USE OF PB AND ZN ISOTOPE SYSTEMATICS TO ASSESS METAL SOURCES WITHIN THE ORLOVKA-SPOKOINOE MINING SITE

The isotopic signatures of Pb and Zn in geologic samples (barren and ore-bearing granites and host rocks), processed products (ore concentrates and tailings) and environmental samples (lichens and birch leaves) were used to trace the sources of Pb and Zn within the Orlovka-Spokoinoe mining site in Eastern Transbaikalia, Russia. Lichens and leaves were used as receptors of contamination within the mining site.

Lichens and leaves (22 samples in total) exhibited a homogenous Pb isotope distribution being less radiogenic than all the geologic and anthropogenic samples. This indicates Pb deposition from external source and favours atmospheric transfer of Pb.

Zn isotope data of geologic and lichen samples showed variable Zn isotopic signatures with the total range for the geologic suite of -0.4 to +1.2 ‰ and for lichens of +0.4 to +1.4 ‰ in δ⁶⁶Zn relative to Lyon JMC Zn standard. The source of isotopically heavy Zn within the Orlovka-Spokoinoe mining site could be potentially long-range atmospheric aerosols that also contributed Pb to the studied mining site.

Our results indicated the potential of isotopic tracer techniques in the identification of additional sources of potentially toxic elements such as Pb and Zn. It was showed that Zn isotope analysis might be used as a new tool for Zn source assessment. In addition, our results demonstrate that mining activity may not necessarily be responsible for local metal pollution.