Annual Rate of Lead Accumulation in the Lichen Pseudoparmelia baltimorensis

Abstract
The saxicolous foliose lichen Pseudopoarmelia baltimorensis (Gyelnik) Hale from a site in Maryland [USA] heavily polluted by atmospheric lead accumulates about half of its lead burden in newly formed thallus tissues in the first growing season. Two- and three-year-old tissues contain the highest lead concentrations, suggesting that an equilibrium with the atmospheric lead input is reached very rapidly.