Freshwater eutrophication, driven by excess nitrogen and phosphorus, leads to algal blooms and degraded water quality, exacerbated by anthropogenic activities such as wastewater mismanagement and agricultural runoff (Yang et al. 2022). Constructing dams (impoundments) to create reservoirs significantly alters river hydrology, influencing water retention, quality, and volatile organic compound (VOC) emissions (Krajenbrink et al. 2019). Management operations like drawdowns and climate change-induced droughts expose sediments to atmospheric conditions, enhancing the release of odorous VOCs, including geosmin, 2-MIB, and β-cyclocitral. These compounds cause taste and odour issues in drinking water (Pozzer et al. 2022), yet little research has examined their sources and dynamics in UK reservoirs.
This study investigates the impact of impoundment, seasonal changes, and climate-driven drought on VOC emissions from eutrophic drinking water reservoirs in the Midlands, UK. The research focuses on two drinking water reservoirs: one impounded reservoir that experienced severe drought (2018–2022; down to 20–25% of capacity) and was recently refilled to full capacity (2024), and another non-impounded reservoir that struggles with algal blooms. Seasonal water and sediment samples are analysed using modified Solid Phase Micro-Extraction (SPME) and Gas Chromatography (Lu et al. 2012). Historical water level and abstraction data will also be examined to correlate VOC emissions with anthropogenic and climatic stressors.
Preliminary findings suggest that Swithland will exhibit a more diverse VOC profile, with elevated levels of geosmin, 2-MIB, and β-cyclocitral, particularly in summer. This study will elucidate the link between sediment exposure, resuspension, and VOC emissions, providing critical insights into water quality degradation. The findings will contribute to sustainable reservoir management strategies, guiding mitigation efforts to ensure safe, palatable drinking water supplies.