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Kwame Nkrumah University of Science and Technology (2008)

Wastewater Irrigated Vegetable Production : Contamination pathway for health risk reduction in Accra, Kumasi and Tamale - Ghana

Amoah, Philip

Titre : Wastewater Irrigated Vegetable Production : Contamination pathway for health risk reduction in Accra, Kumasi and Tamale - Ghana

Auteur : Amoah, Philip

Université de soutenance : Kwame Nkrumah University of Science and Technology

Grade : Doctor of Philosophy 2008

Résumé partiel
The study was conducted in three Ghanaian cities (Accra, Kumasi and Tamale) selected from different agro-ecological zones (Coastal Savanna for Accra, Moist Semi Deciduous Forest for Kumasi, and Guinea Savanna for Tamale) in two phases. The main methods used included surveys, crop and analysis, and field trials. In phase I, questionnaire interviews were used to gather background information from a total of 1058 subjects (farmers, sellers and consumers) from the three cities on wastewater use, distribution and handling of wastewater irrigated vegetables. In addition, direct observation and focus group discussions were carried out. Samples of waste water irrigated lettuce, cabbage and spring onions were also collected from selected markets in Accra, Kumasi and Tamale to determine the current level of exposure of the Ghanaian urban population to hazardous pesticide and faecal bacteria contamination through the consumption of fresh vegetables produced with wastewater. All three vegetables were analyzed for total coliform (TC) and faecal coliform (FC) as well as helminth egg populations an all three vegetables using standard methods. Lettuce samples were also analyzed for pesticide residue. In view of the qualitative nature of most of the results from phase I, scientific quantitative data was provided to complement qualitative results, identify intervention points and provide the baseline for assessing the effectiveness of interventions. The requisite quantitative scientific data and implications were covered in the second phase of the study. Lettuce was used as test crop because of the higher level of FC from markets (phase I) compared to cabbage and spring onions. Tamale was also dropped because farmers used similar irrigation water sources as in Accra. At this stage, the microbial and physiochemical quality of irrigation water from different urban sources was assessed. From two vegetable production sites each in Accra and Kumasi, lettuce samples irrigated with water from drain, stream, well and piped water were collected at designated points along the “farm to fork” pathway and analyzed for TC, FC, and helminth egg populations. Attempts were also made to isolate and characterize representative types of faecal coliforms present on farm samples collected during the pathway to study to assess the potential health risk to consumers.

Présentation

Page publiée le 27 septembre 2010, mise à jour le 12 juillet 2018