An overview of dissolved organic carbon in groundwater and implications for drinking water safety

Dissolved organic carbon (DOC) is composed of a diverse array of compounds, predominantly humic substances, and is a near ubiquitous component of natural groundwater, notwithstanding climatic extremes such as arid and hyper-arid settings. Despite being a frequently measured parameter of groundwater quality, the complexity of DOC composition and reaction behaviour means that links between concentration and human health risk are difficult to quantify and few examples are reported in the literature. Measured concentrations from natural/unpolluted groundwater are typically below 4 mg C/l, whilst concentrations above these levels generally indicate anthropogenic influences and/or contamination issues and can potentially compromise water safety. Treatment processes are effective at reducing DOC concentrations, but refractory humic substance reaction with chlorine during the disinfection process produces suspected carcinogenic disinfectant by-products (DBPs). However, despite engineered artificial recharge systems being commonly used to remove DOC from recycled treated wastewaters, little research has been conducted on the presence of DBPs in potable groundwater systems. In recent years, the capacity to measure the influence of organic matter on colloidal contaminants and its influence on the mobility of pathogenic microorganisms has aided understanding of transport processes in aquifers. Additionally, advances in polymerase chain reaction techniques used for the detection, identification, and quantification of waterborne pathogens, provide a method to confidently investigate the behaviour of DOC and its effect on contaminant transfer in aquifers. This paper provides a summary of DOC occurrence in groundwater bodies and associated issues capable of indirectly affecting human health

Growing a Research Culture in an Irish Technological University

Research, along with teaching and engagement is one of the three pillars of higher education. However, in the Irish Institutes of Technology (IoT), where, traditionally, the focus has been on vocational education, providing good quality graduates well trained for the workforce. Their research activity has been underdeveloped and teaching has been the primary focus. Two recent public strategy documents (‘The Hunt Report’ and ‘Towards a Future Higher Education Landscape’) have identified the need for Ireland to develop a ‘Technological University’ sector with an emphasis on research of a more applied nature. Technological University Dublin is on a trajectory to become Ireland’s first Technological University with an obligation to undertake research of global significance, national importance and regional relevance, including identified areas of research strength and minimum quotas of PhD students. The move towards a Technological University is driving IoTs to upgrade their research capabilities and capacities and move from teaching led institutions to research led, however this switch is not without its challenges. This study seeks to determine those factors influencing research activity by academic and research staff across and Irish technological institute. An online survey of academic and research staff will generate insights into barriers and enablers of research activity

Private Groundwater Management and Risk Awareness: A cross-sectional analysis of two age-related subsets in the Republic of Ireland

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 \u3c 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

Risk communication approaches for preventing private groundwater contamination in the Republic of Ireland: a mixed-methods study of multidisciplinary expert opinion

The mechanisms of private-well groundwater contamination are uniquely complex, necessitating a multisector communicative approach to risk management, premised on behaviour promotion. In countries such as the Republic of Ireland (ROI), characterised by oftentimes high groundwater contamination risk and concurrently limited user awareness, incorporation of multidisciplinary, ‘expert-based’ knowledge may facilitate design of evidence-based, practical interventions. Expert interviews represent an efficient form of expert consultation, enabling ease of access to niche information and comparison of procedure, but remain under-utilised within the groundwater management literature. In response, the current study elicited opinion from 50 experts across four broad categories (communications, engineering/science, policy, and risk assessment) via a mixed-methods interview study. Semi-structured qualitative interviews were undertaken with experts from the ROI (n = 25) and European/North American countries (n = 25) and examined using thematic (qualitative) and bivariate statistical (quantitative) analyses. Experts noted financial cost, knowledge and social norms as primary barriers to adopting private-groundwater and other health risk-prevention behaviours. Lack of organisational knowledge as a communication barrier was significantly related to expert category (p = 0.034) and highlighted by a majority of communications experts (95%) compared to policy (75%), risk assessment (67%) and engineering/science (50%) experts. The most frequently suggested communication activities comprised events (24%), radio segments (22%), workshops (24%) and community meetings (30%), allied with family-oriented, discursive approaches to information delivery. Study findings may be used by both national (Irish) and international stakeholders in myriad hydrogeological contexts to develop educational outreach strategies and contribute to the existing groundwater-management-knowledge base

