Your search found 11 records
1 Seidu, R.; Drechsel, Pay; Amoah, Philip; Lofman, Owe; Heistad, Arve; Fodge, Madeliene; Jenssen, P.; Stenstrom, T. A. 2008. Quantitative microbial risk assessment of wastewater and faecal sludge reuse in Ghana. In Hazel, J. (Ed.). Proceedings of the 33rd WEDC International Conference on Access to Sanitation and Safe Water: Global Partnerships and Local Actions, Accra, Ghana, 7-11 April 2008. Leicestershire, UK: Water, Engineering and Development Centre (WEDC). pp.90-97.
Wastewater irrigation ; Excreta ; Faeces ; Vegetables ; Public health ; Health hazards ; Assessment ; Ascaris ; Rotavirus / Ghana
(Location: IWMI HQ Call no: IWMI 631.7.5 G200 SEI Record No: H041285)
2 Seidu, R.; Heistad, A.; Amoah, Philip; Drechsel, Pay; Jenssen, P. D.; Stenstrom, T. A. 2008. Quantification of the health risk associated with wastewater reuse in Accra, Ghana: a contribution toward local guidelines. Journal of Water and Health, 6(4):461-471. [doi: https://doi.org/10.2166/wh.2008.118]
Wastewater irrigation ; Health hazards ; Assessment ; Simulation models ; Rotavirus ; Ascaris ; Farmers ; Consumers ; Water quality ; Irrigation water ; Polluted soil ; Lettuces / Ghana
(Location: IWMI HQ Call no: IWMI 631.7.5 G200 SEI Record No: H041489)
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 £ 1024 and 1 £ 1022 per person per year were used for rotavirus and Ascaris respectively. The risk of Ascaris infection was within a magnitude of 1022 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 (1025) of Ascaris infection for farmers using pipe 2 water. For consumers, the annual risks of Ascaris and rotavirus infections were 100 and 1023 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 1024 with no changes due to post harvest handling. The assessment identified on-farm soil contamination as the most significant health hazard.
3 Mara, D.; Hamilton, A. J.; Sleigh, A.; Karavarsamis, N.; Seidu, R.. 2010. Tools for risk analysis: updating the 2006 WHO guidelines. In Drechsel, Pay; Scott, C. A.; Raschid-Sally, Liqa; Redwood, M.; Bahri, Akissa (Eds.). Wastewater irrigation and health: assessing and mitigating risk in low-income countries. London, UK: Earthscan; Ottawa, Canada: International Development Research Centre (IDRC); Colombo, Sri Lanka: International Water Management Institute (IWMI). pp.89-100. (Also in French).
Risk analysis ; Guidelines ; Models ; Wastewater irrigation ; Diseases ; Public health ; Ascaris ; Vegetables ; Wastewater treatment / West Africa / Ghana
(Location: IWMI HQ Call no: IWMI 631.7.5 G000 DRE Record No: H042605)
(0.23 MB)
This chapter reviews developments since the WHO Guidelines for the safe use of wastewater in agriculture were published in 2006. The six main developments are: the recognition that the tolerable additional disease burden may be too stringent for many developing countries; the benefits of focusing on single-event infection risks as a measure of outbreak potential when evaluating risk acceptability; a more rigorous method for estimating annual risks; the availability of dose-response data for norovirus; the use of QMRA to estimate Ascaris infection risks; and a detailed evaluation of pathogen reductions achieved by produce-washing and disinfection. Application of the developments results in more realistic estimates of the pathogen reductions required for the safe use of wastewater in agriculture and consequently permits the use of simpler wastewater treatment processes.
4 Seidu, R.; Drechsel, Pay. 2010. Cost-effectiveness analysis of interventions for diarrhoeal disease reduction among consumers of wastewater-irrigated lettuce in Ghana. In Drechsel, Pay; Scott, C. A.; Raschid-Sally, Liqa; Redwood, M.; Bahri, Akissa (Eds.). Wastewater irrigation and health: assessing and mitigating risk in low-income countries. London, UK: Earthscan; Ottawa, Canada: International Development Research Centre (IDRC); Colombo, Sri Lanka: International Water Management Institute (IWMI). pp.261-283. (Also in French).
