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Scoullos IM, Adhikari S, Lopez Vazquez CM, van de Vossenberg J, Brdjanovic D. Inactivation of indicator organisms on different surfaces after urban floods. Sci Total Environ 2020; 704:135456. [PMID: 31837866 DOI: 10.1016/j.scitotenv.2019.135456] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 10/12/2019] [Accepted: 11/07/2019] [Indexed: 06/10/2023]
Abstract
The high frequency and intensity of urban floods caused by climate change, urbanisation and infrastructure failures increase public health risks when the flood water contaminated from combined sewer overflows (CSOs) or other sources of faecal contamination remains on urban surfaces. This study contributes to a better understanding of the effects of urban and recreational surfaces on the occurrence of waterborne pathogens. The inactivation of selected indicator organisms was studied under controlled exposure to artificial sunlight for 6 h followed by 18 h in dark conditions. Concrete, asphalt, pavement blocks and glass as control were inoculated with artificial floodwater containing, as indicator organisms, Escherichia coli bacteria, which are common faecal indicator bacteria (FIB) for water quality assessment, Bacillus subtilis spores chosen as surrogates for Cryptosporidium parvum oocysts and Giardia cysts, and bacteriophages MS2 as indicators for viral contamination. On practically all the surfaces in this study, E. coli had the highest inactivation under light conditions followed by MS2 and B. subtilis, except asphalt where MS2 was inactivated faster. The highest inactivation under light conditions was seen with E. coli on a concrete surface (pH 9.6) with an inactivation rate of 1.85 h-1. However, the pH of the surfaces (varying between 7.0 and 9.6) did not have any influence on inactivation rates under dark conditions. MS2 bacteriophage had the highest inactivation under light conditions on asphalt with a rate of 1.29 h-1. No die-off of B. subtilis spores was observed on any of the surfaces during the experiment, neither in light nor in dark conditions. This study underpins the need to use different indicator organisms to test their inactivation after flooding. It also suggests that given the sunlight conditions, concentration of indicator organisms and type of surface, the fate of waterborne pathogens after a flood could be estimated.
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Affiliation(s)
- Iosif Marios Scoullos
- Environmental Engineering & Water Technology Department, IHE Delft Institute for Water Education, P.O. Box 3015, Delft 2601 DA, The Netherlands; Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands.
| | - Sabita Adhikari
- Environmental Engineering & Water Technology Department, IHE Delft Institute for Water Education, P.O. Box 3015, Delft 2601 DA, The Netherlands
| | - Carlos M Lopez Vazquez
- Environmental Engineering & Water Technology Department, IHE Delft Institute for Water Education, P.O. Box 3015, Delft 2601 DA, The Netherlands
| | - Jack van de Vossenberg
- Environmental Engineering & Water Technology Department, IHE Delft Institute for Water Education, P.O. Box 3015, Delft 2601 DA, The Netherlands
| | - Damir Brdjanovic
- Environmental Engineering & Water Technology Department, IHE Delft Institute for Water Education, P.O. Box 3015, Delft 2601 DA, The Netherlands; Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
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Scoullos IM, Lopez Vazquez CM, van de Vossenberg J, Brdjanovic D. Die-off of E. coli as fecal indicator organism on different surfaces after urban floods. J Environ Manage 2019; 250:109516. [PMID: 31513998 DOI: 10.1016/j.jenvman.2019.109516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/24/2019] [Accepted: 09/02/2019] [Indexed: 06/10/2023]
Abstract
A better understanding of the effects of different urban and recreational surfaces on the die-off of water-borne pathogens that can cause infections after urban floods if released from surcharged combined sewers and other sources of fecal contamination is needed. The die-off of fecal indicator Escherichia coli was studied under controlled exposure to simulated sunlight on a range of different surfaces found in urban environments: gravel, sand, asphalt, pavement blocks, concrete, playground rubber tiles and grass, using glass as control. The surfaces were inoculated with artificial flooding water containing 105 colony forming units (CFU) of E. coli per mL and sampled periodically using the sterile cotton swab technique, after lowering the water level. The results show that dark inactivation was not statistically significant for any surface, suggesting that chemical composition and pH (varying between 6.5 ± 0.8 and 9.2 ± 0.4) did not affect the die-off rates. The highest light-induced die-off rates for E. coli after the floodwater recession, observed on rubber (>3.46 h-1) and asphalt (2.7 h-1), were attributed to temperature stress and loss of surface moisture.
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Affiliation(s)
- Iosif Marios Scoullos
- Environmental Engineering & Water Technology Department, IHE Delft Institute for Water Education, P.O. Box 3015, 2601 DA, Delft, the Netherlands; Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands.
| | - Carlos M Lopez Vazquez
- Environmental Engineering & Water Technology Department, IHE Delft Institute for Water Education, P.O. Box 3015, 2601 DA, Delft, the Netherlands.
| | - Jack van de Vossenberg
- Environmental Engineering & Water Technology Department, IHE Delft Institute for Water Education, P.O. Box 3015, 2601 DA, Delft, the Netherlands.
| | - Damir Brdjanovic
- Environmental Engineering & Water Technology Department, IHE Delft Institute for Water Education, P.O. Box 3015, 2601 DA, Delft, the Netherlands; Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands.
