Fluoride injury symptoms in epiphytic lichens and mosses

Abstract

This study was conducted in Arvida, Quebec, where volatile fluorides and HF are released into the atmosphere from an aluminum factory. Lichen and moss-bearing bark discs, cut out from trees in an unpolluted area, were fixed in groups of six in rectangular wooden boards. All discs were photographed in color as well as in black and white. Fifteen sites, in addition to a control site, were selected in different directions from the factory. At each site two boards were fixed with nails in a vertical position at a height of 8–10 m on a tree. One board was removed after 4 months exposure and the other after 12 months. The lichens and mosses exposed in control and polluted areas were compared with respect to their color, external morphology, plasmolysis in algal cells, loss of green color, the nature of reactions towards neutral red and 2,3,5-triphenyl-2H-tetrazolium chloride (TTC), absorption spectra of chlorophyll, and fluoride concentration. Results indicate that F-pollution affects moisture balance, causes chlorophyll damage, and produces other symptoms of injury which could lead to ultimate death of these organisms.