Influence of a Coal-Fired Powerplant on the Element Content of Parmelia chlorochroa

The operations of the Dave Johnston coal-fired powerplant near Glenrock, Wyoming, have had a measurable effect on trace-element concentrations in Parmelia chlorochroa Tuck., which is common to the area. Concentrations of 35 elements were measured in samples collected along upwind and downwind transects. Of these elements, concentrations of calcium, fluorine, lithium, selenium, strontium and uranium, as well as ash yields, decreased with distance from the powerplant. Compared to background levels established for this lichen from the Powder River Basin, only the selenium values near the powerplant are considered unusually high.