School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria 3001, Australia; Centre for Environmental Sustainability and Remediation, RMIT University, Victoria, Australia; CDM Smith, Richmond, Victoria, Australia.
Australian Contaminated Land Consultants Association, Victoria, Australia.
Sci Total Environ. 2018 May 15;624:599-610. doi: 10.1016/j.scitotenv.2017.12.131. Epub 2017 Dec 27.
There has been a global shift in environmental risk assessment towards quantifying ambient background concentrations of metals/metalloids in soil. Whilst bedrock has been shown to be a key driver of metal/metalloid variability in soil, few researchers have assessed controls of ambient background concentrations in soils of similar bedrock. A soil survey was undertaken ofGreater Melbourne, Greater Geelong, Ballarat and Mitchell in Victoria, Australia for elements of potential environmental concern: As, Cd, Cr, Cu, Ni, Hg, Pb and Zn. Samples (n=622) were collected from surface (0 to 0.1m) and sub-surface (0.3 to 0.6m) soils, overlying Tertiary-Quaternary basalt, Tertiary sediments and Silurian siltstone and sandstone. In addition, background soil data from open-source environmental assessment reports (n=5512) were collated to support the understanding of natural enrichment, particularly at depths >0.6m. Factor analysis, supported by correlation analysis and auxiliary geo-spatial data, provided an improved understanding of where and how background metal/metalloid enrichment occurs in the environment. Weathering during paleoclimates was the predominant influence of background metal/metalloid variability in soils overlying similar bedrock. Other key influences of metal/metalloid variability in soil included hydraulic leaching of alkali elements, biological cycling, topography and alluvial transfer of silt and sand from mineralised regions. In addition, urbanisation positively correlated with Pb and Zn concentrations in surface soils suggesting that anthropogenic activities may have resulted in diffuse Pb and Zn contamination of urban soil.
在环境风险评估方面，全球已经发生了一种转变，即量化土壤中金属/类金属的环境背景浓度。尽管基岩已被证明是土壤中金属/类金属变异性的关键驱动因素，但很少有研究人员评估过类似基岩土壤中环境背景浓度的控制因素。对澳大利亚维多利亚州的大墨尔本、大吉朗、巴拉腊特和米切尔进行了一项土壤调查，以评估潜在环境关注元素的含量：砷、镉、铬、铜、镍、汞、铅和锌。从覆盖第三纪-第四纪玄武岩、第三纪沉积物和志留纪粉砂岩和砂岩的表层（0 至 0.1 米）和次表层（0.3 至 0.6 米）采集了样本（n=622）。此外，还收集了来自开源环境评估报告（n=5512）的背景土壤数据，以支持对自然富集的理解，特别是在深度>0.6 米的情况下。因子分析得到相关分析和辅助地理空间数据的支持，有助于更好地理解环境中背景金属/类金属富集发生的地点和方式。古气候时期的风化是影响覆盖类似基岩土壤背景金属/类金属变异性的主要因素。土壤中金属/类金属变异性的其他关键影响因素包括碱元素的水力淋滤、生物循环、地形以及来自矿化区的粉砂和砂的冲积转移。此外，城市化与表层土壤中 Pb 和 Zn 浓度呈正相关，表明人为活动可能导致城市土壤中 Pb 和 Zn 的扩散污染。
