ABSTRACT
Karst watersheds accommodate high landscape complexity and are influenced by both human-induced and natural activity, which affects the formation and process of runoff, sediment connectivity and contaminant transport and alters natural hydrological and nutrient cycling. However, physical monitoring stations are costly and labor-intensive, which has confined the assessment of water quality impairments on spatial scale. The geographical characteristics of catchments are potential influencing factors of water quality, often overlooked in previous studies of highly heterogeneous karst landscape. To solve this problem, we developed a machining learning method and applied Extreme Gradient Boosting (XGBoost) to predict the spatial distribution of water quality in the world's most ecologically fragile karst watershed. We used the Shapley Addition interpretation (SHAP) to explain the potential determinants. Before this process, we first used the water quality damage index (WQI-DET) to evaluate the water quality impairment status and determined that CODMn, TN and TP were causing river water quality impairments in the WRB. Second, we selected 46 watershed features based on the three key processes (sources-mobilization-transport) which affect the temporal and spatial variation of river pollutants to predict water quality in unmonitored reaches and decipher the potential determinants of river impairments. The predicting range of CODMn spanned from 1.39 mg/L to 17.40 mg/L. The predictions of TP and TN ranged from 0.02 to 1.31 mg/L and 0.25-5.72 mg/L, respectively. In general, the XGBoost model performs well in predicting the concentration of water quality in the WRB. SHAP explained that pollutant levels may be driven by three factors: anthropogenic sources (agricultural pollution inputs), fragile soils (low organic carbon content and high soil permeability to water flow), and pollutant transport mechanisms (TWI, carbonate rocks). Our study provides key data to support decision-making for water quality restoration projects in the WRB and information to help bridge the science:policy gap.
Subject(s)
Rivers , Water Pollutants, Chemical , China , Environmental Monitoring/methods , Humans , Machine Learning , Nitrogen/analysis , Soil , Water Pollutants, Chemical/analysis , Water QualityABSTRACT
The public health significance of plastics and microplastics in different environmental matrices has mainly focused on the toxicological effects of human ingestion. But these pollutants can also harbour pathogenic bacteria as the surfaces of plastics in the environment quickly become colonised by microbial biofilm. This novel microbial habitat has been termed the 'plastisphere' and could facilitate the survival and dissemination of important bacterial and fungal pathogens. Importantly, however, the role of plastic pollution as a secondary pathway for the transmission of human pathogenic viruses has never been addressed. Due to the high prevalence of both enteric and respiratory viruses in the population and in the environment, there is significant potential for human viruses to become associated with the plastisphere. In this review we critically evaluate current knowledge on the interaction of human enteric and respiratory viruses with plastic surfaces and identify the main environmental conditions and plastic characteristics that could affect virus survival and persistence in the environment. Our hypothesis is that the plastisphere can enhance the adhesion, survival and dissemination of human pathogenic viruses and potentially lead to more effective transfer and transmission of viral diseases within the environment. We identify key research questions needed to more fully assess the potential human health risks associated with viruses on plastic surfaces. These include understanding, (1) the mechanisms of viral attachment to either naked or biofilm-colonised plastic (2) how the structural characteristics of viruses (e.g., enveloped, or non-enveloped), affect their persistence in the plastisphere, (3) whether the plastisphere offers protection and increases the persistence of infectious viruses in soil, freshwater, and marine environments.
Subject(s)
Viruses , Water Pollutants, Chemical , Environmental Monitoring , Fresh Water , Humans , Microplastics , Plastics/toxicity , Soil , Water Pollutants, Chemical/analysisABSTRACT
Farmed insects can offer an environmentally sustainable aquafeed or livestock feed ingredient. The value of black soldier fly (Hermetia illucens) (BSF) larvae could be improved by enrichment in omega-3 through the dietary inclusion of seaweed. However, the industry practice of drying seaweed at low temperatures to retain nutritional properties may benefit the survival of human pathogenic bacteria, particularly if the seaweed has been harvested from contaminated water. Here we have demonstrated that E. coli and E. coli O157:H7 died-off in seaweed dried at 50 °C, although both were detected in the dried powder following 72 h storage. V. parahaemolyticus fell below the level of detection in stored seaweed after drying at ≥ 50 °C, but L. monocytogenes remained detectable, and continued to grow in seaweed dried at ≤60 °C. Therefore, drying seaweed at low temperatures risks pathogen carry-over into insects destined for animal feed. BSF larvae reared on an artificially contaminated seaweed-supplemented diet also became contaminated by all four bacteria present in the supplement. Water quality at seaweed harvesting sites, seaweed desiccation, and insect rearing practices, represent critical points where development of regulatory standards could achieve targeted control of pathogenic hazards.
