燃煤固废重金属分布特征与环境风险研究

he coal-fired solid waste from thermal power plants is produced in large quatity, and heavy metal pollution risk exists in accumulation treatment or resource utilization. In order to study the distribution characteristics of heavy metals in different coal-fired solid wastes and their effects on human health, the K power Plant in Jiangsu Province was taken as an example and the contents of heavy metals and major elements were measured by inductively coupled plasma mass spectrometry, atomic fluorescence spectrometer and X-ray fluorescence spectrometer. The results show that the content of heavy metal in coal-fired solid waste reduces in the order of Mn（859.51μg/g）> Cr（129.72μg/g）> Pb（87.37μg/g）> Cu（72.59）> Ni（38.81μg/g）> As（32.50μg/g）> Cd（0.42μg/g）> Hg（0.38μg/g）. The distribution of Cu, Ni, Mn and Cr in various wastes decreases in the order of slag, coarse ash and fine ash, accounting for 29-60%, 22-41% and 17-33% respectively. However, the distribution of As, Hg, Cd and Pb exhibits an opposite trend, accounting for 1-8%, 36-41% and 51-61% in the slag, coarse ash and fine ash respectively. The enrichment of heavy metals is characterised by a "stepwise" pattern, which is affected by the element volatility, occurrence form and other chemical components. The evaluation results of potential ecological risk index showed that the comprehensive pollution level of fine ash was strong（RI = 428）, among which Hg, As and Cd were the major contributing factors. The results of US EPA model evaluation show that the non-carcinogenic risk of heavy metals in coal solid waste is low, and the carcinogenic risk is in the acceptable range, among which Cr is the major contributing factor. Attention should be paid to Hg, As, Cd in fine ash and Cr in slag during the prevention and control of heavy metals and the resource utilization of solid waste.