scholarly journals Direct and indirect QMRA of infectious Cryptosporidium oocysts in reclaimed water

2012 ◽  
Vol 10 (4) ◽  
pp. 539-548 ◽  
Author(s):  
M. Agulló-Barceló ◽  
R. Casas-Mangas ◽  
F. Lucena
Keyword(s):  
Uv Light ◽  
Health Hazard ◽  
Reclaimed Water ◽  
Poisson Model ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Treatment Type ◽  
Cryptosporidium Oocysts ◽  
The Mean

Water scarcity leads to an increased use of reclaimed water, which in turn calls for an improvement in water reclamation procedures to ensure adequate quality of the final effluent. The presence of infectious Cryptosporidium oocysts (IOO) in reclaimed water is a health hazard for users of this resource. Here, we gathered information on Cryptosporidium (concentrations, infectivity and genotype) in order to perform quantitative microbial risk assessment (QMRA). Moreover, data concerning the spores of sulphite-reducing clostridia (SRC) were used to undertake QMRA at a screening level. Our results show that the probability of infection (PI) by Cryptosporidium depends on the tertiary treatment type. The mean PI using the exponential dose-response model was 3.69 × 10−6 in tertiary effluents (TE) treated with UV light, whereas it was 3 log10 units higher, 1.89 × 10−3, in TE not treated with this disinfection method. With the β-Poisson model, the mean PI was 1.56 × 10−4 in UV-treated TE and 2 log10 units higher, 4.37 × 10−2, in TE not treated with UV. The use of SRC to perform QMRA of Cryptosporidium showed higher PI than when using directly IOO data. This observation suggests the former technique is a conservative method of QMRA.

scholarly journals Quantification of the health risk associated with wastewater reuse in Accra, Ghana: a contribution toward local guidelines

2008 ◽  
Vol 6 (4) ◽  
pp. 461-471 ◽  
Author(s):  
Razak Seidu ◽  
Arve Heistad ◽  
Philip Amoah ◽  
Pay Drechsel ◽  
Petter D. Jenssen ◽  
...  
Keyword(s):  
Irrigation Water ◽  
Health Hazard ◽  
Wastewater Reuse ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Post Harvest ◽  
Pipe Water ◽  
Tolerable Risk ◽  
Rotavirus Infections

Quantitative Microbial Risk Assessment (QMRA) models with 10,000 Monte Carlo simulations were applied to ascertain the risks of rotavirus and Ascaris infections for farmers using different irrigation water qualities and consumers of lettuce irrigated with the different water qualities after allowing post-harvest handling. A tolerable risk (TR) of infection of 7.7 × 10−4 and 1 × 10−2 per person per year were used for rotavirus and Ascaris respectively. The risk of Ascaris infection was within a magnitude of 10−2 for farmers accidentally ingesting drain or stream irrigation water; ∼100 for farmers accidentally ingesting farm soil and 100 for farmers ingesting any of the irrigation waters and contaminated soil. There was a very low risk (10−5) of Ascaris infection for farmers using pipe−water. For consumers, the annual risks of Ascaris and rotavirus infections were 100 and 10−3 for drain and stream irrigated lettuce respectively with slight increases for rotavirus infections along the post-harvest handling chain. Pipe irrigated lettuce recorded a rotavirus infection of 10−4 with no changes due to post harvest handling. The assessment identified on-farm soil contamination as the most significant health hazard.

Application of QMRA to MAR operations for safe agricultural reuse and marine recreational impacts in coastal areas

2020 ◽  
Author(s):  
Costantino Masciopinto ◽  
Michele Vurro ◽  
Nicola Lorusso ◽  
Domenico Santoro ◽  
Charles N. Haas
Keyword(s):  
Reclaimed Water ◽  
Additional Treatment ◽  
Soil Aquifer Treatment ◽  
Quantitative Microbial Risk Assessment ◽  
Aquifer Recharge ◽  
Fractured Aquifer ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Pathogen Transport ◽  
Vegetables And Fruits

