Quantitative analysis of earthy and musty odors in drinking water sources impacted by wastewater and algal derived contaminants

The goal of this study was to develop a robust method capable of quantifying taste and odor compounds (i.e., geosmin and 2-methylisoborneol) at very low aqueous concentrations in the presence of wastewater and algal derived contaminants. A polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber was used to perform headspace-solid phase microextraction (HS-SPME) to extract and analyze taste and odor compounds from model, source water, and finished drinking water samples. Gas chromatography coupled with mass spectrometery (GC/MS) in full scan mode was used to analyze the compounds desorbed from the fiber in the GC inlet. The following parameters were optimized in order to enhance analyte recovery: extraction temperature, extraction time, desorption time, sonication temperature, sonication time and GC/MS configuration/temperature program. After optimization, the method provided a linear response from 1 to 300 ng L−1 and yielded limit of detections (LODs) of 1 ng L−1 for both 2-MIB and geosmin. In MS full scan mode, wastewater contaminants and other algal derived volatile organic compounds (ADVOCs) relevant to cyanobacterial bloom dynamics were detected and monitored in real source water samples. In the presence of known interferents with similar mass/charge fragments and elution times, the optimized method yielded low detection limits as well as exact molecular confirmation for taste and odor compounds in impacted source water samples. This method could be used as a tool to aid in the development of source water protection plans by identifying potential sources of anthropogenic and algal derived contamination in drinking water sources.

► HS-SPME extraction temperature and time were optimized for geosmin/2-MIB recovery.
► Sonication of raw samples for 10 min at 4 °C minimally degrading target analytes.
► The method in full scan MS mode can detect geosmin and 2-MIB at ng L−1 concentrations.
► Able to monitor wastewater and algal contaminants in drinking water sources.
► The method provides information necessary to develop source water protection plans.