title: Assessment of mobility and bio-availability of heavy metals in dry depositions of Asian dust and implications for environmental risk.
abstract: We assess the potential mobility and bio-availability of selected metals (As, Cd, Co, Cr, Cu, Ni, Mo, Pb, S, Zn, and Zr) in the dry depositions of Asian and non-Asian dust from the city of Daejeon, Korea. For this study, we applied Pb isotopes, total extraction and chemical sequential extraction methods to the dry depositions. In addition, microscopic analysis was performed using X-ray diffraction (XRD) and focused ion beam (FIB)-scanning electron microscopy (SEM-EDS). FIB-SEM cross-section observations and Pb isotope data showed a black carbon is an important carrier of associated heavy metals originating from China. A five-step sequential extraction performed on the dry depositions showed that S and Cd are the most abundant elements in the water-soluble and cation-exchangeable fraction. In addition, Zn and Pb appeared predominantly in the carbonate and reducible fractions. On the other hand, Cu, Mo and, to a lesser degree, As were significantly associated with the organic fraction, while Co, Ni, Cr and Zr were bound to the residual fraction. These results showed that S, Cd, Zn and Pb, which were highly concentrated in potentially mobile fractions, have potential environmental risk because potential changes in redox state and pH may remobilize these metals. In addition, the estimated remobilization concentrations of these metals were significant. Thus, this study shows that frequent and careful monitoring of S, Cd, Z, Pb and, to a lesser degree, Cu, Mo and As is very important for assessing environmental risk in Korea.
authors.affiliation: Geological and Environmental Hazards Department, Korea Institute of Geoscience and Mineral Resources, 30 Kajung-dong, Yusung-ku, Daejon 305-350, Republic of Korea. Electronic address: pklee@kigam.re.kr.
authors.forename: Pyeong-Koo
authors.initials: PK
authors.lastname: Lee
authors.affiliation: Geological and Environmental Hazards Department, Korea Institute of Geoscience and Mineral Resources, 30 Kajung-dong, Yusung-ku, Daejon 305-350, Republic of Korea.
authors.forename: Byoung-Young
authors.initials: BY
authors.lastname: Choi
authors.affiliation: Department of Soil and Groundwater, Korea Environment Corporation, 42 Hwangyeong-Ro, Seo-gu, Incheon 404-708, Republic of Korea.
authors.forename: Min-Ju
authors.initials: MJ
authors.lastname: Kang
mesh_terms: D001682:Biological Availability; D002947:Cities; D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods* / Q000706:statistics & numerical data; D004785:Environmental Pollutants / Q000032:analysis*; D005843:Geography; D019216:Metals, Heavy / Q000032:analysis* / Q000493:pharmacokinetics*; D008855:Microscopy, Electron, Scanning; D056910:Republic of Korea; D018570:Risk Assessment; D014961:X-Ray Diffraction
chemical_list: D004391:Dust; D004785:Environmental Pollutants; D019216:Metals, Heavy
keywords: Bio-availability; Dry depositions of AD and NAD; FIB-SEM; Heavy metals; Mobility