Physical, chemical, biological and ecotoxicological properties of wastewater discharged from Davis Station, Antarctica

• We examined the properties of wastewater generated on an Antarctic station.
• It was more concentrated than standard municipal wastewater.
• BOD, COD, nutrients and solids were above standard municipal levels.
• PBDEs and metals were detected at elevated levels in wastewater.
• Wastewater was toxic to local marine invertebrates at 3.25% after 14–21 days.

The properties and toxicity of untreated wastewater at Davis Station, East Antarctica, were investigated to inform decisions regarding the appropriate level of treatment for local discharge purposes and more generally, to better understand the risk associated with dispersal and impact of wastewaters in Antarctica. Suspended solids, nutrients (nitrogen, phosphorus), biological oxygen demand (BOD), metals, organic contaminants, surfactants and microbiological load were measured at various locations throughout the wastewater discharge system. Wastewater quality and properties varied greatly between buildings on station, each of which has separate holding tanks. Nutrients, BOD and settleable solid levels were higher than standard municipal wastewaters. Microbiological loads were typical of untreated wastewater. Contaminants detected in the wastewater included metals and persistent organic compounds, mainly polybrominated diphenyl ethers (PBDEs). The toxicity of wastewater was also investigated in laboratory bioassays using two local Antarctic marine invertebrates, the amphipod Paramoera walkeri and the microgastropod Skenella paludionoides. Animals were exposed to a range of wastewater concentrations from 3% to 68% (test 1) or 63% (test 2) over 21 days with survival monitored daily. Significant mortality occurred in all concentrations of wastewater after 14 to 21 days, and at higher concentrations (50–68% wastewater) mortality occurred after only one day. Results indicate that the local receiving marine environment at Davis Station is at risk from existing wastewater discharges, and that advanced treatment is required both to remove contaminants shown to cause toxicity to biota, as well as to reduce the environmental risks associated with non-native micro-organisms in wastewater.