Wastewater irrigation ; Lettuces ; Leaf vegetables ; Diseases ; Diarrhoea ; Health hazards ; Risk assessment / Ghana
(Location: IWMI HQ Call no: IWMI 631.7.5 G000 DRE Record No: H042613)
(0.27 MB)
Interventions proposed and implemented for the mitigation of diarrhoeal diseases associated with wastewater reuse in agriculture have received little, if any, comparative assessment of their cost-effectiveness. This chapter assesses the costs, outcomes and cost-effectiveness of the so-called ‘treatment’ and ‘non- or post-treatment’ interventions as well as a combination of these for wastewater irrigation in urban Ghana using an approach that integrates quantitative microbial risk assessment (QMRA), disability-adjusted life years (DALYs) and cost-effectiveness analysis (CEA). The cost-effectiveness ratios (CERs) for the treatment and non-treatment interventions assessed ranged from US$31/DALY to US$812/DALY averted. Risk-reduction measures targeting farming practices and the basic rehabilitation of local wastewater treatment plants were the most attractive interventions with a CER well below the threshold of US$150/DALY, sometimes considered as the upper limit for a health intervention to be cost-effective in developing countries. All combinations associated with the basic rehabilitation of the treatment plants, with either on-farm or post-harvest interventions or both, resulted in CERs within the range of US$40/DALY to US$57/DALY. However, the CERs for the construction of a new wastewater treatment plant either as an independent intervention or in combination with on-farm and post-harvest interventions were unattractive in view of health-risk reduction for wastewater irrigation. Although attractive, the CERs of non-treatment options are largely dependent on compliance (adoption) by farmers and food vendors. In this regard, the CER increased by almost fivefold when the adoption rate was only 25 per cent by farmers and food vendors; but was attractive as long as adoption rates did not fall below 70 per cent. On the other hand, the success of the treatment option depends on the functionality of the treatment plants which is not without challenges in a country like Ghana. Thus, this chapter stresses the need for a balanced risk-management approach through a combination of treatment and non-treatment interventions to hedge against failures that may affect CERs at any end. While this chapter provides a contribution to the debate on interventions for health-risk mitigation in wastewater irrigation, more case studies would be useful to verify the data presented here.
5 Keraita, Bernard; Drechsel,Pay; Seidu, R.; Amerasinghe, Priyanie; Cofie, Olufunke O.; Konradsen, F. 2010. Harnessing farmers’ knowledge and perceptions for health-risk reduction in wastewater-irrigated agriculture. In Drechsel, Pay; Scott, C. A.; Raschid-Sally, Liqa; Redwood, M.; Bahri, Akissa (Eds.). Wastewater irrigation and health: assessing and mitigating risk in low-income countries. London, UK: Earthscan; Ottawa, Canada: International Development Research Centre (IDRC); Colombo, Sri Lanka: International Water Management Institute (IWMI). pp.337-354. (Also in French).
Wastewater irrigation ; Excreta ; Health hazards ; Diseases ; Risk management ; Farmers ; Indigenous knowledge
(Location: IWMI HQ Call no: IWMI 631.7.5 G000 DRE Record No: H042617)
(0.23 MB)
This chapter addresses the importance of understanding farmers’ knowledge and perceptions on health-risk and risk-reduction measures for the development of mutually acceptable risk-management strategies. Drawing on studies from different countries, the chapter shows that it is not realistic to expect high risk awareness. In cases where farmers are aware of health risks, they assess mitigation measures in view of their overall impact on work efficiency and crop yield rather than only the potential health benefits to be gained. The chapter asserts that for on-farm risk-reduction measures to be successful, it is pertinent that farmers’ needs and constraints are incorporated into the formulation of recommended practices. This might happen through indigenous processes but can be supported through farm-based participatory approaches where farmers and scientists work together in developing risk reduction measures. An important first step is the identification of mutually accepted problem indicators. Where health benefits for farmers and consumers are not sufficient reasons for the adoption of safer practices, other triggers have to be identified as well as appropriate communication channels for effective outreach.
6 Drechsel, Pay; Seidu, R.. 2011. Cost-effectiveness of options for reducing health risks in areas where food crops are irrigated with treated or untreated wastewater. Water International, 36(4):535-548. (Special issue on "Wastewater use in agriculture: economics, risks and opportunities" with contributions by IWMI authors). [doi: https://doi.org/10.1080/02508060.2011.594549]
Wastewater treatment ; Health hazards ; Diarrhoea ; Wastewater irrigation ; Risk assessment ; Economic aspects ; Costs ; Case studies / Ghana
(Location: IWMI HQ Call no: PER Record No: H044201)
(0.14 MB)
In this article the authors draw from a comparative assessment of different interventions, examining their costs, risk-reduction potential and cost-effectiveness. They consider a case study in Ghana, using an approach that integrates quantitative microbial risk assessment (QMRA), disability-adjusted life years (DALYs) and cost-effectiveness analysis. Most practices appear highly cost-effective, although only a few are likely to avert more than 80% of the DALY burden. As compliance will always be a challenge, the results support the need for a multi-barrier risk-management approach that, where possible, combines treatment and non-treatment interventions.
