Winter and Summer Evaluation of Bacteriological Water Quality at Recreational Beaches along Todos Santos Bay, Baja California, Mexico

Water bacteriological qualities of 22 recreational beaches in Ensenada Bay, Baja California, Mexico were analyzed during the summer and winter of 2008. Total and fecal coliforms as well as enterococci bacteria were used as pollution indicators. Results showed that bacteria concentrations were higher in winter than summer, associated with Southern California rainy season. Bacteria loads in winter exceeded both the daily and monthly standards showing a clear effect of storm water runoff in the quality of Todos Santos Bay recreational beaches. Statistical analysis showed significant differences between bacteria concentration during summer and winter. The general behavior of the indicators based on daily and monthly standards from high to low was enterococci > FC > TC> total/fecal ratio. Water discharged from 3 sewage treatment plants were responsible for the pollution observed at stations, when the uptake capacity of plants exceeded the storage. During summer pollution was due to non-programmed discharges from sewage treatment plants.