Comparative study of heavy metals in selected mangroves of Sundarban ecosystem, India

Accumulation and partitioning of eight heavy metals Cr, Pb, Zn, Cd, Ni, Cu, Co and Fe were studied in the root, stem and leaf of mangrove species (Sonneratia caseolaris, Acanthus ilicifolius and Excoecaria agallocha) for comparison and in mangrove sediments for calculation of bio concentration factor (BFC) in Sundarban India. Magnitude of Fe was found highest in the sediments (35371.71 mg kg(-1)) and plant parts of the three species (a maximum of 11428.0 mg kg(-1) in the root of S. caseolaris). For other heavy metals, plants showed exclusion and selection mainly based on utilization, regardless of their level in the sediments. In most of the cases significant variation of absorption was found between the three species (F = 11.48 to 157.37; p < 0.001) and between their plant parts (F = 10.98 to 338.03; p < 0.001). S. caseolaris was found to be a less potential heavy metal accumulator than the other two species, except for Fe and Zn in the root. Irrespective of the magnitude of the heavy metals, other species showed significant correlations (r = 0.509 to 0.961; p < 0.001) between heavy metal accumulations, exclusively due to chemical reason, whereas S. caseolaris showed significant correlations (r = 0.554 to 0.926; p < 0.001) between each and every heavy metal, which signifies similar mode of absorption pattern regardless of their utilization. This nonbiased manner of heavy metal accumulation pattern may help the species to withstand in the polluted areas.