Fecal pollution of the river waters, using coprostanol as an indicator

Raw waters in 8 rivers in Fukuoka Prefecture were examined for coprostanol as an indicator of fecal pollution and the correlations between coprostanol and bacterial indicator groups were studied. The results obtained were as follows ; (1) The highest concentration of coprostanol was found in water of the Mikasa River during the drought period, and its value was 5.20 μg/l, which was similar to that of municipal sewage final effluent. (2) There was a significant relationship between fecal sterols and other pollutants (KMnO4 consumption, NH4-N and Cl-), but no significant relationship between fecal sterols and total coliform. (3) The residual amounts of coprostanol and bacterial indicator groups in a declining system were in the order total coliform > coprostanol _??_ fecal coliform > fecal streptococci. This result suggests that the finding of one fecal coliform bacteria in 50 ml is equivalent to detecting coprostanol in 800 ml of water. (4) The rate constants of total coliform, fecal coliform, and fecal streptococci were in the range 0.22-0.29 (day-1), 0.48-0.98 (day-1), 0.78-1.22 (day-1), respectively.