Sterols as a Measure of Fecal Pollution

An analytical method for measuring coprostanol and cholesterol in wastewater plant effluents and surface waters consisting of solvent extraction, hydrolysis of esters to free the sterols, cleanup by thin-layer chromatography, and quantitative measurement by gas chromatography of the trimethylsilyl ether derivatives has been developed. Data have been collected on the amounts of coprostanol and cholesterol in treatment plant effluents, surface waters, and three types of feces. The coprostanol content of human feces is 17 times greater than that of the hog and 175 times that of the cow. In treatment plant effluents, the amount of coprostanol varied from 5 μg/l to 750 μg/l. Surface waters varied from 0.02 μg/l to 5 μg/l. Results obtained from locations on streams adjacent to treatment plants showed distinct increases in the amounts of coprostanol and cholesterol below wastewater outfalls.