Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, IL 60605, USA.
Environ Sci Process Impacts. 2014 Feb;16(2):247-55. doi: 10.1039/c3em00423f.
Bivalves secrete their shells in an annual fashion, resulting in discrete bands of growth within each shell. In doing so, they may incorporate trace elements in concentrations reflecting exposure. This may make it possible to use them as archives of environmental information, such as contamination events. In this study, we used laser ablation inductively coupled plasma-mass spectrometry to analyze trace elements (Cd, Cu, Mn, Pb and Zn) on a fly-scanning transect perpendicular to the growth annuli of the freshwater bivalve Elliptio hopetonensis collected from the Altamaha river system. Concentrations of Mn from multiple shells at each site were correlated and average Mn data series were formed. Periodicity of Mn data was determined and sampling errors removed using an autoregression model. The Mn data series at each site were shown to have regular fluctuations of high and low concentrations. Fluctuations were similar between the shells from the same site but different between shells from different sites, demonstrating that Mn deposition in the shells of E. hopetonensis follows a regular, seasonal pattern but that growth differs between sites with different environments. Cd, Cu, Pb and Zn could not be analyzed in a statistically robust manner. This is the first study to attempt to improve data resolution by using the fly-scanning approach and, additionally, the first to apply an autoregression model to Mn data from bivalve annuli. Further study is required to develop this approach for environmental monitoring.
双壳类动物以年度的方式分泌贝壳，导致每个贝壳内存在离散的生长带。在这个过程中，它们可能会以反映暴露情况的浓度来结合微量元素。这使得它们可以作为环境信息的档案，例如污染事件。在这项研究中，我们使用激光烧蚀电感耦合等离子体质谱法（LA-ICP-MS）来分析从 Altamaha 水系采集的淡水双壳类动物 Elliptio hopetonensis 的垂直于生长环的飞行扫描横截面上的痕量元素（Cd、Cu、Mn、Pb 和 Zn）。每个地点的多个贝壳中的 Mn 浓度进行相关分析，并形成平均 Mn 数据系列。使用自回归模型确定 Mn 数据的周期性并去除采样误差。结果表明，每个地点的 Mn 数据系列均具有高浓度和低浓度的规则波动。同一地点的贝壳之间的波动相似，但不同地点的贝壳之间的波动不同，这表明 Mn 在 E. hopetonensis 贝壳中的沉积遵循有规律的季节性模式，但不同环境的地点之间的生长情况不同。Cd、Cu、Pb 和 Zn 无法以统计上稳健的方式进行分析。这是首次尝试使用飞行扫描方法来提高数据分辨率的研究，此外，也是首次将自回归模型应用于双壳类环中的 Mn 数据。需要进一步研究来开发这种用于环境监测的方法。
