Sanei H, Goodarzi F, Flier-Keller E V
Geological Survey of Canada, Calgary, AB.
J Environ Monit. 2001 Feb;3(1):27-36. doi: 10.1039/b006819p.
Geochemical analysis of elements and organic matter were conducted on vertical profiles of the recent sediments from Pigeon Lake, Alberta, Canada, to determine historical variations in elemental content of the sediments as related to their geochemical fractions. The elements are grouped according to their affinity with different geochemical fractions, by using cluster analysis and sequential extraction experiments. As a result, four elemental fractions were identified: clastic mineral detritus; carbonate; organic; and elements that show less similarity to the previous groups perhaps due to anthropogenic input or the influence of other fractions, such as oxyhydroxides. Following the identification of geochemical fractions in the sediments, a three-step normalizing method was applied using parameters that represent each geochemical fraction. These normalizing techniques appear to be important in verifying whether the variation of elements is indeed the result of anthropogenic and/or natural activities. The normalized data are correlated with the recent history of human activity and natural events near Pigeon Lake. Given the age of the lake sediments, this correlation indicates that the depth profiles of elements after being normalized to the organic and carbonate fractions reflect the variation of detrital input into the lake. However, the former mainly corresponds to the coarse-grained clastic minerals originating from high-energy erosion as the result of natural events (e.g., flooding), whereas the latter corresponds to the low-energy erosion of the fine particles (enriched in lithophile elements) due to deforestation in the drainage basin. Normalizing to the clastic mineral detritus fraction results in the increase of heavy metals in the uppermost part of the sediment profiles, which coincides with industrial activities during the past two decades in central Alberta. However, the concentration of these elements is negligible, as compared to the quantities released by geogenic processes (erosion).
对加拿大艾伯塔省鸽子湖近期沉积物的垂直剖面进行了元素和有机物的地球化学分析，以确定沉积物元素含量与地球化学组分相关的历史变化。通过聚类分析和连续萃取实验，根据元素与不同地球化学组分的亲和性对元素进行分组。结果确定了四个元素组分：碎屑矿物碎屑；碳酸盐；有机物；以及与前几组相似性较低的元素，这可能是由于人为输入或其他组分（如羟基氧化物）的影响。在确定沉积物中的地球化学组分后，使用代表每个地球化学组分的参数应用了三步归一化方法。这些归一化技术对于验证元素的变化是否确实是人为和/或自然活动的结果似乎很重要。归一化数据与鸽子湖附近人类活动和自然事件的近期历史相关。考虑到湖泊沉积物的年龄，这种相关性表明，归一化到有机物和碳酸盐组分后的元素深度剖面反映了进入湖泊的碎屑输入的变化。然而，前者主要对应于自然事件（如洪水）导致的高能侵蚀产生的粗粒碎屑矿物，而后者对应于流域森林砍伐导致的细颗粒（富含亲石元素）的低能侵蚀。归一化到碎屑矿物碎屑组分导致沉积物剖面最上部的重金属增加，这与艾伯塔省中部过去二十年的工业活动相吻合。然而，与地质作用（侵蚀）释放的量相比，这些元素的浓度可以忽略不计。
