Source Apportionment and Ecological Risk of Heavy Metals in Taihu Lake from a spatiotemporal perspective

Guangjing Bao¹Chao Ji^1*Dawei Hou^2*Yuanbin He¹Yan Li¹Dongmei Lei¹Xi Fan^1*

• ¹Yunnan University of Finance And Economics, Kunming, China
• ²Northeast Agricultural University, Harbin, Heilongjiang Province, China

To investigate the source apportionment and ecological risk of heavy metals in water from a spatiotemporal perspective, seven samples were collected and monitored from 2020 to 2022 in Taihu Lake. Correlation analysis and principal component analysis were utilized to identify the sources of heavy metals, while the temporal and spatial characteristics of ecological risks were assessed using the Mann-Kendall test, mean gravity center, and standard-deviation ellipse methods. The results revealed an increasing order of median concentrations for heavy metals as follows: Cd < Pb < Hg < Cu < As < Ni < Zn. These metals were predominantly attributed to industrial and agricultural activities. Overall, the ecological risks posed by heavy metals were considered acceptable, except for Hg, which exhibited considerable potential ecological risk. Furthermore, the potential ecological risk demonstrated a significant decreasing trend, with Z-values passing the 95% confidence interval significance test, except for site S3. The mean gravity centers of the potential ecological risk were located within an ellipse defined by center coordinates (120.2553, 31.3718), a major axis of 44,525 meters, a minor axis of 28,225 meters, and a direction of 0.4463°. This study enriches the research perspectives on ecological risk assessment and provides valuable insights into the development of mitigation strategies for heavy metal pollution in Taihu Lake.