The environmental impact of sewage and wastewater outfalls in Antarctica: An example from Davis station, East Antarctica.
We present a comprehensive scientific assessment of the environmental impacts of an Antarctic wastewater ocean outfall, at Davis station in East Antarctica. We assessed the effectiveness of current wastewater treatment and disposal requirements under the Protocol on Environmental Protection to the Antarctic Treaty. Macerated wastewater has been discharged from an outfall at Davis since the failure of the secondary treatment plant in 2005. Water, sediment and wildlife were tested for presence of human enteric bacteria and antibiotic resistance mechanisms. Epibiotic and sediment macrofaunal communities were tested for differences between sites near the outfall and controls. Local fish were examined for evidence of histopathological abnormalities. Sediments, fish and gastropods were tested for uptake of sewage as measured by stable isotopes of N and C. Escherichia coli carrying antibiotic resistance determinants were found in water, sediments and wildlife (the filter feeding bivalve Laternula eliptica). Fish (Trematomus bernacchii) within close proximity to the outfall had significantly more severe and greater occurrences of histopathological abnormalities than at controls, consistent with exposure to sewage. There was significant enrichment of15N in T. bernacchii and the predatory gastropod Neobuccinum eatoni around the outfall, providing evidence of uptake of sewage. There were significant differences between epibiotic and sediment macrofaunal communities at control and outfall sites (<1.5 km), when sites were separated into groups of similar habitat types. Benthic community composition was also strongly related to habitat and environmental drivers such as sea ice. The combined evidence indicated that the discharge of wastewater from the Davis outfall is causing environmental impacts. These findings suggest that conditions in Antarctic coastal locations, such as Davis, are unlikely to be conducive to initial dilution and rapid dispersal of wastewater as required under the Protocol on Environmental Protection to the Antarctic Treaty. Current minimum requirements for wastewater treatment and disposal in Antarctica are insufficient to ameliorate these risks and are likely to lead to accumulation of contaminants and introduction of non-native microbes and associated genetic elements. This new understanding suggests that modernised approaches to the treatment and disposal of wastewater are required in Antarctica. The most effective solution is advanced levels of wastewater treatment, which are now possible, feasible and a high priority for installation. As a direct outcome of the study, a new advanced treatment system is being installed at Davis, effectively avoiding environmental risks.
Antarctic Conservation and Management Theme, Australian Antarctic Division, Channel Hwy, Kingston, 7050, TAS, Australia. Electronic address: jonny.stark@aad.gov.au.
Jonathan S
JS
Stark
School of Life and Environmental Sciences, Centre for Integrative Ecology, Deakin University, Warrnambool Campus, P.O. Box 423, Warrnambool, VIC 3280, Australia.
Patricia A
PA
Corbett
Ecological Marine Services Pty. Ltd., 2/3 Thomsen St, Millbank, QLD 4670, Australia.
Glenn
G
Dunshea
Antarctic Conservation and Management Theme, Australian Antarctic Division, Channel Hwy, Kingston, 7050, TAS, Australia.
Glenn
G
Johnstone
Antarctic Conservation and Management Theme, Australian Antarctic Division, Channel Hwy, Kingston, 7050, TAS, Australia.
Catherine
C
King
School of Life and Environmental Sciences, Centre for Integrative Ecology, Deakin University, Warrnambool Campus, P.O. Box 423, Warrnambool, VIC 3280, Australia.
Julie A
JA
Mondon
Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia.
Michelle L
ML
Power
Division of Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, 116 Daley Road, Acton, ACT 2601, Australia.
Angelingifta
A
Samuel
Antarctic Conservation and Management Theme, Australian Antarctic Division, Channel Hwy, Kingston, 7050, TAS, Australia.
Ian
I
Snape
Antarctic Conservation and Management Theme, Australian Antarctic Division, Channel Hwy, Kingston, 7050, TAS, Australia.
Martin
M
Riddle
D000818:Animals; D004777:Environment; D004784:Environmental Monitoring; D005399:Fishes; D006801:Humans; D012722:Sewage; D062065:Wastewater
D012722:Sewage; D062065:Wastewater
Antibiotic resistance; Benthic communities; Coastal ecosystem; Escherichia coli; Pollution; Stable isotopes