Heavy Metals Accumulation and Physiological Changes in the Lichens Growing in the Vicinity of Coal-Based Thermal Power of Kanti (Muzaffarpur), Bihar, India

Abstract

The present study was designed with an aim to observe the effect of increasing pollution level on native lichen diversity, metal accumulation and physiological changes around a coal-based thermal power plant of Kanti, Muzaffarpur districts of Bihar, India. Three lichen species namely Phaeophyscia hispidula (Ach.) Essl, Physcia dilatata Nyl., and Pyxine cocoes (Sw.) Nyl., were found growing in their natural habitat in vicinity of fly ash. Among these, Physcia dilatata Nyl., a common foliose lichen, was growing as a most dominant species at highly polluted sites. During present study the species was analyzed for six heavy metals (Fe, Pb, Cr, Zn, Ni and Cu) and further physiological changes at five different sampling sites. The test species accumulated maximum levels of Fe (10,923), Pb (389), Cr (151), Zn (142), Ni (73.5), and Cu (39.5) at highly polluted dumping sites. However, there was high spatial variability in total metal accumulation in different species indicated by coefficient of variation (CV %) and showed higher values for Fe, Pb and Cr but lower for Cu and Ni. The concentration of most of the metals at different sites was statistically significant as compared to control site. Further six physiological parameters i.e., Chl a, Chl b, total pigment, chlorophyll degradation, carotenoid and total protein content were also measured and found maximum at least polluted control sites (residential sites). Total chlorophyll and protein content are most useful and efficient parameter to assess air pollution level of a region. Total chlorophyll was significantly higher at control sites (0.62) as compared to highly polluted dumping site (0.22) and similarly protein content was also higher at control sites (42.53) as compared to polluted sites (12.87). The results of the present study indicated that P. diltata is pollution tolerant (adaptation) and able to withstand local emissions from thermal power plants.