Grahn E, Karlsson S, Düker A
Man-Technology-Environment Research Centre, Department of Natural Sciences, Orebro University, SE-701 82 Orebro, Sweden.
Sci Total Environ. 2006 Aug 31;367(2-3):778-90. doi: 10.1016/j.scitotenv.2006.01.018. Epub 2006 May 15.
This paper presents reference and recent acid-leachable concentrations of some seldom monitored trace elements (SMTE; Ag, Be, Ga, In, Sb and Tl) in sediments from four boreal oligotrophic lakes in a south to north transect in Sweden. For comparison commonly monitored trace elements (As, Cd, Co, Cr, Cu, Ni, Pb and Zn) are included as well as those of relevance for redistribution processes (Al, Ca, Fe, Mg and Mn). Pore water pH and the corresponding solid/solution distribution coefficients (Kd) indicated that redistribution of the elements due to acidification is minor. The depth of impact was defined as the level in the sediment where the mean values became constant on successive exclusion of metal concentrations in overlying strata. Reference concentrations were calculated below the depth of impact. The present concentration changes are estimated by the ratio between the average concentration above the depth of impact and the reference concentration. Reference concentration ranges for the SMT-elements are (mg/kg, dry wt.): Ag 0.16-0.66; Be 1.6-3.7; Ga 2.0-5.1; In 0.05-0.22; Sb 0.05-0.11 and Tl 0.17-0.70. The concentration ratios for these elements ranged in the two most southern lakes from 1.5 to 4.5 and in the two northern ones from 0.6 to 1.6. A high correlation between Kd for the SMT-elements, and iron, except for Sb and Tl, infer that the biogeochemistry of iron is quantitatively important for the accumulation of these elements. The reference concentration ranges for the commonly monitored trace elements are (mg/kg, dry wt.): As 7.0-29.6; Cd 0.33-0.98; Co 5.7-23.8; Cr 15.2-26.1; Cu 27.6-58.4; Ni 5.4-20.8; Pb 44-96. The corresponding concentration ratios were 1.2-18 (second highest 3.9) in the two most southern lakes and 0.8-1.6 in the two northern ones. Declining ratios were found from south to north, most obvious for cobalt and zinc. The copper ratios did not show a regional pattern, partly because of the impact from old mine waste. Increased concentrations of Ag, Be, Ga, In, Sb and Tl in recent sediments up to 4.5 times the reference levels in combination with the geographical pattern infer an elevated loading of these elements.
本文介绍了瑞典从南到北分布的四个北方贫营养湖泊沉积物中一些监测较少的微量元素（SMTE；银、铍、镓、铟、锑和铊）的参考浓度及近期酸可浸出浓度。为作比较，还纳入了常见监测微量元素（砷、镉、钴、铬、铜、镍、铅和锌）以及与再分配过程相关的元素（铝、钙、铁、镁和锰）。孔隙水pH值及相应的固/液分配系数（Kd）表明，酸化导致的元素再分配作用较小。影响深度定义为沉积物中这样一个深度水平，即连续排除上覆地层中的金属浓度后，平均值在此处变得恒定。参考浓度是在影响深度以下计算得出的。当前浓度变化通过影响深度以上的平均浓度与参考浓度之比来估算。SMTE元素的参考浓度范围为（毫克/千克，干重）：银0.16 - 0.66；铍1.6 - 3.7；镓2.0 - 5.1；铟0.05 - 0.22；锑0.05 - 0.11；铊0.17 - 0.70。这些元素的浓度比在最南部的两个湖泊中为1.5至4.5，在最北部的两个湖泊中为0.6至1.6。除锑和铊外，SMTE元素的Kd与铁之间存在高度相关性，这表明铁的生物地球化学对这些元素的积累在数量上具有重要意义。常见监测微量元素的参考浓度范围为（毫克/千克，干重）：砷7.0 - 29.6；镉0.33 - 0.98；钴5.7 - 23.8；铬15.2 - 26.1；铜27.6 - 58.4；镍5.4 - 20.8；铅44 - 96。相应的浓度比在最南部的两个湖泊中为1.2至18（第二高为3.9），在最北部的两个湖泊中为0.8至1.6。从南到北比值呈下降趋势，钴和锌最为明显。铜的比值未呈现区域模式，部分原因是受旧矿废料的影响。近期沉积物中银、铍、镓、铟、锑和铊的浓度增加，最高可达参考水平的4.5倍，结合地理模式推断这些元素的负荷增加。
