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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/9251

Title: Antibiotics in Ghanaian environment: occurrence, uptake, model and risk assessment of vegetables irrigated with low quality water
Authors: Azanu, David
Issue Date: 14-Oct-2016
Abstract: Hospital wastewater and effluents from waste stabilization ponds in Kumasi, Ghana, are directly discharged as low quality water into nearby streams which are eventually used to irrigate vegetables. The presence of 12 commonly used antibiotics in Ghana (metronidazole, ciprofloxacin, erythromycin, trimethoprim, ampicillin, cefuroxime, sulfamethoxazole, amoxicillin, tetracycline, oxytetracycline, chlortetracycline and doxycycline) were investigated in the water samples. Greenhouse uptake studies of tetracycline and amoxicillin antibiotics by lettuce and carrot plants were performed and then used for modelling uptake of antibiotics using STELLA® software. Finally, the occurrence of these 12 antibiotics in lettuces irrigated with low quality water in Kumasi Ghana were investigated. Antibiotics in the water samples were extracted using solid phase extraction, the plants samples were extracted using accelerated solvent extraction followed by clean up on SPE. All samples were analyzed on HPLC-MS/MS. The total load of antibiotics discharged through the WSP effluents and hospital wastewater was up to 3.1 g/day. Low quality water used for vegetable irrigation considered for this study had antibiotics concentrations up to 0.2 ppb. Interestingly, the concentrations of antibiotics in irrigation water were not significantly different from that of the stream samples (p = 0.03). The concentrations of antibiotics determined in lettuce collected from vegetable farms and markets in Kumasi, Ghana ranged from 13.5 to 104.3 ng/kg. Seven out of 12 antibiotics investigated were detected in at least one sample. Estimated daily intakes of erythromycin and sulfamethoxazole for the consumption of lettuce were 6.4 x 10-7 and 2.0 x 10-7 μg/kg body weight/d respectively. These estimated daily intakes are several times lower than acceptable daily intakes of 0.5 and 50 μg/kg body weight/d respectively, implying no toxic effect to human consumption. The outcomes of this study suggest there could be indirect exposure of humans to antibiotics through vegetable consumption and drinking water in Ghana. Although the levels found in lettuce plant could not cause toxic effect to human’s further research needs to be v investigated since low levels of antibiotics in food and low quality water could contribute to development of bacterial resistance.
Description: A thesis submitted to the Department of Chemistry, College of Science, Kwame Nkrumah University of Science and Technology, Kumasi in partial fulfilment of the requirements for the award of the degree Doctor of Philosophy in Analytical Chemistry, 2016
URI: http://hdl.handle.net/123456789/9251
Appears in Collections:College of Science

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