7 Keraita, Bernard; Drechsel, Pay; Seidu, R.; Amerasinghe, Priyanie.; Cofie, Olufunke; Konradsen, F. 2011. Mobiliser les connaissances et les perceptions des agriculteurs pour reduire les risques sanitaires de l’agriculture irriguee avec des eaux usees. In French. [Harnessing farmers’ knowledge and perceptions for health-risk reduction in wastewater-irrigated agriculture]. In Drechsel, Pay; Scott, C. A.; Raschid-Sally, Liqa; Redwood, M.; Bahri, Akissa. L’irrigation avec des eaux usees et la sante: evaluer et attenuer les risques dans les pays a faible revenu. Colombo, Sri Lanka: International Water Management Institute (IWMI); Ottawa, Canada: International Development Research Centre (IDRC); Quebec, Canada: University of Quebec. pp.363-383. (Also in English).
Wastewater irrigation ; Excreta ; Health hazards ; Diseases ; Risk management ; Farmers ; Indigenous knowledge
(Location: IWMI HQ Call no: IWMI Record No: H044474)
http://www.iwmi.cgiar.org/Research_Impacts/Research_Themes/Theme_3/PDF/French%20book.pdf
https://vlibrary.iwmi.org/pdf/H044474.pdf
https://vlibrary.iwmi.org/pdf/H044474.pdf
(0.98 MB) (5.96MB)
This chapter addresses the importance of understanding farmers’ knowledge and perceptions on health-risk and risk-reduction measures for the development of mutually acceptable risk-management strategies. Drawing on studies from different countries, the chapter shows that it is not realistic to expect high risk awareness. In cases where farmers are aware of health risks, they assess mitigation measures in view of their overall impact on work efficiency and crop yield rather than only the potential health benefits to be gained. The chapter asserts that for on-farm risk-reduction measures to be successful, it is pertinent that farmers’ needs and constraints are incorporated into the formulation of recommended practices. This might happen through indigenous processes but can be supported through farm-based participatory approaches where farmers and scientists work together in developing risk reduction measures. An important first step is the identification of mutually accepted problem indicators. Where health benefits for farmers and consumers are not sufficient reasons for the adoption of safer practices, other triggers have to be identified as well as appropriate communication channels for effective outreach.
8 Seidu, R.; Drechsel, Pay. 2011. Analyse cout-efficacite des interventions pour reduire les maladies diarrheiques chez les consommateurs de laitues irriguees avec des eaux usees au Ghana. In French. [Cost-effectiveness analysis of interventions for diarrhoeal disease reduction among consumers of wastewater-irrigated lettuce in Ghana]. In Drechsel, Pay; Scott, C. A.; Raschid-Sally, Liqa; Redwood, M.; Bahri, Akissa. L’irrigation avec des eaux usees et la sante: evaluer et attenuer les risques dans les pays a faible revenu. Colombo, Sri Lanka: International Water Management Institute (IWMI); Ottawa, Canada: International Development Research Centre (IDRC); Quebec, Canada: University of Quebec. pp.281-305. (Also in English).
Wastewater irrigation ; Lettuces ; Leaf vegetables ; Diseases ; Diarrhoea ; Health hazards ; Risk assessment / Ghana
(Location: IWMI HQ Call no: IWMI Record No: H044470)
http://www.iwmi.cgiar.org/Research_Impacts/Research_Themes/Theme_3/PDF/French%20book.pdf
https://vlibrary.iwmi.org/pdf/H044470.pdf
https://vlibrary.iwmi.org/pdf/H044470.pdf
(0.95 MB) (5.96MB)
Interventions proposed and implemented for the mitigation of diarrhoeal diseases associated with wastewater reuse in agriculture have received little, if any, comparative assessment of their cost-effectiveness. This chapter assesses the costs, outcomes and cost-effectiveness of the so-called ‘treatment’ and ‘non- or post-treatment’ interventions as well as a combination of these for wastewater irrigation in urban Ghana using an approach that integrates quantitative microbial risk assessment (QMRA), disability-adjusted life years (DALYs) and cost-effectiveness analysis (CEA). The cost-effectiveness ratios (CERs) for the treatment and non-treatment interventions assessed ranged from US$31/DALY to US$812/DALY averted. Risk-reduction measures targeting farming practices and the basic rehabilitation of local wastewater treatment plants were the most attractive interventions with a CER well below the threshold of US$150/DALY, sometimes considered as the upper limit for a health intervention to be cost-effective in developing countries. All combinations associated with the basic rehabilitation of the treatment plants, with either on-farm or post-harvest interventions or both, resulted in CERs within the range of US$40/DALY to US$57/DALY. However, the CERs for the construction of a new wastewater treatment plant either as an independent intervention or in combination with on-farm and post-harvest interventions were unattractive in view of health-risk reduction for wastewater irrigation. Although attractive, the CERs of non-treatment options are largely dependent on compliance (adoption) by farmers and food vendors. In this regard, the CER increased by almost fivefold when the adoption rate was only 25 per cent by farmers and food vendors; but was attractive as long as adoption rates did not fall below 70 per cent. On the other hand, the success of the treatment option depends on the functionality of the treatment plants which is not without challenges in a country like Ghana. Thus, this chapter stresses the need for a balanced risk-management approach through a combination of treatment and non-treatment interventions to hedge against failures that may affect CERs at any end. While this chapter provides a contribution to the debate on interventions for health-risk mitigation in wastewater irrigation, more case studies would be useful to verify the data presented here.