<p>The Municipality of Fasano (Puglia, Italy), i.e. owning one of 32 managed aquifer recharge (MAR) sites in operation in the Puglia region, has pioneered the reuse of tertiary-treated municipal effluent for both soil irrigations and the containment of seawater intrusion via groundwater recharge by ditches.</p><p>In this work, quantitative microbial risk assessment (QMRA) methodologies have been applied to assess the degree of safety associated with such integrated practices by assessing the risks for public health resulting from the exposure to the reclaimed water. Escherichia coli (E.coli) dose-response model was used in this work since the pathogenic E.coli is reported to potentially occur in reclaimed water obtained from treated municipal effluents. The target count of pathogens ingested during swimming or inoculated by contaminated (uncooked) vegetables and fruits, was determined from the Monte Carlo Markov Chain (MCMC) Bayesian procedure applied to the results obtained from a monitoring campaign carried out in 2019. An optimization routine was applied in order to determine the most probable target pathogen count by minimizing the number of water samplings. The monitoring positions along the coast were defined by means of mathematical modeling, which highlighted the preferential pathways followed by pathogens when released into the fractured aquifer at a recharge operation flow rate of 10-30 L/s.</p><p>QMRA results indicated a negligible risk impact (12% probability of 0.4 infections per year) for soil irrigation practices and no impact on the seawater quality as a result of the additional treatment barrier provided by the so-called "soil-aquifer treatment" during the pathogen transport through the fractures of groundwater.</p><p> </p>

scholarly journals Quantitative Microbial Risk Assessment Models for Consumption of Raw Vegetables Irrigated with Reclaimed Water

2006 ◽  
Vol 72 (5) ◽  
pp. 3284-3290 ◽  
Author(s):  
Andrew J. Hamilton ◽  
Frank Stagnitti ◽  
Robert Premier ◽  
Anne-Maree Boland ◽  
Glenn Hale
Keyword(s):  
Risk Assessment ◽  
Reclaimed Water ◽  
Quantitative Microbial Risk Assessment ◽  
Risk Of Infection ◽  
Worst Case ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Risk Assessment Models ◽  
Crop Type ◽  
Annual Risk

ABSTRACT Quantitative microbial risk assessment models for estimating the annual risk of enteric virus infection associated with consuming raw vegetables that have been overhead irrigated with nondisinfected secondary treated reclaimed water were constructed. We ran models for several different scenarios of crop type, viral concentration in effluent, and time since last irrigation event. The mean annual risk of infection was always less for cucumber than for broccoli, cabbage, or lettuce. Across the various crops, effluent qualities, and viral decay rates considered, the annual risk of infection ranged from 10−3 to 10−1 when reclaimed-water irrigation ceased 1 day before harvest and from 10−9 to 10−3 when it ceased 2 weeks before harvest. Two previously published decay coefficients were used to describe the die-off of viruses in the environment. For all combinations of crop type and effluent quality, application of the more aggressive decay coefficient led to annual risks of infection that satisfied the commonly propounded benchmark of ≤10−4, i.e., one infection or less per 10,000 people per year, providing that 14 days had elapsed since irrigation with reclaimed water. Conversely, this benchmark was not attained for any combination of crop and water quality when this withholding period was 1 day. The lower decay rate conferred markedly less protection, with broccoli and cucumber being the only crops satisfying the 10−4 standard for all water qualities after a 14-day withholding period. Sensitivity analyses on the models revealed that in nearly all cases, variation in the amount of produce consumed had the most significant effect on the total uncertainty surrounding the estimate of annual infection risk. The models presented cover what would generally be considered to be worst-case scenarios: overhead irrigation and consumption of vegetables raw. Practices such as subsurface, furrow, or drip irrigation and postharvest washing/disinfection and food preparation could substantially lower risks and need to be considered in future models, particularly for developed nations where these extra risk reduction measures are more common.

scholarly journals Evaluation of a Disinfectant Wipe Intervention on Fomite-to-Finger Microbial Transfer

2014 ◽  
Vol 80 (10) ◽  
pp. 3113-3118 ◽  
Author(s):  
Gerardo U. Lopez ◽  
Masaaki Kitajima ◽  
Aaron Havas ◽  
Charles P. Gerba ◽  
Kelly A. Reynolds
Keyword(s):  
Escherichia Coli ◽  
Respiratory Pathogens ◽  
Quantitative Microbial Risk Assessment ◽  
Content Type ◽  
Microbial Risk Assessment ◽  
Surface Disinfection ◽  
Microbial Risk ◽  
Risk Assessment Models ◽  
The Mean ◽  
The Impact

