Total Coliform and Escherichia Coli Counts in 99 Florida Lakes with Relations to Some Common Limnological Factors

Hoyer, M.V., J.L. Donze, E.J. Schulz, D.J. Willis and D.E. Canfield, Jr. 2006. Total coliform and Escherichia coli counts in 99 Florida lakes with relations to some common limnological factors. Lake and Reserv. Manage. 22(2):141-150. The degree of bacterial contamination of 99 Florida lakes was studied using total coliform and Escherichia coli (E. coli) counts as indicators. Over 75% of the 4055 samples analyzed for total colifoms and over 98% analyzed for E. coli were below Florida’s state standards for total and fecal coliform bacteria, respectively. Thus, there is little evidence of widespread fecal contamination in the Florida lakes examined during this study. Future bacterial sampling in lake systems should consider the facts that openwater samples had significantly lower total coliform and E. coli counts than littoral samples, and that the variance in bacterial counts is greater among lakes over time than spatially within lakes. Additionally, lake trophic status and aquatic bird abundance were also positively related to both total coliform and E. coli counts, while lake surface area and percent area covered with aquatic macrophytes (PAC) showed no significant relations. The method of waste management around lakes is often a concern to many people citing septic tank systems for polluting aquatic systems. However, the data examined in this study showed no difference in bacterial counts between lakes managing waste with septic tanks and those with central waste water treatment systems. A routine, inexpensive bacterial monitoring program is recommended for lakes used for body-contact recreational activities to be safe and relieve concerns of the public about potential health problems.