Iron speciation of size-resolved atmospheric particles in the vicinity of iron and steelmaking industries

Abstract

Emission of particles to the atmosphere from iron and steel processing industries is an increasing concern due to deleterious effects on human health, environment and process efficiency. The negative impacts of atmospheric particles on human health and environment are dependent on their physical (particle size, shape) and chemical properties (concentration, chemistry and speciation of metals and other elements of concern). Iron was found to be the major trace metal present in atmospheric particles in the vicinity of iron and steelmaking industries. Toxicity of iron in atmospheric particles has been identified to be closely related to its soluble fraction, which depends on the chemical speciation form of iron. The aim of this paper is to provide the speciation assessment of iron in size-resolved atmospheric particles collected in the vicinity of Australian iron and steelmaking industries. Atmospheric particles were collected near three different iron and steelmaking sites and one background urban site in Australia using an eight staged Micro Orifice Uniform Deposit Impactor. The collected size-resolved particles were then subjected to experimental analysis using the synchrotron-based X-ray Absorption Near-Edge Structure (XANES) and the Particle Induced X-ray Emission (PIXE) techniques. Speciation of iron in the size-resolved atmospheric particles was qualitatively assessed based on a set of selected iron based standards, which included divalent, trivalent, hydroxide and sulfide forms of iron. The relative proportion of each iron chemical form present in the different size range of atmospheric particles and their corresponding environmental speciation based impacts are further discussed in this paper.