School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China.
Int J Environ Res Public Health. 2023 Mar 2;20(5):4465. doi: 10.3390/ijerph20054465.
Variability in the distribution of natural total Sb and Cd in freshwater sediments leads to difficulties in background value (BV) determination. This study aimed to establish a method to determine BV more accurately by investigating the vertical distribution of Sb and Cd in sediment cores collected from a typical river in alluvial plain in China and revealed the factors that control the variation of Sb and Cd BV, which has not been studied in alluvial freshwater sediment. The results suggested that uncontaminated samples for BV calculation should be determined by statistical analysis as human and natural disturbance led to high variation in contamination depth, from <5 cm to >55 cm. The sequential chemical extraction method showed a considerable amount of non-residual fractions of Sb and Cd, which accounted for 48% and 43% of the total, respectively. Acid extractable Cd (16%) was associated to the limestone geology in the area. Fine particles which governed by sedimentary environment contained more natural Sb and Cd, as strong positive correlation was found between clay content and Sb concentration (r = 0.89, < 0.01), as well as Cd concentration (r = 0.54, < 0.01). Based on these findings, a method combined with standard deviation and geochemical method was established to calculate the BV of Sb and Cd, and counter maps were made to cover the variation of BV in the Taipu river sediment. The pollution level has been evaluated by the geoaccumulation index more accurately.
淡水沉积物中天然总 Sb 和 Cd 的分布具有变异性，这给背景值（BV）的确定带来了困难。本研究旨在通过调查中国冲积平原典型河流沉积物芯中 Sb 和 Cd 的垂直分布，建立一种更准确确定 BV 的方法，并揭示控制 Sb 和 Cd BV 变化的因素，这在冲积淡水沉积物中尚未得到研究。结果表明，BV 的计算应通过统计分析来确定无污染的样本，因为人为和自然干扰导致污染深度的变化很大，从<5cm 到>55cm。顺序化学提取方法显示 Sb 和 Cd 的非残留部分相当多，分别占总量的 48%和 43%。可提取酸的 Cd（16%）与该地区的石灰岩地质有关。受沉积环境控制的细颗粒含有更多的天然 Sb 和 Cd，因为粘土含量与 Sb 浓度（r=0.89，<0.01）以及 Cd 浓度（r=0.54，<0.01）之间存在很强的正相关关系。基于这些发现，建立了一种结合标准差和地球化学方法来计算 Sb 和 Cd 的 BV 的方法，并制作了反演图来覆盖太浦河沉积物中 BV 的变化。利用地积累指数更准确地评价了污染水平。
