Provenance of Anthropogenic Pb and Atmospheric Dust to Northwestern North America

Abstract

Industrial activities release aerosols containing toxic metals into the atmosphere, where they are transported far from their sources, impacting ecosystems and human health. Concomitantly, long-range-transported mineral dust aerosols play a role in Earth’s radiative balance and supply micronutrients to iron-limited ecosystems. To evaluate the sources of dust and pollutant aerosols to Alaska following the 2001 phase-out of leaded gasoline in China, we measured Pb-Sr-Nd isotopic compositions of particles collected in 2016 from snow pits across an elevational transect (2180–5240 m-a.s.l) in Denali National Park, USA. We also determined Pb flux and enrichment from 1991–2011 in the Denali ice core (3870 m-a.s.l). Chinese coal-burning and non-ferrous metal smelting account for up to 64% of Pb deposition at our sites, a value consistent across the western Arctic. Pb isotope ratios in the aerosols did not change between 2001 and 2016, despite the ban on lead additives. Emissions estimates demonstrate that industrial activities have more than compensated for the phase-out of leaded gasoline, with China emitting ∼37,000 metric tons year –1 of Pb during 2013–2015, approximately 78% of the Pb from East Asia. The Pb flux to Alaska now equals that measured in southern Greenland during peak pollution from North America.

Lake Sediment Archive Reveals a Distinct Response to Anthropogenic Pb and Zn Deposition with Historical Periods: Pb–Zn Isotope Evidence

“…Given the low degrees of industrialization in China, we can, therefore, conclude that Pb in this period mainly originated from the long-distance transport of atmospheric Pb from other regions. A decline in Pb was also observed at numerous sites worldwide, most likely as a result of the implementation of cleaner production standards and the elimination of leaded gasoline in Europe and North America. ,, Based on the Bayesian model, the contribution of Pb from long-range transport decreased to 62.9% between 1950 and 1980, with the addition of Chinese coal contributing 22.1% (Figure and Table S6).…”

“…A decline in Pb was also observed at numerous sites worldwide, most likely as a result of the implementation of cleaner production standards and the elimination of leaded gasoline in Europe and North America. 14,68,69 Based on the Bayesian model, the contribution of Pb from long-range transport decreased to 62.9% between 1950 and 1980, with the addition of Chinese coal contributing 22.1% (Figure 4 and Table S6).…”

“…The international community has held China accountable for its coeval emission of heavy metals into the global atmosphere since its rapid industrialization in the 1980s. , However, this remains debatable because before its industrialization, China had experienced trans-boundary atmospheric heavy metal deposition from other areas. , The impact of industrial development on Pb and Zn emissions in China can be solved by investigating the historical records of Pb and Zn in natural archives. Sediment cores collected from enclosed lakes can undertake this task, given that these lakes receive materials mainly via atmospheric deposition with limited contribution from the ambient surface due to small watersheds. , The chronology of sediment cores can be precisely established via 210 Pb dating. , Multiplying metal concentrations by their sedimentation rates can yield an influx of metals into lakes .…”

“…The international community has held China accountable for its coeval emission of heavy metals into the global atmosphere since its rapid industrialization in the 1980s. 14,15 However, this remains debatable because before its industri-alization, China had experienced trans-boundary atmospheric heavy metal deposition from other areas. 16,17 The impact of industrial development on Pb and Zn emissions in China can be solved by investigating the historical records of Pb and Zn in natural archives.…”

Mixing mechanisms of lead nanoparticles with mineral particles: implication of atmospheric transportation of lead

“…1,4,5 The SD particles affected and altered the air quality by providing the reaction interfaces for anthropogenic pollutants, [6][7][8][9][10][11][12][13][14][15][16][17] human health was affected through the attack on the respiratory system, [18][19][20] and the climate and weather systems were impacted by changing the radiation balance. [21][22][23][24] More importantly, the SD particles mixed with the anthropogenic pollutants, 22,[25][26][27][28][29][30] such as heavy metals, organic and inorganic compounds, and biomaterials were transported to the areas without SD storms, 31,32 leading to a wide-ranging risk to the environment.…”