Bioindicators: Study on Uptake and Accumulation of Heavy Metals in Plant Leaves of State Highway Road, Bagalkot, India: Advanced Study

In this study, Caesalpinia (Caesalpinia pulcherrima) and grass (Cyndon dactylon) was evaluated as
the bioindicators of heavy metals such as the Lead (Pb), Copper (Cu), Cadmium (Cd), Manganese
(Mn), Zinc (Zn), Chromium (Cr) and Nickel (Ni) contaminated in Bagalkot and along the state high way
upto Mudhol. The soil samples at depth (0-20 cm) and caesalpinia and grass leaves were taken from
different sampling stations namely Navnagar bypass road (S1), Gaddanakeri cross (S2), Tulasigeri
(S3), Kaladagi (S4), Lokapur (S5), Chichakhandi (S6) and Mudhol (S7). The concentrations of Pb, Cu,
Cd, Mn, Zn, Cr and Ni were measured using GBC- 932 plus Atomic Absorption Spectrophotometer
(Austrelia). The results of the study shows that the concentrations of heavy metals in caesalpinia
ranged from Pb 20.36 to 29.39 μg/gmm, Cu 3.92 – 5.94 μg/gm, Zn 24.40 to 35.7 μg/gm, Cd 1.01 to
1.78 μg/gm, Mn 27.01 to 69.10 μg/gm, Cr 1.20 to 7.8 μg/gm and Ni 7.9 to 13.1 μg/gm. In grass heavy
metal ranges between for Pb 20.16 to 28.01, Cu 3.95 to 5.76 μg/gm, Zn 24.50 to 35.8 μg/gm, Cd 1.15
to 1.52 μg/gm, Mn 28.91 to 72.51 μg/gm, Cr 1.28 to 8.0 μg/gm, Ni 8.1 to 15.1 μg/gm. Similarly in
roadside soil heavy metal ranges between Pb 81.91 to 139.8 μg/gm, Cu 39.54 to 58.58 μg/gm, Zn
32.29 to 381.54 μg/gm, Cd 1.51 to 2.08 μg/gm, Mn 1257.9 to 2051 μg/gm, Cr 131.9 to 951.2 μg/gm
and Ni 69.53 to 108.6 μg/gm. According to these results the concentration of heavy metals in grass
was found high as compared to caesalpinia. Thus, compared to the metal accumulation potential
grass is said to be heavy metal accumulator. The variation in heavy metal concentrations is due to
changes in traffic density and anthropogenic activities. Thus, generally it is considered that grass and
caesalpinia are good bioindicators and can be used in air pollution monitoring studies.