Microbial quality of irrigation water and irrigated vegetables in Kano State, Nigeria

This work examined the quality of wastewater used for irrigation of vegetables in Kano State, Nigeria. It also assessed the sanitary quality of the irrigated vegetables by detecting the incidence of faecal indicator bacteria over a 9 months period between May 2010 to March 2011. Irrigation water sources received pollutants from various effluents discharged from industries, domestic sewage, abattoir and other non point sources of pollution. Physicochemical parameters of irrigation water were observed to be higher than acceptable limits. The counts of faecal coliform in the water and irrigated vegetables also exceeded the 1,000 CFU/100 ml guideline for water used in fresh produce. The presence of faecal-indicator bacteria in the irrigation water and vegetable samples suggests faecal pollution raising the possibility of the presence of pathogenic microorganisms in these vegetables and a threat to public health. We recommend adequate treatment of effluents before discharge. The need for proper disinfection of raw vegetables before consumption cannot be overemphasized.