Birch G F, Lean J, Gunns T
Environmental Geology Group, School of Geosciences, The University of Sydney, Sydney, NSW, 2006, Australia,
Environ Monit Assess. 2015 Jun;187(6):314. doi: 10.1007/s10661-015-4481-y. Epub 2015 May 4.
Sydney estuary (Australia), like many urbanised waterways, is degraded due to an extended history of anthropogenic activity. Two major sources of contamination to this estuary are discharge by former shoreline industries and historic and contemporary catchment stormwater. The objectives of the present study were to document changes in shoreline land use from European settlement to the present day and determine the influence of this trend on the metal content of adjacent estuarine sediments. Temporal analysis of land use for seven time horizons between 1788 and 2010 showed rapid expansion of industry along much of the Sydney estuary foreshore soon after European settlement due to the benefits of easy and inexpensive access and readily available water for cooling and power. Shoreline industry attained maximum development in 1978 (32-km length) and declined rapidly to the present-day (9-km length) through redevelopment of industrial sites into medium- to high-density, high-value residential housing. Cores taken adjacent to 11 long-term industrial sites showed that past industrial practices contributed significantly to contamination of estuarine sediment. Subsurface metal concentrations were up to 35 times that of present-day surface sediment and over 100 times greater than natural background concentrations. Sedimentation rates for areas adjacent to shoreline industry were between 0.6 and 2.5 cm/year, and relaxation times were estimated at 50 to 100 years. Natural relaxation and non-disturbance of sediments may be the best management practice in most locations.
悉尼河口（澳大利亚）与许多城市化的水道一样，由于长期的人为活动历史而退化。该河口的两个主要污染源是前沿海工业的排放以及历史和当代集水区的雨水。本研究的目的是记录从欧洲殖民时期至今海岸线土地利用的变化，并确定这种趋势对相邻河口沉积物金属含量的影响。对1788年至2010年期间七个时间跨度的土地利用进行的时间分析表明，欧洲殖民后不久，由于交通便利、成本低廉以及有现成的水用于冷却和发电，悉尼河口大部分海岸线上的工业迅速扩张。海岸线工业在1978年达到最大发展规模（长度为32公里），随着工业用地被重新开发为中高密度、高价值的住宅，其规模迅速缩减至如今的规模（长度为9公里）。在11个长期工业场地附近采集的岩芯显示，过去的工业活动对河口沉积物的污染有显著影响。地下金属浓度高达当今表层沉积物的35倍，比自然背景浓度高出100多倍。海岸线工业附近区域的沉积速率在每年0.6至2.5厘米之间，估计恢复时间为50至100年。在大多数地方，让沉积物自然恢复和不受干扰可能是最佳管理方式。
