Effects of sewage effluent on 'outfall' infaunal assemblages.

This experiment tested the effects of secondary treated sewage effluent on infaunal assemblages that were collected 50m from a sewage outfall ('outfall' assemblage). Twelve intact sediment cores were collected from this site on the Western Treatment Plant foreshore (Port Phillip Bay, Victoria) and brought back to the laboratory. Four cores were assigned to each of three treatments, which were no dose of effluent, high dose (7mls effluent per minute) or a 'no escape' treatment. The experiment ran for 13 days in December 1999. Throughout the experimental period, dissolved oxygen levels were measured and animals that migrated from the sediment were collected, counted and identified. At the end of the experiment, infauna remaining in the sediment were counted and identified and the wet weight biomass of each species group was recorded.