Investigating Taste and Odour Characteristics in a Drinking Water Source: A Comprehensive 3-Year Monitoring Study

Area of Science:

• Environmental Science
• Microbiology
• Public Health

Background:

• Drinking water quality monitoring is essential for public health.
• Taste and odour (T&O) episodes, caused by compounds like geosmin and 2-methylisoborneol (2-MIB), erode public trust in water quality.
• Understanding the dynamics of T&O compound production is critical for managing drinking water sources.

Purpose of the Study:

• To monitor the water quality of a key drinking water source.
• To investigate the production dynamics of geosmin and 2-MIB, the primary causes of T&O issues.
• To identify the microbial communities responsible for producing and degrading these T&O compounds.

Main Methods:

• Lake trophic status was assessed.
• Physicochemical parameters, temperature, and depth were correlated with geosmin and 2-MIB concentrations.
• Gas chromatography-mass spectrometry (GC-MS) was used for compound quantification.
• Polymerase chain reaction (PCR) and metabarcoding identified microbial communities (Cyanobacteria, Actinobacteria, and others).

Main Results:

• The lake's trophic status was classified as mesotrophic.
• 2-MIB concentrations correlated positively with temperature, while geosmin correlated positively with depth.
• Peak concentrations of both compounds occurred during thermal stratification periods.
• Specific bacterial genera (e.g., Planktothrix, Streptomyces) were identified as potential producers, while others (e.g., Micrococcus, Pseudomonas) were identified as potential degraders.

Conclusions:

• Autochthonous bacterial communities play a significant role in the T&O dynamics of drinking water sources.
• Temperature and thermal stratification are key environmental factors influencing the production of geosmin and 2-MIB.
• Effective management strategies for T&O episodes require understanding microbial ecology and limnological conditions.