ABSTRACTInanimate surfaces, or fomites, can serve as routes of transmission of enteric and respiratory pathogens. No previous studies have evaluated the impact of surface disinfection on the level of pathogen transfer from fomites to fingers. Thus, the present study investigated the change in microbial transfer from contaminated fomites to fingers following disinfecting wipe use.Escherichia coli(108to 109CFU/ml),Staphylococcus aureus(109CFU/ml),Bacillus thuringiensisspores (107to 108CFU/ml), and poliovirus 1 (108PFU/ml) were seeded on ceramic tile, laminate, and granite in 10-μl drops and allowed to dry for 30 min at a relative humidity of 15 to 32%. The seeded fomites were treated with a disinfectant wipe and allowed to dry for an additional 10 min. Fomite-to-finger transfer trials were conducted to measure concentrations of transferred microorganisms on the fingers after the disinfectant wipe intervention. The mean log10reduction of the test microorganisms on fomites by the disinfectant wipe treatment varied from 1.9 to 5.0, depending on the microorganism and the fomite. Microbial transfer from disinfectant-wipe-treated fomites was lower (up to <0.1% on average) than from nontreated surfaces (up to 36.3% on average, reported in our previous study) for all types of microorganisms and fomites. This is the first study quantifying microbial transfer from contaminated fomites to fingers after the use of disinfectant wipe intervention. The data generated in the present study can be used in quantitative microbial risk assessment models to predict the effect of disinfectant wipes in reducing microbial exposure.

scholarly journals Legionella pneumophila as a Health Hazard to Miners: A Pilot Study of Water Quality and QMRA

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1528
Author(s):  
Valerie Madera-García ◽  
Alexis L. Mraz ◽  
Nicolás López-Gálvez ◽  
Mark H. Weir ◽  
James Werner ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Health Hazard ◽  
Ventilation System ◽  
Sprinkler System ◽  
Dust Control ◽  
Quantitative Microbial Risk Assessment ◽  
Mining Operations ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Life Years

Legionella pneumophila (L. pneumophila), the causative agent of legionellosis, is an aquatic bacterium that grows in warm water. Humans are only presented with a health risk when aerosolized water containing L. pneumophila is inhaled. In mining operations, aerosolized water is used as dust control and as part of the drilling operations, a currently ignored exposure route. This study characterized L. pneumophila concentrations in the mine’s non-potable water and the relationship between L. pneumophila and chlorine concentrations. These concentrations informed a quantitative microbial risk assessment (QMRA) model to estimate the infection risk to miners exposed to aerosolized water containing L. pneumophila. Fourteen water samples were collected from seven locations at a mine and analyzed for temperature, pH, chlorine, and L. pneumophila serogroup. Most samples (93%) tested positive for L. pneumophila cells. The faucet from the sprinkler system on the adit level (entrance to the underground mine levels) showed the highest concentration of L. pneumophila (8.35 × 104 MPN/L). Disability adjusted life years (DALYs) were estimated in the QMRA model and showed that the risk for all miners was significantly lower (p < 0.0001) with the ventilation system on than when the system was off. Our study showed that the use of a ventilation system at the adit level of the mine reduced the risk of infection with aerosolized L. pneumophila.

scholarly journals Quantitative microbial risk assessment (QMRA) for water re-use via aquifers

2009 ◽  
Vol 30 (1) ◽  
pp. 20
Author(s):  
Declan Page ◽  
Simon Toze
Keyword(s):  
Risk Assessment ◽  
Reclaimed Water ◽  
Managed Aquifer Recharge ◽  
Urban Water ◽  
Quantitative Microbial Risk Assessment ◽  
Aquifer Recharge ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Wide Range ◽  
Potential Risks

Worldwide, there is an increasing interest in the recharge of aquifers as a method for augmenting urban water supplies. Managed aquifer recharge (MAR) can utilise a variety of non-traditional source waters including urban stormwater and reclaimed water from sewage effluent. However, these alternate water sources may contain a wide range of pathogenic hazards that pose risks to human health. Hence the safe use of recycling water via aquifers requires potential risks to be reduced to acceptable levels. This article outlines the approach recommended by the draft Australian Guidelines for Water Recycling (AGWR) (Phase 2C Managed Aquifer Recharge) to quantify the aquifer treatment using a quantitative microbial risk assessment (QMRA) approach.

Enteric virus presence in green vegetables and associated irrigation waters in a rural area from Argentina. A quantitative microbial risk assessment

LWT ◽  
2021 ◽  
Vol 144 ◽  
pp. 111201 ◽  
Author(s):  
Prez Verónica Emilse ◽  
Victoria Matías ◽  
Martínez Laura Cecilia ◽  
Giordano Miguel Oscar ◽  
Masachessi Gisela ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Rural Area ◽  
Enteric Virus ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Irrigation Waters
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