Investigation of the relationship between wave action and the transport of bacteria in freshwater : implications for the management of aquatic and human health risk

The sampling regime used to monitor the microbiological quality of water typically involves the collection of whole water samples, where bacteria are assumed to be planktonic. This practice ignores sedimentary pathogen sources and highlights the lack of understanding regarding the effect of shear stress on the erosion of bacteria from sediment particles. This study utilized a wave flume and an environmental test bacterial strain to examine the effect of increasing wave energy on bacterial loading and the partitioning of free-floating and floc-associated bacteria in water. A positive correlation was found between wave energy, total suspended solids, and bacterial loading in water. Experiments examining free-floating and floc-associated bacteria under low (0.60 N/s) and high (5.35 N/s) wave energy demonstrated the importance of floc as a vector for the transport of bacteria. These results imply that current beach sampling and analysis methods may not reflect overall beach water quality.