Product Guide/1980

Trace element concentrations of the lichen, Flavoparmelia caperata, were determined by neutron activation analysis before and after stringent participate controls were employed in an industrialized section of the Ohio River Valley; Initial studies in 1973 showed elevated concentrations of arsenic, cobalt, iron, vanadium, and titanium in lichens collected near coalfired power plants. Elevated values for cerium, chromium, and lanthanum were found in samples near a ferro-alloys foundry. A repeat study in 1987 demonstrated that lichen trace element concentrations were much lower after improved particulate controls were installed on the power plants and ferro-alloys foundry.