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Improving our understanding of groundwater quality threats to human health and the environment is essential to protect and manage groundwater resources effectively. This essay highlights some global groundwater quality challenges, describes key contaminant groups and threats of emerging concern, including antimicrobial resistance, and discusses novel approaches to assessing groundwater quality. Groundwater quality monitoring needs to improve significantly in order to effectively identify and mitigate threats to groundwater from historical, current and future pollution.

Latest IPCC projections (2022) suggest significantly increased future incidence of infectious disease due to global warming and shifting climate patterns. Due to increasing global mean temperatures and extreme weather event frequency, assessing the potential impacts of climate change on infectious disease represents a critical challenge for public health authorities. This is particularly significant for environmentally-acquired infections which are directly or indirectly driven by local weather conditions. The current study sought to explore the relationship between antecedent weather and three gastrointestinal infections in the Republic of Ireland, namely cryptosporidiosis, Verotoxigenic E. Coli (VTEC) and campylobacteriosis.Irreversibly anonymised cases of infection were acquired from the national Computerised Infectious Disease Reporting (CIDR) database. Overall, 4,509 cases of cryptosporidiosis (2007 - 2017), 2,755 cases of VTEC enteritis (2013 - 2017) and 20,274 cases of campylobacteriosis (2011 - 2018) were employed. Individual cases were geographically linked to a Census Small Area (SA).Weekly seasonal adjustment of developed time series (trend & residuals of seasonally decomposed time-series) were undertaken for both climate and infection variables (incidence rate per 100k population). Climate variables were lagged from 1 to 20 weeks to account for likely delayed associations. A series of Spearman’s correlation matrices were subsequently developed. Infections hotspots were identified and used to construct space-time cluster frequency maps (Boudou et al., 2021, Cleary et al. 2021), with Monte-Carlo simulations used to simulate the effects of weekly mean temperature and rainfall changes on space-time cluster frequency. Analyses were delineated (restricted) based on season and settlement type (i.e., rural, urban, commuter areas).Spearman’s correlation matrices confirmed the presence of ranked associations between rainfall, temperature and all three infections. Weekly VTEC and campylobacteriosis incidence were positively associated with the non-lagged mean temperature (Rho >0.6). Maximum positive associations were obtained between non-lagged rainfall (mm) for VTEC (Rho=0.68) and campylobacteriosis (Rho= 0.6), while a delayed positive association was found for cryptosporidiosis with a maximum Rho of 0.21 (Week 19). Findings from Monte-Carlo simulation provided strong insights on the direct impacts of temperature and rainfall changes on infection cluster frequency. An increase of 1oC in weekly temperature was simulated to result in an 25% increase in the number of Small Areas reporting a space-time cluster of campylobacteriosis. Similarly, a 5mm increase in weekly rainfall was shown to increase the number of rural SAs reporting a space-time cluster of cryptosporidiosis by ≈4%.Study findings leave little doubt as to the significance of climate patterns for all three infections, with all shown to increase (incidence rates and/or cluster occurrence) in concurrence with increasing temperatures and rainfall volumes. Accordingly, there is a pressing need for development of adapted health strategies within the context of predicted climate change (i.e., increased testing/surveillance and treatment capacity, improved risk communication during extreme weather events,…). This result points out the need to promote multidisciplinary researches by including meteorologists, hydrologists and engineer in public health planning strategies.

While developed nations are assumed to provide high groundwater quality security, populations reliant on (typically rural, unregulated) private domestic groundwater wells are often uniquely vulnerable to supply contamination. The potential health ramifications of exposure to contaminated groundwater may be especially grave for immunosuppressed populations residing in service-deprived and climate-vulnerable areas, necessitating concerted government (educational) and household-level (behavioural) action. In response, a growing number of studies (spanning quantitative contamination risk assessments, policy strategies, communicative interventions and householder surveys) have emerged within the last several decades. To date, few investigations have sought to synthesise this literature and ascertain the potential generality of drivers of both private groundwater contamination and preventive responses in high-income countries. The developed regions of the Republic of Ireland (ROI) and Ontario represent an appropriate point of comparison to establish research transferability. Both regions are characterised by high private groundwater reliance (> 10% of their respective populations), pervasive microbial groundwater contamination and significant associations between acute gastrointestinal illness (AGI) and private well use. Consumption of private well water contributes to approximately 4,800 annual cases of AGI in Ontario and as many as 80% of annual cases of verotoxigenic E.coli (VTEC) in the ROI. However, despite similarities, regional discrepancies exist with respect to policy landscapes (e.g., monetary requirements for private water quality testing) and contamination risk profiles (e.g., frequency of extreme weather event concurrence). In efforts to elucidate the potential implications of these phenomena, a scoping review of literature (1990-2022) in the ROI and Ontario outlining risk management measures to prevent private groundwater contamination in the was undertaken. The SPICE (Setting, Population/Phenomenon, Intervention, Setting, Perspective) methodology was utilised to inform literature search terms, with Scopus and Web of Science selected as primary databases for article searches. Following removal of duplicate studies and article screening, 92 articles (Canada = 70, ROI = 22) were retained for analysis. Articles were predominantly comprised of quantitative contamination risk assessment studies (n = 68), with qualitative and quantitative questionnaire investigations (n = 16), interventions (n = 2) and policy studies (n = 6) noticeably less frequent. Quantitative risk assessments published after the year 2000 demonstrated an overwhelming focus on microbial supply contamination, identifying well type and proximity of agricultural activity as significant determinants of supply contamination. Survey studies in both regions also consistently highlighted gender, perceived confidence in maintaining supply and economic and convenience barriers as significant determinants of well user knowledge and behaviour. However, well users in Ontario demonstrated markedly higher rates of prior well testing (irrespective of adherence to regional guidelines), suggesting that incentivised (or free) well testing may lead to significant increases in uptake of well water quality testing. The paucity of identified intervention studies suggests that increased research investigating methods of well user outreach and groundwater risk communication will be necessary in the future to determine the broad efficacy of risk communication in developed nations.

Antimicrobial-resistant Escherichia coli isolates have emerged in various ecologic compartments and evolved to spread globally. We sought to (1.) investigate the occurrence of ESBL-producing E. coli (ESBL-Ec) in feces from free-range chickens in a rural region and (2.) characterize the genetic background of antimicrobial resistance and the genetic relatedness of collected isolates. Ninety-five feces swabs from free-range chickens associated with two households (House 1/House 2) in a rural region in northern Tunisia were collected. Samples were screened to recover ESBL-Ec, and collected isolates were characterized for phenotype/genotype of antimicrobial resistance, integrons, and molecular typing (pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST)). Overall, 47 ESBL-Ec were identified, with the following genes detected: 35 blaCTX-M-1, 5 blaCTX-M-55, 5 blaCTX-M-15, 1 blaSHV-2, and 1 blaSHV-12. Resistance to fluoroquinolones, tetracycline, sulfonamides, and colistin was encoded by aac(6′)-Ib-cr (n = 21), qnrB (n = 1), and qnrS (n = 2); tetA (n = 17)/tetB (n = 26); sul1 (n = 29)/sul2 (n = 18); and mcr-2 (n = 2) genes, respectively. PFGE and MLST identified genetic homogeneity of isolates in House 1; however, isolates from House 2 were heterogeneous. Notably, among nine identified sequence types, ST58, ST69, ST224, and ST410 belong to pandemic high-risk clonal lineages associated with extrapathogenic E. coli. Minor clones belonging to ST410 and ST471 were shared by chickens from both households. The virulence genes fyuA, fimH, papGIII, and iutA were detected in 35, 47, 17, and 23 isolates, respectively. Findings indicate a high occurrence of ESBL-Ec in free-range chickens and highlight the occurrence of pandemic zoonotic clones.

