ORIGINAL RESEARCH
Ecological Risk Assessment of Heavy Metal
Occurrences in the Coal-Fired Furnace
Bottom Slags of Power Plants
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1
Academician Workstation in Anhui Province, Anhui University of Science and Technology, Huainan 232001, China
2
School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China
3
Anhui Province Engineering Laboratory of Water and Soil Resources Comprehensive Utilization
and Ecological Protection in High Groundwater Mining Area, Huainan 232001, China
Submission date: 2025-02-12
Final revision date: 2025-03-31
Acceptance date: 2025-04-13
Online publication date: 2025-06-04
Corresponding author
Yonghong Zheng
Anhui Province Engineering Laboratory of Water and Soil Resources Comprehensive Utilization
and Ecological Protection in High Groundwater Mining Area, Huainan 232001, China
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ABSTRACT
This study explored the ecological risks related to bulk resource utilization of industrial solid
waste slag from the Yuanyanghu Power Plant in the Ningdong Energy and Chemical Industry
Base. Scanning electron microscopy, energy spectrum analysis, and X-ray diffraction were used to
characterize and analyze the physical and chemical properties of the slag. The total amount, effective
forms, and different occurrence forms of six heavy metals, including lead (Pb), chromium (Cr), nickel
(Ni), copper (Cu), cadmium (Cd), and arsenic (As), were determined. The ecological and environmental
risks of the heavy metals in the power plant slag were comprehensively evaluated using the potential
ecological risk index method and risk assessment coding (RAC) method. The results show that:
(1) The slag exhibited a porous microstructure characterized by high concentrations of calcium
(36.27%). The mineral composition of the furnace bottom slag was mainly mullite and quartz,
and the contents of available potassium and organic matter were abundant. (2) The total concentrations
of the six heavy metals in the furnace bottom slag did not exceed the screening value for soil pollution
risk in agricultural land. Pb, Cd, Cr, As, and Ni in the slag mainly existed in the form of residue
(F5), with Ni and As in the exchangeable state (F1), accounting for 28.05% and 25.49%, respectively.
(3) The potential ecological risk index method indicates that the total RI index of the six elements
in the slag is at level II, with a moderate ecological hazard level. Among all the metals, Cd and As
contribute most to ecological risk. The RAC evaluation results indicate that Ni and As have moderate
risk, Cd, Cu, and Cr have low risk, and Pb is risk-free. Based on a comprehensive evaluation, Cd, Ni, and As elements in slag are the main potential pollutants. In large-scale resource utilization,
it is necessary to monitor and strengthen ecological risk prevention and control regularly.