Microbial source tracking services

Environmental protection and long-term operational efficiency

Together with our RSK partners at ADAS Biotechnology, we have developed a microbial source tracking (MST) service that enables the accurate and sensitive quantification of DNA markers that indicates the source of faecal contamination (human versus animal host groups) in any aquatic environment.

Our MST service leverages the World Health Organization’s One Health approach, considering animal, human and environment health as one. It enables targeted interventions for faecal pollution, reducing unnecessary infrastructure spending and streamlining remediation efforts. Its scientifically validated methodology ensures reliable results, while the flexibility of the service enables it to be tailored to diverse client needs.

We provide a full service from site evaluation and human/agricultural risk assessment to mitigation strategies (nature-based solutions) to improve water quality for regulatory compliance and catchment management. This makes MST a cost-effective investment in both environmental protection and long-term operational efficiency.

WRc

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The challenges faced in the industry

Faecal pollution in water is a major public health and environmental challenge. It introduces disease-causing microorganisms, including bacteria, viruses and parasites, into drinking water sources, rivers, lakes, groundwater and coastal waters, creating risks for water supplies, recreational water users, aquacultural activities and aquatic ecosystems. The problem is becoming more complex because of population growth, urbanisation, ageing wastewater infrastructure, agricultural intensification and climate change: heavy rainfall and flooding increasingly mobilise faecal material from contamination sources.

Faecal pollution can come from a wide range of sources, including human wastewater from treatment plant discharges, combined sewer overflows and septic tank leakages, in addition to non-human sources such as agricultural waste and wildlife. A key challenge is that conventional, regulatory monitoring using faecal indicator bacteria such as Escherichia coli and intestinal enterococci can only identify the presence of faecal contamination but generally, cannot determine its source, making it difficult for regulators and water companies to understand the root causes of faecal pollution challenges and thus to implement targeted mitigation measures. This uncertainty can lead to prolonged investigations, ineffective interventions and increased costs, while mixed pollution sources and highly variable contamination events further complicate risk assessment and management.

The key advantages of MST

Regulatory compliance support

Providing robust evidence to meet environmental standards and support investigations.

Pollution source identification

Identifying the origin of faecal contamination (human, agricultural or wildlife) for targeted action.

Bathing water quality assessments

Supporting safe recreational coastal and inland bathing water use by identifying contamination risks and guiding mitigation.

Infrastructure planning and investment

Informing decisions on wastewater treatment upgrades and storm overflow management.

Additionally, we have the capacity to link faecal indicator bacteria and MST marker data and use them for quantitative microbial risk assessment (QMRA), utilising internationally recognised tools. This approach gives health-risk-based metrics, such as probability of infection (e.g., annual risk per person), enabling decisions to be made based on the public health significance of contamination. QMRA can inform on required pathogen reduction levels, identify treatment needs, high-risk events and critical control points, assisting in informed decision-making on treatment levels and infrastructure upgrades.

WRc’s research and projects

We have conducted three case studies during the service development phase to validate our quantitative methodology for the human, ruminant and gull markers we currently offer. We have also worked with various water companies and other stakeholders to assist in identifying faecal pollution sources at bathing sites and drinking water sources and drinking water treatment weaknesses.

What are we swimming in? The growing need for Microbial Source Tracking. The Microbiologist, 2025. https://www.the-microbiologist.com/features/what-are-we-swimming-in-the-growing-need-for-microbial-source-tracking/7035.article
Microbial Source Tracking: turning faecal pollution data into practical water management solutions. IWater Magazine, 2026. https://library.myebook.com/InstituteofWaterMagazine/spring-2026/6543/#page/24
Study to detect pollution markers in river water. RSK, 2024. https://rskgroup.com/projects/study-detect-pollution-markers-in-river-water/
Suitability of bacterial and viral markers for faecal source tracking in the coastal environment. Journal of Applied Microbiology, 2026, vol 137. https://doi.org/10.1093/jambio/lxag140

Microbial source tracking at catchments: MST service to determine human versus ruminant pollution sources in samples taken in two catchments in the UK for five weeks. We provided weekly reports on marker concentrations and data interpretation using R and QGIS (including graphs, charts and heatmaps, as appropriate) for each weekly batch (a UK consultancy).
Microbial source tracking in groundwater sources and during drinking water treatment: A water company struggling with sporadic coliform detections before/after drinking water treatment collected high volume samples to be tested for human and ruminant markers. For a more holistic understanding of pollution, next generation sequencing was also utilised (a UK water company).
Microbial source tracking to assess catchment to coast faecal pollution: Our team provides MST marker quantification (utilising human, ruminant and gull markers) for a year-long study performed by a university to assess the magnitude of land-derived pollution (a UK university).
Microbial source tracking at bathing water sites: We compared MST marker levels in the winter versus summer periods to provide insights into potential routes of contamination for regulatory purposes (a UK regulator).