Health risk assessment associated with the reuse of compost, urine and greywater in agricultural field in sahelian climate.
par Alexis Loukou BROU
Fondation 2iE - Master Environnement option Eau et Assainissement 2014
Health Risk Assessment Associated with the Reuse of Compost, Urine and Greywater in Agricultural Field in Sahelian Climate
DISSERTATION FOR THE
Alexis Loukou BROU
Under the Supervision of: Dr. Nowaki HIJIKATA/Researcher/2iE Foundation
Dr. Mariam SOU/Lecturer/2iE Foundation
Mr. Seyram SOSSOU/Research Engineer/2iE Foundation
President: Pr. Rabah LAMAR
Members and correctors: Dr. MariamSOU
Dr. Lynda SAWADOGO
Dr. Nowaki HIJIKATA
For my Only Lord JESUS CHRIST
For my beloved wife Anne Aurélie N'Goné CISSE
In memory of my dear late father KOUAME Brou Paul and my dear motherKOFFI Affoué who diedon August 15, 2012 before I started this course
I would like to express our deep gratitude to the people whose support, availability and advice contributed to the development of this dissertation.
I am thankful for the scholarship that the government of the Republic of Côte d'Ivoire granted me to enroll for the Master's program.
I would like to thank all the supervising team for their support, relevant criticism, remarks and suggestions in order to improve this work particularly Dr. Mariam SOU, Dr. Nowaki HIJIKATA and Mr. Seyram SOSSOU.
I am thankful to Madam Aminata N'Diaye for her help to improve quality of this dissertation.
I am grateful to the Laboratory assistants Mr. Noel TINDOUREand Mr. Sohamaï HEMAfor their availability at the time of ours analysis for this study.
I have appreciated the precious support I was provided with by all the team of Ameli-EAUR project during the field study,and especially, that ofMr.Innocent ZERBO, Mr. Koualè IDO and Mr. Bernard ZONGO.
Thank to my colleague trainees Yves Rodrigue KABORE; Danielle Miranise OUEDRAOGO and Florence GAJU KAGABIGA for their support and their team spirit
I would like to praise the support and advice I have had from my great brothers Pierre BROU and Toussaint BROU and I thank all my relatives for their prayers
Thank to my brothers and friends Richard EBA, Yves Oscar BROUand Jean-Michel KOFFI for their support and advice.
My bath of master (2012-2014) for happy and difficult moments which were overcome.
Finally, I highly-appreciate the support provided by all those people that have contributed to the development of this dissertation and which have not been listed.
The aim of this study is to assess the health risks associated with the reuse of human excreta (compost and urine) and greywater in the agricultural field. It will firstly have to assess the health risk from farmers associated with the reuse of human excreta and greywater in agriculture field; and secondary to assess the health risk from consumers associated with the reuse of human excreta and greywater in agriculture field. To achieve these objectives, some hypotheses were considered as for the different exposed groups. For farmers, we assume that they handle compost and urine in fields, and they irrigate crops with greywater without adequate equipment protection (gloves, clothing and shoes). For consumers, we assume that they eat lettuce without washing it thoroughly. Different onsite experimentations havebeen carried out. It is about combiningCompost and Top Water (C+TW), Urine and Top Water (U+TW), Compost, Urine and Greywater (C+U+GW) and Non fertilizer (NoF) which is used as a like controlling tool. An initial number of indicators and pathogens cited above were determined in irrigation greywater, compost and urine before applicationin the field. Microbiological quality of soil in different combinations was monitored weekly from E.coli, Faecal coliform, Faecal Enterococci, and Salmonella, and helminthes eggs over two months. Quantitative microbial risk assessment was subsequently evaluated for Salmonella and Ascarison these combinations.Results vary from different treatments: For C+TW treatment, there areannual risks of Salmonella infection in scenarios where it is assumed that farmersmay ingest accidentally 10 to 100 mg of soil which is3.87x10-3 pppy. Concerning Ascaris infection, annual risk is4.67x10-2. From lettuce consumption, Salmonella annual risk infection is 1.54x10-1. For U+TW treatment, Salmonella annual risk infection in scenario where it is assumed that farmers can ingest accidentally soil spread with urine is 9.55x10-1. For lettuce consumption, annual risk is 1.30x10-7. From GW treatment, Salmonella annual risk infection in scenario which assumes that farmers ingest accidentally 10 to 100 mg of soil irrigated with greywater is 8.89x10-6. From ingestion of irrigation greywater, annual risk infection is 1.02x10-4. Concerning lettuce consumption, Salmonella risk infection is 9.42x10-4.
From C+U+GW treatment, in case of soil ingestion, Salmonella annual risk infection is 1.44x10-4. For Ascaris infection, risk is 4.67x10-2. From ingestion of irrigation greywater, Salmonella annual risk infection is 1.53x10-3. For Ascaris infection, risk is 3.97x10-1. From lettuce consumption, Salmonella annual risk infection is 5.00x10-7. For Ascaris infection, risk is 2.41x10-2.
Keywords: Health Risk Assessment, Compost, Urine, Greywater, Quantitative Microbial Risk Analysis, Ascaris, Salmonella, Reuse and Agriculture.