Subject(s)
Animal Feed/microbiology , Bacteria/isolation & purification , Diptera/microbiology , Seaweed/microbiology , Animal Feed/standards , Animals , Bacteria/classification , Bacteria/pathogenicity , Dietary Supplements/microbiology , Dietary Supplements/standards , Diptera/growth & development , Food Handling/methods , Food Microbiology/standards , Food Safety , Humans , Larva/growth & development , Larva/microbiology , TemperatureABSTRACT
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.
Subject(s)
Bathing Beaches , Water Quality , Environmental Monitoring , Escherichia coli , Humans , Motivation , Water MicrobiologyABSTRACT
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.
Subject(s)
Diptera/microbiology , Escherichia coli O157 , Feces/microbiology , Animal Migration , Animals , Bathing Beaches , Colony Count, Microbial , Humans , Risk Assessment , SeaweedABSTRACT
The relationship between culturable counts (CFU) and quantitative PCR (qPCR) cell equivalent counts of Escherichia coli in dairy feces exposed to different environmental conditions and temperature extremes was investigated. Fecal samples were collected in summer and winter from dairy cowpats held under two treatments: field-exposed versus polytunnel-protected. A significant correlation in quantified E. coli was recorded between the qPCR and culture-based methods (r = 0.82). Evaluation of the persistence profiles of E. coli over time revealed no significant difference in the E. coli numbers determined as either CFU or gene copies during the summer for the field-exposed cowpats, whereas significantly higher counts were observed by qPCR for the polytunnel-protected cowpats, which were exposed to higher ambient temperatures. In winter, the qPCR returned significantly higher counts of E. coli for the field-exposed cowpats, thus representing a reversal of the findings from the summer sampling campaign. Results from this study suggest that with increasing time post-defecation and with the onset of challenging environmental conditions, such as extremes in temperature, culture-based counts begin to underestimate the true resilience of viable E. coli populations in livestock feces. This is important not only in the long term as the Earth changes in response to climate-change drivers but also in the short term during spells of extremely cold or hot weather.
Subject(s)
Escherichia coli , Livestock , Animals , Colony Count, Microbial , Feces , Humans , Polymerase Chain Reaction , TemperatureABSTRACT
Dairy farming generates large volumes of liquid manure (slurry), which is ultimately recycled to agricultural land as a valuable source of plant nutrients. Different methods of slurry application to land exist; some spread the slurry to the sward surface whereas others deliver the slurry under the sward and into the soil, thus helping to reduce greenhouse gas (GHG) emissions from agriculture. The aim of this study was to investigate the impact of two slurry application methods (surface broadcast versus shallow injection) on the survival of faecal indicator organisms (FIOs) delivered via dairy slurry to replicated grassland plots across contrasting seasons. A significant increase in FIO persistence (measured by the half-life of E. coli and intestinal enterococci) was observed when slurry was applied to grassland via shallow injection, and FIO decay rates were significantly higher for FIOs applied to grassland in spring relative to summer and autumn. Significant differences in the behaviour of E. coli and intestinal enterococci over time were also observed, with E. coli half-lives influenced more strongly by season of application relative to the intestinal enterococci population. While shallow injection of slurry can reduce agricultural GHG emissions to air it can also prolong the persistence of FIOs in soil, potentially increasing the risk of their subsequent transfer to water. Awareness of (and evidence for) the potential for 'pollution-swapping' is critical in order to guard against unintended environmental impacts of agricultural management decisions.