This systematic literature review aimed to provide an overview of the characteristics and methods used in studies applying the Disability-Adjusted Life Years (DALY) concept for infectious diseases within European Union (EU)/European Economic Area (EEA)/European Free Trade Association (EFTA) countries and the United Kingdom. Electronic databases and grey literature were searched for articles reporting the assessment of DALY and its components. We considered studies in which researchers performed DALY calculations using primary epidemiological data input sources. We screened 3,053 studies of which 2,948 were excluded and 105 studies met our inclusion criteria. Of these studies, 22 were multi-country and 83 were single-country studies, of which 46 were from the Netherlands. Food- and water-borne diseases were the most frequently studied infectious diseases. Between 2015 and 2022, the number of burden of infectious disease studies was 1.6 times higher compared to that published between 2000 and 2014. Almost all studies (97%) estimated DALYs based on the incidence- and pathogen-based approach and without social weighting functions; however, there was less methodological consensus with regards to the disability weights and life tables that were applied. The number of burden of infectious disease studies undertaken across Europe has increased over time. Development and use of guidelines will promote performing burden of infectious disease studies and facilitate comparability of the results., peer-reviewed

Milk and beef derived from pasture-based systems have been characterized by higher nutritional values and a lower environmental footprint than their equivalents obtained via indoor systems. However, intensification of pasture-based production can have adverse impacts on biodiversity and the environment. To date, studies on pro-environmental diversification options leading to improvement of environmental performance of pasture-based dairy and beef production have rarely been synthesized. The present study sought to review current on-farm pro-environmental measures with the potential for enhancing biodiversity status and/or reducing the environmental impacts of pasture-based agriculture. Literature on farmer attitudes toward these measures was also reviewed to identify potential obstacles and opportunities for transitioning to pro-environmental agriculture. A systematic search of published research from high-income island countries characterized by oceanic temperate climate with a high dependence on pasture-based agriculture—the Republic of Ireland, the United Kingdom and New Zealand, was conducted. Thirty studies that assessed the impact of pro-environmental measures, eight ‘attitudinal’ studies of dairy and beef farmers and one study covering both aspects were identified. Inductive thematical analysis was subsequently undertaken. Environmentally sensitive management practices such as hedgerows and field margins management, mixed grazing (where two or more herbivorous animals graze the same land), rare livestock breeds, multispecies swards, organic farming and agroforestry were identified as primary themes studied under the auspices of pro-environmental diversification, while forestry, bioenergy crops and organic farming were the main themes identified within attitudinal research studies. Findings suggest that environmentally sensitive practices have varied effects on biodiversity. Mixed grazing was found to improve livestock production, while studies of organic farming reported multiple positive impacts on biodiversity and animal welfare. Effect of multispecies swards on methane emissions and urinary nitrogen extraction were found to be inconsistent. Attitudinal research suggests that the main barrier to implementing afforestation is its lack of attractiveness compared to ‘traditional’ farming and that organic farmer decisions regarding agricultural management practices might be less profit-oriented and influenced by ecological beliefs to a greater extent than decisions of conventional farmers. The results of this study confirm that pro-environmental diversification inherently encompasses multiple scientific disciplines; however, previous study designs and outcomes were found to be fragmented and narrowly focused. Considering the urgency and importance of climate and biodiversity crises, pro-environmental diversification of pasture-based dairy and beef production has rarely been holistically approached and remains understudied. The development of practical, sustainable solutions for farming based on circular economy and respect to nature and additional strategies to increase farmer and consumer environmental awareness should be prioritized by policymakers, advisory and scientific bodies.

The role of the natural environment in the dissemination of antimicrobial resistant bacteria has been increasingly recognised in the literature. However, knowledge surrounding the critical factors and mechanisms mediating their occurrence is still limited, particularly in relatively 'pristine' groundwater environments. In the Republic of Ireland (RoI), a country characterised by high groundwater reliance, household-based (unregulated) wells provide drinking water to 11% of the population. These private wells are generally located in rural areas, where the risk of microbiological contamination is high due to intensive agricultural practices and high reliance on domestic wastewater treatment systems; both of which are also potential sources of antimicrobials and antimicrobial resistant bacteria. Accordingly, the current research sought to elucidate current rates of antimicrobial resistant bacteria and the principal factors associated with their presence in private wells in the RoI. A total of 250 samples (from 132 wells nationwide) were assessed for the presence of faecal (Escherichia coli) and environmental (Pseudomonas aeruginosa) bacteria, with single isolates from each contaminated sample tested phenotypically against 18 and 9 antimicrobials, respectively. Findings show that while 16.7% of E. coli (n = 8/48) were categorically resistant to ≥1 antimicrobial, with a further 79.2% classified as intermediately resistant, no categorical resistance was found among P. aeruginosa isolates (n = 0/6), with just one intermediately resistant isolate detected. Multivariate regression modelling indicates significantly higher odds of resistant E. coli detection in concurrence with elevated cattle density (OR = 1.028, p = 0.032), aligning with findings of highest resistance rates to veterinary antimicrobials (e.g., streptomycin = 14.6%, tetracycline = 12.5%, and ampicillin = 12.5%). Multivariate model results also suggest overland flow culminating in direct wellhead ingress as a primary ingress mechanism for resistant E. coli. Study findings may inform groundwater source protection initiatives and antimicrobial resistance surveillance moving forward.

Over recent years, Ireland has reported the highest crude incidence rates of Shiga toxin-producing Escherichia coli (STEC) enteritis in Europe. Unregulated private groundwater sources have emerged as an important potential transmission route for STEC, with up to 750,000 Irish residents reliant on these sources for domestic waters. This study aimed to investigate the prevalence and serogroup profile of STEC contamination from domestic private wells in western Ireland. Fifty-two groundwater sources were analysed during two sampling campaigns in the autumn (September/October) of 2019 (n = 21) and 2021 (n = 31). Untreated groundwater samples (30 L) were collected and analysed using the "CapE" (capture, amplify, extract) method. Extracted DNA was tested using multiplex real-time PCR for Shiga toxin stx1 and/or stx2 and eae genes. STEC positive DNA samples were tested for clinically relevant serogroups by real-time PCR. Data relating to 27 potential groundwater contamination risk factors were geospatially linked to each well and assessed for association with E. coli, stx1 and/or stx2 and eae presence/absence. Overall, 20/52 wells (38.4 %) were positive for E. coli (median concentration 8.5 MPN/100 mL as assessed by Colilert-18 method). Stx1 and/or stx2 was detected in 10/52 (19.2 %) wells overall and 8/20 E. coli positive wells, equating to a STEC to "generic" E. coli detection ratio of 40 %. Six of these wells (30 %) were also positive for eae. One or more serogroup-specific gene targets were identified in all but one stx1 and/or stx2 positive sample, with O145 (n = 6), O157 (n = 5) and O103 (n = 4) most prevalent. STEC presence was significantly associated with decreasing well depth (U = -2.243; p = 0.024) and increasing 30-day mean antecedent rainfall (U = 2.126; p = 0.034). Serogroup O104 was associated with increased sheep density (U = 2.089; p = 0.044) and detection of stx1 and/or stx2 + eae with increased septic tank density (U = 2.246 p = 0.023). Findings indicate high detection rates of clinically relevant STEC in E. coli contaminated groundwater sources in Ireland.

