An assessment of the public health hazard potential of wastewater reuse for crop production: a case study of Gaborone, Botswana

Wastewater reuse is one possible way in which food production and security can be achieved especially in semi-arid countries like Botswana which are in the rain shadow. However, there is a potential public health risk associated with wastewater use. Health concerns are centered on pathogens and other health related pollutants that normally occur in the effluent. This research was conducted in Gaborone, Botswana during the period February 2008 to May 2008. Gaborone is a semi-arid area with an average rainfall of between 250 and 450 mm/annum. It is frequently hit by droughts and water scarcity problems. The study aimed at assessing the potential health impacts of effluent reuse for irrigating crops. Samples were collected from effluent, field soils and vegetables and analyzed for selected parameters of health significance. The methods used in this research included the statistical analysis of the effluent quality and questionnaire analysis of the collected data. The effluent quality was within the required standards except for fiscal coliforms, turbidity and COD. Farmers’ knowledge on potential risks were investigated through a questionnaire. The results show that 50% of the respondents were aware of related health risks of using wastewater for irrigation. There is some health risk related to use of the effluent and the consumption of the vegetables irrigated with treated effluent. It is recommended that farmers must minimize direct contact with the effluent; consumers must wash vegetables with potable water and cook them before consumption.