title: Dispersal and dilution of wastewater from an ocean outfall at Davis Station, Antarctica, and resulting environmental contamination.
abstract: The Antarctic Treaty permits the discharge of wastewater into Antarctic marine waters providing that conditions exist for initial dilution and rapid dispersal. We investigated the dilution and dispersal of macerated wastewater around Australia's Davis Station in East Antarctica and examined sediments for evidence of contaminants. Methods used to examine hydrodynamic conditions included current meters, dye release experiments and measurement of sewage-associated microbial markers and surfactants in the water column. We measured marine sediments for metals, nutrients, PBDEs, hydrocarbons and faecal sterols. We propose that if there is adequate dilution and dispersal there would be no significant difference in contaminant concentrations in sediments around the outfall compared to distant control sites. Currents were strongly correlated with prevailing wind conditions. Modelling indicated that diffusivity of wastewater had the greatest effect on dilution factors and that neither discharge rates nor local currents had as much effect. During summer conditions of open water, wastewater is likely to be constrained in a narrow plume close to the coast. Concentrations of sewage bacteria were high around the outfall and detected up to 1.5 km away, along with dye. There were significant differences in sediment concentrations of metals, PBDEs, hydrocarbons, nutrients and faecal sterols between sites within 2 km of the outfall and control sites. We conclude that dilution and dispersal conditions at the Davis outfall are insufficient to prevent the accumulation of contaminants in local sediments and that microbial hazards posed by wastewater are an environmental risk to local wildlife.
authors.affiliation: Antarctic Conservation and Management Theme, Australian Antarctic Division, Channel Hwy, Kingston 7050, TAS, Australia. Electronic address: jonny.stark@aad.gov.au.
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Stark
authors.affiliation: AsureQuality, 1C Quadrant Drive, Waiwhetu, Lower Hutt 50106, New Zealand.
authors.forename: Phil
authors.initials: P
authors.lastname: Bridgen
authors.affiliation: Antarctic Conservation and Management Theme, Australian Antarctic Division, Channel Hwy, Kingston 7050, TAS, Australia.
authors.forename: Glenn
authors.initials: G
authors.lastname: Dunshea
authors.affiliation: ACE-CRC, Antarctic Climate & Ecosystems Cooperative Research Centre, Private Bag 80, Hobart 7001, TAS, Australia.
authors.forename: Ben
authors.initials: B
authors.lastname: Galton-Fenzi
authors.affiliation: ACE-CRC, Antarctic Climate & Ecosystems Cooperative Research Centre, Private Bag 80, Hobart 7001, TAS, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Hunter
authors.affiliation: Antarctic Conservation and Management Theme, Australian Antarctic Division, Channel Hwy, Kingston 7050, TAS, Australia.
authors.forename: Glenn
authors.initials: G
authors.lastname: Johnstone
authors.affiliation: Antarctic Conservation and Management Theme, Australian Antarctic Division, Channel Hwy, Kingston 7050, TAS, Australia.
authors.forename: Catherine
authors.initials: C
authors.lastname: King
authors.affiliation: CSIRO Marine and Atmospheric Research, Hobart 7000, TAS, Australia.
authors.forename: Rhys
authors.initials: R
authors.lastname: Leeming
authors.affiliation: Antarctic Conservation and Management Theme, Australian Antarctic Division, Channel Hwy, Kingston 7050, TAS, Australia.
authors.forename: Anne
authors.initials: A
authors.lastname: Palmer
authors.affiliation: School of Earth, Environmental and Biological Sciences, Faculty of Science and Engineering, Queensland University of Technology, Brisbane, QLD, Australia.
authors.forename: James
authors.initials: J
authors.lastname: Smith
authors.affiliation: Antarctic Conservation and Management Theme, Australian Antarctic Division, Channel Hwy, Kingston 7050, TAS, Australia.
authors.forename: Ian
authors.initials: I
authors.lastname: Snape
authors.affiliation: Antarctic Conservation and Management Theme, Australian Antarctic Division, Channel Hwy, Kingston 7050, TAS, Australia.
authors.forename: Scott
authors.initials: S
authors.lastname: Stark
authors.affiliation: Antarctic Conservation and Management Theme, Australian Antarctic Division, Channel Hwy, Kingston 7050, TAS, Australia.
authors.forename: Martin
authors.initials: M
authors.lastname: Riddle
mesh_terms: D000864:Antarctic Regions; D004784:Environmental Monitoring / Q000379:methods*; D005243:Feces / Q000737:chemistry; D019015:Geologic Sediments / Q000032:analysis* / Q000382:microbiology; D008962:Models, Theoretical; D009792:Oceans and Seas; D012621:Seasons; D012623:Seawater / Q000737:chemistry* / Q000382:microbiology; D012722:Sewage / Q000032:analysis* / Q000382:microbiology; D062065:Wastewater / Q000032:analysis* / Q000382:microbiology; D014871:Water Microbiology; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014919:Wind
chemical_list: D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Coastal currents; Hydrocarbons; Metals; Microbial; PBDE; Sewage