Differential decomposition of bacterial and viral fecal indicators in common human pollution types. (15th November 2016)

• Record Type: Journal Article
• Authors: Wanjugi, Pauline; Sivaganesan, Mano; Korajkic, Asja; Kelty, Catherine A.; McMinn, Brian; Ulrich, Robert; Harwood, Valerie J.; Shanks, Orin C.
• Is Part Of: Water research. Volume 105(2016)
• Page Start: 591
• Page End: 601
• Publication Date: 2016-11-15
• Subjects: Human fecal pollution -- Coliphage -- Fecal indicator bacteria -- Microbial source tracking; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2016.09.041
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Understanding the decomposition of microorganisms associated with different human fecal pollution types is necessary for proper implementation of many water quality management practices, as well as predicting associated public health risks. Here, the decomposition of select cultivated and molecular indicators of fecal pollution originating from fresh human feces, septage, and primary effluent sewage in a subtropical marine environment was assessed over a six day period with an emphasis on the influence of ambient sunlight and indigenous microbiota. Ambient water mixed with each fecal pollution type was placed in dialysis bags and incubated in situ in a submersible aquatic mesocosm. Genetic and cultivated fecal indicators including fecal indicator bacteria (enterococci, E. coli, and Bacteroidales ), coliphage (somatic and F+), Bacteroides fragilis phage (GB-124), and human-associated genetic indicators (HF183/BacR287 and HumM2) were measured in each sample. Simple linear regression assessing treatment trends in each pollution type over time showed significant decay (p ≤ 0.05) in most treatments for feces and sewage (27/28 and 32/40, respectively), compared to septage (6/26). A two-way analysis of variance of log10 reduction values for sewage and feces experiments indicated that treatments differentially impact survival of cultivated bacteria, cultivated phage, and genetic indicators. Findings suggest that sunlight is critical for phage decay, and indigenous microbiota play a lesser role. For bacterial cultivated and genetic indicators, the influence of indigenous microbiota varied by pollution type. This study offers new insights on the decomposition of common human fecal pollution types in a subtropical marine environment with important implications for water quality management applications. Graphical abstract: Highlights: Common human waste pollution types exhibit markedly different decomposition trends. Most indicator concentrations did not change over time in septage experiments (p > 0.05). Clear patterns are evident between viral, bacterial, cultivation and genetic indicator types. Indigenous microbiota can strongly influence indicator decay, especially after 48 h. Variation in decay trends can have serious implications for water quality applications.