We used pine tree rings and soil geochemistry to expose the activity of a Pb-Zn smelter in Kabwe, Zambia. We found that local soils are extremely contaminated (up to 16000 mg/kg Pb; 14000 mg/kg Zn; 600 mg/kg Cu in the topsoil). Also, metal bearing particles share their Pb isotopic signature with smelting by-products, and more concerning, metals in tree biomass. We concluded that these metals enter the tree though the bark and leaves, not the roots, implying airborne contamination. Using Pb and C isotopes we mapped the dendrochronology of the tree and verified its susceptibility to changes in smelter production throughout the late 20th century.
Baieta R., Mihaljevič M., Ettler V., Vaněk A., Penížek V., Trubač J., Kříbek B., Ježek J., Svoboda M., Sracek O., Nyambe I. (2021): Depicting the historical pollution in a Pb–Zn mining/smelting site in Kabwe (Zambia) using tree rings. Journal of African Earth Sciences 181, 104246. (DOI)