Background Geocoding (the process of converting a text address into spatial data) quality may affect geospatial epidemiological study findings. No national standards for best geocoding practice exist in Ireland. Irish postcodes (Eircodes) are not routinely recorded for infectious disease notifications and > 35% of dwellings have non-unique addresses. This may result in incomplete geocoding and introduce systematic errors into studies. Aims This study aimed to develop a reliable and reproducible methodology to geocode cryptosporidiosis notifications to fine-resolution spatial units (Census 2016 Small Areas), to enhance data validity and completeness, thus improving geospatial epidemiological studies. Methods A protocol was devised to utilise geocoding tools developed by the Health Service Executive’s Health Intelligence Unit. Geocoding employed finite-string automated and manual matching, undertaken sequentially in three additive phases. The protocol was applied to a cryptosporidiosis notification dataset (2008–2017) from Ireland’s Computerised Infectious Disease Reporting System. Outputs were validated against devised criteria. Results Overall, 92.1% (4266/4633) of cases were successfully geocoded to one Small Area, and 95.5% (n = 4425) to larger spatial units. The proportion of records geocoded increased by 14% using the multiphase approach, with 5% of records re-assigned to a different spatial unit. Conclusions The developed multiphase protocol improved the completeness and validity of geocoding, thus increasing the power of subsequent studies. The authors recommend capturing Eircodes ideally using application programming interface for infectious disease or other health-related datasets, for more efficient and reliable geocoding. Where Eircodes are not recorded/available, for best geocoding practice, we recommend this (or a similar) quality driven protocol.

Understanding the water consumption patterns within a specific population informs development of increasingly accurate, spatially specific exposure and/or risk assessment of waterborne infection. The current study examined the consumption patterns of private well users in Ontario while considering potentially influential underlying sociodemographics, household characteristics, and experiential factors. A province-wide online survey was circulated between May and August 2018 (n = 1,162). Overall, 81.5% of respondents reported daily well water consumption (i.e., tap water). Results indicate a mean daily well water consumption rate of 1,132 mL/day (SD = 649 mL/day) among well water consumers. Gender was significantly associated with well water consumption, with higher consumption rates found among female respondents. The experience of acute gastrointestinal illness (AGI) symptoms or diagnosis in the past 12 months did not impact the volume of water consumed, suggesting that experiencing previous AGI does not decrease consumption volumes, and therefore exposure over time. Significantly higher rates of well water consumption were found among respondents who reported previous testing or ongoing water treatment. Approximately 45.5% of survey respondents who stated that they do not consume well water selected bottled water as their primary household drinking water supply. Bottled water consumption was also not associated with previous AGI experiences. Findings will inform future quantitative microbial risk assessments associated with private well water use by providing spatially and demographically specific estimates of well water consumption.

Antimicrobial resistance represents a global health problem, with infections due to pathogenic antimicrobial resistant bacteria (ARB) predicted to be the most frequent cause of human mortality by 2050. The phenomenon of antimicrobial resistance has spread to and across all ecological niches, and particularly in livestock used for food production with antimicrobials consumed in high volumes. Similarly, hospitals and other healthcare facilities are recognized as significant ‘hotspots’ of ARB and antimicrobial resistance genes (ARGs); however, over the past decade, new and previously overlooked ecological niches are emerging as hidden reservoirs of ARB/ARGs. Increasingly extensive and intensive industrial activities, degradation of natural environments, burgeoning food requirements, urbanization, and global climatic change have all dramatically affected the evolution and proliferation of ARB/ARGs, which now stand at extremely concerning ecological levels. While antimicrobial resistant bacteria and genes as they originate and emanate from livestock and human hosts have been extensively studied over the past 30 years, numerous ecological niches have received considerably less attention. In the current descriptive review, the authors have sought to highlight the importance of wildlife as sources/reservoirs, pathways and receptors of ARB/ARGs in the environment, thus paving the way for future primary research in these areas.

Available evidence indicates Extreme Weather Event (EWE) frequency has increased significantly in the last ⁓ 70 years along a 0.5°C global temperature rise. As such, a major concern arising from global warming projections are the potential impacts of increasingly frequent and intense EWEs on public health and societal well-being. The substantial toll of EWEs on socio-economic and physical health is well understood. Yet, due to a range of methodological impediments, the impact EWEs on psychological health and well-being remain less certain. Within this context, this literature review aimed to provide an “empirical” baseline of the psychological and well-being impacts of individuals exclusively exposed to EWEs. Given the wide range of psychological and well-being metrics available in the literature, the review was grounded on a ‘holistic’ approach with the all-encompassing concept of “psychological impairment” adopted. Here, impairment data, or morbidity, was pooled at the level of key Diagnostic and Statistical Manual of Mental Disorders (DSM) psychological “Domains”, including PTSD, Anxiety and Depression. Morbidity data was also pooled at a “composite” (any impairment) category encompassing all employed DSM-based domains. Further, reported risk factors (p < 0.05) and pooled odds ratios (pOR) were extracted and calculated from each pertinent study. Overall, 59 peer-reviewed investigations accounting for 61,443 EWE-exposed individuals comprised the review dataset. A “composite” post-exposure pooled-prevalence rate of 23% was estimated along with values of 24% for depression and ⁓ 17% for both PTSD and anxiety. Notably, estimated pOR (1.9) indicate a > 90% likelihood of a negative psychological outcome or impaired well-being among exposed individuals. Methodologically, a prevalent lack of integration of “control” criterion among reviewed investigations was identified. In this context, pooled data collated can be considered more akin to “prevalence” rates rather than a finite metric of “incidence” linking EWE exposure and outcomes. Collation of reported risk factors indicate more pronounced impacts among individuals with higher levels of EWE exposure (14.5%) and socio-demographic traits which are often associated with vulnerable population sub-groups, including female gender (10%), lower socio-economic status (5.5%), and a lower education level (5.2%). Regionally, Asia exhibited the highest impairment rates which is tentatively attributed to a combination of high EWE frequency and population density. The findings of this study provide a quantitative evidence base which can be used to inform public health intervention strategies focusing on exposed populations in the aftermath of EWEs.

Groundwater is a vital drinking water resource and its protection from microbiological contamination is paramount to safeguard public health. The Republic of Ireland (RoI) is characterised by the highest incidence of verocytotoxigenic Escherichia coli (VTEC) enteritis in the European Union (EU), linked to high reliance on unregulated groundwater sources (~16% of the population). Yet, the spatio-temporal factors influencing the frequency and magnitude of microbial contamination remain largely unknown, with past studies typically constrained to spatio-temporally 'limited' sampling campaigns. Accordingly, the current investigation sought to analyse an extensive spatially distributed time-series (2011-2020) of groundwater monitoring data in the RoI. The dataset, compiled by the Environmental Protection Agency (EPA), showed 'high' contamination rates, with 66.7% (88/132) of supplies testing positive for E. coli, and 29.5% (39/132) exceeding concentrations of 10MPN/100 ml (i.e. gross contamination) at least once during the 10-year monitoring period. Seasonal decomposition analyses indicate that E. coli detection rates peak during late autumn/early winter, coinciding with increases in annual rainfall, while gross contamination peaks in spring (May) and late-summer (August), likely reflecting seasonal shifts in agricultural practices. Mixed effects logistic regression modelling indicates that monitoring sources located in karst limestone are statistically associated with E. coli presence (OR = 2.76, p = 0.03) and gross contamination (OR = 2.54, p = 0.037) when compared to poorly productive aquifers (i.e., transmissivity below 10m

