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SEPA unveil new method to detect chemicals in water environment

SEPA will now be able to screen for hundreds of chemical compounds in one go by providing a broad-spectrum analysis of all chemicals present in a single sample.

The new method of water analysis offers a more comprehensive understanding of Scotland’s aquatic ecosystems. It will allow SEPA to conduct large-scale analysis of diverse chemical compounds, including pesticides, pharmaceuticals, and veterinary medicines. 

Traditionally, chemistry water sampling requires you to know what you want to look for first to run a targeted analysis of specific substances.

Now, analysis will be done using advanced liquid chromatography with high resolution mass spectrometry. This wide-reaching horizon scan technique could enable SEPA to detect chemicals that were previously unknown or unmonitored, identifying potential risks before they become significant threats to Scotland’s ecosystems and communities.

Jennifer Best, Principal Specialist Scientist at SEPA, said: "This new method of water sampling analysis represents a breakthrough in how we monitor Scotland’s water resources and is a game changer for environmental chemistry more widely. 

"Instead of limiting our analysis to a predetermined set of chemicals, we’re using a single water sample to scan for a broad spectrum of compounds, letting us see chemicals that may have previously gone unnoticed and building a more complete picture of Scotland’s water environment."

Broader, greener and more efficient water analysis

Unlike traditional approaches that focused on detecting specific substances, this methodology is designed for open-ended investigation, allowing SEPA the opportunity to take a closer look at a diverse range of chemicals without pre-selection. If an “unknown” substance is detected, the original sample data can be reprocessed to determine its concentration without having to re-analyse the water sample.

The methodology offers significant environmental and operational advantages as it requires smaller water samples, reducing the environmental footprint of the sampling process, and enables the creation of an archive of data that can be revisited and reprocessed with emerging analysis methods.

The first dataset from this new method is expected in 2025. Insights will be shared with a range of stakeholders including regulators. The data will inform the UK Prioritisation and Early Warning System (an initiative developed by the Environment Agency to identify and respond to emerging substances of concern), and help the cross-government Pharmaceuticals in the Environment Group, the One Health Breakthrough Partnership, and academic researchers. 

This data will also complement SEPA’s research into developing new methodology for environmental DNA analysis. Together they will help provide a more comprehensive understanding of both the presence of chemicals and their effects on Scotland’s diverse aquatic habitats.

Protecting Scotland’s environment and communities

Compounds such as pharmaceuticals and pesticides can impact human health and biodiversity. Increased understanding of which chemicals are present in the water can help SEPA and partner agencies track chemical build-up and assist pollution investigations by helping identify chemical pollutants and their potential sources.

This technique offers benefits for the farming community too, as it can help track agricultural runoff and assess the impact of plant protection products and veterinary medicines in waterways. And for urban communities, where pharmaceuticals and industrial runoff may play a more prominent role, SEPA’s analysis can pinpoint specific pollutants and inform local actions to mitigate potential hazards.

Jennifer Best added: "This way of detecting, monitoring and identifying chemicals in the water environment is not only a scientific breakthrough for SEPA but also a vital step in safeguarding Scotland’s communities. 

"Water quality is a fundamental aspect of community life. We rely on local rivers, lochs, and streams not only for recreation but also for drinking water, agriculture, and as a source of livelihood. The presence potentially harmful chemicals can impact the health of these ecosystems, which in turn affects public health, food safety, and the wellbeing of local communities.

"By increasing our understanding of which chemicals are present, we can assess and address more potential threats, better protecting our people, environment and wildlife."

Notes to Editors

• Liquid chromatography is an essential analytical chromatographic technique used for separating, identifying, and purifying mixture components for quantitative and qualitative analysis.
• Mass spectrometry is an analytical chemistry technique that helps identify the amount and type of chemicals present in a sample by measuring the mass-to-charge ratio and abundance of gas-phase ions.
• SEPA are currently completing data checks on the targeted data (quantitative and screening), with the first dataset on targeted screening analysis expected to be published in 2025.
• In 2025, SEPA will conduct further monitoring across Scotland’s water environment, complete the data analysis of targeted screening samples collected in 2024 and begin data analysis for unknown chemicals in the 2024 data. SEPA will also continue to develop the methodology by validating its use with freshwater loch water and seawater samples.