Comparison of Levels and Sources of Lead in Modern and Ancient Soils in Low Volga SteppesT. V. Pampura, V. A. Demkin, M. Meili, M. E. Kylander, K. Holm and A. ProbstE3S Web of Conferences, 1 (2013) 08002DOI: https://doi.org/10.1051/e3sconf/20130108002