Browsing by Author "Maher, WA"
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- ItemCoral record of harbour dredging: Townsville, Australia(Elsevier, 2004-12) Esslemont, G; Russell, RA; Maher, WAConcentrations of Ba/Ca, Cu/Ca, Sr/Ca and Zn/Ca were measured by secondary ion mass spectrometry in a branching coral, Pocillopora damicornis, from a coral reef receiving suspended sediments from Townsville Harbour dredging activities. The Sr/Ca record correlated with observed sea surface temperatures (SST), which allowed pulse inclusions of barium, copper and zinc to be dated and compared with various environmental records. Copper and zinc concentrations in this coral skeleton correlated with short exposures to labile metals in resuspended fine sediment. The biota–sediment accumulation factor (BSAF) indicated that concentrations of these metals in the coral skeleton were lower than the labile fraction in the sediment (BSAF=0.15 and 0.18, respectively). Distortions to the timing and amplitude of pulse-records in the coral record may have been caused by seasonal variation in skeleton growth. High barium concentrations in the coral skeleton recorded during a dry period corresponded with weather events that resuspended fine, inner-shelf sediment, specifically local winds interacting with swells driven by offshore trade winds, and dredging of the harbour's access channel. This coral has recorded entry of resuspended fine sediment into the reef. Irregularities in the strontium paleothermometer were similar to the solar radiation profile, which preceded variation of seawater temperature by about a month. When coral records were temporally adjusted to fit variation in solar radiation, the correlation between strontium and solar radiation was greater than the strontium–temperature correlation used to date the coral. © 2004 Elsevier B.V
- ItemHistory of human impact on Lake Kutubu, Papua New Guinea: the geochemical signatures of oil and gas mining activities in sediments(Elsevier, 2016-04-01) Schneider, L; Haberle, SG; Maher, WA; Krikowa, F; Zawadzki, A; Heijnis, HLake Kutubu, a large tropical lake in Papua New Guinea, is well known for its ecological importance; however, there have been recent changes to the pristine nature of this lake due to activities associated with the largest oil and gas project in PNG. The aim of this study was to determine the geochemical profile of sediment cores of Lake Kutubu and to comprehend the contamination changes undergone in this lake due to mining activities utilising the hydraulic fracturing method. Sediment core profiles of Na, Mg, Al, Si, P, Ca, Ti, Cr, Fe, Mn, Ni, Cu, Zn, As, Se, Sr, Cd, Ba, Ce, Pb and U, grain size and dating analyses were conducted for five sites in the lake. Grain size and dating demonstrated that the northwest side of Lake Kutubu has sediments of allocthonous origin while the southeast sediments are of autochthonous origin. Ba was the element with the largest changes in concentrations since 1990 and the best tracer of mining activities near the lake. Sites KTB 02 and KTB 10 northwest of the lake showed the most distinct changes in element concentrations. Element enrichment factors (EF = 2.8, 4.2 and 3.2 respectively) demonstrated that Mn, Se and Ba have undergone a moderate enrichment in the lake since mining activities started. Ni, Cd and Se concentrations exceed sediment guidelines in some samples. No guideline is available for Ba, and special attention should be given to this element in this lake. This study demonstrated that Lake Kutubu oil/gas extraction activities are significant sources of elements to this lake and highlights the need for studies on the partitioning and speciation of elements to understand organism metal exposure. © 2016, Elsevier Ltd.
- ItemHistory of sediment geochemical signals in an area of oil reserve development in Lake Kutubu, PNG(University of New South Wales and Australian Nuclear Science and Technology Organisation, 2015-07-09) Schneider, L; Harberle, S; Maher, WA; Krikowa, F; Zawadzki, A; Heijnis, HNot provided to ANSTO Library.
- ItemHow significant is atmospheric metal contamination from mining activity adjacent to the Tasmanian Wilderness World Heritage Area? A spatial analysis of metal concentrations using air trajectories models(Elsevier, 2019-03-15) Schneider, L; Mariani, M; Saunders, KM; Maher, WA; Harrison, JJ; Fletcher, MS; Zawadzki, A; Heijnis, H; Haberle, SGThis study investigated metal contamination from historical mining in lakes in the Tasmanian Wilderness World Heritage Area (TWWHA) and surrounding region. The largest increase in sedimentation and metal contamination occurred ca. 1930 when open-cut mining commenced and new mining technology was introduced into the region. The geochemical signal of lake sediments changed from reflecting the underlying geology and lithology to that reflecting mining activities. The HYSPLIT air particle trajectory model explains metal distribution in the lakes, with those in the northwest region closest to the mines having the highest metal contamination. Lake metal concentrations since mining activities commenced are in the order: Owen Tarn > Basin Lake > Perched Lake > Lake Dove > Lake Dobson > Lake Cygnus, with Perched Lake and Lakes Dove, Dobson and Cygnus in the TWWHA. Metal contamination affected centres up to 130 km down-wind of mining sites. Enrichment factors (EF) for Pb, Cu, As and Cd are >1 for all lakes, with Owen Tarn and Basin Lake having very high EFs for Cu and Pb (98 and 91, respectively). Pb, Cu, As and Cd concentrations are above the Australia/New Zealand lower sediment guidelines, with Pb, Cu and As above the high guidelines in Owen Tarn and Basin Lake. This study demonstrated the legacy of metal contamination in the TWWHA by mining activities and the consequences of a lack of execution of environmental regulations by past governments in Tasmania.© 2018 Elsevier B.V