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Historical trends in trace element deposition were analyzed using herbaria specimens. We determined Al, Fe, Mg, Mn, Ca, Na, P, K, S, As, Cd, Cr, Cu, Ni, Pb and Zn contents in leaves of eight specimens collected in 1941. To assess changes, we collected the same plants from a botanical garden in 2012. The concentrations of major elements showed large species variability. However, temporal trends were predominately detected for heavy metals. The Cd, Ni and Cr contents in the 2012 leaves were 10, 13 and 16 times higher, respectively, than in 1941. Urban activities have substantially raised the levels of these metals in urban atmospheres due to changes in human activities over 70 years of urban growth. Nevertheless, Pb has decreased (−126%) in recent decades thanks to controlled lead fuel combustion. In short, metal deposition trend to increase Cr, Ni and Cd levels.
•Herbarium material used for retrospective analyses in environmental pollution.•Temporal trends were predominately detected for heavy metal content.•Cd, Ni and Cr contents increased 10–16 times in over 70 years of urban growth.•Decreasing Pb is linked to the control of leaded fuels combustion.
Herbaria specimens showed that urban activities have high levels of Cr, Ni and Cd in urban atmospheres due to changes in human activities after more than 70 years of urban growth.