title: Chemical speciation of Fe and Ni in residual oil fly ash fine particulate matter using X-ray absorption spectroscopy.
abstract: Epidemiological studies have linked residual oil fly ash fine particulate matter with aerodynamic diameter <2.5 μm (ROFA PM(2.5)) to morbidity and mortality from cardiovascular and respiratory illnesses. Bioavailable transition metals within PM have been cited as one of the components that induce such illnesses. By combining synchrotron-based X-ray absorption spectroscopy with leaching experiment, we studied the effect of residual oil compositions and combustion conditions on the speciation of Fe and Ni in ROFA PM(2.5) and the implication of these species for human health and environment. PM(2.5) samples were obtained from two types of combustors, a fire tube boiler (FTB) and a refractory line combustor (RLC). The study reveals that only Fe(2)(SO(4))(3)·nH(2)O is present in RLC PM(2.5) while Fe(2)(SO(4))(3)·nH(2)O predominates in FTB PM(2.5) with inclusion of varying amounts of nickel ferrite. The finding that RLC PM(2.5) is more bioavailable and hence more toxic than FTB PM(2.5) is significant. The reduction of toxicity of FTB PM(2.5) is due to the immobilization of a portion of Fe and Ni in the formation of an insoluble NiFe(2)O(4). This may explain the variation of toxicity from exposure to different ROFA PM(2.5). Additionally, the speciation data are sought for developing emission inventories for source apportionment study and understanding the mechanism of PM formation.
authors.affiliation: Department of Applied Physics and Ballistics, F.M. University, Balasore 756 019, India. sidpattanaik@yahoo.com
authors.forename: Sidhartha
authors.initials: S
authors.lastname: Pattanaik
authors.forename: Frank E
authors.initials: FE
authors.lastname: Huggins
authors.forename: Gerald P
authors.initials: GP
authors.lastname: Huffman
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D060729:Coal Ash / Q000737:chemistry*; D005290:Ferric Compounds / Q000032:analysis; D006801:Humans; D007501:Iron / Q000032:analysis*; D009532:Nickel / Q000032:analysis*; D010316:Particle Size; D052638:Particulate Matter / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy
chemical_list: D000393:Air Pollutants; D060729:Coal Ash; D005290:Ferric Compounds; D052638:Particulate Matter; C550717:nickel ferrite; D009532:Nickel; D007501:Iron