The Center for Ecological-Noosphere Studies NAS, Yerevan, 0025, Abovian-68, Armenia.
The Center for Ecological-Noosphere Studies NAS, Yerevan, 0025, Abovian-68, Armenia.
Environ Pollut. 2024 Oct 15;359:124553. doi: 10.1016/j.envpol.2024.124553. Epub 2024 Jul 14.
The long-term study of the chemical composition of river sediments within urban areas and the establishment of baseline values of major and trace elements is an important task. Therefore, this study aims to provide a geochemical characterization of the sediments, establish a local geochemical baseline, unveil geochemical associations of elements, study the trend of changes in element pollution levels and the associated ecological risks. The results indicate that the change of the local physical characteristics across the river flow (canyon-flat relief surrounded by buildings-reservoir-flat relief under the influence of contamination sources) and locations of contamination sources conditioned the formation of positive extreme values detected for the majority of the studied elements. An analogous variation pattern of major and trace elements median values (2019-2023) was observed for Cr, V, Cu, Fe, Co, Zr Mn, Zn, K, Ba over 5 years representing the geochemical signature of the local geological composition (basalt, andesibasalts, andesite, tuff, K-feldspar). The pollution level and the ecological risk assessment showed that during the study period moderately and highly hazardous levels of multi-element pollution were detected in the southwestern part of the river located near the industrial enterprises. In the meantime, moderate (in 2020) and considerable (in 2021) ecological risk levels were observed at the site near the artificial reservoir. A hierarchical clustering combined with the geochemical ratio analysis reveals three groups of geochemical associations that have a natural (Fe, Mn, Co, V, Ti, Zr, K, Rb, Ba); anthropogenic (Cu, Zn, Pb, Mo) and mixed (Ca, Sr, Cr) origin. Moreover, the anthropogenic association shows affinity to Ca hence denominating the dominant role of carbonates in the fixation and coprecipitation of Cu, Pb, Mo, Zn ions. The comparison of the baseline values of the studied elements with the upper continental crust values confirmed their applicability for differentiation of their origin.
对城市地区河流沉积物的化学成分进行长期研究，并建立主要和微量元素的基线值是一项重要任务。因此，本研究旨在对沉积物进行地球化学特征描述，建立当地地球化学基线，揭示元素的地球化学关联，研究元素污染水平的变化趋势及其相关的生态风险。结果表明，河流流动（峡谷-平地地形，周围环绕着建筑物-受污染源影响的水库-平地地形）和污染源位置的局部物理特征的变化条件决定了大多数研究元素的正极端值的形成。Cr、V、Cu、Fe、Co、Zr、Mn、Zn、K、Ba 的主要和微量元素中值（2019-2023 年）在 5 年内表现出类似的变化模式，代表了当地地质组成（玄武岩、安山玄武岩、安山岩、凝灰岩、钾长石）的地球化学特征。污染水平和生态风险评估表明，在研究期间，位于靠近工业企业的河流西南部地区检测到多种元素污染的中到高危害水平。与此同时，在人工水库附近的地点观察到中度（2020 年）和相当大（2021 年）的生态风险水平。层次聚类结合地球化学比分析揭示了三组地球化学关联，它们具有自然（Fe、Mn、Co、V、Ti、Zr、K、Rb、Ba）、人为（Cu、Zn、Pb、Mo）和混合（Ca、Sr、Cr）起源。此外，人为关联显示出对 Ca 的亲和力，因此在固定和共沉淀 Cu、Pb、Mo、Zn 离子方面，碳酸盐起着主导作用。将研究元素的基线值与上地壳值进行比较，证实了它们在区分其来源方面的适用性。
