The difference a day can make: The temporal dynamics of drinking water access and quality in urban slums

In urban slums – home to approximately 1 billion people worldwide - access to clean drinking water is woefully inadequate despite the United Nations' declaration that access to safe water is a fundamental human right. Households in slums are frequently forced to rely on multiple drinking water sources to meet their needs. Numerous factors influence choice of water source, including water quality, availability, reliability, and affordability. These factors are not temporally static, but instead vary over multiple timescales (from sub-daily changes to annual changes and beyond) in response to changes in the water source itself and changes in the household's ability to use that source. For example, the cost of water can may change over time in response to water availability (e.g. rainy season versus dry season) and a slum household's ability to pay for water may change over time in response to changes in household income. However, existing national and global monitoring of safe water access, including Sustainable Development Goal 6, overlook these temporal dynamics of water access, quality and health risk in slums. This paper proposes a research agenda for exploring temporal changes in drinking water access and quality in urban slums and their potential influence on health risk. It argues that in the design of research studies, policy interventions, and drinking water monitoring aimed at improving access and health in urban slums, temporal dynamics should be considered over at least three interlinked time scales: short-term (from sub-daily to week-to-week), medium-term (from month-to-month to season-to-season) and long-term (from year-to-year). The paper concludes with recommendations for future research on temporal dynamics of drinking water and health in slums

Plastic pollution as a novel reservoir for the environmental survival of the drug resistant fungal pathogen Candida auris

The WHO recently classified Candida auris as a fungal pathogen of "critical concern". Evidence suggests that C. auris emerged from the natural environment, yet the ability of this pathogenic yeast to survive in the natural environment is still poorly understood. The aim of this study, therefore, was to quantify the persistence of C. auris in simulated environmental matrices and explore the role of plastic pollution for facilitating survival and potential transfer of C. auris. Multi-drug resistant strains of C. auris persisted for over 30 days in river water or seawater, either planktonically, or in biofilms colonising high-density polyethylene (HDPE) or glass. C. auris could be transferred from plastic beads onto simulated beach sand, particularly when the sand was wet. Importantly, all C. auris cells recovered from plastics retained their pathogenicity; therefore, plastic pollution could play a significant role in the widescale environmental dissemination of this recently emerged pathogen.</p

The disparity between regulatory measurements of E. coli in public bathing waters and the public expectation of bathing water quality

The main objectives of the European Union (EU) Bathing Water Directive (BWD) 2006/7/EC are to safeguard public health and protect designated aquatic environments from microbial pollution. The BWD is implemented through legislation by individual EU Member States and uses faecal indicator organisms (FIOs) as microbial pollution compliance parameters to determine season-end bathing water classifications (either ‘Excellent’ ‘Good’ ‘Sufficient’ or ‘Poor’). These classifications are based on epidemiological studies that have linked human exposure to FIOs with the risk of contracting a gastrointestinal illness (GI). However, understanding public attitudes towards bathing water quality, together with perceptions of relative exposure risks, is often overlooked and yet critically important for informing environmental management decisions at the beach and ensuring effective risk communication. Therefore, this study aimed to determine the effectiveness of current regulatory strategies for informing beach users about bathing water quality, and to assess public understanding of the BWD classifications in terms of exposure risk and public health. Two UK designated bathing waters were selected as case studies, and questionnaires were deployed to beach-users. The bathing waters had different classification histories and both had electronic signage in operation for communicating daily water quality predictions. The majority of respondents did not recognise the standardised EU bathing water quality classification signs, and were unaware of information boards or the electronic signs predicting the water quality on that particular day. In general, respondents perceived the bathing water at their respective beach to be either ‘good’ or ‘sufficient’ which were also the lowest classifications of water quality they would be willing to accept for bathing. However, the lowest level of risk of contracting a gastrointestinal illness that respondents would be willing to accept suggested a significant misunderstanding of the BWD classification system, with the majority (91%) of respondents finding only a < 1% risk level acceptable. The ‘Good’ classification is much less stringent in terms of likelihood of GI. This study has shown that the current public understanding of the BWD classifications in terms of exposure risk and public health is limited, and an investment in methods for disseminating information to the public is needed in order to allow beach-users to make more informed decisions about using bathing waters

Quantifying the potential of 'on-farm' seed priming to increase crop performance in developing countries. A meta-analysis