Understanding patient progression from symptomatic COVID-19 infection to a severe outcome represents an important tool for improved diagnoses, surveillance, and triage. A series of models have been developed and validated to elucidate hospitalization, admission to an intensive care unit (ICU) and mortality in patients from the Republic of Ireland. This retrospective cohort study of patients with laboratory-confirmed symptomatic COVID-19 infection included data extracted from national COVID-19 surveillance forms (i.e., age, gender, underlying health conditions, occupation) and geographically-referenced potential predictors (i.e., urban/rural classification, socio-economic profile). Generalised linear models and recursive partitioning and regression trees were used to elucidate COVID-19 progression. The incidence of symptomatic infection over the study-period was 0.96% (n = 47,265), of whom 3781 (8%) required hospitalisation, 615 (1.3%) were admitted to ICU and 1326 (2.8%) died. Models demonstrated an increasingly efficacious fit for predicting hospitalization [AUC 0.816 (95% CI 0.809, 0.822)], admission to ICU [AUC 0.885 (95% CI 0.88 0.89)] and death [AUC of 0.955 (95% CI 0.951 0.959)]. Severe obesity (BMI ≥ 40) was identified as a risk factor across all prognostic models; severely obese patients were substantially more likely to receive ICU treatment [OR 19.630] or die [OR 10.802]. Rural living was associated with an increased risk of hospitalization (OR 1.200 (95% CI 1.143–1.261)]. Urban living was associated with ICU admission [OR 1.533 (95% CI 1.606–1.682)]. Models provide approaches for predicting COVID-19 prognoses, allowing for evidence-based decision-making pertaining to targeted non-pharmaceutical interventions, risk-based vaccination priorities and improved patient triage.

Privately owned wells are vulnerable to contamination and as such pose a significant public health threat to those who rely on them for domestic water use. While a myriad of studies have sought to ...

A spatiotemporally static total coliform (TC) concentration threshold of five colony-forming units (CFU) per 100 mL is used in Ontario to determine whether well water is of acceptable quality for drinking. The current study sought to assess the role of TC and associated thresholds as microbial water quality parameters as the authors hypothesized that, since static TC thresholds are not evidence-based, they may not be appropriate for all well water consumers. A dataset containing the microbial water quality information of 795,023 samples (including TC and Escherichia coli (E. coli) counts) collected from 253,136 private wells in Ontario between 2010 and 2017 was used. To accurately assess the relationship between E. coli and non-E. coli TC, "non-E. coli coliform" (NEC) counts were calculated from microbial water quality data and replaced TC throughout analyses. This study analysed NEC and E. coli detection rates to determine differences between the two, and NEC:E. coli concentration ratios to assess links, if any, between NEC and E. coli contamination. Study findings suggest that spatiotemporally static NEC thresholds are not appropriate because seasonal, spatial, and well-specific susceptibility factors are associated with distinct contamination trends. For example, NEC detection rates exhibited bimodality, with summer (29.4 %) and autumn (30.2 %) detection rates being significantly higher (p0.05) than winter (21.9 %) and spring (19.9 %). E. coli detection rates also varied seasonally, but peaked in summer rather than autumn. As such, it is recommended that these factors be considered during the development of private well water guidelines and that static thresholds be avoided. Furthermore, the authors propose that, because NEC:E. coli concentration ratios change in the context of the aforementioned factors, they may have a role in inferring groundwater contamination mechanisms, with high ratios being associated with generalized aquifer contamination mechanisms and low ratios with localized contamination mechanisms.

During the COVID-19 pandemic, many governments have adopted responses revolving around the open-ended use of non-pharmaceutical interventions (NPIs), including “lockdowns”, “stay-at-home” orders, travel restrictions, mask-wearing, and regulated social distancing. Initially these were introduced with the stated goals of “flattening the curve” of hospital demand and/or the eradication of the virus from the country (i.e., “zero covid” policies). Over time, these goals have shifted to maintaining sufficient NPIs in place until such time as population-wide vaccination programmes have achieved an appropriate level of herd immunity to allow lifting of these measures without excessive hospital demand. Supporters of this approach have claimed to be “following the science”, insisting that criticism of any aspects of these measures is non-scientific or even “scientific misinformation”. This idea that only one set of scientifically valid opinions on COVID-19 exists has encouraged the media, social media and even scientific journals to suppress and/or dismiss any differing scientific opinions as “erroneous”, “discredited” or “debunked”, resulting in discouragement of open-minded scientific inquiry or discussion. Accordingly, in the current article we identify two distinct scientific paradigms to analysing COVID-19 adopted within the medical and scientific community. Paradigm 1 is primarily model-driven, while Paradigm 2 is primarily empirically-driven. Using these two paradigms we have analysed the epidemiological data for 30 northern hemisphere countries (with a total population of 882 million). Remarkably, we find using each paradigm leads to diametrically opposite conclusions on many policy-relevant issues. We discuss how these conflicting results might be reconciled and provide recommendations for scientists and policymakers.

BackgroundTo constrain propagation and mitigate the burden of COVID-19, most countries initiated and continue to implement several non-pharmaceutical interventions (NPIs), including national and regional lockdowns. In the Republic of Ireland, the first national lockdown was decreed on 23rdof March 2020, followed by a succession of restriction increases and decreases (phases) over the the following year. To date, the effects of these interventions remain unclear, and particularly within differing population subsets. The current study sought to assess the impact of individual NPI phases on COVID-19 transmission patterns within delineated population subgroups in the Republic of Ireland.Methods and FindingsConfirmed, anonymised COVID-19 cases occurring between the 29thof February 2020 and 30thNovember 2020 (n= 72,654) were obtained. Segmented modelling via breakpoint regression with multiple turning points was employed to identify structural breaks across sub-populations, including primary/secondary infections, age deciles, urban/commuter/rural areas, patients with underlying health conditions, and socio-demographic profiles. These were subsequently compared with initiation dates of eight overarching NPI phases.Five distinct breakpoints were identified. The first breakpoint, associated with a decrease in the daily COVID-19 incidence, was reported within 14 days of the first set of restrictions in mid-March 2020 for most population sub-groups. Results suggest that moderately strict NCIs were more effective than the strictest Phase 5 (National Lockdown). Divergences were observed across population sub-groups; lagged response times were observed among populations >80 years, residents of rural/ commuter regions, and cases associated with a below-median deprivation score.ConclusionsStudy findings suggest that many NPIs have been successful in decreasing COVID-19 incidence rates, however the strictest Phase 5 NPI was not. Moreover, NPIs were not equally successful across all sub-populations, with differing response times noted. Mitigation strategies and interventions may need to be increasingly bespoke, based on sub-population profiles and required responses.

