Assessment of Pb2+ and Cd2+ among planted and natural vegetation prone to vehicular pollution.
An increased use of vehicles leads to the excessive emissions of smoke which generates pollutants, particularly metallic components such as Pb2+ and Cd2+. This problem has been addressed worldwide because of adverse effects of presence of Pb2+ and Cd2+ in human and natural biota exposed to smoke on roadside. To evaluate the effects of these metal pollutants, a study has been planned to assess the concentration of Pb2+ and Cd2+ in the washed as well as unwashed leaves of some plant species along Motorway (M-3) and National Highway (N-5). Wild vegetation i.e. Cenchrus ciliaris, Calotropis procera, Phoenix roebelenii and Sesuvium portulacastrum were selected for study along M-3 whereas Vichellia nilotica, Parthenium hysterophorus, Cenchrus ciliaris, Nerium oleander and Calotropis procera were selected along N-5. The deposited dust at leaves of selected plant species, before and after washing with distilled water, was digested and detected by atomic absorption spectroscopy (AAS). The ANOVA for mean value of both understudy metals showed maximum distribution of Pb2+ (0.001 mg g-1) for C. procera growing along M-3 and 0.00057 mg g-1 of Pb2+ was recorded N. oleander leaves along N-5. High Cd2+ (0.0001 mg g-1) was determined in C. cilliaris leaves along M-3 and 0.000495 mg g-1 was detected for P. hysterophorus growing along N-5. The maximum and minimum concentrations of Pb2+ and Cd2+ among leaves of C. cilliaris and N. oleander highlights the potential threat of accumulation and transfer of these metals into the soil and grazers which are directly feed on leaves irrespective of dust or not. The present study revealed that vehicle exhaust is polluting the air and must be deteriorating the health of individuals.