Faecal clostridia and indicator bacteria levels in an eutrophic impoundment

Numbers of faecal clostridia, faecal coliforms and faecal streptococci in the Roodeplaat dam and 2 inflowing rivers (Pienaars river, Hartbeesspruit river) were monitored over 8 months (January-August 1985). The Pienaars river which received sewage effluent had the greatest number of faecal indicator bacteria. In both rivers there was no consistency in the ratio of faecal clostridia to faecal coliforms. In mid-dam sampling stations faecal clostridia were present in greater numbers than faecal streptococci with faecal coliform numbers being lowest. Seventy eight per cent of the 135 faecal clostridia isolates were Clostridium perfringens.