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Correction: Rasheduzzaman, M., et al. Reverse QMRA as a Decision Support Tool: Setting Acceptable Concentration Limits for Pseudomonas aeruginosa and Naegleria fowleri. Water 2019, 11, 1850
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Correction published on 28 November 2019, see Water 2019, 11(12), 2523.
Open AccessArticle

Reverse QMRA as a Decision Support Tool: Setting Acceptable Concentration Limits for Pseudomonas aeruginosa and Naegleria fowleri

1
Department of Civil, Architectural and Environmental Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
2
The Biodesign Institute Center for Environmental Health Engineering & The School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ 85281, USA
*
Author to whom correspondence should be addressed.
Water 2019, 11(9), 1850; https://doi.org/10.3390/w11091850
Received: 3 July 2019 / Revised: 27 August 2019 / Accepted: 29 August 2019 / Published: 5 September 2019
(This article belongs to the Special Issue Health Risks of Alternative Water Sources)
Opportunistic premise plumbing pathogens such as Pseudomonas aeruginosa and Naegleria fowleri are a growing concern in building water systems because of their potential risks to human health. The aim of this study was to determine the critical concentrations of P. aeruginosa and N. fowleri in water that are associated with meaningful public health risks. To determine these concentrations, a reverse quantitative microbial risk assessment (QMRA) was conducted. Environmental concentrations of P. aeruginosa and N. fowleri corresponding to the risk target of one micro-disability-adjusted life year (DALY) per person per year and 10−4 annual risks of illness were calculated for several applicable exposure scenarios. To calculate the concentration of P. aeruginosa, cleaning contact lenses with potentially contaminated tap water in the absence of an appropriate cleaning solution was considered. For N. fowleri, two exposure scenarios, recreational exposure (swimming) and nasal cleansing (via the use of a neti pot™ or similar device) were considered. The highest critical concentration for P. aeruginosa was found to be 33 CFU/L with a 95% confidence interval of (2.0, 118) for the drop exposure scenario using the 10−4 annual risk target. For N. fowleri, based on the DALY approach, critical concentrations were 0.000030 N. fowleri/L for swimming and 0.00000060 N. fowleri/L for neti pot™ use scenario. Considering heat inactivation, the critical concentration limits for P. aeruginosa using the DALY approach and the 10−4 annual risk target approach were found to be 0.55 CFU/L and 55 CFU/L, respectively. For N. fowleri, the 10−4 annual risk target approach resulted in 0.022 N. fowleri/L and the DALY approach resulted in 0.00000064 N. fowleri/L for the neti pot™ scenario. For P. aeruginosa, N50 (the median infective dose) and alpha (α) contributed the most and contact rates the least to the variability and uncertainty of the estimates for all the scenarios. For N. fowleri, N50 and contact rates contributed the most and α the least to the variability and uncertainty to calculate the concentrations for all the scenarios. The QMRA framework implemented in this research can be used to incorporate more information regarding opportunistic pathogens to inform management decisions, and to prioritize the best interventions regarding estimated reduction in infections caused by opportunistic pathogens. View Full-Text
Keywords: Naegleria fowleri; Pseudomonas aeruginosa; microbial risk; risk assessment; premise plumbing; dose-response; reverse QMRA; quantitative risk assessment Naegleria fowleri; Pseudomonas aeruginosa; microbial risk; risk assessment; premise plumbing; dose-response; reverse QMRA; quantitative risk assessment
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Rasheduzzaman, M.; Singh, R.; Haas, C.N.; Tolofari, D.; Yassaghi, H.; Hamilton, K.A.; Yang, Z.; Gurian, P.L. Reverse QMRA as a Decision Support Tool: Setting Acceptable Concentration Limits for Pseudomonas aeruginosa and Naegleria fowleri. Water 2019, 11, 1850.

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