performance of the assays for all three organisms in multiplex. Actinobacillus pleuropneumoniae was cultured in lab as a bacterial process control. Bacterial cocktail was spiked into thirty-six 50 mL tubes each containing 12 mL sludge, with same numbers of tubes incubated at 4, 22, and 35°C, including six spiked samples and six non-spiked controls. From days 0-5, one spiked and one control sample were processed daily for each temperature.   Frist, for all three assays targeting M. tuberculosis, N. meningitidis, and B. pertussis, in vivo testing revealed no cross-reactivity among twelve clinically relevant bacterial targets. Second, all three bacteria were predominantly detected in the solids phase, with limited detections in liquids. Across all 6 days, we detected M. tuberculosis in 18/18 solids and 10/18 liquids samples, B. pertussis in 18/18 solids and 4/18 liquids samples, and N. meningitidis in 11/18 solids and 1/18 liquids samples. The frequency of liquids detection across all organisms did not vary by temperature (Kruskal-Wallis test, n=54, p = 0.34). Third, persistence varied by temperature and the greatest reductions occurred during storage at 4°C. The time until a one-log reduction in concentration, T90, at 4°C ranged from 3.3 days for N. meningitidis and 8.5 days for M. tuberculosis to 34 days for B. pertussis. No significant decay was observed at 35°C for all three organisms. Additionally, the raw sludge sample used for the experiment was negative for M. tuberculosis and N. meningitidis but did contain B. pertussis at a concentration of 7,500 gc/dry g (67% confidence interval: 5,000 - 11,000 gc/dry g), indicating the presence of its DNA in raw samples.  Our results suggest that future studies measuring these pathogens in wastewater process centrifuged solids from wastewater sludge for higher detectability, and that samples stored at 4°C be processed as quickly as possible to prevent bacterial degradation. This work fills a vital gap in the literature around bacterial pathogen behavior in wastewater at a time when wastewater monitoring is expanding from virus monitoring to bacterial pathogens, and will enable federal, state, and private laboratories to select appropriate methodologies for bacterial wastewater monitoring.

Watershed Rehabilitation Alters Environmental Controls of E. coli at a Recreational Beach

Environmental variables are widely used to predict microbial water quality, but major watershed alterations may change which variables are most useful predictors over time. Long-term E. coli density monitoring data from Maumee Bay State Park Beach (Oregon, Ohio; 2008–2022) were evaluated to determine the extent to which local watershed rehabilitation (renovation of an adjacent drainage ditch/wetland complex) influenced the ability of multiple environmental variables to predict recreational water quality. Environmental predictors evaluated included meteorological, hydrologic, lake, river, and water quality variables. Breakpoint analysis assessed whether temporal shifts in the relationship between turbidity and E. coli coincided with the construction of Berger ditch. Cross-validated LASSO regression with year-block bootstrapping identified predictors that were consistently selected with nonzero coefficients across bootstrap models while accounting for interannual variability. Mixed-effects models evaluated the strength and direction of the relationships.  Breakpoint analysis identified the period between 2015 and 2016 as the most likely breakpoint, coinciding with the construction of Berger ditch rehabilitation. Mean E. coli increased from approximately 200 to 320 CFU/100 mL after rehabilitation, and exceedance frequency increased from 19.8% to 37.2% despite a substantial decline in turbidity and E. coli discharged from Berger ditch. Prior to rehabilitation, turbidity was among the strongest and most consistent predictors of E. coli density, being selected in 95% of all year-block bootstrap models, while following rehabilitation, the predictive potential of turbidity weakened significantly and only appeared in 4.6% of models. Conversely, rainfall, lake level, Maumee River discharge, total Kjeldahl nitrogen, and antecedent total phosphorus were selected more frequently as predictors following rehabilitation, suggesting a shift from sediment-associated controls toward controls driven by hydrologic, riverine, and nearshore processes. Monte Carlo simulations based on post-rehabilitation relationships combining 2°C in observed water temperatures with more frequent heavy rain fall and extreme river flows could increase predicted mean E. coli densities by 10–15%. Overall, data analysis suggested that watershed rehabilitation altered environmental processes that control E. coli densities in recreational waters, most notably turbidity, which lost predictive power. The findings highlight the need to reassess beach-water-quality relationships following major changes to watershed hydrology and sediment transport.