Environmental impact assessment of the sewage outfall at Davis Station, East Antarctica
conference contribution
posted on 2011-01-01, 00:00authored byJ Stark, C King, M Riddle, I Snape, M Lindsay, S Stark, G Johnstone, J Smith, M Powers, Trish Corbett, Julie MondonJulie Mondon, R Leeming
During the summer 2009/10, an environmental impact assessment of the sewage outfall was conducted at Davis Station, East Antarctica. An investigation of the nature and extent of impacts to the marine environment associated with current sewage treatment and effluent discharge practices included ecological surveys of macrobiological communities, physico-chemical analysis of sediments and receiving waters, microbiological analysis, and histopathological analysis of fish. Ecotoxicological testing using local invertebrates to determine effluent toxicity was interpreted alongside dispersal modelling data of the discharge plume to determine the potential extent of impacts and inform recommendations on the level of treatment and dilution of sewage required to minimise impacts. No evidence of impacts was detected on soft sediment infaunal or epifaunal communities, and only low levels of contamination and accumulation were found in sediments and waters in the immediate vicinity of the outfall and in the direction of primary current flow. In contrast, sterol biomarkers and faecal coliforms (E. coli) were detected in sediments collected adjacent to the outfall and in most water column samples. Marine invertebrates (Abatus and Laternula) also tested positive for E. coli and antibiotic resistance mechanisms were present in Laternula indicating the introduction and dispersal through the water column of foreign microbes and bacteria associated with human effluent. Fish (Trematomus bernacchii) close to the outfall showed significant histological alterations in all major tissues (liver, gill, gonad, muscle) resulting from exposure to sewage. Effluent was toxic to amphipods (Paramoera walkeri) and microgastropods (Skenella paludionoides), with reduced survival in concentrations as low as 3.125% over a 21d exposure period. Acute effects were also observed in both species following 24h exposure, with 100% mortality at the highest effluent concentrations tested (68%). The application of these results to support and guide decisions regarding the planned installation of new sewage treatment facilities at Davis will be discussed.
History
Event
Enviro Tox (2011 : Darwin, N.T.)
Pagination
62 - 62
Publisher
SETAC-AU
Location
Darwin, N.T.
Place of publication
[Darwin, N.T.]
Start date
2011-04-17
End date
2011-04-20
Language
eng
Publication classification
E2 Full written paper - non-refereed / Abstract reviewed
Title of proceedings
Enviro Tox 2011 : Sharing knowledge for a healthier environment