Reduction of human fecal markers and enteric viruses in Sydney estuarine waters receiving wet weather overflows

• DOI: 10.1016/j.scitotenv.2023.165008
• Publication Date: 2023-06-20T16:03:23Z
• Authors: Warish Ahmed; Sudhi Payyappat; Michele Cassidy; Nathan Harrison; Colin Besley
• Keywords: Indicator bacteria

The current microbial source tracking (MST) study tracked the reduction of culturable fecal indicator bacteria enterococci, four human markers (Bacteroides HF183, Lachnospiraceae Lachno3, cross-assembly phage (CrAssphage) and pepper mild mottle virus (PMMoV)) along with enteric viruses - adenovirus 40/41 (HAdV 40/41), enterovirus (EV), norovirus GI (HNoV GI) GII GII) post wet weather overflows (WWOs) at two estuarine water sites from depths under separate six-day sampling campaigns over seven 12 days in Sydney, NSW, Australia. Neither HNoV nor was detected, while 13.9 % (10/72) samples had detections EV. Quantifiable concentrations (0.64 to 2.00 log10 gene copies (GC)/100 mL) for HAdV were returned 65.2 (47/72) collected across 30 quantifications recorded surface layer samples. In contrast presence CrAssphage, PMMoV observed all 36 (100 %) both sites. Detection frequencies these slightly lower 1 m above bottom surface. compared established gastrointestinal (GI) risk benchmarks. Lachno3 CrAssphage marker only exceeded benchmark until day 3, indicative exceedance on 7 WWOs that much longer than indicated by enterococci within this 2 4 sites, respectively.