Isotopically constrained lead sources in fugitive dust from unsurfaced roads in the southeast Missouri mining district.
The isotopic composition of lead (Pb) in fugitive dust suspended by a vehicle from 13 unsurfaced roads in Missouri was measured to identify the source of Pb within an established long-term mining area. A three end-member model using (207)Pb/(206)Pb and concentration as tracers resulted in fugitive dust samples plotting in the mixing field of well characterized heterogeneous end members. End members selected for this investigation include the (207)Pb/(206)Pb for 1) a Pb-mixture representing mine tailings, 2) aerosol Pb-impacted soils within close proximity to the Buick secondary recycling smelter, and 3) an average of soils, rock cores and drill cuttings representing the background conditions. Aqua regia total concentrations and (207)Pb/(206)Pb of mining area dust suggest that 35.4-84.3% of the source Pb in dust is associated with the mine tailings mixture, 9.1-52.7% is associated with the smelter mixture, and 0-21.6% is associated with background materials. Isotope ratios varied minimally within the operational phases of sequential extraction suggesting that mixing of all three Pb mixtures occurs throughout. Labile forms of Pb were attributed to all three end members. The extractable carbonate phase had as much as 96.6% of the total concentration associated with mine tailings, 51.8% associated with smelter deposition, and 34.2% with background. The next most labile geochemical phase (Fe + Mn Oxides) showed similar results with as much as 85.3% associated with mine tailings, 56.8% associated with smelter deposition, and 4.2% associated with the background soil.
U.S. Geological Survey, Center of Excellence for Geospatial Information Science, Rolla, MO 65409, USA; Missouri University of Science & Technology, Department of Geologic Sciences and Engineering, Rolla, MO 65409, USA. Electronic address: ecwitt@usgs.gov.
Emitt C
EC
Witt
U.S. Geological Survey, Central Mineral and Environmental Resources Science Center, USA. Electronic address: mpribil@usgs.gov.
Michael J
MJ
Pribil
Missouri University of Science & Technology, Department of Geologic Sciences and Engineering, Rolla, MO 65409, USA. Electronic address: jphogan@mst.edu.
John P
JP
Hogan
Missouri University of Science & Technology, Department of Geologic Sciences and Engineering, Rolla, MO 65409, USA; Missouri University of Science & Technology, Environmental Research Center for Emerging Contaminants, Rolla, MO 65409, USA. Electronic address: wronk@mst.edu.
David J
DJ
Wronkiewicz
D000336:Aerosols; D004391:Dust / Q000032:analysis; D007554:Isotopes / Q000032:analysis; D007854:Lead / Q000032:analysis*; D008906:Mining; D008923:Missouri; D012989:Soil Pollutants / Q000032:analysis*
D000336:Aerosols; D004391:Dust; D007554:Isotopes; D012989:Soil Pollutants; D007854:Lead
Pb apportionment; Pb isotopic ratios; Road dust; Sequential extraction; Unsurfaced roads