In this study, faecal sterols were used to identify human faecal pollution in a non-sewered catchment in Southeast Queensland, Australia. In all, 36 water samples were collected from six sites on six occasions and the concentration of sterols were determined using gas chromatography and mass spectrometry. The stanols concentration in water samples generally increased with increased catchment runoff. After moderate rainfall, high coprostanols levels found in water samples indicated human faecal pollution via defective septic systems. In contrast, it appears that during dry weather human faecal pollution is not occurring in the study catchment. Sterol profiles also pointed to a cattle farm polluting during modest catchment runoff. The method used in this study was able to identify the sources of faecal pollution to the catchment due to rainfall.
Keywords: coprostanol, faecal pollution, faecal source tracking, faecal sterols, septic systems