Levels and sources of heavy metals in soil, sediment, and food crop in the vicinity of electric arc furnace (EAF) steelmaking plant: a case study from Taiwan

Abstract

The distribution and characteristics of heavy metals around an electric arc furnace (EAF) plant in Taichung City, Taiwan, were investigated. The aim of this research was to predict the main steelmaking processes causing contamination of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the environment. Food crop, surface water, sediments, and soils were collected from a total of 65 and 53 sampling sites during November 2011 and June 2012, thus establishing the basic environmental information. The heavy metals in samples were assessed by potential ecological risk indices. The correlation between the source and receptors of contamination was evaluated through the statistical significance of isotope approach and hierarchical cluster analysis. The heavy metal contamination was mainly from the storage facility of waste iron and the discharging device of fly ash in the EAF plant. Surface runoff and rainwash were the two potential routes distributing the metallurgical Cd and Pb to the surrounding environment. Based on the mathematical simulation of dispersion modeling, the impact of heavy metals through the two specific flue gases on the farmland was insignificant; the particulate matter (PM), SO2, and NOx were concentrated southward in the atmosphere, and they were 1.71 μg—PM/Nm3, 2.80 ppb—SO2, and 1.87 ppb—NOx, respectively. Because of topographical features, the contaminated sediment produced by steelmaking activities is washed into downstream via surface runoff, which is supposed to be the major source of long-term accumulation of heavy metals in the environments, although the contamination with heavy metals was graded as low.