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Assessing the microbial risk of faecal sludge use in Ugandan agriculture by comparing field and theoretical model output

Butte, G. and Niwagaba, C. and Nordin, Annika (2021). Assessing the microbial risk of faecal sludge use in Ugandan agriculture by comparing field and theoretical model output. Water Research. 197 , 117068
[Research article]

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Reuse of faecal sludge in agriculture has many potential benefits, but also poses risks to human health. To better understand the potential risks, Quantitative Microbial Risk Assessment (QMRA) was performed for three population groups in Kampala, Uganda: wastewater and faecal sludge treatment plant workers; farmers using faecal sludge; and consumers of faecal sludge-fertilised vegetables. Two models were applied for farmers and consumers, one based on pathogen concentrations from field sampling of sludge, soils and vegetables, and one based on theoretical pathogen contribution from the last sludge application, including decay and soil to crop transfer of pathogens. The risk was evaluated for two pathogens (enterohaemorrhagic E. coli (EHEC) and Ascaris lumbricoides ). The field data on sludge, soil and vegetables indicated that the last application of faecal sludge was not the sole pathogen source . Correspondingly, the model using field data resulted in higher risks for farmers and consumers than the theoretical model assuming risk from sludge only, except when negligible for both. For farmers, the yearly risk of illness, based on measured concentrations, was 26% from EHEC and 70% from Ascaris, compared with 1.2% and 1.4%, respectively, considering the theoretically assumed contribution from the sludge. For consumers, the risk of illness based on field samples was higher from consumption of leafy vegetables (100% from EHEC, 99% from Ascaris) than from consumption of cabbages (negligible for EHEC, 26% from Ascaris). With the theoretical model, the risk of illness from EHEC was negligible for both crops, whereas the risk of illness from Ascaris was 64% and 16% for leafy vegetables and cabbage, respectively. For treatment plant workers, yearly risk of illness was 100% from EHEC and 99.4% from Ascaris . Mitigation practices evaluated could reduce the relative risk by 30-70%. These results can help guide treatment and use of faecal sludge in Kampala, to protect plant workers, farmers and consumers.(c)& nbsp;2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

Authors/Creators:Butte, G. and Niwagaba, C. and Nordin, Annika
Title:Assessing the microbial risk of faecal sludge use in Ugandan agriculture by comparing field and theoretical model output
Series Name/Journal:Water Research
Year of publishing :2021
Article number:117068
Number of Pages:14
Publication Type:Research article
Article category:Scientific peer reviewed
Version:Published version
Copyright:Creative Commons: Attribution 4.0
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 405 Other Agricultural Sciences > Environmental Sciences related to Agriculture and Land-use
Keywords:Faecal sludge, Fertiliser, Health burden, Reuse, Wastewater sludge, QMRA
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Additional ID:
Type of IDID
Web of Science (WoS)000644359600021
ID Code:23915
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Dept. of Energy and Technology
Deposited By: SLUpub Connector
Deposited On:27 May 2021 12:43
Metadata Last Modified:27 May 2021 12:51

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