Risk Evaluation of Brick Kiln Smoke to Acacia arabica

Risk analysis is an important technique to estimate impacts on the environment for adopting effective measures to avoid risks. This field study was conducted to investigate the risk of brick kiln (BK) smoke on the shoots of Acacia arabica. Different phenotypic parameters including morphology and growth of shoots and epidermal imprints of the leaves were studied in the vicinity of a brick kiln situated 500 meters away from Lahore-Raiwind Road, Lahore, Pakistan. Results show that smoke exposure has posed differential effects on shoots i.e. some shoots of same tree remained normal, others died and still others were badly affected by the smoke. Moreover, the number of leaves and fresh weight in the smoke affected shoots significantly reduced as compared with normal ones. The study of the epidermal imprints of the leaves of these normal and smoke effected shoots revealed that the mean values of the stomatal size of both adaxial and abaxial surfaces of the normal and smoke effected leaves were not statistically significant. However, the number of stomata on both epidermal layers of smoke effected leaves was significantly reduced as compared with normal ones. This study showed that due to the exposure to BK smoke, the growth of Acacia arabica trees in the field was significantly suppressed.