Subject(s)
Dairy Products/analysis , Dairying/methods , Feces/chemistry , Feces/microbiology , Seasons , Soil/chemistry , Animals , Dairy Products/microbiology , Enterococcus/isolation & purification , Environmental Monitoring/methods , Environmental Pollution/analysis , Escherichia coli/isolation & purification , Grassland , Half-Life , Manure/analysis , Manure/microbiology , Soil MicrobiologyABSTRACT
Understanding and quantifying the trade-off between the requirement for clean safe bathing water and beaches and their wider ecosystem services is central to the aims of the European Union (EU) Marine Strategy Framework Directive (MSFD), and vital for the sustainability and economic viability of designated bathing waters. Uncertainty surrounding the impacts of ensuing bathing water policy transitions, e.g. the EU revised Bathing Waters Directive (rBWD), puts new urgency on our need to understand the importance of natural beach assets for human recreation, wildlife habitat and for protection from flooding and erosion. However, managing coastal zones solely in terms of public health could have potentially negative consequences on a range of other social and cultural ecosystem services, e.g. recreation. Improving our knowledge of how bathing waters, surrounding beach environments and local economies might respond to shifts in management decisions is critical in order to inform reliable decision-making, and to evaluate future implications for human health. In this paper we explore the conflicts and trade-offs that emerge at public beach environments, and propose the development of an evaluative framework of viable alternatives in environmental management whereby bathing waters are managed for their greatest utility, driven by identifying the optimal ecosystem service provision at any particular site.
Subject(s)
Bathing Beaches/standards , Ecosystem , Public Health/standards , Water Microbiology/standards , Water Pollution/prevention & control , Bathing Beaches/economics , Bathing Beaches/legislation & jurisprudence , European Union , Fresh Water , Government Regulation , Humans , Public Health/economics , Public Health/legislation & jurisprudence , Recreation , United States , Water Pollution/economics , Water Pollution/legislation & jurisprudenceABSTRACT
Eutrophication is a major water pollution issue and can lead to excessive growth of aquatic plant biomass (APB). However, the assimilation of nutrients into APB provides a significant target for their recovery and reuse, and harvesting problematic APB in impacted freshwater bodies offers a complementary approach to aquatic restoration, which could potentially deliver multiple wider ecosystem benefits. This critical review provides an assessment of opportunities and risks linked to nutrient recovery from agriculturally impacted water-bodies through the harvesting of APB for recycling and reuse as fertilisers and soil amendments. By evaluating the economic, social, environmental and health-related dimensions of this resource recovery from 'waste' process we propose a research agenda for closing the loop on nutrient transfer from land to water. We identify that environmental benefits are rarely, if ever, prioritised as essential criteria for the exploitation of resources from waste and yet this is key for addressing the current imbalance that sees environmental managers routinely undervaluing the wider environmental benefits that may accrue beyond resource recovery. The approach we advocate for the recycling of 'waste' APB nutrients is to couple the remediation of eutrophic waters with the sustainable production of feed and fertiliser, whilst providing multiple downstream benefits and minimising environmental trade-offs. This integrated 'ecosystem services approach' has the potential to holistically close the loop on agricultural nutrient loss, and thus sustainably recover finite resources such as phosphorus from waste.
Subject(s)
Conservation of Natural Resources , Eutrophication , Plants/metabolism , Water Pollutants, Chemical/metabolism , Water Pollution, Chemical/prevention & control , Aquatic Organisms , Biomass , Ecosystem , Fertilizers/analysis , RecyclingABSTRACT
Understanding the role of different rainfall scenarios on faecal indicator organism (FIO) dynamics under variable field conditions is important to strengthen the evidence base on which regulators and land managers can base informed decisions regarding diffuse microbial pollution risks. We sought to investigate the impact of low intensity summer rainfall on Escherichia coli-discharge (Q) patterns at the headwater catchment scale in order to provide new empirical data on FIO concentrations observed during baseflow conditions. In addition, we evaluated the potential impact of using automatic samplers to collect and store freshwater samples for subsequent microbial analysis during summer storm sampling campaigns. The temporal variation of E. coli concentrations with Q was captured during six events throughout a relatively dry summer in central Scotland. The relationship between E. coli concentration and Q was complex with no discernible patterns of cell emergence with Q that were repeated across all events. On several occasions, an order of magnitude increase in E. coli concentrations occurred even with slight increases in Q, but responses were not consistent and highlighted the challenges of attempting to characterise temporal responses of E. coli concentrations relative to Q during low intensity rainfall. Cross-comparison of E. coli concentrations determined in water samples using simultaneous manual grab and automated sample collection was undertaken with no difference in concentrations observed between methods. However, the duration of sample storage within the autosampler unit was found to be more problematic in terms of impacting on the representativeness of microbial water quality, with unrefrigerated autosamplers exhibiting significantly different concentrations of E. coli relative to initial samples after 12-h storage. The findings from this study provide important empirical contributions to the growing evidence base in the field of catchment microbial dynamics.
