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.

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 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.

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.

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.

scholarly journals Quantitative microbial risk assessment to estimate health risks attributable to water supply: Can the technique be applied in developing countries with limited data?

2006 ◽  
Vol 4 (1) ◽  
pp. 49-65 ◽  
Author(s):  
Guy Howard ◽  
Steve Pedley ◽  
Sarah Tibatemwa
Keyword(s):  
Risk Assessment ◽  
Developing Countries ◽  
Drinking Water ◽  
Water Supply ◽  
Disease Burden ◽  
Quantitative Microbial Risk Assessment ◽  
Limited Data ◽  
Water Supplies ◽  
Microbial Risk Assessment ◽  
Microbial Risk

In the 3rd edition of its Guidelines for Drinking-Water Quality (2004) (GDWQ) the World Health Organization (WHO) promotes the use of risk assessment coupled with risk management for the control of water safety in drinking water supplies. Quantitative microbial risk assessment (QMRA) provides a tool for estimating the disease-burden from pathogenic microorganisms in water using information about the distribution and occurrence of the pathogen or an appropriate surrogate. This information may then be used to inform decisions about appropriate management of the water supply system. Although QMRA has been used to estimate disease burden from water supplies in developed countries, the method has not been evaluated in developing countries where relevant data may be scarce. In this paper, we describe a simplified risk assessment procedure to calculate the disease burden from three reference pathogens – pathogenic Escherichia coli, Cryptosporidium parvum and rotavirus – in water supplies in Kampala, Uganda. The study shows how QMRA can be used in countries with limited data, and that the outcome can provide valuable information for the management of water supplies.

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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