Duodu Godfred Odame, Goonetilleke Ashantha, Ayoko Godwin A
Queensland University of Technology, Science and Engineering Faculty, GPO Box 2434, Brisbane, QLD, 4001, Australia.
Queensland University of Technology, Science and Engineering Faculty, GPO Box 2434, Brisbane, QLD, 4001, Australia.
Environ Pollut. 2016 Dec;219:1077-1091. doi: 10.1016/j.envpol.2016.09.008. Epub 2016 Sep 7.
Estuarine environment is complex and receives different contaminants from numerous sources that are persistent, bioaccumulative and toxic. The distribution, source, contamination and ecological risk status of heavy metals in sediment of Brisbane River, Australia were investigated. Sediment samples were analysed for major and minor elements using LA-ICP-MS. Principal component analysis and cluster analysis identified three main sources of metals in the samples: marine sand intrusion, mixed lithogenic and sand intrusion as well as transport related. To overcome inherent deficiencies in using a single index, a range of sediment quality indices, including contamination factor, enrichment factor, index of geo-accumulation, modified degree of contamination, pollution index and modified pollution index were utilised to ascertain the sediment quality. Generally, the sediment is deemed to be "slightly" to "heavily" polluted. A further comparison with the Australian Sediment Quality Guidelines indicated that Ag, Cr, Cu, Ni, Pb and Zn had the potential to rarely cause biological effects while Hg could frequently cause biological effects. Application of potential ecological risk index (RI) revealed that the sediment poses moderate to considerable ecological risk. However, RI could not account for the complex sediment behaviour because it uses a simple contamination factor. Consequently, a modified ecological risk index (MRI) employing enrichment factor is proposed. This provides a more reliable understanding of whole sediment behaviour and classified the ecological risk of the sediment as moderate to very high. The results demonstrate the need for further investigation into heavy metal speciation and bioavailability in the sediment to ascertain the degree of toxicity.
河口环境复杂，会从众多来源接收持久性、生物累积性和毒性污染物。对澳大利亚布里斯班河沉积物中重金属的分布、来源、污染及生态风险状况进行了调查。利用激光烧蚀电感耦合等离子体质谱仪（LA-ICP-MS）对沉积物样品中的主次元素进行了分析。主成分分析和聚类分析确定了样品中金属的三个主要来源：海砂入侵、混合岩石成因与砂入侵以及与运输相关。为克服使用单一指标的固有缺陷，采用了一系列沉积物质量指标，包括污染因子、富集因子、地累积指数、修正污染程度、污染指数和修正污染指数来确定沉积物质量。总体而言，沉积物被认为受到“轻度”至“重度”污染。与澳大利亚沉积物质量指南的进一步比较表明，银、铬、铜、镍、铅和锌很少有可能造成生物效应，而汞则经常会造成生物效应。潜在生态风险指数（RI）的应用表明，沉积物具有中度至相当大的生态风险。然而，RI无法解释复杂的沉积物行为，因为它使用的是一个简单的污染因子。因此，提出了一种采用富集因子的修正生态风险指数（MRI）。这能更可靠地了解整个沉积物行为，并将沉积物的生态风险分类为中度至非常高。结果表明，有必要进一步研究沉积物中重金属的形态和生物有效性，以确定毒性程度。
