Fluoride accumulations in soil and vegetation in the vicinity of a phosphorus plant

Abstract

In 1970, vegetation in the vicinity of the ERCO phosphorus reduction plant at Long Harbour, Newfoundland (47°26′N, 53°47′W) began to show symptoms of fume damage, e.g. tip-burn and margin-burn. Samples of vegetation and soil were collected in the summers of 1973, 1974 and 1975 within a radius of 20 km of the plant in an attempt to assess levels of accumulation of fluoride in soil and vegetation. The degree of damage to vegetation and fluoride levels in soil-humus were inversely related to the distance of sites from the phosphorus plant. The average levels of fluroide in vegetation ranged from 281 ppm in severely damaged areas to 44 ppm in lightly damaged areas. The corresponding fluoride level in controls was only 7 ppm. In soil-humus, the available and total fluoride concentrations ranged from 58 to 3·8 ppm and 908 to 16 ppm, respectively. The levels in controls were 2·4 and 10 ppm. The extremely high levels of calcium closer to the plant indicated that the rock-dust fallout contributed significantly to the high level of total fluoride in the soil-humus. The fluoride emissions from the plant were composed of both gaseous and particulate forms of fluoride; however, the particulate forms appeared to affect only aareas closer to the plant.