Challenges
The drought of 2018 raised the profile of droughts in Scotland, with broad coverage of impacts. Future occurrence and magnitude of droughts are predicted to increase, with periods previously only occurring once every 40 years happening once every 20 years by 2050. Recent work by NatureScot found increases in extreme droughts across Scotland with the highest likelihood in eastern Scotland including Grampian and Caithness. However, these spatial patterns do not always map to surface water and groundwater vulnerabilities.
Antimicrobial resistance (AMR) is a biological emerging contaminant (EC) with the potential to have significant consequences. ECs, such as pharmaceuticals, personal care products (PPCPs) and microplastics have been detected in surface and ground waters, sewage effluent and at trace concentrations in drinking waters and river sediment. There are data gaps in baseline information on pharmaceuticals in the water environment in Scotland in 18 local authority areas and a bias towards effluents. ECs have the potential to cause both ecotoxicological effects and impacts on human health, therefore their prevalence is of particular concern concerning drinking water sources. Microplastics threaten biodiversity, ecosystem services and potentially human health, yet minimal data pertain to their detection in Scottish freshwaters.
While the impacts of future changes on water quality in Scotland represent a major knowledge gap, water quality modelling frequently suffers from a lack of available data at a high-enough spatial and temporal resolution as well as high uncertainty. Therefore, novel monitoring and modelling approaches are urgently needed to address these challenges. Monthly data typically available from national regulatory water quality monitoring is at risk of underestimating true pollutant concentrations and loads, making it difficult to inform cost-effective targeting of pollution mitigation measures. Wide deployment of high-temporal resolution monitoring instruments continues to be hindered by high cost and there is an urgent need for innovative techniques for cheaper, reliable high-resolution field assessment to understand pollutant sources, pathways, and responses to mitigation measures.
While modelling facilitates an understanding of both current drivers and future risks to the water environment, the application of models to AMR is rare and hindered by a lack of data, limited mechanistic understanding and a failure to consider the role of environmental factors on transmission. The temporal and spatial dynamics of Antibiotic resistance genes (ARGs) in catchment systems is likely to be important in influencing risk levels across seasons and scales but is not well represented in models to date. Further, while new ECs appear every year, for many we do not have sufficient monitoring data or knowledge to characterise their behaviour in the environment.
The key drivers of this research are the needs of policymakers and managers to:
- Have tools to predict where and when drought may occur in Scotland.
- Understand where vulnerabilities to drought lie in our environment, economy and society.
- Understand future changes in water quality in Scottish catchments; what drivers of change are and how this impacts ecosystem services and water users.
- Improve and monitor rural drinking water quality and increase awareness of potential health risks from their water supplies.
Questions
- Water scarcity and drought - what are the risks and vulnerabilities within Scotland, and how do we build resilience?
- Water quality in the environment – what are the emerging and future risks and how can we mitigate these?
- How do we continue to improve drinking water quality?
Solutions
This project is integrating model-based assessment of future risks to water quality and quantity under a range of scenarios, with new empirical water quality data and socio-economic risk assessment for drinking water supplies.
Understanding the vulnerabilities of Scotland’s water resources to drought
We review grey and academic literature, catchment-level studies of changes in flow paths and groundwater storage during the 2018 drought and how threshold thinking could improve the assessment of sectoral vulnerabilities and adaptive strategies for different stakeholders. For drought-impacted sectors like agriculture, we review recent research on a multi-level framework for agricultural drought adaptation and surface and groundwater drought studies. We then collate climate data from UK and international sources and review available modelling approaches to drought risk and vulnerabilities.
Informed by the insights of this review, we are building a free and open-source integrated drought risk modelling approach for meteorological, soil, and hydrological drought based on existing datasets and open-source models at a national scale, depending on the availability of relevant national datasets. We are also building a trans-disciplinary probabilistic vulnerability model and a Decision Support Tool based on Bayesian Belief Networks (BBN) and focussed on selected case studies, bringing together diverse data and stakeholder perspectives.
Developing a baseline understanding of emerging contaminants in Scotland’s freshwaters
We are undertaking flow-integrated spatiotemporal sampling in contrasting catchments and national-scale spatially distributed sampling to understand relationships between ECs and environmental drivers. We consider:
- ARGs and co-selector
- PPCPs
- Endocrine disrupters, pesticides
- Microplastics/phthalates
- Perfluoroalkyl and Polyfluoroalkyl Substances (PFAs)
- Human and animal pathogens, including viruses
This activity fills key data gaps by identifying and mapping key ECs in freshwaters. This project links to work done by the Flows of Antimicrobial resistance and pathogens through environment to food chain project on antibiotic and ARG quantification methods in soils, manures and crops and some shared aspects of BBN modelling, and the Understanding the dynamics of antimicrobial resistance genes (ARGs) flux in the soil, animals and humans in different fertilisation practices for grasslands project on quantifying antibiotics in soil samples.
Understanding the emergent and future risks to water quality in the environment
Monitoring Approaches
We are developing and testing novel near-real-time monitoring approaches using in-situ sensors to aid the understanding of current and future water quality in terms of nutrients and ECs and inform adaptive management in Scotland. The application of UV-vis/Raman sensors for monitoring emerging contaminants (pesticides/pharmaceutical) will be investigated, using colorimetric approaches and nanoparticles. UV-Vis spectroscopic “fingerprinting” will be explored to establish typical natural waters conditions and detect pollution anomalies. Fluorescence and UV-Vis spectroscopy is being applied to a) assess the effect of peatland restoration on dissolved organic matter quality and quantity by comparison of degraded and restored peatland sites (linked to the CentrePeat project) b) understand sources of stream organic carbon (linked to the Achieving Multi-purpose Nature-based Solutions project).