Socio-hydrogeology has been recently proposed as a new approach in the field of human-water research, focusing on the assessment of the reciprocity between people and groundwater. Notwithstanding some obvious similarities with socio-hydrology, there are notable, and indeed important differences; while socio-hydrology aims to investigate and understand the dynamic interactions and feedbacks between (surface)water and people, due to the more private and local nature of groundwater in many instances, socio-hydrogeology seeks to understand individuals and communities as a primary source, pathway and receptor for potable groundwater supplies, including the role of (local) knowledge, beliefs, risk perception, tradition/history, and consumption. In essence, the “socio” in socio-hydrology might be said to represent society, while its counterpart within socio-hydrogeology embodies sociology, including social, cognitive, behavioural and socio-epidemiological science. Moreover, while socio-hydrology tends towards examination of human-water interactions at relatively larges scales via coupled modelling, socio-hydrogeology is often focused at a significantly smaller scale (e.g. individual household or community supplies), and as such, employs a wide range of mixed methods, including modelling, albeit to a lesser degree. Being at its early development stage, the discipline is still being defined and formalized. Nevertheless, several researchers are currently implementing this approach worldwide.By presenting a comparative analysis of the approaches and outcomes from several socio-hydrogeological studies undertaken across a range of socio-demographic and climatic regions including Canada, Italy, India, Ireland, Myanmar and Tunisia, this presentation will highlight the benefits and shortcomings of going beyond classical hydrogeological and hydrogeochemical investigations targeted to assess the impact of human activities on groundwater quality and quantity, and indeed, the effects of these impacts on associated individuals and communities (i.e. humans frequently represent the issue, the receptor and the solution). By shedding light on the added value of understanding the cause-effect relations between people and the hidden component of the water cycle (e.g. to jointly assess how scarce and polluted groundwater affect human/social wellbeing), socio-hydrogeology can provide evidence-based solutions to regionally bespoke problems. Similarly, otherwise neglected local or regional information can add value to scientific outcomes and contribute to foster new groundwater management actions tailored on the needs of local populations as well as on the overall achievement of long-term sustainability. Socio-hydrogeology can therefore provide new insights useful for socio-hydrological modelling, and, together, they can effectively underpin successful Integrated Water Resources Management plans at local and regional scale. Perhaps most importantly, it is hoped that by initiating discussion between practitioners of both sub-disciplines, experiences, expertise and perspectives can be shared and employed (e.g. more “technical” modelling within socio-hydrogeology, increased integration of “non-expert” knowledge within socio-hydrology) in order to bolster both areas of study, with an overarching objective of protecting the entire hydrological cycle, and the people supplied and impacted by it.

Risk communication represents the optimal instrument for decreasing the incidence of private groundwater contamination and associated waterborne illnesses. However, despite attempts to promote voluntary well maintenance in high groundwater-reliant regions such as the Republic of Ireland, awareness levels of supply status (e.g. structural integrity) have remained low. As investigations of supply awareness are often thematically narrow and homogeneous with respect to sub-population, revised analyses of awareness among both current and future supply owners (i.e. adults of typical well owner and student age) are necessary. Accordingly, the current study utilised a national survey of well users and an age-based comparison of supply awareness. Awareness was measured among 560 Irish private well users using a multi-domain scoring framework and analysed in conjunction with experiential variables including experience of extreme weather events and previous household infections, and perceived self-efficacy in maintaining supply. Respondents displayed a median overall awareness score of 66.7%, with supply owners (n = 399) and students (n = 161) exhibiting median scores of 75% and 58.3%. Awareness among both combined respondent subsets and well owners was significantly related to gender, well use factors and self-perceived behavioural efficacy while awareness among students was not correlated with any independent variable. Cluster analysis identified three distinct respondent groups characterised by awareness score and gender in both current and future well owner subsets. Male well owners and students displayed higher perceived self-efficacy irrespective of awareness score while female well owners that demonstrated high awareness were significantly more likely to report postgraduate educational (p < 0.001). Findings suggest that recent experience of extreme weather events does not significantly influence supply awareness and mirror previously identified knowledge differences between well owners and young adults. Age, gender, supply use and perceived self-efficacy emerge as recurring focal points and accordingly merit consideration from groundwater and health communication practitioners for future risk interventions.

Extreme Weather Events (EWEs) impose a substantial health and socio-economic burden on exposed populations. Projected impacts on public health, based on increasing EWE frequencies since the 1950s, alongside evidence of human-mediated climatic change represents a growing concern. To date, the impacts of EWEs on mental health remain ambiguous, largely due to the inherent complexities in linking extreme weather phenomena with psychological status. This exploratory investigation provides a new empirical and global perspective on the psychological toll of EWEs by exclusively focusing on psychological morbidity among individuals exposed to such events. Morbidity data collated from a range of existing psychological and well-being measures have been integrated to develop a single ("holistic") metric, namely, psychological impairment. Morbidity, and impairment, were subsequently pooled for key disorders-, specifically PTSD, anxiety and depression. A "composite" (any impairment) post-exposure pooled-prevalence rate of 23% was estimated, with values of 24% calculated for depression and ⁓17% for both PTSD and anxiety. Notably, calculated pooled odds ratios (pOR = 1.9) indicate a high likelihood of any negative psychological outcome (+90%) following EWE exposure. Pooled analyses of reported risk factors (p < 0.05) highlight the pronounced impacts of EWEs among individuals with higher levels of event exposure or experienced stressors (14.5%) and socio-demographic traits traditionally linked to vulnerable sub-populations, including female gender (10%), previous history (i.e., pre-event) of psychological impairment (5.5%), lower socio-economic status (5.5%), and a lower education level (5.2%). Inherent limitations associated with collating mental health data from populations exposed to EWEs, and key knowledge gaps in the field are highlighted. Study findings provide a robust evidence base for developing and implementing public health intervention strategies aimed at ameliorating the psychological impacts of extreme weather among exposed populations.

A significant volume of research over the past two decades has highlighted both direct and indirect links between climate change and groundwater quality. However, to date, few studies have sought to explore the relationship(s) between drought conditions and groundwater quality in i) private (unregulated) groundwater sources, or ii) temperate maritime climates not commonly prone to drought events. The Republic of Ireland (ROI) represents an appropriate case-study due to its’ high reliance on private groundwater supplies, and while the region is largely unaffected by climatological extremes, modelling studies indicate that drier summers and drought conditions will increase in frequency. Accordingly, the current study sought to quantify the effects of the Summer 2018 drought experienced throughout Europe on private groundwater quality in the southwest of Ireland via an opportunistic field study. A repeated measures sampling campaign comprised of “drought” (June/July) and “post-drought” (October/November) analyses of 74 wells was undertaken, with complementary mapping and statistical analyses. Both Total Coliforms (TCs) and Escherichia coli (E. coli) were present during both drought (TCs: 42/74; 56.8%, E. coli: 7/74; 9.5%) and post-drought (TCs: 42/74; 56.8%, E. coli: 18/74; 24.3%) sampling periods. E. coli contamination during drought conditions was unexpected due to an absence of recharge or infiltration for microbial transport. Bivariate analyses suggest a hydrodynamic change, with the significance of E. coli sources and pathways shown to switch between sampling periods i.e. a shift from a combination of regional and local (site specific) contamination mechanisms, to solely site-specific mechanisms. More specifically, during drought conditions, septic tank density (p = 0.001) and local subsoil type (p = 0.009) were both associated with the presence of E. coli, while neither variable was significant during post-drought conditions. The current study is the first to provide a quantitative comparison of private groundwater quality during and after a large-scale drought event in a temperate maritime climate and may be used to improve our understanding of the effects of extreme events, and thus necessary preventative and monitoring strategies, going forward.

The Republic of Ireland (ROI) currently reports the highest incidence rates of Shiga-toxin producing Escherichia coli (STEC) enteritis and cryptosporidiosis in Europe, with the spatial distribution of both infections exhibiting a clear urban/rural divide. To date, no investigation of the role of socio-demographic profile on the incidence of either infection in the ROI has been undertaken. The current study employed bivariate analyses and Random Forest classification to identify associations between individual components of a national deprivation index and spatially aggregated cases of STEC enteritis and cryptosporidiosis. Classification accuracies ranged from 78.2% (STEC, urban) to 90.6% (cryptosporidiosis, rural). STEC incidence was (negatively) associated with a mean number of persons per room and percentage of local authority housing in both urban and rural areas, addition to lower levels of education in rural areas, while lower unemployment rates were associated with both infections, irrespective of settlement type. Lower levels of third-level education were associated with cryptosporidiosis in rural areas only. This study highlights settlement-specific disparities with respect to education, unemployment and household composition, associated with the incidence of enteric infection. Study findings may be employed for improved risk communication and surveillance to safeguard public health across socio-demographic profiles.

