Research ArticleENVIRONMENTAL CHEMISTRY

Pb pollution from leaded gasoline in South America in the context of a 2000-year metallurgical history

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Science Advances  06 Mar 2015:
Vol. 1, no. 2, e1400196
DOI: 10.1126/sciadv.1400196

Figures

  • Fig. 1 Location of the drilling area and sites mentioned in the text.

    Upper right: Map of South America with the Illimani drilling site (red star). Left: Topographic map showing the mines, metallurgical and historical centers (yellow dots), and the Peruvian and Bolivian lake sediment sites (green stars) discussed in the text. The satellite image ©PlanetObserver was extracted from DVD-ROM “’Der Große 3D-Globus 4.0 Premium,” #2008 United Soft Media Verlag GmbH. Lower right: Frequency plot of 5-day back trajectories for the Zongo valley close to the Illimani for the period 1989–1998 using HYSPLIT and the NCEP/NCAR reanalysis. Back trajectories were run every 6 hours.

  • Fig. 2 Ice core records of Pb and Ce concentrations, Pb isotope ratios, and lake levels of the Lake Titicaca for the period AD 0–2000.

    Concentrations are shown as 10-year medians (gray lines) and 100-year lowpass-filtered data (Pb, green bold line; Ce, brown bold line), whereas isotope ratios 208Pb/207Pb and 206Pb/207Pb are presented as 50-year means (±SE) together with the background range for Bolivia (local dust and soils + Porco and Cerro de Potosí mine tailings) (42) (hatched areas). Reconstructed lake levels of Lake Titicaca [meters below overflow level (BOL)] are from (31). The prolonged dusty/dry period during the Medieval Climate Optimum and the Industrial period (Ind.) are marked in orange and red, respectively.

  • Fig. 3 Ice core Pb EF record compared to sediment core Pb concentrations from Bolivian and Peruvian lakes.

    Illimani Pb EF record (gray, 10-year medians; blue, 100-year low-pass filtered data) together with sediment core Pb concentrations from Laguna Lobato [orange, period AD 20–1995 (15)], Laguna Taypi Chaka [brown, period AD 4–1923 (15)], Laguna Llamacocha [black, period AD 25–2008 (21)], and Laguna Pirhuacocha [green, period AD 560–2005 (22)]. Periods of generalized Andean archaeological history together with causes of enhanced or reduced Pb deposition are marked in blue.

  • Fig. 4 Colonial drawings of silver-smelting furnaces (huayras) in the Bolivian Andes.

    Left: Watercolor painting from the late 16th century showing three huayras with flames emerging from the orifices in the walls; two huayras smoke and are tended by individuals in indigenous ponchos and Spanish-style hats, from the Atlas of Sea Charts, courtesy of The Hispanic Society of America, New York. Right: After Barba 1640. [from (56)]

  • Fig. 5 Ice core records of nitrate concentrations, Pb EFs, and Pb isotope ratios for the period AD 1850–2000.

    Nitrate concentrations (10-year medians, green) and Pb EFs (10-year medians, black) are shown together with the number of motor vehicles in Bolivia (Bol), Brasilia (Bra), Chile (Chi), and Peru (Per) (67) (brown) and the estimated Pb emissions in South America (S.A.) (24) (blue dashed line, emissions from metal production; blue bold line, total emissions from gasoline and metal production). The isotope ratios 206Pb/207Pb (black) and 208Pb/207Pb (gray) are presented as 10-year averages (±SE). The period of enhanced Pb pollution from leaded gasoline is marked in green.

  • Fig. 6 Three-isotope plot of the Illimani Pb record for the period AD 1850–2000.

    Ice core values are given as 10-year averages (±SE) for the periods AD 1850–1965 (pink) and AD 1965–2000 (red). The gray range represents the isotopic composition of background soils and dust in Bolivia and Porco and Cerro de Potosí mine tailings (42). The Pb isotopic composition of aerosols from South America and the United States in the period AD 1994–1999 (68) is shown in blue and green, respectively. The three black circles mark areas typical for Australian Broken Hill Pb used in European gasoline, Mississippi Valley–type Pb used in U.S. gasoline, and the composition of Peruvian/Mexican ores (68).

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