Microbiological and Physicochemical Characterization of Irrigation Water in Market Gardening in Korhogo

Several sources of water are used by farmers without concern for quality, which can have consequences on the health of the consumer of market garden products. The aim of this study is to evaluate the microbiological and physicochemical qualities of irrigation water. Microorganisms were counted using the membrane filtration and incorporation into the agar methods. The physicochemical parameters were measured using multiparameter and spectrophotometric methods. The average values of the physicochemical parameters are between 6.46 and 6.9 (pH), 27.15 and 29.9°C (temperature), 170 and 760 μS/cm (electrical conductivity), 70 and 380 mg/L (total dissolved solids), 3.85 and 77.59 mg/L (nitrates), and between 0.13 and 2.35 mg/L for ammonium. Irrigation water in market gardening is highly contaminated by microorganisms. Loads ranging from 3.64 to 4.35 log₁₀ cfu/100 mL, 2.44 to 3.31 log₁₀ cfu/100 mL, 2.44 to 2.9 log₁₀ cfu/100 mL, and 2.07 to 3.63 log₁₀ cfu/100 mL were obtained for total coliforms, E. coli, fecal enterococci, and sulphite-reducing clostridia, respectively. Mean loadings ranging from 4.95 to 5.98 log₁₀ cfu/100 mL, 1.8 to 2.08 log₁₀ cfu/100 mL, and 1.5 to 1.98 log₁₀ cfu/100 mL were obtained for mesophilic aerobic germs, moulds, and yeasts, respectively. Four different mould strains were identified in irrigation water. These strains belong to the genus Aspergillus. Shallows water was more contaminated with microorganisms. These results show that water should be treated before being used for irrigation; market garden products must be properly washed and disinfected before consumption.