scholarly journals Application of Helminth ova infection dose curve to estimate the risks associated with biosolid application on soil

2008 ◽  
Vol 7 (1) ◽  
pp. 31-44 ◽  
Author(s):  
I. Navarro ◽  
B. Jiménez ◽  
S. Lucario ◽  
E. Cifuentes
Keyword(s):  
Developing Countries ◽  
Health Risk ◽  
Ascaris Lumbricoides ◽  
Quantitative Microbial Risk Assessment ◽  
Protection Measures ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Untreated Wastewater ◽  
Application Rates ◽  
Additional Protection

Helminth ova (HO) are the main biological concern when reusing sludge for agricultural production. Worldwide sludge regulations consider a permissible range of 0.25–1 HO/gTS. Such limits are unaffordable to most developing countries, due to high helminth ova content in sludge, and the lack of viable technology to inactivate them as needed. The quantitative microbial risk assessment (QMRA) is a useful tool to estimate the risk of treated sludge, considering feasible and viable limits. QMRA, however, has not been applied before for HO because no dose-infection curve was available. Therefore, the objectives of this paper are: to build up a risk-based model designed for untreated wastewater exposure (i.e., land irrigation) using Ascaris lumbricoides eggs as indicators for HO, and apply the results to assess health risk (i.e., Ascaris lumbricoides infection) associated with consumption of crops grown on biosolid-enriched soil. Data showed that it may be feasible to update HO threshold in biosolids from developing countries without significantly increasing risks. To reduce health risk from HO, it may be wiser to achieve feasible and evidence-based standards, than to set unaffordable limits in these countries. QMRA data suggested additional protection measures, such as biosolid application rates, crop restriction, and produce better washing practices.

Methodology to Set Regulations for Safe Reuse of Wastewater and Sludge for Agriculture in Developing Countries Based on a Scientific Approach and Following the New WHO Guidelines

2011 ◽  
pp. 690-709 ◽  
Author(s):  
B. Jimenez ◽  
I. Navarro
Keyword(s):  
Risk Assessment ◽  
Developing Countries ◽  
Ascaris Lumbricoides ◽  
Wastewater Reuse ◽  
Quantitative Microbial Risk Assessment ◽  
Who Guidelines ◽  
Sludge Treatment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Untreated Wastewater

This chapter describes, using the quantitative microbial risk assessment (QMRA) methodology proposed by WHO, how to set affordable standards for reuse of wastewater or sludge in agriculture using helminth eggs (Ascaris lumbricoides) as an example. The development of a risk-based model for Ascaris lumbricoides infection and its application to assess human risks associated with helminths egg exposure from crops irrigated with untreated wastewater, as well as crops grown in biosolid-enriched soil are explained. From QMRA results it becomes evident that WHO guidelines for wastewater reuse in agriculture seem more stringent than needed in developing countries, while for sludge reuse it will be the opposite. Even though more information is needed to confirm this conclusion from a single research, cautious approach when revalorizing sludge for agricultural purposes is recommended. Additionally, this work shows that intervention methods, other than wastewater and sludge treatment as suggested by WHO, can play an important role in controlling risks.

scholarly journals Quantitative Microbial Risk Assessment for Workers Exposed to Bioaerosol in Wastewater Treatment Plants Aimed at the Choice and Setup of Safety Measures

2018 ◽  
Vol 15 (7) ◽  
pp. 1490 ◽  
Author(s):  
Annalaura Carducci ◽  
Gabriele Donzelli ◽  
Lorenzo Cioni ◽  
Ileana Federigi ◽  
Roberto Lombardi ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Sensitivity Analysis ◽  
Wastewater Treatment ◽  
Health Risk ◽  
Average Risk ◽  
Quantitative Microbial Risk Assessment ◽  
Exposure Limits ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
The Impact

Biological risk assessment in occupational settings currently is based on either qualitative or semiquantitative analysis. In this study, a quantitative microbial risk assessment (QMRA) has been applied to estimate the human adenovirus (HAdV) health risk due to bioaerosol exposure in a wastewater treatment plant (WWTP). A stochastic QMRA model was developed considering HAdV as the index pathogen, using its concentrations in different areas and published dose–response relationship for inhalation. A sensitivity analysis was employed to examine the impact of input parameters on health risk. The QMRA estimated a higher average risk in sewage influent and biological oxidation tanks (15.64% and 12.73% for an exposure of 3 min). Sensitivity analysis indicated HAdV concentration as a predominant factor in the estimated risk. QMRA results were used to calculate the exposure limits considering four different risk levels (one illness case per 100, 1.000, 10.000, and 100.000 workers): for 3 min exposures, we obtained 565, 170, 54, and 6 GC/m3 of HAdV. We also calculated the maximum time of exposure for each level for different areas. Our findings can be useful to better define the effectiveness of control measures, which would thus reduce the virus concentration or the exposure time.

