PAthways of Chemicals Into Freshwaters and their ecological ImpaCts (PACIFIC)
Lead Research Organisation:
UK CENTRE FOR ECOLOGY & HYDROLOGY
Department Name: Soils and Land Use (Wallingford)
Abstract
Manufactured chemicals are essential for the maintenance of public health, food production, and quality of life, including a diverse range of pharmaceuticals, pesticides, and personal care products. The use of these compounds throughout society has led to increasing concentrations and chemodiversity in the environment. Whilst there has been a focus on understanding the impacts of chemicals on a subset of freshwater biodiversity (particularly invertebrates and fish), we understand less about how chemical pollution impacts freshwater microbes. These microbial communities (the 'microbiome') number in the millions to billions of cells per milliliter of water or gram of sediment and form the most biodiverse and functionally important component of freshwater ecosystems. The biogeochemical and ecological functions delivered by freshwater microbes are essential to wider freshwater ecosystem health.
The PAthways of Chemicals Into Freshwaters and their ecological ImpaCts (PACIFIC) project will focus on understanding the link between sources of anthropogenic chemicals and their pathways, fate and ecological impacts in freshwater ecosystems, with an emphasis on freshwater microbial ecosystems and the functions they perform. We will investigate the relationship between predicted diffuse and point source chemical pathways and measured chemical concentrations in water and sediments at locations across the Thames and Bristol Avon catchments, chosen to represent gradients of diffuse pollution sources. These locations will be chosen to coincide with Wastewater Treatment Works (WwTWs) to understand how sewage effluent contributes to chemical burden across these gradients. Liquid chromatography coupled with (high resolution) tandem mass spectrometry and QTOF (quadrupole Time-of-Flight) mass spectrometry will be used to perform targeted and untargeted profiling of chemical groups proven and suspected to impact freshwater ecology. A range of microbial community ecosystem endpoints will also be measured at each location to identify the impact of chemical exposure, including bacterial and fungal community composition via DNA sequencing, the expression of nutrient cycling and chemical stress and resistance genes, the production of extracellular enzymes involved with biogeochemical cycling, and the functional gene repertoire of whole microbial communities.
We will perform experimental microcosm exposures on freshwater microbial communities, with increasing complexity and realism, deploying high-throughput screening to identify novel chemical groups (and their structural features) with the capacity to restructure these communities. Exemplar microbial community modifying chemicals will be investigated in more detail by applying cutting-edge molecular techniques to determine ecological exposure thresholds that represent different taxonomic and functional aspects of freshwater microbial ecosystems. Novel field-based mesocosms will be used to explore wastewater exposures in more realistic, but controlled settings, allowing us to explore how chemical pollution may interact with other ecological drivers such as nutrients and temperature, and how microbial responses scale up to higher trophic levels and alter ecosystem functioning.
Spatially and temporally up-scaled models of diffuse and point source chemical pollution pathways will be combined with novel thresholds developed from the lab and field exposures, to determine chemical threats to freshwater microbes, supporting the development of tools for the better management of the risks of chemical pollution to freshwater ecosystem health. These will be combined with future hydrological, climate, and socio-economic scenarios, informed by responses in our experiments and co-developed with project collaborators, the Environment Agency, to explore future threats to microbial freshwater ecosystems and wider ecosystem health.
The PAthways of Chemicals Into Freshwaters and their ecological ImpaCts (PACIFIC) project will focus on understanding the link between sources of anthropogenic chemicals and their pathways, fate and ecological impacts in freshwater ecosystems, with an emphasis on freshwater microbial ecosystems and the functions they perform. We will investigate the relationship between predicted diffuse and point source chemical pathways and measured chemical concentrations in water and sediments at locations across the Thames and Bristol Avon catchments, chosen to represent gradients of diffuse pollution sources. These locations will be chosen to coincide with Wastewater Treatment Works (WwTWs) to understand how sewage effluent contributes to chemical burden across these gradients. Liquid chromatography coupled with (high resolution) tandem mass spectrometry and QTOF (quadrupole Time-of-Flight) mass spectrometry will be used to perform targeted and untargeted profiling of chemical groups proven and suspected to impact freshwater ecology. A range of microbial community ecosystem endpoints will also be measured at each location to identify the impact of chemical exposure, including bacterial and fungal community composition via DNA sequencing, the expression of nutrient cycling and chemical stress and resistance genes, the production of extracellular enzymes involved with biogeochemical cycling, and the functional gene repertoire of whole microbial communities.
We will perform experimental microcosm exposures on freshwater microbial communities, with increasing complexity and realism, deploying high-throughput screening to identify novel chemical groups (and their structural features) with the capacity to restructure these communities. Exemplar microbial community modifying chemicals will be investigated in more detail by applying cutting-edge molecular techniques to determine ecological exposure thresholds that represent different taxonomic and functional aspects of freshwater microbial ecosystems. Novel field-based mesocosms will be used to explore wastewater exposures in more realistic, but controlled settings, allowing us to explore how chemical pollution may interact with other ecological drivers such as nutrients and temperature, and how microbial responses scale up to higher trophic levels and alter ecosystem functioning.
