DEVELOPMENT OF A NOVEL PASSIVE SAMPLING APPROACH FOR MONITORING GEOSMIN AND 2-MIB IN WATER

Abstract

The increased eutrophication of freshwater sources has led to a rise in taste and odour events notoriously caused by geosmin and 2-methylisoborneol (2-MIB). This places more pressure on current monitoring methods due to increased sampling frequency. Unfortunately, conventional grab sampling methods and the required sample preparation steps are laborious, time-consuming and provide only a single-time snapshot of geosmin and 2-MIB levels in the water. An alternative sampling approach for water quality monitoring is passive sampling, which extracts and allows the accumulation of the target analytes directly from the water. The simplicity and robustness of passive sampling makes it more suitable for routine monitoring. The goal of this study was to develop a simple passive sampling protocol for the detection of geosmin and 2-MIB in drinking water source lakes. In bench scale experiments, various passive sampling parameters (adsorbent, elution solvent, sorbent mass to elution volume ratio and elution method) were optimized prior to accessing the method’s performance characteristics (i.e., linearity, precision, accuracy, matrix effects, limits of detection and quantitation). Recoveries of 50 and 53% for geosmin and 2-MIB, respectively were obtained with excellent intra and inter day precision (≤15% RSD). Semi-quantitative detection limits of 0.014 and 0.044 μg L-1 for geosmin and 2-MIB, respectively, were obtained. The validated passive sampling method was used to conduct a field study at eight lake water sites in Atlantic Canada within a three-month period. The study demonstrated that the developed passive sampling method could be utilized for the reliable detection of geosmin and 2-MIB in source water as well as provide improved resolution for its early detection in drinking water supplies.