Sources of faecal indicator bacteria in a brackish, tropical stream and their impact on recreational water quality

Abstract

This study assessed the contribution of water from a stream on the microbial quality of a swimming beach. The faecal indicator bacterial concentrations/100mL in Kaelepulu Stream greatly exceeded the three USEPA recreational water quality standards (200 faecal coliform, 126 E. coli, 33 enterococci). The primary sources for these indicator bacteria were determined to be environmental/non-point sources (tributary streams, storm drains, duck faeces, soil, rain). Sewage discharge is another, although sporadic source. Monitoring waters for C. perfringens was the most reliable indicator of sewage contamination primarily because soil is not a major source of this bacterium. Water from this inland system was a source of faecal indicator recovered from shoreline water samples obtained from Kailua Beach, one of the most popular beaches in the state of Hawaii.