HOTSPOTS OF FLUORIDE POLLUTION IN FIELDS AROUND THE COAL-FIRED BRICK KILNS

Development sector especially brick baking industry is dependent upon the burning of lignite coal in Pakistan. Due to lack of clean and green technologies, coal burning is ultimately source of pollution emission in atmosphere like NOx, SOx and fluoride compounds. Whereas, kilns are the main source of releasing fluoride pollution, as fluoride is naturally occurring in coal as well as in brick raw material. The fluoride pollution has phytotoxic effect to nearby growing plants. The objective of this research was to investigate the concentration of fluoride in the soil and crop samples of wheat and maize fields surrounded by kilns in Islamabad and Rawalpindi and to study the spatial distribution pattern of fluoride pollution using geospatial statistical technique, i.e., Getis-Ord. Geospatial statistical analysis was done in ArcGIS 10.2. Two hundred and fifty one samples were collected from different wheat and maize fields. Results of Getis -Ord revealed the significant clustering of high values of fluoride in Jhangi Syedan, Dhok Gujran, Chak jalal-ud-din, and Bara-Giran indicated by hot spots on the basis of lesser p value and high z score. Findings indicated that fields and crop plants nearer to the kilns were affected with the fluoride pollution as compared to the far distant fields. The crop samples in the year 2017 were found more damaged than the samples in the year 2015 and 2016. This temporal variation of fluoride pollution indicating the poor regulation of kiln industry. The result of the study further suggested that fields in vicinity of kilns need serious attention of government to prevent the damages caused by fluoride to crop plants.