9 Mara, D.; Hamilton, A. J.; Sleigh, A.; Karavarsamis, N.; Seidu, R.. 2011. Outils pour l’analyse des risques: mise a jour des directives de 2006 de l’OMS. In French. [Tools for risk analysis: updating the 2006 WHO guidelines]. In Drechsel, Pay; Scott, C. A.; Raschid-Sally, Liqa; Redwood, M.; Bahri, Akissa. L’irrigation avec des eaux usees et la sante: evaluer et attenuer les risques dans les pays a faible revenu. Colombo, Sri Lanka: International Water Management Institute (IWMI); Ottawa, Canada: International Development Research Centre (IDRC); Quebec, Canada: University of Quebec. pp.95-108. (Also in English).
Risk analysis ; Guidelines ; Models ; Wastewater irrigation ; Diseases ; Public health ; Ascaris ; Vegetables ; Wastewater treatment / West Africa / Ghana
(Location: IWMI HQ Call no: IWMI Record No: H044462)
(5.96MB)
This chapter reviews developments since the WHO Guidelines for the safe use of wastewater in agriculture were published in 2006. The six main developments are: the recognition that the tolerable additional disease burden may be too stringent for many developing countries; the benefits of focusing on single-event infection risks as a measure of outbreak potential when evaluating risk acceptability; a more rigorous method for estimating annual risks; the availability of dose-response data for norovirus; the use of QMRA to estimate Ascaris infection risks; and a detailed evaluation of pathogen reductions achieved by produce-washing and disinfection. Application of the developments results in more realistic estimates of the pathogen reductions required for the safe use of wastewater in agriculture and consequently permits the use of simpler wastewater treatment processes.
10 Seidu, R.; Lofman, O.; Drechsel, Pay; Stenstrom, T. A. 2013. Risk factor analysis of diarrhoeal disease incidence in faecal sludge-applying farmers’ households in Tamale, Ghana. Journal of Water, Sanitation and Hygiene for Development, 3(2):134-143. [doi: https://doi.org/10.2166/washdev.2013.042]
Sewage sludge ; Excreta ; Agriculture ; Diarrhoea ; Risk analysis ; Households ; Farmers ; Statistical analysis ; Socioeconomic environment / Ghana / Tamale
(Location: IWMI HQ Call no: e-copy only Record No: H045758)
(0.27 MB)
This study assesses the effect of risk factors and their inter-related mediation on diarrhoeal disease incidence in households applying faecal sludge in agricultural fields in Tamale, Ghana. Risk factors were assigned to three inter-related blocks: distal socio-economic, proximal public and domestic domains. The study involved 1,431 individuals living in 165 faecal sludge-applying households followed bi-weekly for 12 months. The incidence rate of diarrhoeal disease in the sludge-applying households was 1.09 (95% CI: 0.78–1.23) diarrhoeal episodes per person year at risk. Risk factors for diarrhoeal disease transmission in the public domain included sludge drying time (population attributable fraction (PAF) of 6%) and distance covered to collect water (PAF¼ 18%). The main distal socio-economic risk factor was wealth status (PAF¼ 15%). In the domestic domain, the risk factor significantly associated with diarrhoeal disease transmission was, not washing hands with soap after defecation (PAF ¼ 18%). About 17% of the effect of sludge drying time (including distance to water facilities) was mediated by the domestic domain risk factors. The study recommends risk management strategies in sludge-applying households that address public and domestic domain risk factors in addition to specific farm level interventions.
11 Drechsel, Pay; Keraita, B.; Seidu, R.; Abaidoo, R. C. 2014. Human health risks from wastewater-irrigated vegetable farming. In Drechsel, Pay; Keraita, B. (Eds.) Irrigated urban vegetable production in Ghana: characteristics, benefits and risk mitigation. Colombo, Sri Lanka: International Water Management Institute (IWMI). pp.104-115.
Public health ; Health hazards ; Wastewater irrigation ; Vegetables ; Biological contamination ; Heavy metals ; Pesticides / Ghana / Accra
(Location: IWMI HQ Call no: IWMI Record No: H046606)
(149 KB)
Contamination levels of water and crops which exceed common standards are only a first indication of human health risks. This chapter shows estimates of human health risks from consumption of wastewater-irrigated vegetables based for example on dose-response modeling. The chapter focuses on human health risks and risk perceptions of microbiological and chemical contaminants such as heavy metals and pesticides.
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