title: Identifying iron foundries as a new source of unintentional polychlorinated naphthalenes and characterizing their emission profiles.
abstract: Iron foundries have been identified as dioxin sources in previous field investigations. Similar formation mechanisms between dioxins and unintentional polychlorinated naphthalenes (PCNs) have led us to speculate that iron foundries are also potential PCN sources. In this study, PCNs in stack gas and fly ash samples representing atmospheric and residue emissions from 13 typical iron foundry plants were analyzed. The average emission factor of ∑(2-8)PCNs to residue was calculated to be 61 μg t(-1), with a range of 10-107 μg t(-1). The emission factors of ∑(2-8)PCNs to air in two case plants were 267 and 1472 μg t(-1). The derived emission factors might be useful for estimating annual emissions and understanding the contribution of PCNs from iron foundries. The possible formation mechanisms of PCNs, based on the PCN profiles, are discussed. Successive reductions in the abundance of homologues were observed to occur with the increase in chlorine substituted numbers. Abundances of congeners containing more β-position chlorines in the naphthalene skeleton were much higher than those of congeners containing more α-position chlorines for penta-, hexa-, and hepta- homologues, which suggests that the β-positions are favored for chlorination. Potential chlorination pathways from tetra- to octa- homologues are proposed.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , P.O. Box 2871, Beijing 100085, China.
authors.forename: Guorui
authors.initials: G
authors.lastname: Liu
authors.forename: Pu
authors.initials: P
authors.lastname: Lv
authors.forename: Xiaoxu
authors.initials: X
authors.lastname: Jiang
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Nie
authors.forename: Minghui
authors.initials: M
authors.lastname: Zheng
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry; D060729:Coal Ash / Q000032:analysis; D054879:Halogenation; D006843:Hydrocarbons, Chlorinated / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity; D007221:Industry; D007501:Iron / Q000032:analysis*; D009281:Naphthalenes / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity
chemical_list: D000393:Air Pollutants; D060729:Coal Ash; D006843:Hydrocarbons, Chlorinated; D009281:Naphthalenes; C031721:naphthalene; D007501:Iron