Subject(s)
Escherichia coli , Rain , Water Microbiology , Environmental Monitoring , Feces , Fresh Water , Scotland , Seasons , Water QualityABSTRACT
Septic tank systems (STS) in rural catchments represent a potential source of microbial pollution to watercourses; however, data concerning the risk of faecal indicator organism (FIO) export from STS to surface waters are scarce. In the absence of empirical data, elicitation of expert judgements can provide an alternative approach to aid understanding of FIO pollution risk from STS. Our study employed a structured elicitation process using the Sheffield Elicitation Framework to obtain expert judgements on the proportion of FIOs likely to be delivered from STS to watercourses, based on 36 scenarios combining: (i) septic tank effluent movement risk, driven by soil hydro-morphological characteristics; (ii) distance of septic tank to watercourse; and (iii) degree of slope. Experts used the tertile method to elicit a range of values representing their beliefs of the proportion of FIOs likely to be delivered to a watercourse for each scenario. The experts judged that 93 % of FIOs would likely be delivered from an STS to a watercourse under the highest risk scenario that combined (i) very high STS effluent movement risk, (ii) STS distance to watercourse <10 m, and (iii) a location on a steep slope with gradient >25 %. Under the lowest risk scenario, the proportion of FIOs reaching a watercourse would likely reduce to 5 %. Expert confidence was high for scenarios that represented extremes of risk, while uncertainty increased for scenarios depicting intermediate risk conditions. The behavioural aggregation process employed to obtain a consensus among the experts proved to be useful for highlighting both areas of strong consensus and high uncertainty. The latter therefore represent priorities for future empirical research to further improve our understanding of potential pollution risk from septic tanks and in turn enable better assessments of potential threats to water quality in rural catchments throughout the world where decentralised wastewater systems are common.
Subject(s)
Judgment , Water Quality , FecesABSTRACT
Emerging evidence indicates that micro- and macro-plastics present in water can support a diverse microbial community, including potential human pathogens (e.g., bacteria, viruses). This interaction raises important concerns surrounding the role and suitability of current bathing water regulations and associated pathogen exposure risk within beach environments. In response to this, we critically evaluated the available evidence on plastic-pathogen interactions and identified major gaps in knowledge. This review highlighted the need for a conceptual shift in risk management at public beaches recognising: (i) interconnected environmental risks, e.g., associations between microbial compliance parameters, potential pathogens and both contemporary and legacy plastic pollution; and (ii) an appreciation of risk of exposure to plastic co-pollutants for both water and waterside users. We present a decision-making framework to identify options to manage plastic-associated pathogen risks alongside short- and longer-term research priorities. This advance will help deliver improvements in managing plastic-associated pathogen risk, acknowledging that human exposure potential is not limited to only those who engage in water-based activity. We argue that adopting these recommendations will help create an integrated approach to managing and reducing human exposure to pathogens at bathing, recreational water and beach environments.
Subject(s)
Bathing Beaches , Plastics , Risk Management , Humans , Water Microbiology , Water PollutionABSTRACT
Legacy stores of faecal pollution in streambed sediments can result in delayed impacts on environmental quality and human health if resuspended into the overlying water column. Different catchment sources of faecal pollution can contribute to a legacy store of microbial pollutants, with size of stores influenced by microbial die-off and faecal accrual rates in the streambed. The aim of this study was to use a mesocosm experiment to characterise the persistence of E. coli derived from faeces of dairy cows, deer, and geese once introduced to streambed sediment under different temperature regimes. The settling rate of solid constituents of faecal material into streambed sediment once delivered into an aquatic environment was also quantified. The persistence patterns of E. coli in streambed sediment were found to vary as a function of faecal source and temperature; die-off of E. coli in sediment contaminated with goose faeces was more rapid than in sediments contaminated with dairy cow or deer faeces. Goose faeces also recorded a more rapid settling rate of faecal particles through the water column relative to dairy cow and deer faeces, suggesting a more efficient delivery of E. coli to streambed sediments associated with this faecal source. Our findings provide new evidence to improve understanding of the potential longer-term risks to both the environment and public health posed by sediments when contaminated with livestock, wildlife, and wildfowl faeces.
