Phytomonitoring of urban-industrial pollutants: A new approach.

Biological effect monitoring of urban-industrial pollutants was carried out using an 'air pollution tolerance index' (APTI) of plants. For the purpose four leaf parameters - namely, ascorbic acid, total chlorophyll, relative water content and leaf extract pH - were combined together in a formulation signifying the APTI of plants. The index indicated the plant response at the cell membrane and chloroplast levels. SitesP 1,P 2 andP 3 were selected in western parts of Varanasi, India, near the junction of a national highway and a railway track. The control site was selected in the University campus. In the prevailing wind direction from siteP 1, pollution zones I, II and III were marked. None of the four above mentioned plant parameters indicated a consistent response to pollutants. However, the APTI showed the most sensitive and consistent response of plants to urban-industrial pollutants. The APTI of plants showed a marked gradation as the pollutant load decreased from zone I, II and III to the control site. The APTI can be used as a good indicator of the impact of pollution on plants.