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Scoullos IM, Lopez Vazquez CM, van de Vossenberg J, Hammond M, Brdjanovic D. Effect of Artificial Solar Radiation on the Die-Off of Pathogen Indicator Organisms in Urban Floods. Int J Environ Res 2018; 13:107-116. [PMID: 30873212 PMCID: PMC6383957 DOI: 10.1007/s41742-018-0160-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/04/2018] [Accepted: 11/12/2018] [Indexed: 05/26/2023]
Abstract
In the last decade, flooding has caused the death of over 60,000 people and affected over 900 million people globally. This is expected to increase as a result of climate change, increased populations and urbanisation. Floods can cause infections due to the release of water-borne pathogenic microorganisms from surcharged combined sewers and other sources of fecal contamination. This research contributes to a better understanding of how the occurrence of water-borne pathogens in contaminated shallow water bodies is affected by different environmental conditions. The inactivation of fecal indicator bacteria Escherichia coli was studied in an open stirred reactor, under controlled exposure to simulated sunlight, mimicking the effect of different latitudes and seasons, and different concentrations of total suspended solids (TSS) corresponding to different levels of dilution and runoff. While attachment of bacteria on the solid particles did not take place, the decay rate coefficient, k (d-1), was found to depend on light intensity, I (W m-2), and duration of exposure to sunlight, T (h d-1), in a linear way (k = k D+ 0.03·I and k = k D+ 0.65·T, respectively) and on the concentration of TSS (mg L-1), in an inversely proportional exponential way (k = k D+ 14.57·e-0.02·[TSS] ). The first-order inactivation rate coefficient in dark conditions, k D= 0.37 d-1, represents the effect of stresses other than light. This study suggests that given the sunlight conditions during an urban flood, and the concentration of indicator organisms and TSS, the above equations can give an estimate of the fate of selected pathogens, allowing rapid implementation of appropriate measures to mitigate public health risks.
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Affiliation(s)
- I. M. Scoullos
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
- Department of Environmental Engineering and Water Technology, IHE Delft Institute for Water Education, P.O. Box 3015, 2601 DA Delft, The Netherlands
| | - C. M. Lopez Vazquez
- Department of Environmental Engineering and Water Technology, IHE Delft Institute for Water Education, P.O. Box 3015, 2601 DA Delft, The Netherlands
| | - J. van de Vossenberg
- Department of Environmental Engineering and Water Technology, IHE Delft Institute for Water Education, P.O. Box 3015, 2601 DA Delft, The Netherlands
| | - M. Hammond
- Environment and Natural Resources Global Practice, World Bank Group, Washington, DC USA
| | - D. Brdjanovic
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
- Department of Environmental Engineering and Water Technology, IHE Delft Institute for Water Education, P.O. Box 3015, 2601 DA Delft, The Netherlands
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Fiorentino A, De Luca G, Rizzo L, Viccione G, Lofrano G, Carotenuto M. Simulating the fate of indigenous antibiotic resistant bacteria in a mild slope wastewater polluted stream. J Environ Sci (China) 2018; 69:95-104. [PMID: 29941273 DOI: 10.1016/j.jes.2017.04.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/03/2017] [Accepted: 04/20/2017] [Indexed: 06/08/2023]
Abstract
The fate of indigenous surface-water and wastewater antibiotic resistant bacteria in a mild slope stream simulated through a hydraulic channel was investigated in outdoor experiments. The effect of (i) natural (dark) decay, (ii) sunlight, (iii) cloudy cover, (iv) adsorption to the sediment, (v) hydraulic conditions, (vi) discharge of urban wastewater treatment plant (UWTP) effluent and (vii) bacterial species (presumptive Escherichia coli and enterococci) was evaluated. Half-life time (T1/2) of E. coli under sunlight was in the range 6.48-27.7min (initial bacterial concentration of 105CFU/mL) depending on hydraulic and sunlight conditions. E. coli inactivation was quite similar in sunny and cloudy day experiments in the early 2hr, despite of the light intensity gradient was in the range of 15-59W/m2; but subsequently the inactivation rate decreased in the cloudy day experiment (T1/2=23.0min) compared to sunny day (T1/2=17.4min). The adsorption of bacterial cells to the sediment (biofilm) increased in the first hour and then was quite stable for the remaining experimental time. Finally, when the discharge of an UWTP effluent in the stream was simulated, the proportion of indigenous antibiotic resistant E. coli and enterococci was found to increase as the exposure time increased, thus showing a higher resistance to solar inactivation compared to the respective total populations.
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Affiliation(s)
- Antonino Fiorentino
- Department of Civil Engineering, University of Salerno, 84084 Fisciano, SA, Italy.
| | - Giuliana De Luca
- Department of Chemistry and Biology, University of Salerno, 84084 Fisciano, SA, Italy
| | - Luigi Rizzo
- Department of Civil Engineering, University of Salerno, 84084 Fisciano, SA, Italy.
| | - Giacomo Viccione
- Department of Civil Engineering, University of Salerno, 84084 Fisciano, SA, Italy
| | - Giusy Lofrano
- Department of Chemistry and Biology, University of Salerno, 84084 Fisciano, SA, Italy
| | - Maurizio Carotenuto
- Department of Chemistry and Biology, University of Salerno, 84084 Fisciano, SA, Italy
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