Subject(s)
Deer , Escherichia coli , Humans , Female , Cattle , Animals , Geese , Feces , Water , Geologic Sediments , Environmental MonitoringABSTRACT
Large quantities of microplastics are regularly discharged from wastewater treatment plants (WWTPs) into the aquatic environment. Once released, these plastics can rapidly become colonised by microbial biofilm, forming distinct plastisphere communities which may include potential pathogens. We hypothesised that the protective environment afforded by the plastisphere would facilitate the survival of potential pathogens during transitions between downstream environmental matrices and thus increase persistence and the potential for environmental dissemination of pathogens. The survival of Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa colonising polyethylene or glass particles has been quantified in mesocosm incubation experiments designed to simulate, (1) the direct release of microplastics from WWTPs into freshwater and seawater environments; and (2) the movement of microplastics downstream following discharge from the WWTP through the river-estuary-marine-beach continuum. Culturable E. coli, E. faecalis and P. aeruginosa were successfully able to survive and persist on particles whether they remained in one environmental matrix or transitioned between different environmental matrices. All three bacteria were still detectable on both microplastic and glass particles after 25 days, with higher concentrations on microplastic compared to glass particles; however, there were no differences in bacterial die-off rates between the two materials. This potential for environmental survival of pathogens in the plastisphere could facilitate their transition into places where human exposure is greater (e.g., bathing waters and beach environments). Therefore, risks associated with pathogen-microplastic co-pollutants in the environment, emphasises the urgency for updated regulations on wastewater discharge and the management of microplastic generation and release.
Subject(s)
Microplastics , Water Pollutants, Chemical , Humans , Plastics , Wastewater , Escherichia coli , Water Pollutants, Chemical/analysis , Environmental Monitoring , Fresh Water/analysisABSTRACT
Plastic waste is ubiquitous in the environment and there are increasing reports of such waste being colonised by human pathogens. However, the ability of pathogens to persist on plastics for long periods, and the risk that they pose to human health, is unknown. Here, under simulated environmental conditions, we aimed to determine if pathogenic bacteria can retain their virulence following a prolonged period on plastic. Using antibiotic selection and luciferase expression for quantification, we show that clinically important strains of E. coli can survive on plastic for at least 28-days. Importantly, these pathogens also retained their virulence (determined by using a Galleria mellonella model as a surrogate for human infection) and in some cases, had enhanced virulence following their recovery from the plastisphere. This indicates that plastics in the environment can act as reservoirs for human pathogens and could facilitate their persistence for extended periods of time. Most importantly human pathogens in the plastisphere are capable of retaining their pathogenicity. Pathogens colonising environmental plastic waste therefore pose a heightened public health risk, particularly in areas where people are exposed to pollution.
Subject(s)
Escherichia coli , Plastics , Humans , Virulence , Environmental Pollution , BacteriaABSTRACT
Freshwater (inland) blue space environments provide a range of public health benefits to visitors. However, health related exposure outcomes are dynamic and can vary depending on several factors, including the environmental characteristics of freshwater environments and their surroundings. Developing and managing inland blue spaces to promote health and wellbeing therefore requires an understanding of whether specific freshwater attributes, and prevailing weather conditions, enhance or devalue landscape aesthetics. The aim of this study was to utilise a mixed-methods research approach to investigate aesthetic preferences of inland blue spaces. A three-phase data collection method was adopted involving (i) analysis of a national-scale landscape image dataset; in combination with (ii) a national-scale online survey; and (iii) a series of in-person focus groups. We found environmental characteristics associated with the waterbody itself, as well as the characteristics of the nearby green space, to have a significant impact on the overall aesthetic appeal of inland blue spaces. Strong preference was demonstrated for inland blue spaces perceived to be of a high environmental quality and which have a natural, rather than human-modified, appearance. The findings highlight the need to conserve the quality of both the waterbody and waterside environment to encourage frequent recreational use and maintain the beneficial public health outcomes associated with inland blue spaces.