Extreme weather events (EWEs) may significantly increase pathogenic contamination of private (unregulated) groundwater supplies. Given the current paucity of guidance in this context, well owners may be ill-equipped to undertake responsive actions. With rising cases of waterborne illness documented in groundwater-dependent rural regions, a better understanding of well user risk perception is required to develop appropriate interventions. To this end, a survey was developed to identify current risk perceptions among Irish private well owners concerning EWEs and groundwater contamination. Respondents were surveyed on actions taken in the aftermath of five recent national weather events including drought and flood and clustered based on perceived consequences. Results suggest that well owners are not inclined to undertake systematic well maintenance in the wake of an event, with only 13.1% (n = 37) of affected respondents subsequently testing their water. Two-step cluster analysis identified three distinct respondent groups based on perception of climate change impacts on well contamination, with perception level significantly related to respondent age (p = 0.003), education (p = 0.000) and gender (p = 0.002). These findings may enable development of customized risk information for private well owners and reduce the risk of human illness associated with groundwater.

Extreme weather events (EWEs) may significantly increase pathogenic contamination of private (unregulated) groundwater supplies. However, due to the paucity of protective guidance, private well users may be ill-equipped to undertake adaptive actions. With rising instances of waterborne illness documented in groundwater-dependent, developed regions such as the Republic of Ireland, a better understanding of well user risk perceptions pertaining to EWEs is required to establish appropriate educational interventions. To this end, the current study employed an online and physical questionnaire to identify current risk perceptions and correspondent predictors among Irish private well users concerning extreme weather. Respondents were elicited via purposive sampling, with 515 private well users elucidating perceived supply contamination risk in the wake of five EWEs between the years 2013-2018 including drought and pluvial flooding. A novel scoring protocol was devised to quantify overall risk perception (i.e. perceived likelihood, severity and consequences) of extreme weather impacts. Overall risk perception of EWEs was found to demonstrate a significant relationship with gender (p = 0.017) and event experience (p 0.001), with female respondents and those reporting prior event experience exhibiting higher median risk perception scores. Risk perception was additionally mediated by perceived self-efficacy in undertaking supply maintenance (p = 0.001), as well users citing confidence in ability scored significantly lower than those citing no confidence. Two-step cluster analysis identified three distinct respondent subsets based on risk perception of EWEs (high, moderate and low perception), with female respondents and those with a third-level education significantly more likely to fall within the high perception cluster. Study findings affirm that certain demographic, experiential and cognitive factors exert a significant influence on private well user risk perceptions of EWE impacts and highlight potential focal points for future educational interventions seeking to reduce the risk of human infection associated with groundwater and extreme weather.

peer-reviewed Verocytotoxin-producing E. coli (VTEC) are important agents of diarrhoeal disease in humans globally. As a noted waterborne disease, emphasis has been given to the study VTEC in surface waters, readily susceptible to microbial contamination. Conversely, the status of VTEC in potable groundwater sources, generally regarded as a “safe” drinking-water supply remains largely understudied. As such, this investigation presents the first scoping review seeking to determine the global prevalence of VTEC in groundwater supply sources intended for human consumption. Twenty-three peer-reviewed studies were identified and included for data extraction. Groundwater sample and supply detection rates (estimated 0.6 and 1.3%, respectively) indicate VTEC is infrequently present in domestic groundwater sources. However, where generic (fecal indicator) E. coli are present, the VTEC to E. coli ratio was found to be 9.9%, representing a latent health concern for groundwater consumers. Geographically, extracted data indicates higher VTEC detection rates in urban (5.4%) and peri–urban (4.9%) environments than in rural areas (0.9%); however, this finding is confounded by the predominance of research studies in lower income regions. Climate trends indicate local environments classified as ‘temperate’ (14/554; 2.5%) and ‘cold’ (8/392; 2%) accounted for a majority of supply sources with VTEC present, with similar detection rates encountered among supplies sampled during periods typically characterized by ‘high’ precipitation (15/649; 2.3%). Proposed prevalence figures may find application in preventive risk-based catchment and groundwater quality management including development of Quantitative Microbial Risk Assessments (QMRA). Notwithstanding, to an extent, a large geographical disparity in available investigations, lack of standardized reporting, and bias in source selection, restrict the transferability of research findings. Overall, the mechanisms responsible for VTEC transport and ingress into groundwater supplies remain ambiguous, representing a critical knowledge gap, and denoting a distinctive lack of integration between hydrogeological and public health research. Key recommendations and guidelines are provided for prospective studies directed at increasingly integrative and multi-disciplinary research.

Approximately 1.5 million individuals in Ontario are supplied by private water wells (private groundwater supplies). Unlike municipal supplies, private well water quality remains unregulated, with owners responsible for testing, treating, and maintaining their own water supplies. The primary goal of this study was to assess the effect of repeat sampling of private well water in Ontario and investigate the efficacy of geographically- and/or temporally specific testing recommendations and health risk assessments. The current study combines the Well Water Information System Dataset and the Well Water Testing Dataset from 2010 to 2017, inclusive. These two large existing province-wide datasets collated over an eight-year period were merged using an integrated spatial fuzzy logic and (next)- nearest neighbour approach. Provincial sampling data from 239,244 wells (702,861 samples) were analyzed for Escherichia coli to study the relationship between sampling frequency and Escherichia coli detection. Dataset variables were delineated based on hydrogeological setting (e.g. aquifer type, overburden depth, well depth, bedrock type) and seasonality to provide an in-depth understanding of Escherichia coli detection in private well water. Findings reveal differences between detection rates in consolidated and unconsolidated aquifers (p = 0.0191), and across seasons (p < 0.0001). The variability associated with Escherichia coli detection rates was explored by estimating sentinel sampling rates for private wells sampled three times, twelve times and twenty-four times per year. As sample size increases on an annual basis, so too does detection rate, highlighting the need to address current testing frequency guidelines. Future health risk assessments for private well water should consider the impact of spatial and temporal factors on the susceptibility of this drinking water source, leading to an increasingly accurate depiction of private well water contamination and the estimated effects on human health.

