An analytical method to determine faecal sterols was developed and applied
to the analysis of samples including pig manure, sewage treatment plant slu
dge and combined sewer overflow effluent. Compounds including coprostanol (
5 beta -cholestan-3 beta -ol), epicoprostanol (5 beta -cholestan-3 alpha -o
l), cholesterol (cholestan-5en-3 beta -ol) and dihydrocholesterol (cholesta
nol, 5 alpha -cholestan-3 beta -ol) were quantified in these source samples
and their relative ratios calculated to investigate their potential applic
ation as source tracers. A mean coprostanol:epicoprostanol ratio of 7.6 +/-
1.17 was calculated for pig manure samples from three Ontario livestock op
erations. This ratio was much lower (approximately 1.8) for sewage treatmen
t plant sludge while the ratio for a combined sewer overflow effluent was v
ery high (approximately 70). This approach, with the addition of physical m
easurements (e.g., current velocities) and meteorological data, may assist
in determination of the influence of shore-based activities, including sewa
ge treatment and livestock operations, on aquatic systems.