Quantitative microbial risk assessment for waterborne pathogens in a wastewater treatment plant and its receiving surfac
- PDF / 974,753 Bytes
- 12 Pages / 595.276 x 790.866 pts Page_size
- 45 Downloads / 191 Views
RESEARCH ARTICLE
Open Access
Quantitative microbial risk assessment for waterborne pathogens in a wastewater treatment plant and its receiving surface water body Joshua Mbanga1,2* , Akebe Luther King Abia1, Daniel Gyamfi Amoako1 and Sabiha. Y. Essack1
Abstract Background: Access to safe water for drinking and domestic activities remains a challenge in emerging economies like South Africa, forcing resource-limited communities to use microbiologically polluted river water for personal and household purposes, posing a public health risk. This study quantified bacterial contamination and the potential health hazards that wastewater treatment plant (WWTP) workers and communities may face after exposure to waterborne pathogenic bacteria in a WWTP and its associated surface water, respectively. Results: Escherichia coli (Colilert®-18/ Quanti-Tray® 2000) and enterococci (Enterolert®/ Quanti-Tray® 2000) were quantified and definitively identified by real-time polymerase chain reaction targeting the uidA and tuf genes, respectively. An approximate beta-Poisson dose-response model was used to estimate the probability of infection (Pi) with pathogenic E. coli. Mean E. coli concentration ranged from 2.60E+ 02/100 mL to 4.84E+ 06/100 mL; enterococci ranged from 2.60E+ 02/100 mL to 3.19E+ 06/100 mL across all sampled sites. Of the 580 E. coli isolates obtained from this study, 89.1% were intestinal, and 7.6% were extraintestinal pathogenic E. coli. The 579 enterococci obtained were 50.4% E. faecalis (50.4%), 31.4% E. faecium, 3.5%, E. casseliflavus and 0.7% E. gallinarum. The community health risk stemming from the use of the water for recreational and domestic purposes revealed a greater health risk (Pi) from the ingestion of 1 mL of river water from upstream (range, 55.1–92.9%) than downstream (range, 26.8–65.3%) sites. The occupational risk of infection with pathogenic E. coli for workers resulting from a once-off unintentional consumption of 1 mL of water was 0% (effluent) and 23.8% (raw influent). Multiple weekly exposures of 1 mL over a year could result in a Pi of 1.2 and 100% for the effluent and influent, respectively. Conclusion: Our findings reveal that there is a potentially high risk of infection for WWTP workers and communities that use river water upstream and downstream of the investigated WWTP. Keywords: Quantitative microbial risk assessment, Wastewater treatment plants, Escherichia coli, Enterococcus
* Correspondence: [email protected]; [email protected] 1 Antimicrobial Research Unit, College of Health Sciences, University of Kwazulu-Natal, Private Bag X54001, Durban 4000, South Africa 2 Department of Applied Biology and Biochemistry, National University of Science and Technology, P.O Box AC 939 Ascot, Bulawayo 00263, Zimbabwe © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original au
Data Loading...
