Guan'gai paishui xuebao (Dec 2023)
Heavy Metal Pollution in Sediment of Irrigation Channels in Xiangjiang River Tributaries
Abstract
【Objective】 Environmental contamination by heavy metals is ubiquitous in many ecosystems. In this paper, we assess heavy metal pollution in sediments of the irrigation canals in the Xiangjiang River basin, as well as their ecological risks. 【Method】 Taking Lei Shui region, an important tributary of the Xiangjiang River, as an example, we analyzed the total contents of As, Cd, Cr, Cu, Ni, Pb and Zn, as well as their water-soluble forms in sediments of the irrigation canals. The geo-accumulation index method and ecological risk coefficient/index method were used to evaluate sediment contamination and its ecological risk. Correlation analysis and principal component analysis were used to elucidate the origin of the heavy metals found in the sediments. 【Result】 The sediments in the irrigation canals in the studied region were severely polluted, with a particularly notable concentration of Cd contamination. The total content of heavy metals in the sediments was 6.4 times the background value, predominantly caused by anthropogenic activities. Ecological risk in the area is hence high, especially the risk of Cd followed by As. The accumulation of As-Cd-Zn and Pb-Cu in the sediments was due to industrial and mining activities, respectively, while Ni, Cr and accumulation of As-Cd-Zn and Pb-Cu was caused by both industrial and mining activities. Ni and Cr in the sediments were naturally originated. 【Conclusion】 The sediments in the irrigation canals in the studied region were severely polluted, with Cd content pronouncedly high exceeding the geological background level by 6.4-fold. Such contamination was predominantly caused by anthropogenic activities. In terms of the ecological risk, Cd was most significant followed by As. The accumulation of As-Cd-Zn and Pb-Cu in the sediments emanated from industrial and mining activities. In contrast, Ni and Cr are naturally originated.
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