Quantitative microbial risk assessment (QMRA) to support decisions for water supply in affluent and developing countries

2019 ◽  
Vol 14 (3) ◽  
pp. 542-548 ◽  
Author(s):  
P. W. M. H. Smeets
Keyword(s):  
Risk Assessment ◽  
Developing Countries ◽  
Drinking Water ◽  
Water Supply ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
The Past ◽  
Relative Risks ◽  
Microbial Risks

Abstract Providing microbially safe water is a main goal of water supply to prevent endemic waterborne disease and outbreaks. Since increasing the level of safety requires resources, it is important to identify most relevant risks and efficient ways to reach health-based targets. Over the past decades, quantitative microbial risk assessment (QMRA) developed into a systematic, science-based approach to assess microbial risks through drinking water supply. In this study we present the QMRA approach and how it can be used to support decisions in both affluent and developing countries. This includes examples from the statutory QMRA in the Netherlands that led to efficient and effective improvements in water supply, not only in treatment, but also in monitoring and operation. In developing countries people often need to use various sources of drinking water. We will demonstrate how QMRA can help to improve insight in the relative risks of these routes and the effect of interventions.

Quantification of Giardia and Cryptosporidium in surface water: a risk assessment and molecular characterization

2019 ◽  
Vol 19 (6) ◽  
pp. 1823-1830 ◽  
Author(s):  
M. O. Bataiero ◽  
R. S. Araujo ◽  
A. C. Nardocci ◽  
M. H. Matté ◽  
M. I. Z. Sato ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Positive Impact ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Quantitative Microbial Risk Assessment ◽  
Protection Measures ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Contaminated Drinking Water ◽  
Annual Risk

Abstract This study aimed to estimate the annual probability of Giardia and Cryptosporidium infection for a population supplied by contaminated drinking water sources. Parasites were quantified by the USEPA Method 1623.1/2012. Annual risk was estimated using the quantitative microbial risk assessment (QMRA) approach. Genotyping was performed using specific primers based on the 18S rRNA gene for Cryptosporidium and gdh gene for Giardia. Giardia was detected in 83.3% of the samples (<0.1 to 8.6 cysts/L) and Cryptosporidium in 37.5% (<0.1 to 2 oocysts/L). In general, annual risk values for Giardia were 1 log higher when compared with those obtained for Cryptosporidium. Giardia intestinalis A and B were present as well as C. hominis and C. parvum. The lack of protection measures for the water supply catchment point put the population's health at risk. The results provide data to support decision-makers to take actions to improve environmental quality resulting in a positive impact on consumers' health.

Evaluation of the WHO helminth eggs criteria using a QMRA approach for the safe reuse of wastewater and sludge in developing countries

2011 ◽  
Vol 63 (7) ◽  
pp. 1499-1505 ◽  
Author(s):  
I. Navarro ◽  
B Jiménez
Keyword(s):  
Developing Countries ◽  
Wastewater Reuse ◽  
Polluted Water ◽  
Quantitative Microbial Risk Assessment ◽  
Who Guidelines ◽  
Sludge Treatment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Helminth Eggs ◽  
Single Piece

An analysis of the actual WHO recommendations to develop standards for the safe reuse of wastewater, excreta or sludge in agriculture using a quantitative microbial risk assessment (QMRA) is presented. The proposed values are defined using a risk-based model for Ascaris lumbricoides infection to assess the human risks associated with exposure to this pathogen from crops irrigated with polluted water, or from crops grown in biosolid-enriched soil. From the results it becomes evident that, with regard to helminth eggs, the WHO guidelines for wastewater reuse in agriculture seem more stringent than are needed in developing countries, while for the reuse of sludge they appear to be the opposite. Although more information is needed to confirm this conclusion, which was derived from a single piece of research, at the very least a more cautious approach is recommended when evaluating excreta or sludge for agricultural purposes in developing countries. Additionally, this work shows that the application of some barriers, other than wastewater and sludge treatment as suggested by WHO, can play an important role in controlling risks.

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