Environmentally associated infectious diseases, including those driven by extreme weather events, represent a critical challenge for public health as their source and transmission are frequently sporadic and associated mechanisms often not well understood. Over the past decade, the Republic of Ireland (ROI) has persistently reported the highest incidence of confirmed verotoxigenic E. coli (VTEC) and cryptosporidiosis infection in the European Union. Moreover, recent climate projections indicate that the incidence, severity and timing of extreme rainfall events and flooding will increase dramatically over the next century, with Ireland forecast to be the second most affected European country with respect to the mean proportion of the population residing in flood-prone areas by 2100. This study aimed to assess the association(s) between potential flood risk exposure and the spatial occurrence of confirmed VTEC and cryptosporidiosis infection in Ireland over a 10-year period (2008-2017).In 2012, the Irish Office of Public Works (OPW) initiated the National Catchment Flood Risk Assessment and Management (CFRAM) Programme within the framework of the Flood Directive (2007/60/CE), with high-resolution flood maps produced for coastal and fluvial risks and three risk scenarios based on calculated return periods (low, medium and high probability). Small area identifiers (national census area centroids) were used to attach anonymised spatially referenced case data to CFRAM polygons using Geographical Information Systems (GIS) to produce an anonymised dataframe of confirmed infection events linked to geographically explicit flood risk attributes. Generalised linear modelling with binary link functions (infection presence/absence) were used to calculate probabilistic odds ratios (OR) between flood risk (presence/absence and scenarios) and confirmed human infection.Preliminary results indicate a clear relationship between both infections and hydrological risk. Over one third of all infection cases were reported within areas exposed to flood risk (VTEC 948/2755 cases; cryptosporidiosis 1548/4509 cases). Census areas categorised by a high (10-year Return Period) fluvial flood risk probability exhibited significantly higher incidence rates for both VTEC (OR: 1.83, P = 0.0003) and cryptosporidiosis (OR: 1.80, P = 0.0015). Similarly, areas characterised by low (1000-year Return Period) coastal flood risk probability were over twice as likely to report ≥1 confirmed case of cryptosporidiosis during the study period (OR: 2.2, P= 0.003). Space-time scan statistics (temporally-specific spatial autocorrelation) indicate an unseasonal peak of cryptosporidiosis cases occurring during April 2016, a majority of which took place within or adjacent to high flood risk areas (56% of total cases), revealing a potential relationship with the exceptional flooding events experienced during winter 2015-2016 (November-January). Further work will seek to identify the individual/combined flood risk (CFRAM) elements most significantly associated with the incidence of infections.Flood risk assessment mapping may represent an innovative approach to assessing the human health impacts of flood risk exposure and climate change. The outcomes of this study will contribute to predictive modelling of VTEC and cryptosporidiosis in Ireland, thus aiding surveillance and control of these diseases in the future, and the causative nature of regional hydrology and climate.

Antimicrobial resistant organisms and genes are now recognised as emerging water contaminants with significant potential adverse human and ecological health impacts. For example, the World Health Organisation have recently estimated that the global human health burden associated with antimicrobial infection will likely outstrip cancer mortalities by the year 2050, with >10 million deaths predicted due to these infections. The presence of antimicrobial resistant bacteria in drinking water supplies represents a particular concern due to daily associated exposures, with untreated groundwater consumption posing a substantial risk due to its unregulated nature. In the Republic of Ireland, high reliance on unregulated, private water wells and on-site domestic wastewater treatment in concurrence with a unique agricultural profile and diverse (hydro)geological settings, has resulted in the ‘perfect storm’ with respect to the relative ubiquity of sources and hydrological pathways for microbiological contamination, including antimicrobial resistant bacteria. The current study sought to identify the occurrence of antimicrobial resistant bacteria in the Irish subsurface environment, and apply spatiotemporal statistical modelling to identify environmental (e.g., hydrogeological, climatic, etc.) and anthropogenic (e.g., antimicrobial use, bacterial sources, etc.) drivers, and thus hydrological mechanisms associated with this occurrence. Private (unregulated) wells (n = 132) in 21/26 administrative counties were assessed and temporally sampled relative to periods of varying (human and veterinary) antimicrobial usage. Samples were analysed for bacterial (Escherichia coli and Pseudomonas aeruginosa) presence and, where isolated, antimicrobial resistance profiles were quantified. Data pertaining to well location, design and condition, adjacent (< 100 m) contamination sources, groundwater vulnerability and antecedent meteorology were geospatially collated to identify resistance hotspots and associated climatic, hydrogeological and anthropogenic risk factors. Preliminary results highlight the prevalence of bacterial contamination in Irish groundwater wells; 35 (26.5%) and 8 (6%) of the 132 supplies analysed during the first round of sampling (Autumn 2019) tested positive for E. coli and P. aeruginosa, respectively. While P. aeruginosa (an opportunistic soil/water resident) were only found in supplies from high (H=6.5%) and extreme (E=6.5%; X=14.3%) groundwater vulnerability categories, E. coli (faecal indicator) were found across all vulnerability categories. Differences in antimicrobial resistance levels across and within these two bacterial species will be used to provide insights into hydrological contamination pathways (i.e. ‘traditional’ recharge, direct ingress/preferential flow, or a combination depending on hydrogeological setting). Findings will provide evidence of the extent of antimicrobial resistance in domestic groundwater supplies, and valuable insights into the hydrogeological and microbiological mechanisms governing the potential public health risks associated with untreated groundwater consumption.

Approximately 500 million Europeans use a groundwater source for water consumption on a daily basis. Private (unregulated) groundwater wells are key sources of domestic drinking water in the Republic of Ireland (ROI) with approximately 750,000 users. The distribution of groundwater wells in the ROI is highly concentrated in rural areas in correspondence with the absence of piped infrastructure. The nexus of key (extra-)local factors, including high private groundwater reliance, ubiquity of domestic wastewater treatment systems and pastoral agriculture in rural areas, in conjunction with a temperate maritime climate and distinctive hydro(geo)logical settings, has been linked to a high groundwater susceptibility to contamination and risk of waterborne enteric infection.DESIGN focuses on the incidence and sources of verotoxigenic-producing Escherichia coli (VTEC) and Cryptosporidium spp. – the most prevalent waterborne pathogens inducing enteric illness in the ROI – associated with private groundwater wells. The findings of a systematic literature review focusing on the prevalence of Cryptosporidium in domestic groundwater supplies are presented. Calculated detection rates for groundwater wells (19%) and samples (13%) indicate Cryptosporidium spp. contamination of domestic groundwater supplies is common, representing a latent health risk of direct concern to groundwater consumers and public health authorities. Presented figures provide unprecedented “baselines” highly applicable in groundwater/catchment management and epidemiology (e.g., QMRA). Several knowledge gaps were identified with the lack of standardized reporting among investigations emerging as a key concern.The results of temporal (i.e., repeat) sampling regimes analysing the spatio-temporal incidence of Cryptosporidium and VTEC in groundwater wells are also presented. Sampling locations (n = 80) were geo-referenced and linked to multiple variables (e.g., land-use, agricultural statistics, hydrogeology) compiled in a novel geo-database. In conjunction with supply infrastructural data, relevant risk factors associated with VTEC and Cryptosporidium well contamination were identified. Furthermore, incorporating previously available data from project partners, stochastic QMRA and Environmental Fate Model(s) were produced to assess the relative risk of VTEC well contamination and seasonal influence. The explorative Cryptosporidium sampling regime provides the first national account of (oocyst) incidence in domestic groundwater infrastructure enabling insights into potential environmental sources and (surface-groundwater) transport mechanisms. The results obtained represent a stepping stone towards the development of bespoke groundwater management strategies in the ROI based on the ‘One Health’ concept.

