Spatio-temporal study of the fecal pollution of the waters of the ono lagoon in the commune of bonoua (côte d'ivoire)

he objective of this study is to evaluate the bacteriological quality of the Ono lagoon. The bacteria sought are total coliforms, fecal coliforms, E.coli, Enterococci, Clostridium perfringens. For this purpose, surface water was collected by dipping 500 mL glass bottles previously sterilized for laboratory analysis. The water samples to be analyzed were spread on agar media without any trace of moisture. After incubation, the colonies that grew on the surface were counted. The results also showed the presence of the bacteria sought in the lagoon. These varied seasonally at six (6) stations. The bacteriological loads recorded are higher in the rainy season than in the low water and flood seasons. The fecal coliform loads recorded in the Ono lagoon at the different stations 1, 5 and 6 in the low water season, at stations 4, 5 and 6 in the rainy season and at station 4 in the flood season showed the poor quality of these waters at these stations. Seasonal variation showed that the average fecal coliform load recorded in flood season is 4.5 ± 2.4x102 CFU/100mL. On the other hand, those recorded in low water season is 1.7 ± 1.3x103 CFU/100mL and in rainy season is 3.4 ± 1.9x103 CFU/100mL. Compared to the values of the general grid of microbiological quality (SEEE, 2008) of Morocco, our results obtained allow us to say that the waters of the Ono lagoon are of good quality in flood season and average quality in low water and rainy seasons.