SENSORY GC ANALYSIS OF DECAYING VEGETATION AND SEPTIC ODORS

A study was undertaken to identify the chemicals responsible for septi c and decaying vegetation odors, not only in odor reference standards but also in natural waters. Two complementary extraction methods-close d-loop stripping analysis and simultaneous distillation extraction-wer e used. Chemical identification was performed by gas chromatography (G C) with mass spectrometry, and sensory identification was accomplished by flavor profile analysis and sensory GC. Dimethyl disulfide, dimeth yl trisulfide, and 2-isobutyl-3-methoxypyrazine were the principal con tributors to decaying vegetation odors, whereas dimethyl trisulfide an d indole were strongly associated with septic odors. In addition, the study confirmed the presence of these chemicals as well as 2-isopropyl -3-methoxypyrazine (associated with decaying vegetation) in water supp lies.