Global climate change models predict an increase in both the frequency and severity of extreme weather events, including prolonged drought conditions, thus posing a unique set of challenges for regions traditionally unaccustomed to severe climate phenomena. This is particularly significant for the occurrence of severe drought events in areas characterised by temperate maritime climates, such as the Republic of Ireland (ROI). While numerous studies have explored the impacts of drought on groundwater levels and chemical contamination, few studies have sought to investigate the impacts of sporadic drought events on the microbial quality of groundwater for human consumption. Accordingly, the 2018 (June-August) European drought event represented a unique opportunity to investigate the effects of prolonged low rainfall and elevated temperature (relative to seasonal means) on the incidence of faecal indicator organisms (FIOs) among unregulated domestic groundwater supplies in the ROI.A dual-sampling fieldwork regime (during and post-event) of private wells (n=74) and subsequent risk factor (logistic regression) and bivariate analyses were used to evaluate the potential role of meteorological and site specific (hydrogeology, contaminant sources etc.) conditions on the incidence of microbial contamination. During absolute drought conditions (≥15 days characterised by no measureable precipitation, June 2018), the sampled cohort exhibited a significantly decreased risk of microbial contamination (OR: 0.356, p = 0.024) with 12.2% (n = 9/74) of supplies contaminated with Escherichia coli (E. coli), increasing to 28.4% (n = 21/74) upon abatement of drought conditions (October 2018). No analysed risk factors were associated with E. coli presence at the 95% confidence level, although, the presence of onsite domestic wastewater treatment systems (U = 1.03 p = 0.057) approached statistical significance during the drought. Findings suggest that the 2018 European drought served to decrease background levels of FIO within private wells in the ROI, likely due to reduced hydraulic loading from the surface, soil moisture deficits and consequently, significantly decreased bacterial survival. Results would seem to reiterate the significance of onsite domestic wastewater treatment systems as a source of subsurface contaminants in Ireland. The presented opportunistic field study provides a critical characterization of the impacts of unprecedented drought events on microbiological water quality in domestic groundwater supplies in temperate regions, and may be used by sanitary/environmental engineers, hydrologists, hydrogeologists, policy-makers, planners and healthcare practitioners to safeguard against the future human health effects of climate change and extreme weather events.

Private groundwater sources in the Republic of Ireland provide drinking water to an estimated 750,000 people or 16% of the national population. Consumers of untreated groundwater are at increased risk of infection from pathogenic microorganisms. However, given the volume of private wells in operation, remediation or even quantification of public risk is both costly and time consuming. In this study, a hierarchical logistic regression model was developed to ‘predict’ contamination with E. coli based on the results of groundwater quality analyses of private wells (n = 132) during the period of September 2011 to November 2012. Assessment of potential microbial contamination risk factors were categorised into three groups: Intrinsic (environmental factors), Specific (local features) and Infrastructural (groundwater source characteristics) which included a total of 15 variables. Overall, 51.4% of wells tested positive for E. coli during the study period with univariate analysis indicating that 11 of the 15 assessed risk factors, including local bedrock type, local subsoil type, septic tank reliance, 5 day antecedent precipitation and temperature, along with well type and depth, were all significantly associated with E. coli presence (p

Wastewater reclamation now represents an effective measure for sustainable water resource management in arid regions, however wastewater components (organic micropollutants) may potentially impact local ecological and/or human health. Previous studies have shown that sodium bentonite/natural clay (BC) mixes may be used to effectively reduce riverbed infiltration in regions characterised by excessively high hydraulic conductivity. Accordingly, the current study sought to investigate the contaminant removal efficiency (Re) of several BC mass ratios in simulated dry riverbeds. Results indicate that the measured Re of NH4 +-N, CODcr and BOD5 increased in concurrence with an increasing sodium bentonite ratio, up to a maximum Re of 97.4% (NH4 +-N), 55.2% (CODcr), and 51.5% (BOD5). The primary contaminant removal site was shown to be the infiltration-reducing (BC) layer, accounting for approximately 40%, 60%, and 70% of NH4 +-N, CODcr and BOD5 removal, respectively. Conversely, the removal efficiency of NO3-N was found to be low (

A significant body of research has focused on the role of domestic wastewater treatment systems (DWWTSs) as sources of human-specific aquatic contaminants in both developed and developing regions. However, to date few studies have sought to investigate the awareness, attitudes and behaviours of DWWTS owners and the efficacy of associated communication initiatives. The current study provides an examination of a public national engagement campaign undertaken in the Republic of Ireland which seeks to minimise the impact of DWWTSs on human and ecological health via concurrent inspection and information dissemination. Overall, 1634 respondents were surveyed using a “before and after” study design to capture if and how awareness, attitudes and behaviours evolved over time. Findings suggest that whilst the campaign provided a modest baseline to raise general awareness associated with the basic operational and maintenance requirements of DWWTS, there has been little or no behavioural engagement as a result, suggesting a significant awareness-behaviour gap. Accordingly, efforts to minimise potential human and ecological impacts have been unsuccessful. Moreover, results suggest that public attitudes towards water-related regulation and policy became increasingly negative over the study period due to parallel political and economic issues, further complicating future engagement. Future strategies, both in Ireland and further afield, should focus on health-based demographically-focused message framing to achieve significant knowledge and attitudinal shifts amongst specific population cohorts, and thus bring about significant behavioural change. Study findings and recommendations may be used by myriad stakeholders including local, provincial and national authorities to effectively engage with individuals and communities prior to and during implementation of legislative and policy-based instruments within numerous spheres including climate change adaptation, environmental quality, hydrological risk, and hydro-ecology.

Groundwater quality monitoring typically employs testing for the presence of E. coli as a fecal indicator of recent ingress of human or animal fecal material. The efficacy of fecal indicator organisms is based on the primary criteria that the organism does not reproduce in the aquatic environment. However, recent studies have reported that E. coli may proliferate (i.e., has adapted to) in the external environment, including soil and surface water. To date, the presence of environmentally-adapted E. coli in groundwater has not been examined. The current study employed Clermont phylotyping and the presence of six accessory genes to identify the likely presence of adapted E. coli in private groundwater sources. E. coli isolates (n = 325) from 76 contaminated private water wells located in a southeastern Ontario watershed were compared with geographically analogous human and animal fecal E. coli isolates (n = 234). Cryptic clades III-V, a well-described environmentally-adapted Escherichia population, were identified in three separate groundwater wells, one of which exclusively comprised this adapted population. Dimensionality reduction (via Principal Component Analysis) was used to develop an “E. coli adaptation model”, comprising three distinct components (groundwater, animal feces, human feces) and suggests adaptation occurs frequently in the groundwater environment. Model findings indicate that 23/76 (30.3%) wells had an entirely adapted community. Accordingly, the use of E. coli as a FIO returned a false positive result in these instances, while an additional 23/76 (30.3%) wells exhibited some evidence of adaptation (i.e., not all isolates were adapted) representing an over-estimate of the magnitude (concentration) of contamination. Study findings highlight the need to further characterize environmentally-adapted E. coli in the groundwater environment and the potential implications with respect to water quality policy, legislation and determinants of human health risk both regionally and internationally.

Globally, approximately 2.2 billion people rely on groundwater for daily consumption. It is widely accepted that groundwater is more pristine than surface water but while this assumption is frequently the case, groundwater is not ubiquitously free of contaminants; accordingly, this presumption can result in an unfounded and potentially hazardous sense of security among owners, operators and users. The current paper presents a review of published literature providing epidemiological evidence of the contribution of groundwater to global human enteric infection. An emphasis is placed on enteric pathogens transmitted via the faecal-oral route, and specifically those associated with acute gastrointestinal illness (AGI). The review identified 649 published groundwater outbreaks globally between 1948 and 2013 and several epidemiological studies that show there is an increased risk of AGI associated with the consumption of untreated groundwater. The review identified that the following five pathogens were responsible for most outbreaks: norovirus, Campylobacter, Shigella, Hepatitis A and Giardia. Crudely, the authors estimate that between 35.2 and 59.4 million cases of AGI per year globally could be attributable to the consumption of groundwater. Although groundwater is frequently presumed to be a microbiologically safe source of water for consumption, this review demonstrates that consumers served by an untreated groundwater supply remain at risk to enteric disease. The authors conclude that collaboration between microbiologists, hydrogeologists and epidemiologists is needed to better understand pathogen occurrence, persistence, detection and transport in groundwater as well as build stronger epidemiological evidence documenting the true magnitude of disease associated with groundwater globally.