From Signals to Smells: Integrating Microbial Ecology and Environmental Drivers to Predict Taste and Odour Events

Taste and odour (T&O) issues caused by geosmin and 2-MIB persist worldwide in drinking water. Though posing minimal health risks, their low odour thresholds lead to customer complaints and costly treatments. These compounds in freshwater reservoirs mainly stem from cyanobacterial activity, influenced by interactions among microbes, nutrients, and physical processes like stratification and redox cycling. Conventional prediction methods rely on environmental factors or cyanobacterial biomass but don’t fully capture the biological mechanisms behind T&O production. This review synthesises current understanding of the environmental drivers of geosmin and 2-MIB and evaluates existing modelling approaches. A case study introduces an environmental DNA (eDNA)-informed modelling framework integrating biological indicators, chemical variables, and physical drivers within Generalised Additive Models (GAMs) to forecast geosmin concentrations in three UK drinking-water reservoirs. Integrating biological indicators into predictive models provides a promising pathway toward operational early-warning systems for proactive T&O management.