Determining the primary sources of fecal pollution using microbial source tracking assays combined with land-use information in the Edwards Aquifer

Hinojosa, Jessica; Green, Jemima; Estrada, Fabiola; Herrera, Jonathan J.; Mata, Troy; Phan, Duc; Pasha, Akbar; Matta, Akanksha; Johnson, Drew; Kapoor, Vikram

doi:10.1016/j.watres.2020.116211

Cited by 27 publications

(29 citation statements)

References 54 publications

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“…This technique uses polymerase chain reaction (PCR) technology to target and amplify DNA sequences indicative of host-specific bacterial groups, typically in the genus Bacteroides , that are found in the intestines of particular species of endothermic vertebrates and shed in feces (Reischer et al, 2013). Understanding the source of fecal contamination contributes substantially to making informed decisions on best management practices (BMPs) to reduce levels of contamination (Hinojosa et al, 2020; Shrestha et al, 2020; Steele et al, 2018). This technology has been implemented in modeling techniques for environmental risk assessment such as Quantitative Microbial Risk Assessment (QMRA) and Soil & Water Assessment Tool (SWAT) to assess the concentration at which MST markers indicate a risk to public health (Boehm et al, 2018; Frey et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Using Watershed Characteristics for Improving Fecal Source Identification

Hart¹,

Jamison

McNair³

et al. 2022

Preprint

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Fecal pollution is one of the most prevalent forms of pollution affecting waterbodies across the United States, threatening public health and negatively impacting aquatic environments. Microbial source tracking (MST) applies polymerase chain reaction (PCR) technology to help identify the source of fecal pollution. In this study, we combine spatial data for two watersheds with general and host-specific MST markers to target human, bovine, and general ruminant sources. Two different PCR technologies were applied for quantifying the targets: quantitative PCR (qPCR) and droplet digital PCR (ddPCR). We found that ddPCR had a higher detection rate (75%) of quantifiable samples compared to qPCR (27%), indicating that ddPCR is more sensitive than qPCR. The three host-specific markers were detected at all sites (n=25) , suggesting that humans, cows, and ruminants are contributing to fecal contamination in these watersheds. MST results, combined with watershed characteristics, suggest that streams draining low-infiltration soil groups, high septic system prevalence, and high agricultural land use are at an increased risk for fecal contamination. Microbial source tracking has been applied in numerous studies to aid in identifying the source of fecal contamination, however these studies lacked information on the involvement of watershed characteristics. This study combined MST results, applying more sensitive PCR techniques, in addition to watershed characteristics to provide more comprehensive insight into the factors that influence fecal contamination in order to implement the most effective best management practices.

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Section: Introductionmentioning

confidence: 99%

Using Watershed Characteristics for Improving Fecal Source Identification

Hart¹,

Jamison

McNair³

et al. 2022

Preprint

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“…The karstic Edwards Aquifer of Central Texas (USA) supplies water for more than 2 million people [1] and is recognized for high stygobiont biodiversity [2]. The 10,500 km 2 Edwards Aquifer occurs in a broad arc of Cretaceous limestones that stretch approximately 400 km across Central Texas, USA, and is hydrologically connected to the 91,744 km 2 Edwards-Trinity Aquifer (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Stygobiont Diversity in the San Marcos Artesian Well and Edwards Aquifer Groundwater Ecosystem, Texas, USA

et al. 2021

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The Edwards Aquifer and related Edwards-Trinity Aquifer of Central Texas, USA, is a global hotspot of stygobiont biodiversity. We summarize 125 years of biological investigation at the San Marcos Artesian Well (SMAW), the best studied and most biodiverse groundwater site (55 stygobiont taxa: 39 described and 16 undescribed) within the Edwards Aquifer Groundwater Ecosystem. Cluster analysis and redundancy analysis (RDA) incorporating temporally derived, distance-based Moran’s Eigenvector Mapping (dbMem) illustrate temporal dynamics in community composition in 85 high-frequency samples from the SMAW. Although hydraulic variability related to precipitation and discharge partially explained changes in community composition at the SMAW, a large amount of temporal autocorrelation between samples remains unexplained. We summarize potential mechanisms by which hydraulic changes can affect community structure in deep, phreatic karst aquifers. We also compile information on 12 other Edwards and Edwards-Trinity Aquifer sites with 10 or more documented stygobionts and used distance-based RDA to assess the relative influences of distance and site type on three measures of β-diversity. Distance between sites was the most important predictor of total dissimilarity and replacement, although site type was also important. Species richness difference was not predicted by either distance or site type.

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“…The effluent of wastewater treatment plants is an important route by which ARGs may enter the aquatic environment (Rizzo et al, 2013;Marti et al, 2014b;Rodriguez-Mozaz et al, 2015;Lekunberri et al, 2017;Zhou et al, 2020;Nguyen et al, 2021). Sewerage misconnections and leaking septic tanks may be a source of untreated sewage entering rivers and other waterbodies (Kay et al, 2008;Hinojosa et al, 2020;Reynolds et al, 2021). Furthermore, agricultural land run-off may also negatively impact water quality and introduce ARGs into waterbodies (Unc and Goss, 2004;Ballesté et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Bacterial and Bacteriophage Antibiotic Resistance in Marine Bathing Waters in Relation to Rivers and Urban Streams

et al. 2021

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Fecal pollution of surface water may introduce bacteria and bacteriophages harboring antibiotic resistance genes (ARGs) into the aquatic environment. Watercourses discharging into the marine environment, especially close to designated bathing waters, may expose recreational users to fecal pollution and therefore may increase the likelihood that they will be exposed to ARGs. This study compares the bacterial and bacteriophage ARG profiles of two rivers (River Tolka and Liffey) and two small urban streams (Elm Park and Trimleston Streams) that discharge close to two marine bathing waters in Dublin Bay. Despite the potential differences in pollution pressures experienced by these waterways, microbial source tracking analysis showed that the main source of pollution in both rivers and streams in the urban environment is human contamination. All ARGs included in this study, blaTEM, blaSHV, qnrS, and sul1, were present in all four waterways in both the bacterial and bacteriophage fractions, displaying a similar ARG profile. We show that nearshore marine bathing waters are strongly influenced by urban rivers and streams discharging into these, since they shared a similar ARG profile. In comparison to rivers and streams, the levels of bacterial ARGs were significantly reduced in the marine environment. In contrast, the bacteriophage ARG levels in freshwater and the marine were not significantly different. Nearshore marine bathing waters could therefore be a potential reservoir of bacteriophages carrying ARGs. In addition to being considered potential additional fecal indicators organism, bacteriophages may also be viewed as indicators of the spread of antimicrobial resistance.

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Determining the primary sources of fecal pollution using microbial source tracking assays combined with land-use information in the Edwards Aquifer

Cited by 27 publications

References 54 publications

Using Watershed Characteristics for Improving Fecal Source Identification

Using Watershed Characteristics for Improving Fecal Source Identification

Stygobiont Diversity in the San Marcos Artesian Well and Edwards Aquifer Groundwater Ecosystem, Texas, USA

Bacterial and Bacteriophage Antibiotic Resistance in Marine Bathing Waters in Relation to Rivers and Urban Streams

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