Modelling Approaches
We are using a BBN to simulate the fate and risks of future water quality from ECs. The BBN can represent relationships in a causal model structure, incorporate uncertainty and variability using stochastic modelling and apply sensitivity analysis for model validation. Non-biophysical variables can be included, thus building a holistic trans-disciplinary system-based approach to quantitative risk assessment.
Increasing the resilience and quality of drinking water
We are further understanding the risks, impacts, and responses that arise from growing uncertainty and variability in drinking water supplies and quality. We are providing recommendations to support rural supply planning, assess the risks to drinking water through the development of novel tests and engage rural communities to enhance the resilience of these supplies. Rural drinking water is one area of supply that is significantly impacted by the above threats. Rural private water companies are an appropriate case study for examining: the socio-economic factors that amplify and mitigate vulnerability to water shortages and water quality issues, attitudes and perceptions of risk associated with water supplies, and the feasibility of self-monitoring to support a wider self-supply management model. This activity contributes to the evidence base supporting resilience of rural communities in The Benefits of a Rural Green Recovery: Pinpointing Opportunities, Assets and Support Needs project by highlighting roles of housing security and connectivity as factors influencing community resilience to water-related climate impacts.
Changes made to regulations have introduced new obligations for monitoring somatic coliphages in water sources and treatment processes. Existing methods for testing are time-consuming. We are exploring more rapid molecular-based methods, such as RT-qPCR quantification and metagenomic sequencing.
Project Partners
Progress
Understanding the vulnerabilities of Scotland's water resources to drought
We have worked closely with national policy and management stakeholders and identified the need to:
A. Improve the short-term forecasting ability (days to weeks) of water scarcity status and recovery of water bodies.
B. Improve processes and rules of the Scottish Environment Protection Agency's (SEPA's) Drought Risk Assessment Tool, including thresholds for triggering and resetting of significant water scarcity events.
We have reviewed existing data and modelling approaches related to drought and water scarcity in Scotland; summarised in a short report on 'Understanding the vulnerabilities of Scotland's water resources to drought: summary of stakeholder engagement, review of related studies, and an outline of our research'. The review highlighted that despite clear evidence that the likelihood and consequences of meteorological and hydrological droughts are increasing in Scotland, there are low levels of knowledge in key areas including: large scale changes in soil moisture and the socio-economic impacts on agriculture and impacts on wildlife, how low flow events are assessed, the socio-economic impacts of different thresholds, and how surface water bodies and wetlands recover following drought events. We identified the need to consider multiple process and data-based models, and the role of Bayesian networks (BN) to explore relationships between multiple drought indices and the socio-economic and ecological impact of drought events.
Developing a baseline understanding of emerging contaminants in Scotland's freshwaters
We held a stakeholder workshop to decide on which emerging contaminants to target and to determine study sites. Eight months of sampling was completed at 12 sites from rural to urban settings, including 100 water and sediment samples, analysed for organisms such as E. coli and coliforms, suspended sediments, pH and conductivity, nutrients, metals, PPCPs and DNA for the initial screening of 384 ARGs. Nutrient analysis included determination of the levels of nitrogen (N), phosphorus (P), dissolved organic carbon (DOC) and total N in the collected samples.
Understanding the emergent and future risks to water quality in the environment
We have set up a national scale model of the risk of nitrate leaching to groundwaters and are developing a risk-based model of pharmaceutical pollution at both national and catchment scale. Collaboration projects have been established with the NHS Highland and the Hydro Nation Chair at the University of Stirling that support the co-development of the pharmaceutical risk-assessment work. Testing of UV-VIS spectroscopic analysis for simultaneous detection of nitrate, DOC and P, using chemometric methods found good accuracy of prediction for nitrate and DOC and novel correlations with total P, that can be inferred from other components as it doesn't have its own spectral signature.
Increasing the resilience and quality of drinking water
A literature review found variation in household water insecurity happens at two levels: i) point of use/supply, i.e., individual or household; and ii) contextual to the point of use, i.e., community level and in three dimensions a) socio-economic; b) beliefs, perceptions and narratives; and c) socio-technical arrangements, i.e., technology used, testing practices. The design of pilot interviews has been completed, and the ethics review for the pilot interviews has been submitted. Rapid evidence review on self-monitoring of Private Water Supplies identified several technological innovations that could be implemented, however these must be low cost to assure accessibility for vulnerable and underprivileged populations. A review of standard protocols for detection of somatic coliphages in drinking water has begun.
Long-term impact of current project
A drought forecasting framework for Scotland is being co-developed with SEPA and should lead to significant impact by the end of the project. A risk-based model on pharmaceutical pollution, co-developed with the NHS Highland project funded by the Medical Research Council, is also likely to lead to significant national impact. In future years, our empirical data collection will contribute pertinent data to SEPA's Pharmaceuticals in the Water Environment visualisation tool. The enhanced understanding of vulnerabilities and risks to drinking water generated during this project will inform recommendations useful for Drinking Water Quality Regulator for Scotland (DWQR), local authorities and private water supply users for developing resilient water supplies. The development of a rapid somatic coliphage test could be used by regulators to test water quality and protect public health.
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