Witt Emitt C, Pribil Michael J, Hogan John P, Wronkiewicz David J
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.
U.S. Geological Survey, Central Mineral and Environmental Resources Science Center, USA.
Environ Pollut. 2016 Sep;216:450-459. doi: 10.1016/j.envpol.2016.05.070. Epub 2016 Jun 17.
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.
为确定已建成的长期矿区内铅（Pb）的来源，对密苏里州13条未铺设路面道路上车辆扬起的扬尘中铅的同位素组成进行了测量。采用以（207）Pb/（206）Pb和浓度为示踪剂的三端元模型，扬尘样本落在特征明确的非均质端元混合区域内。本次调查选定的端元包括：1）代表尾矿的铅混合物的（207）Pb/（206）Pb；2）别克二次回收冶炼厂附近受气溶胶铅影响的土壤的（207）Pb/（206）Pb；3）代表背景条件的土壤、岩芯和钻屑的平均值。矿区粉尘的王水总浓度和（207）Pb/（206）Pb表明，粉尘中35.4 - 84.3%的源铅与尾矿混合物有关，9.1 - 52.7%与冶炼厂混合物有关，0 - 21.6%与背景物质有关。在连续萃取的操作阶段，同位素比值变化极小，表明所有三种铅混合物全程都在混合。铅的不稳定形态归因于所有三个端元。可萃取碳酸盐相中，总浓度的96.6%与尾矿有关，51.8%与冶炼厂沉积物有关，34.2%与背景有关。下一个最不稳定的地球化学相（铁 + 锰氧化物）也有类似结果，高达85.3%与尾矿有关，56.8%与冶炼厂沉积物有关，4.2%与背景土壤有关。