Spatially and temporally up-scaled models of diffuse and point source chemical pollution pathways will be combined with novel thresholds developed from the lab and field exposures, to determine chemical threats to freshwater microbes, supporting the development of tools for the better management of the risks of chemical pollution to freshwater ecosystem health. These will be combined with future hydrological, climate, and socio-economic scenarios, informed by responses in our experiments and co-developed with project collaborators, the Environment Agency, to explore future threats to microbial freshwater ecosystems and wider ecosystem health.
Organisations
- UK CENTRE FOR ECOLOGY & HYDROLOGY (Lead Research Organisation)
- UNIVERSITY OF OXFORD (Collaboration)
- University of Bath (Collaboration)
- Environment Agency (Collaboration)
- Bristol Avon Rivers Trust (Project Partner)
- Thames21 (Project Partner)
- Thames Water (United Kingdom) (Project Partner)
- YTL (United Kingdom) (Project Partner)
Publications

Tipper HJ
(2024)
Do storm overflows influence AMR in the environment and is this relevant to human health? A UK perspective on a global issue.
in Water research

Warren J
(2024)
Influence of storage time on the stability of diatom assemblages using DNA from riverine biofilm samples
in Metabarcoding and Metagenomics
Description | Molecular Data Generation and Biobanking River Biofilm Samples (SC220034) |
Amount | £393,000 (GBP) |
Funding ID | SC220034 |
Organisation | Environment Agency |
Sector | Public |
Country | United Kingdom |
Start | 01/2023 |
End | 03/2024 |
Description | Rivers Trust eDNA microbial source tracking |
Amount | £4,431 (GBP) |
Organisation | Rivers Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 11/2023 |
End | 02/2024 |
Description | Thames Water pathogen persistence experiments |
Amount | £15,000 (GBP) |
Organisation | Thames Water Utilities Limited |
Sector | Private |
Country | United Kingdom |
Start | 01/2024 |
End | 03/2024 |
Description | Collaboration between UKCEH and University of Oxford |
Organisation | University of Oxford |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Provide project management, and wet lab support including DNA extractions and metagenomic sequencing and analysis of samples. |
Collaborator Contribution | Design and perform complex mesocosm experiments to disentangle the drivers of microbial structure and function in freshwater ecosystems. Provide support with analyses and intellectual input for the project |
Impact | No outputs yet - data analysis underway. |
Start Year | 2023 |
Description | Collaboration between UKCEH and the Environment Agency |
Organisation | Environment Agency |
Country | United Kingdom |
Sector | Public |
PI Contribution | Research into the use and development of molecular tools for assessing freshwater ecosystem health. |
Collaborator Contribution | Samples, contextual data, GIS analysis, interpretation. |
Impact | No outputs yet |
Start Year | 2023 |
Description | Collaboration between UKCEH and the University of Bath |
Organisation | University of Bath |
Department | Department of Chemistry |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Provide project management, and wet lab support including DNA extractions and metagenomic sequencing and analysis of samples. |
Collaborator Contribution | Identify relevant sample collection sites from wastewater treatment works (WwTWs) and rivers in the Bristol Avon catchment, arrange access to WwTWs and collect samples. Perform high resolution masss spectrometry analysis for checmial contaminants. Provide support with analyses and intellectual input for the project |
Impact | No outputs yet - data analysis underway. |
Start Year | 2022 |
Description | Better Water Quality for Wales conference presentation |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | Better Water Quality for Wales conference presentation to describe the PACIFIC project and its intended outcomes |
Year(s) Of Engagement Activity | 2023 |
Description | Environment Agency /Natural England Science profession seminar |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | Environment Agency / Natural England Science Profession seminar to describe the PACIFC project and its intended outcomes. |
Year(s) Of Engagement Activity | 2023 |
Description | Meeting with Chief Medical Officer (CMO) to discuss the role of wastewater on public health |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Policymakers/politicians |
Results and Impact | Meeting with Chief Medical Officer (CMO) to discuss the potential impacts of wastewater on the dissemination of pathogens and AMR in the aquatic environment |
Year(s) Of Engagement Activity | 2023 |
Description | UK Freshwater Quality Research Programme launch event |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | Presentation on the PACIFIC project at the UK Freshwater Quality Research Programme Webinar launch event |
Year(s) Of Engagement Activity | 2023 |
Description | Wastewater and Public Health workshop |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | Participation at a workshop organised by the Royal Academy of Engineering bringing together experts across industry, regulators, academia and recreational water users. They considered the viability of a range of interventions to mitigate risks to public health of wastewater. The workshop was to inform an Academy report on the topic requested by the Chief Medical Officer for England. |
Year(s) Of Engagement Activity | 2024 |
URL | https://nepc.raeng.org.uk/wastewater-public-health |