ICP-OES研究北运河表层沉积物中重金属的空间分布特征及生态风险评价

doi:10.3964/j.issn.1000-0593(2020)12-3912-07

Abstract
References
Related Citation (15)

Download: PDF (0 KB)
Export: BibTeX | EndNote (RIS)

Abstract The ecological risk assessments of heavy metal in river sediments is of great significance to study heavy metals pollution level, migration and transformation. The North Canal is an important sink in the Beijing-Tianjin-Hebei region, but the distribution characteristics and ecological risk assessments in the whole river are less known. In order to survey the occurrence of heavy metals in the sediments of the whole basin, 17 national and provincial control sections were selected from the upper, middle and lower reaches of the North Canal. Sediment samples were pretreated by aqua regia extraction, water bath digestion and BCR extraction. The contents of As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn were measured by inductively coupled plasma emission spectroscopy (ICP-OES). The results indicated that the average content of heavy metals in the surface sediments declined as the following order Mn, Pb, Zn, Cu, Cr, Ni, Cd, As. The contents of Pb, Zn and Cu were higher than background values. It is noteworthy that the average value of Pb was 4 times more than their background value. Moreover, the values of different heavy metals varied significantly with the spatial reaches, and the contents in middle and lower reaches are relatively high. The metal speciation analysis indicated that Cd and Zn in the sediments were dominated by acid soluble and reducible species, and have high mobility and bioavailability. While As, Cr, Cu, Mn, Ni and Pb in the sediments were dominated by oxidizable and residual species, and have weak biological activities and pose little harm to the environment. The geological accumulative index (I_geo) indicates that anthropogenic sources mainly contaminated the surface sediments of heavy metals. Pb (I_geo=2.24) reaches the level of moderately to heavily polluted, Cu (I_geo=1.44) and Cr (I_geo=1.45) reaches the level of moderately polluted, Zn (I_geo=0.99) reaches the level of unpolluted to moderately polluted. The calculated values of I_geo for As, Cr, Mn and Ni were less than 0, indicating that As, Cr, Mn and Ni are all at practically unpolluted levels. The potential ecological risk index (PERI) indicated that the comprehensive ecological risk of the surface sediments was generally focused on Cd. The principal component analysis showed that the heavy metals in the surface sediments mainly originated from the discharge of industry and traffic, the unreasonable use of chemical fertilizers and atmospheric precipitation. Compared with other main rivers in China, the North Canal has lower heavy metal content in sediments. These results highlighted the effectiveness of remediation strategy in Beijing, Tianjin and Hebei, which has effectively reduced the risk of heavy metals in the North Canal and will provide important information for the management of the North Canal pollution control.

Key words：ICP-OES; Surface sediments; Heavy metals; Speciation analysis; Ecological risk assessment; Source apportionment

Received: 2019-11-05 Accepted: 2020-03-25

ZTFLH:

O657.3

Corresponding Authors: ZHANG Ting-ting E-mail: zhangtt@mail.buct.edu.cn

Cite this article:

URL:

https://www.gpxygpfx.com/EN/10.3964/j.issn.1000-0593(2020)12-3912-07 OR https://www.gpxygpfx.com/EN/Y2020/V40/I12/3912