Afonydd Cymru is sponsoring two PhDs whose findings will help future management of Welsh rivers.

The first of these started in 2024 and is using environmental DNA (eDNA) to characterise the relationship between the distribution of pollutants and changes in biodiversity in the river Ely.

The study is using water samples to look at the diversity of plants, animals and bacteria at a range of sites between the headwaters of these rivers and Cardiff Bay. These samples are also being analysed to detect types of pollutants and their quantity.

Along with Natural Resources Wales, Welsh Government and South East Wales Rivers Trust, we are also supporting a PhD that will be looking at ways to overcome the challenges of measuring chemical contamination in freshwater systems and evaluating new risks.

Up to now, some chemicals in rivers have been difficult to quantify, despite their toxicity. Monitoring efforts have often involved sampling of dead fish, killed specifically for the programme. Other monitoring has involved the use of predator carcasses (often otters killed on roads), although this a method with obvious limitations.

The use of passive samplers to measure chemical threats could therefore have significant advantages but effective methods are yet to be established in the context of rivers and the freshwater environment. Using active and passive sampling of water, active sampling of biota and bio-banked otter tissues, this study will evaluate the strengths and limitations of these methods.