Browsing by Author "Maher, W"

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    History of metal contamination in Lake Illawarra, NSW, Australia
    (Elsevier, 2015-01-01) Schneider, L; Maher, W; Potts, J; Gruber, B; Batley, GE; Taylor, A; Chariton, AA; Krikowa, F; Zawadzki, A; Heijnis, H
    Lake Illawarra has a long history of sediment contamination, particularly by metals, as a result of past and current industrial operations and land uses within the catchment. In this study, we examined the history of metal contamination in sediments using metal analysis and 210Pb and 137Cs dating. The distributions of copper, zinc, arsenic, selenium, cadmium and lead concentrations within sediment cores were in agreement with historical events in the lake, and indicated that metal contamination had been occurring since the start of industrial activities in Port Kembla in the late 1800s. Most metal contamination, however, has occurred since the 1960s. Sedimentation rates were found to be 0.2 cm year−1 in Griffins Bay and 0.3 cm year−1 in the centre of the lake. Inputs from creeks bringing metals from Port Kembla in the northeast of the lake and a copper slag emplacement from a former copper refinery on the Windang Peninsula were the main sources of metal inputs to Lake Illawarra. The metals of highest concern were zinc and copper, which exceeded the Australian and New Zealand sediment quality guideline values at some sites. Results showed that while historical contamination persists, current management practices have resulted in reduced metal concentrations in surface sediments in the depositional zones in the centre of the lake.© 2015, Elsevier Ltd.
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    Recent history of sediment metal contamination in Lake Macquarie, Australia, and an assessment of ash handling procedure effectiveness in mitigating metal contamination from coal-fired power stations
    (Elsevier, 2014-08-15) Schneider, L; Maher, W; Potts, J; Gruber, B; Batley, GE; Taylor, A; Chariton, AA; Krikowa, F; Zawadzki, A; Heijnis, H
    This study assessed historical changes in metal concentrations in sediments of southern Lake Macquarie resulting from the activities of coal-fired power stations, using a multi-proxy approach which combines 210Pb, 137Cs and metal concentrations in sediment cores. Metal concentrations in the lake were on average, Zn: 67 mg/kg, Cu: 15 mg/kg, As: 8 mg/kg, Se: 2 mg/kg, Cd: 1.5 mg/kg, Pb: 8 mg/kg with a maximum of Zn: 280 mg/kg, Cu: 80 mg/kg, As: 21 mg/kg, Se: 5 mg/kg, Cd: 4 mg/kg, Pb: 48 mg/kg. The ratios of measured concentrations in sediment cores to their sediment guidelines were Cd 1.8, As 1.0, Cu 0.5, Pb 0.2 and Zn 0.2, with the highest concern being for cadmium. Of special interest was assessment of the effects of changes in ash handling procedures by the Vales Point power station on the metal concentrations in the sediments. Comparing sediment layers before and after ash handling procedures were implemented, zinc concentrations have decreased 10%, arsenic 37%, selenium 20%, cadmium 38% and lead 14%. An analysis of contaminant depth profiles showed that, after implementation of new ash handling procedures in 1995, selenium and cadmium, the main contaminants in Australian black coal had decreased significantly in this estuary. © 2014, Elsevier B.V.