Shannon Diversity Index (H) as an Ecological Indicator of Environmental Pollution - A GIS Approach

The present work deals with the application of Shannon Index to explore the spatial extent and pattern of air pollution around a paper mill. The index measures the change in lichen diversity in response to the polluted environment around a paper mill in Assam, North-East India. The Shannon index around the paper mill ranged from 0.56 at 2.4 km to 1.20 at 13.7 km with a mean value of 0.92. About 47% of the sites have Shannon index value below mean value. The index does not show significant correlation with the distance from the paper mill. The values are plotted with the help of kriging interpolation and an air quality model is prepared. The dark shades in the model indicate highly polluted regions while the brighter shades indicate less polluted to clean areas. Higher polluted areas with low values of Shannon index are the regions around and nearer to the paper mill, town area, and around stone crusher units. It is concluded that the Shannon index is a potential indicator to measure the effect of air pollution and can be used to delineate the pollution zones around any industrial area.