ABSTRACT
Engaging with natural environments benefits human health by providing opportunities for social interactions, enhancing mental wellbeing and enabling outdoor spaces for physical exercise. Open water swimming has seen a rapid increase in popularity, partly due to the physical health benefits it can provide but also with the growing interest in (re)connecting with nature for environment-health interactions. Using a national-scale online survey of 717 open water swimmers, the aim of this study was to investigate patterns and trends in the perceived benefits and risks of open water swimming to both public health and the environment; and to understand whether these perceived risks and benefits vary across different typologies of swimmers and open water, or 'blue space', environments. Strong associations were found between the most important self-reported benefit associated with open water swimming and both participant age and the categorisation of their typical swim style. All but one of the age-groups surveyed perceived mental wellbeing benefits to be the most important benefit of open water swimming; whilst those aged over 65 identified physical rather than mental wellbeing benefits to be the most important outcome. Participants who preferred lake swimming reported greater concern regarding possible environmental damage caused by the increasing popularity of open water swimming compared to those engaging in river or sea swimming. However, the majority of participants perceived the risks to the environment from open water swimming to be minimal. Our study adds to the growing evidence that open water swimming is perceived by participants as benefitting their mental and physical wellbeing. Improved understanding of the benefits and risks of engaging with blue spaces used for open water swimming can contribute to co-designed policy development to promote safer, healthier and more sustainable outdoor recreation opportunities associated with this increasingly popular outdoor pursuit.
Subject(s)
Lakes , Swimming , Humans , Aged , Self Report , Cross-Sectional Studies , Water , Risk Assessment , ScotlandABSTRACT
Karst terrain seasonal monsoonal rainfall is often associated with high concentrations of nitrate-N in streams draining agricultural land. Such high concentrations can pose problems for environmental and human health. However, the relationship between rainfall events that mobilize nitrate and resulting nitrate export remains poorly understood in karst terrain. To better understand the processes that drive nitrate dynamics during rainfall events, the characteristics of individual rainfall events were analyzed using sensor technology. Thirty-eight rainfall events were separated from the high-frequency dataset spanning 19 months at a karst spring site. The results revealed that nitrate-discharge (N-Q) hysteresis in 79% of rainfall events showed anticlockwise hysteresis loop patterns, indicating nitrate export from long distances within short event periods. Karstic hydrological connectivity and source availability were considered two major determining factors of N-Q hysteresis. Gradual increase in hydrological connectivity during intensive rainfall period accelerated nitrate transportation by karst aquifer systems. Four principal components (PCs, including antecedent conditions PC1&3 and rainfall characteristics PC2&4 explained 82% of the cumulative variance contribution to the rainfall events. Multiple linear regression of four PCs explained more than 50% of the variation of nitrate loading and amplitude during rainfall events, but poorly described nitrate concentrations and hydro-chemistry parameters, which may be influenced by other factors, e.g., nitrate transformation, fertilization time and water-rock interaction. Although variation of N concentration during event flow is evident, accounting for antecedent conditions and rainfall factors can help to predict rainfall event N loading during rainfall events. Pollution of the karstic catchment occurred by a flush of nitrate input following rainfall events; antecedent and rainfall conditions are therefore important factors to consider for the water quality management. Reducing source availability during the wet season may facilitate to reduction of nitrogen loading in similar karst areas.
Subject(s)
Groundwater , Nitrates , Humans , Nitrates/analysis , Environmental Monitoring/methods , Agriculture , Water QualityABSTRACT
Disposable diapers are becoming increasingly popular and present an emerging challenge for global waste management, particularly within LMICs. They offer a cheap and convenient way for caregivers to manage child excreta; however, insufficient understanding of safe disposal methods, combined with limited access to waste management services results in hazardous disposal. Used diapers are being increasingly found dumped in the open environment, including in water bodies and in open fields, leading to faecal contamination of the environment and an enhanced risk of transmission of faecal-oral diseases such as cholera and typhoid. United Nations SDG 6 aims to end open defaecation globally by 2030; however, improper disposal of used diapers will hamper progress towards reaching this goal. In this review, we identify current trends in use and subsequent disposal of single use disposable diapers in LMICs, and critically discuss the environmental and public health impacts of current practices, and potential solutions to address these challenges. Contemporary methods for managing the disposal of single use diapers for communities in LMICs tend to be cost prohibitive with few alternative options other than dumping in the environment. Modern cloth diapers offer a low waste alternative to disposable diapers but often carry an unaffordable high upfront cost. Here, in addition to advocating improved efforts by governments to upgrade access and quality of waste management services, we recommend the design and implementation of intervention schemes aimed to increase awareness of safe and hygienic disposal practices for disposable diapers.
Subject(s)
Defecation , Waste Management , Child , HumansABSTRACT
This article focuses on the clinical and administrative decision-making processes involved in medevacing psychiatric patients from Kandahar Airfield, Afghanistan, during major surge operations. This article highlights organizational realities pertaining to the medevac process and offers recommendations for incoming providers to optimize their effectiveness in managing at-risk patients in a combat zone.