The Southeast Florida Outfall Experiment II (SEFLOE II) study was conducted at four ocean outfalls to determine the dispersion characteristics and biotoxicity of their effluent in the coastal ocean. The effluent from these facilities is secondary treated municipal wastewater. This paper deals with the impact of coastal oceanographic characteristics upon the biotoxicity aspect of the SEFLOE II study on data collected at the Broward County outfall.

During the study, whole effluent toxicity (WET) bioassays were compared to bioassays analyzed on samples taken from the outfall dispersion plumes. The ocean bioassays results were then evaluated along with contemporaneous current direction and speed data to determine initial and farfield dilutions and calculate Eularian and Lagrangian exposure impacts.

The bioassay comparison appears to indicate that standard WET methodology does not adequately take into consideration the substantial differences in dilution ratios and exposure times used in laboratory analyses with those experienced in actual environmental field conditions especially for ocean outfalls.