Preface: Hydrogeology and human health

In the mid-1800s, Dr. John Snow (1813–1858), an obstetrician and anaesthesiologist, theorised that cholera, a highly infectious gastrointestinal infection associated with extremely high rates of mortality, was caused by faecal contamination of water supplies (Donaldson and Scally 2009). During the summer of 1854, a significant cholera outbreak occurred in the Soho district of London (UK), resulting in the deaths of 616 people. As part of this first modern epidemiological investigation, Dr. Snow noted that “within 250 yards of the spot where Cambridge Street joins Broad Street there were upwards of 500 fatal attacks of cholera in 10 days (…) suspected some contamination of the water of the much-frequented street-pump (a public well) in Broad Street.” Snow subsequently developed what is now referred to as “The Ghost Map”, a geographical grid indicating where and when cholera cases and associated mortalities occurred in relation to the public well (Hempel 2007). Not only did the map confirm that almost all cases related to drinking water from the pump, but also that specific residential clusters were not associated with infection; for example, workers in an adjacent brewery did not contract the illness due to their daily allowance of beer. Later research discovered that the hand-dug well had been constructed just 0.9 m from a defunct septic tank/cesspit (Johnson 2006; Hempel 2007). Thus, it might be said that the science of epidemiology, considered the cornerstone of public health and defined as “the study and analysis of the patterns, causes, and effects of health and disease conditions within a specific population” (Porta 2008), has its very roots in hydrogeology and the subsurface

Evaluation of hydrometric network efficacy and user requirements in the Republic of Ireland via expert opinion and statistical analysis

Decreased funding and shifting governmental priorities have resulted in a contraction of hydrometric measurement in many regions over the past two decades. Moreover, concerns exist with respect to appropriate data usage and (transboundary) exchange, in addition to the compatibility and extent of existing hydrometric datasets. These issues are undoubtedly magnified due to enhanced data demands and increased financial pressures on network managers, thus requiring new approaches to optimising the societal benefits and overall efficacy of hydrometric information for future socio-hydrological resilience. The current study employed a quantitative cross-sectional expert elicitation of 203 respondents to collate, analyse and assess hydrometric network users’ opinions, knowledge and experience. Current usage patterns, perceived network strengths, requirements, and limitations have been identified and discussed within the context of hydrometric resilience in a changing social, economic and natural environment. Findings indicate that small (\u3c30 km2) catchment data are most frequently employed in the Republic of Ireland, particularly with respect to extreme event prediction and flood management. Similarly, small catchments and areas characterised by previous/recent flooding were prioritised for resilience management via network amendment. Over half of those surveyed (50.5%) reported the current network as inadequate for their professional requirements. Conversely, respondents indicated network efficacy has improved (53.2%) or remained stable (26.6%) over the course of their professional career, however, improvements (as defined by individual respondents i.e. network density, data quality, data availability) have not occurred at a sufficient rate. User-defined efficacy (adequacy, resilience) was found to be a somewhat vague, multivariate concept, with no individual predictor identified, however, general data quality, network density, and urban catchment data were the most significant issues among respondents. A significant majority (85.4%) of respondents indicate that future resilience would be best achieved via network density amendment, with over 60% favouring geographically and/or categorically focused network increases, as opposed to more general national increases

Geospatial drivers of the groundwater δ18O isoscape in a temperate maritime climate (Republic of Ireland)

In recent years, the concept of “isoscapes” has been used to describe spatiotemporal stable isotope distributions within natural environments including groundwater systems at multiple scales. This study presents an updated groundwater δ18O isoscape for the Republic of Ireland and describes the climatic and geological drivers influencing 18O composition. In all, 142 geographically and geologically representative groundwater installations were sampled and analysed, in addition to 35 samples from six nested boreholes. Geospatially, Irish groundwater exhibits high δ18O values in southern and western coastal regions, becoming progressively depleted inland before reaching lowest measured values along the eastern coast, equating to a national groundwater δ18O profile range of approximately 3‰. Groundwater δ18O composition is primarily driven by location with respect to orographically influenced rainfall deposition and annual precipitation volume, with a bias towards winter recharge. Results also demonstrate that local/regional (hydro)geological setting exerts a secondary influence on δ18O composition via infiltration and recharge mechanisms. “Flashy” groundwater systems (e.g. karst limestones) are more likely to exhibit seasonal groundwater δ18O patterns, whereas low productivity systems with high residence times (e.g. granites), tend to display a dampened composition to groundwater recharge and exhibit more temporally constant δ18O values. The derived δ18O isoscape enhances current understanding of what is a geologically distinct groundwater setting, whilst also potentially serving as a δ18O “sentinel” for continental Europe, with respect to both groundwater and precipitation, due to Ireland’s geographic location

Review: Epidemiological evidence of groundwater contribution to global enteric disease, 1948–2015

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

Impact of the 2018 European Drought on Microbial Groundwater Quality in Private Domestic Wells: A case study from a temperate maritime climate

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

Efficacy of a National Hydrological Risk Communication Strategy: Domestic Wastewater Treatment Systems in the Republic of Ireland

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