Instituto Tecnológico Vale (ITV), Rua Boaventura da Silva, 955, Belém 66055-090, PA, Brazil; Programa de Pós-graduação em Geologia e Geoquímica, Instituto de Geociências (IG), Universidade Federal do Pará (UFPA), Rua Augusto Corrêa, 1, Belém 66075-110, PA, Brazil.
Instituto Tecnológico Vale (ITV), Rua Boaventura da Silva, 955, Belém 66055-090, PA, Brazil; Department of Environmental Science and Technology, School of Environment and Earth Sciences, Central University of Punjab, VPO-Ghudda, Bathinda 151401, Punjab, India.
Sci Total Environ. 2022 Jul 1;828:154327. doi: 10.1016/j.scitotenv.2022.154327. Epub 2022 Mar 8.
Trace elements (TE) contamination in forested areas of the Itacaiúnas River Watershed (IRW), Brazilian Amazon, arouses growing interest owing to the rapid deforestation and mining activities. In this study, soils (surface, SS; bottom, BS) and stream sediments (SD) from forested/deforested areas of IRW were analyzed with the aim of (1) evaluating the major sources of TE (mainly As, Ba, Cd, Cu, Co, Cr, Hg, Mo, Mn, Ni, Pb, V, and Zn), and (2) examining the soil-sediment TE link related to land-use change and/or geologic factors. Compositional data analysis (CoDA) was used to eliminate data closure issues and the centred log-ratio (clr) transformation yielded better results in Principal Component Analysis (PCA). The TE distribution pattern was significantly different (p < 0.05) between forested and deforested areas, but in both areas the TE distribution pattern is significantly correlated between SS, BS, and SD, indicating a strong lithogenic control. PCA (clr-transformed) identified the major geochemical bedrock signature as Fe-Ti-V-Cu-Cr-Ni, which is nearly similar in soil and sediments. The more accentuated enrichment and the maximum number of anomalies of these elements were found in the Carajás Basin and are highly coincident with mineral deposits/local lithologies without clear indication of anthropogenic contamination from point sources. Besides geogenic factors, deforestation is also affecting TE distribution in the basin. In deforested areas, Mn was significantly enriched in the surface horizon. Furthermore, linear regression analysis shows stronger TE relationships between soils and sediments in deforested areas than in forested ones, reflecting higher erosion in the former. This could be the reason for the relatively higher enrichment of TE (e.g., Fe, Mn, Cu, Cr, Ni) in deforested sediments. The TE contamination using regional background values provides more accurate results than worldwide reference values. Thus, the former should be considered for a more realistic environmental risk assessment in IRW and other forest ecosystems in the Brazilian Amazon.
林区微量元素（TE）污染受到越来越多的关注，这是由于巴西亚马逊流域伊塔卡亚努斯河（IRW）的森林砍伐和矿业活动迅速增加所致。本研究分析了 IRW 林区和非林区的土壤（表层，SS；底层，BS）和溪流沉积物（SD），目的是（1）评估 TE 的主要来源（主要是 As、Ba、Cd、Cu、Co、Cr、Hg、Mo、Mn、Ni、Pb、V 和 Zn），（2）研究与土地利用变化和/或地质因素相关的土壤-沉积物 TE 关系。成分数据分析（CoDA）用于消除数据封闭问题，中心化对数比（clr）变换在主成分分析（PCA）中产生了更好的结果。TE 的分布模式在林区和非林区之间有显著差异（p < 0.05），但在这两个区域，SS、BS 和 SD 之间的 TE 分布模式具有显著相关性，表明存在强烈的岩生性控制。PCA（clr 变换）确定了主要的地球化学基岩特征为 Fe-Ti-V-Cu-Cr-Ni，这在土壤和沉积物中几乎相似。这些元素的富集程度更高，异常数量也更多，出现在卡拉雅斯盆地，与矿产/局部岩性高度吻合，没有明显表明来自点源的人为污染。除了地球化学因素外，森林砍伐也影响了流域内 TE 的分布。在非林区，Mn 在表层土壤中显著富集。此外，线性回归分析表明，在非林区土壤和沉积物之间的 TE 关系比在林区更强，反映出前者的侵蚀程度更高。这可能是导致非林区沉积物中 TE（如 Fe、Mn、Cu、Cr、Ni）相对更高富集的原因。使用区域背景值进行 TE 污染评估比使用全球参考值提供更准确的结果。因此，在 IRW 和巴西亚马逊其他森林生态系统中，应考虑前者进行更现实的环境风险评估。