Low-input agriculture in marginal areas of developing countries faces considerable challenges during crop development. A key stage in crop growth is seed germination, which is often constrained by abiotic factors such as low water potential, high temperatures and soil crusting, which can result in poor establishment. This is exacerbated by low soil fertility, salinity, drought, pests and diseases, which ultimately leads to reduced yields. Over the last 20 years, the potential of 'on-farm' seed priming, a traditional, low-cost technique, consisting of soaking seeds in water prior to sowing, has been applied to different crops and conditions with varying degrees of success. To understand the significance of this potentially transformative agronomic strategy, we have conducted a global meta-analysis of on-farm seed priming by quantifying (i) the rate of emergence, (ii) final emergence and (iii) total yield from 44 published papers on 17 crops across 10 countries. Our results show that on-farm seed priming has a significantly positive effect on crop performance: seeds emerge 22% faster, with an increased final emergence of 11%, with total yields 21% higher than conventionally sown seeds. Furthermore, sub-group analyses demonstrated that on-farm seed priming is more advantageous under stressful abiotic conditions with case studies categorized as being either 'nutrient deficient', 'salinity-stressed' or 'dry climates' gaining the highest yield improvements (22–28%). On-farm seed priming can be particularly beneficial to resource-poor farmers working in low-input agricultural systems where yield potential is limited by intrinsically stressed agronomic environments. Here, we demonstrate for the first time that on-farm seed priming is perfectly adapted to local situations in developing countries. Our results provide the evidence that on-farm seed priming could be effectively adopted by resource-poor farmers as a strategy to increase food security in some of the most marginal agricultural areas

Colonisation of plastic pellets (nurdles) by E. coli at public bathing beaches

The hard surface of waterborne plastic provides an ideal environment for the formation of biofilm by opportunistic microbial colonisers, and could facilitate a novel means of dispersal for microorganisms across coastal and marine environments. Biofilms that colonise the so-called 'plastisphere' could also be a reservoir for faecal indicator organisms (FIOs), such as Escherichia coli, or pathogenic bacteria such as species of Vibrio. Therefore, the aim of this study was to map the spatial distribution of beach-cast plastic resin pellets (nurdles) at five public bathing beaches, and quantify their colonisation by E. coli and Vibrio spp. Nurdles were heterogeneously distributed along the high tide mark at all five beaches, and each beach contained nurdles that were colonised by E. coli and Vibrio spp. Knowledge of E. coli colonisation and persistence on nurdles should now be used to inform coastal managers about the additional risks associated with plastic debris

Microbial hitchhikers on marine plastic debris: Human exposure risks at bathing waters and beach environments

Marine plastic debris is well characterized in terms of its ability to negatively impact terrestrial and marine environments, endanger coastal wildlife, and interfere with navigation, tourism and commercial fisheries. However, the impacts of potentially harmful microorganisms and pathogens colonising plastic litter are not well understood. The hard surface of plastics provides an ideal environment for opportunistic microbial colonisers to form biofilms and might offer a protective niche capable of supporting a diversity of different microorganisms, known as the &ldquo;Plastisphere&rdquo;. This biotope could act as an important vector for the persistence and spread of pathogens, faecal indicator organisms (FIOs) and harmful algal bloom species (HABs) across beach and bathing environments. This review will focus on the existent knowledge and research gaps, and identify the possible consequences of plastic-associated microbes on human health, the spread of infectious diseases and bathing water quality

Managing multiple catchment demands for sustainablewater use and ecosystem service provision

Ensuring water, food and energy security for a growing world population represents a 21st century catchment management challenge. Failure to recognise the complexity of interactions across ecosystem service provision can risk the loss of other key environmental and socioeconomic benefits from the natural capital of catchment systems. In particular, the ability of soil and water to meet human needs is undermined by uncertainties around climate change effects, ecosystem service interactions and conflicting stakeholder interests across catchments. This critical review draws from an extensive literature to discuss the benefits and challenges of utilising an ecosystem service approach for integrated catchment management (ICM). State-of-the-art research on ecosystem service assessment, mapping and participatory approaches is evaluated and a roadmap of the key short- and longer-term research needs for maximising landscape-scale ecosystem service provision from catchments is proposed. &copy; 2017 by the authors. Licensee MDPI, Basel, Switzerland

Quantifying stakeholder understanding of an ecosystem service trade-off

Sustainable management of global natural resources is challenged by social and environmental drivers, adding pressure to ecosystem service provision in many regions of the world where there are competing demands on environmental resources. Understanding trade-offs between ecosystem services and how they are valued by different stakeholder groups is therefore critical to maximise benefits and avoid conflict between competing uses. In this study we developed a novel participatory trade-off experiment to elicit the perception of 43 participants, from across four key stakeholder groups, working in land and water management (Environmental Regulators, Farming Advisors, Water Industry Staff and Catchment Scientists). Using the Production Possibility Frontier (PPF) concept, we quantified stakeholder assessment of both the shape and the uncertainty around the PPF in a trade-off between agricultural intensity and the ecological health of freshwater systems. The majority of stakeholder groups selected threshold and logistic decay trade-off curves to describe the relationship of the trade-off, and estimated the uncertainty around the curves to be intermediate or large. The views of the four stakeholder groups differed significantly regarding how they estimated stakeholder trade-off prioritisation; the largest difference in perspectives was identified between Environmental Regulators and Farm Advisors. The methodology considered the cultural, socio-economic and institutional specificities of an ecosystem service interaction and identified potential sources of conflict but also possible solutions for win-win opportunities to explore and share understanding between stakeholders. Valuing stakeholder knowledge as a form of expert data and integrating this into participatory decision-making processes for land and water management thus contributes considerable value beyond traditional approaches to ecosystem service assessments

