Ribbed mussels (Geukensia demissa) were collected from a highly contaminated Guion Creek, Mamaroneck Harbor, NY and were compared with Harbor Island Park and Shore Acres Beach, for amounts of bacteria. Mussels were also collected from a pristine beach, Read Sanctuary, Rye. The water flow rate was measured at all sites. The results showed that the amount of E. coli and coliform bacteria recovered from mussels were significantly higher in Guion Creek and its water flow rate was significantly lower when compared to three other sites. On the contrary, the highest water flow rate and lowest amounts of bacteria were recovered from mussels collected at Read Sanctuary. A negative correlation of water flow rate with amounts of E. coli and coliform recovered from mussels at all sites was found. Results suggested that a slow water flow rate in Guion Creek might be one of the contributing factors to the high bacterial loads.