title: Effect of fuel zinc content on toxicological responses of particulate matter from pellet combustion in vitro.
abstract: Significant amounts of transition metals such as zinc, cadmium and copper can become enriched in the fine particle fraction during biomass combustion with Zn being one of the most abundant transition metals in wood combustion. These metals may have an important role in the toxicological properties of particulate matter (PM). Indeed, many epidemiological studies have found associations between mortality and PM Zn content. The role of Zn toxicity on combustion PM was investigated. Pellets enriched with 170, 480 and 2300 mg Zn/kg of fuel were manufactured. Emission samples were generated using a pellet boiler and the four types of PM samples; native, Zn-low, Zn-medium and Zn-high were collected with an impactor from diluted flue gas. The RAW 264.7 macrophage cell line was exposed for 24h to different doses (15, 50,150 and 300 μg ml(-1)) of the emission samples to investigate their ability to cause cytotoxicity, to generate reactive oxygen species (ROS), to altering the cell cycle and to trigger genotoxicity as well as to promote inflammation. Zn enriched pellets combusted in a pellet boiler produced emission PM containing ZnO. Even the Zn-low sample caused extensive cell cycle arrest and there was massive cell death of RAW 264.7 macrophages at the two highest PM doses. Moreover, only the Zn-enriched emission samples induced a dose dependent ROS response in the exposed cells. Inflammatory responses were at a low level but macrophage inflammatory protein 2 reached a statistically significant level after exposure of RAW 264.7 macrophages to ZnO containing emission particles. ZnO content of the samples was associated with significant toxicity in almost all measured endpoints. Thus, ZnO may be a key component producing toxicological responses in the PM emissions from efficient wood combustion. Zn as well as the other transition metals, may contribute a significant amount to the ROS responses evoked by ambient PM.
authors.affiliation: University of Eastern Finland, Department of Environmental Science, P.O. Box 1627, FI-70211 Kuopio, Finland; National Institute for Health and Welfare, Department of Environmental Health, P.O. Box 95, FI-70701 Kuopio, Finland. Electronic address: oskari.uski@uef.fi.
authors.forename: O
authors.initials: O
authors.lastname: Uski
authors.affiliation: University of Eastern Finland, Department of Environmental Science, P.O. Box 1627, FI-70211 Kuopio, Finland. Electronic address: pasi.jalava@uef.fi.
authors.forename: P I
authors.initials: PI
authors.lastname: Jalava
authors.affiliation: University of Eastern Finland, Department of Environmental Science, P.O. Box 1627, FI-70211 Kuopio, Finland. Electronic address: mikko.happo@uef.fi.
authors.forename: M S
authors.initials: MS
authors.lastname: Happo
authors.affiliation: University of Eastern Finland, Department of Environmental Science, P.O. Box 1627, FI-70211 Kuopio, Finland. Electronic address: tiina.torvela@uef.fi.
authors.forename: T
authors.initials: T
authors.lastname: Torvela
authors.affiliation: University of Eastern Finland, Department of Environmental Science, P.O. Box 1627, FI-70211 Kuopio, Finland. Electronic address: jani.leskinen@uef.fi.
authors.forename: J
authors.initials: J
authors.lastname: Leskinen
authors.affiliation: National Institute for Health and Welfare, Department of Environmental Health, P.O. Box 95, FI-70701 Kuopio, Finland. Electronic address: jorma.maki-paakkanen@thl.fi.
authors.forename: J
authors.initials: J
authors.lastname: Mäki-Paakkanen
authors.affiliation: University of Eastern Finland, Department of Environmental Science, P.O. Box 1627, FI-70211 Kuopio, Finland. Electronic address: jarkko.tissari@uef.fi.
authors.forename: J
authors.initials: J
authors.lastname: Tissari
authors.affiliation: University of Eastern Finland, Department of Environmental Science, P.O. Box 1627, FI-70211 Kuopio, Finland. Electronic address: olli.sippula@uef.fi.
authors.forename: O
authors.initials: O
authors.lastname: Sippula
authors.affiliation: University of Eastern Finland, Department of Environmental Science, P.O. Box 1627, FI-70211 Kuopio, Finland. Electronic address: heikki.lamberg@uef.fi.
authors.forename: H
authors.initials: H
authors.lastname: Lamberg
authors.affiliation: University of Eastern Finland, Department of Environmental Science, P.O. Box 1627, FI-70211 Kuopio, Finland; VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Espoo, Finland. Electronic address: jorma.jokiniemi@uef.fi.
authors.forename: J
authors.initials: J
authors.lastname: Jokiniemi
authors.affiliation: University of Eastern Finland, Department of Environmental Science, P.O. Box 1627, FI-70211 Kuopio, Finland; National Institute for Health and Welfare, Department of Environmental Health, P.O. Box 95, FI-70701 Kuopio, Finland. Electronic address: maija-riitta.hirvonen@uef.fi.
authors.forename: M-R
authors.initials: MR
authors.lastname: Hirvonen
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D002460:Cell Line; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000032:analysis; D015032:Zinc / Q000737:chemistry / Q000633:toxicity*
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D017382:Reactive Oxygen Species; D015032:Zinc
keywords: Chemical composition; Health effects; Particulate matter; Transition metals; Wood combustion; Zinc