A Survey of Fluoride Pollution Effects on the Forest Ecosystem Around an Aluminium Factory in Mirzapur, U.P., India

Abstract

A survey of vegetation around an aluminium factory in Renukoot, Mirzapur, U.P., India, was made in the course of a study of the polluting effects on plants of gaseous hydrogen fluoride. These ‘pollugenic’ effects were analyzed by examining the chlorotic and necrotic symptoms of injury on the leaf surfaces, the plants then being classified into three categories on the basis of their sensitivity.The study revealed the absence, from the vicinity of the factory, of certain plant species which are normally present in the surrounding unpolluted areas. The tree species were the first to be affected, followed by shrubs, grasses, and finally forbs. These differences in response could be attributed in part to differences between the ambient air and ground-level concentrations of the pollutant. The concentrations in the ambient air, being higher than those at ground-level, were responsible for the greater impact on trees, with less on shrubs and grasses, and least on forbs, this being in part a function of the exposure-height of the plant species.The gradual improvement noted in the performance of the plants and the number of their species at increasing distances from the aluminium factory, was consequent on the gradual decrease in the concentration of the polluting hydrogen fluoride. Such a trend is clearly evident in the north-east direction, where the pollutant fallout was directed by the prevailingly southwesterly winds.