The seaweed fly (Coelopidae) can facilitate environmental survival and transmission of E. coli O157 at sandy beaches

The sustainable management of recreational beaches is essential for minimising risk of human exposure to microbial pathogens whilst simultaneously maintaining valuable ecosystem services. Decaying seaweed on public beaches is gaining recognition as a substrate for microbial contamination, and is a potentially significant reservoir for human pathogens in close proximity to beach users. Closely associated with beds of decaying seaweed are dense populations of the seaweed fly (Coelopidae), which could influence the spatio-temporal fate of seaweed-associated human pathogens within beach environments. Replicated mesocosms containing seaweed inoculated with a bioluminescent strain of the zoonotic pathogen E. coli O157:H7, were used to determine the effects of two seaweed flies, Coelopa frigida and C. pilipes, on E. coli O157:H7 survival dynamics. Multiple generations of seaweed flies and their larvae significantly enhanced persistence of E. coli O157:H7 in simulated wrack habitats, demonstrating that both female and male C. frigida flies are capable of transferring E. coli O157:H7 between individual wrack beds and into the sand. Adult fly faeces can contain significant concentrations of E. coli O157:H7, which suggests they are capable of acting as biological vectors and bridge hosts between wrack habitats and other seaweed fly populations, and facilitate the persistence and dispersal of E. coli O157:H7 in sandy beach environments. This study provides the first evidence that seaweed fly populations inhabiting natural wrack beds contaminated with the human pathogen E. coli O157:H7 have the capacity to amplify the hazard source, and therefore potential transmission risk, to beach users exposed to seaweed and sand in the intertidal zone. The risk to public health from seaweed flies and decaying wrack beds is usually limited by human avoidance behaviour; however, seaweed fly migration and nuisance inland plagues in urban areas could increase human exposure routes beyond the beach environment

COVID-19: The environmental implications of shedding SARS-CoV-2 in human faeces

First paragraph: The ongoing COVID-19 pandemic is having significant public health repercussions, with a global response to limit the predicted mortality associated with this outbreak. The virus, ‘severe acute respiratory syndrome coronavirus 2’ (SARS-CoV-2), is a respiratory virus disseminated though droplets from coughs and sneezes from an infected person or from fomites (Hellewell et al., 2020). Therefore, many countries have put ‘social distancing’ measures in place to reduce person-to-person spread of the disease. However, recently it has been confirmed that infectious virions can also be present in human faeces (Ling et al., 2020), and there are reports that viral RNA can be persistently shed in faeces for a maximum of 33 days after the patient has tested negative for respiratory viral RNA (Wu et al 2020). Although it remains unclear whether SARS-CoV-2 can be transmitted via the faecal-oral route (Xu et al., 2020), viral shedding from the digestive system can last longer than shedding from the respiratory tract. As such, faecal-oral transmission may be an important, but as yet unquantified, pathway for increased exposure during the current outbreak (Wu et al., 2020). Therefore, safely managing faecal wastes from infected, recovering and recovered patients poses a significant nosocomial challenge. For example, during the SARS outbreak of 2002–2003, the closely related SARS-CoV-1 was detected in sewage discharged by two hospitals (Wang et al., 2005), which emphasises the care needed when handling such faecal wastes. However, these challenges are not limited to hospital wastes, as it has been predicted that most of the population will experience only mild symptoms of COVID 19 and convalesce at home, whilst others, including children, can carry the virus asymptomatically, and are still capable of shedding the virus in their faeces (Kam et al., 2020, Tang et al., 2020). This means that the virus could soon become widespread throughout wastewater systems (Naddeo and Liu, 2020). Whilst a lack of testing for the majority of the population makes it difficult to predict the spatially-distributed volume of potentially infectious faeces delivered through the sewerage infrastructure to wastewater treatment works (WWTWs), wastewater surveillance may be a useful tool to indicate where the virus is circulating in the human population (Lodder and de Roda Husman, 2020). However, whilst knowingly infected individuals can take steps to increase their level of hygiene, asymptomatic carriers do not change their behaviour, and can anonymously spread enteric pathogens within the community (Quilliam et al., 2013)