A tiered approach for the identification of faecal pollution sources on an Auckland urban beach

Abstract

Microbiological contamination arising from faecal pollution is a widespread effect of human activity on aquatic systems, with management of the issue complicated because contamination sources are often unknown. Recent advances in molecular techniques have permitted the use of host-specific genetic markers to apportion sources of faecal pollution. In this study, we used a tiered approach employing faecal indicator bacteria and Bacteroidales markers to identify faecal sources in an urban setting. Canine sources were the most common source of faecal contamination, which led to a programme of education and targeted management. A single, but substantial, source of human faecal contamination was identified that was subject to corrective action and its effectiveness validated by supplementary monitoring. This study supports the use of a tiered approach for the identification of faecal contamination sources in New Zealand, including the use of faecal indicator bacteria and more complex source-tracking analysis using genetic markers.