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The distribution of trace metals (spatial and temporal) and sedimentary fractions were investigated to identify the concentrations and sources of trace metals within Kogarah Bay, NSW, Australia. A total of 59 surface sediments and six subsurface samples from core of the sediment were collected. The contamination factor and pollution load index indices used to evaluate environmental effects of trace metals. The study area was found to be uncontaminated with Cr and Ni, moderately contaminated with As and considerably contaminated with Cu, Zn and Pb. The concentrations of Cr and Ni were below both effect range low and effect range median, while As, Cu, Zn and Pb were slightly above effect range low. The highest concentrations of these trace metals such as Cu, Zn and Pb were found in the north, northwest and southeast of the bay, close to discharge points, stormwater outlets and around boatyards and watercrafts. The spatial distributions of metals were strongly related to muddy particles and organic matter. The temporal sediments of metals declined with increased sediment depth, which reflects accumulation of trace metals since European settlement in this area. Furthermore, the source of the trace metals was found to be stormwater outlets, gasoline fumes, boatyards and other human activities. AbstractThe distribution of trace metals (spatial and temporal) and sedimentary fractions were investigated to identify the concentrations and sources of trace metals within Kogarah Bay, NSW, Australia. A total of 59 surface sediments and six subsurface samples from core of the sediment were collected. The contamination factor and pollution load index indices used to evaluate environmental effects of trace metals. The study area was found to be uncontaminated with Cr and Ni, moderately contaminated with As and considerably contaminated with Cu, Zn and Pb. The concentrations of Cr and Ni were below both Effect Range Low and Effect Range Median, while As, Cu, Zn and Pb were slightly above Effect Range Low. The highest concentrations of these trace metals such as Cu, Zn and Pb were found in the north, north west and south east of the bay, close to discharge points, stormwater outlets and around boatyards and watercrafts. The spatial distributions of metals were strongly related to muddy particles and organic matter. The temporal sediments of metals declined with increased sediment depth, which reflects accumulation of trace metals since European settlement in this area. Furthermore, the source of the trace metals was found to be stormwater outlets, gasoline fumes, boatyards and other human activities.

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Measurement of elevated trace elements is an important component of environmental assessment and management of estuarine marine sediments in systems adjacent to concentrated human activity. The present study surveys the estuarine sediments in selected tributary bays, creeks, and the upper segments of the Georges River system, NSW, Australia, which flows into the Tasman Sea through Botany Bay. A total of 146 surface sediment samples were analysed by X-ray fluorescence. Potential pollution of sediments was evaluated using potential load index, modified degree of contamination, and potential ecological risk index. The spatial distribution of trace elements varies between sites. Variable sources of contamination, including runoff from catchment areas, and emissions from watercraft and boatyards are contributing sources. Bay morphologies and their interactions with catchment and tidal flows play significant roles in the distribution of trace elements. The greatest concentration of trace elements occurs around discharge points and in the inner parts of bays that have high percentages of mud particles and organic matter. The lowest contamination by trace elements was found in sandy sediments along the shoreline and edges of the bays. Trace element distributions decline in concentration in residential-free areas and reach background levels in deeper sediment cores. The concentrations of trace elements were controlled by discharge points from the catchment area, marine boat activities, bay morphology, and sediment types (sand, silt, and clay). The highest pollutant concentrations are the result of past legal, but uncontrolled, discharge of waste from manufacturing into Salt Pan Creek. Creek.

This paper examines present and future resource utilization in the tidal section of the Georges River in the southern part of Sydney. Over the last 30 years, the physical characteristics of the river have changed as a result of urbanization, changed hydrologic regime and sand dredging. Urbanization has resulted in an increase in population from 190,000 in 1947 to 550,000. This has resulted in an increase in runoff, sediment input to the river and waste disposal. The change in hydrologic regime has resulted in a substantial increase in the magnitude and frequency of flooding which has increased erosion. Sand dredging has increased the channel capacity, enlarged the tidal prism and increased water turbidity. It has also resulted in extensive bank erosion in the upper part of the river and extensive deposition lower down as tailings are deposited. Although most of these changes have resulted in the deterioration of environmental quality, use of the river for recreation and as an urban amenity has increased.