A survey on heavy metal bioaccumulation in organs of Phallusia nigra

Abstract

Introduction: Invertebrates, including tunicates, are able to accumulate metals at various
concentrations in their tissues and organs. The aim of this study was to investigate the ability
of a tunicate (Phallusia nigra) to remove cadmium, chromium, zinc, nickel, copper and lead
from the waters of Chabahar Bay through their accumulation in various organs.
Materials & Methods: Sampling of water and tunicates were performed before and after
Monsoon.
Result: The heavy metal concentration in waters in two seasons were in the order of
Zn>Ni>Cr>Cd>Cu>Pb. No significant difference was observed in the concentration of
heavy metals between seasons (p>0.05). Analysis of different organs of P. nigra showed
that the concentration of heavy metals in mantle is higher than tunic. The trend of changes
in metal concentrations in both mantel and tunic is Zn>Pb>Cu>Ni>Cr>Cd. The trend of
changes in the bioaccumulation factor of heavy metals was obtained as
Pb>Zn>Cu>Cr>Ni>Cd. The highest accumulation factor with value of 109964±3141was
obtained in lead and the lowest accumulation factor with value of 187±39 was related to
cadmium, both of which were observed after Monsoon.
Conclusion: High values of bioaccumulation factor showed that P. nigra can not only be
used as an experimental animal for the accumulation of heavy metals but also for
continuously monitoring the water quality of the particular coastal waters as far as the heavy
metals are concerned. Determining the concentration of metals in living organisms in the
coastal area should be an important part of the pollution monitoring program in the marine
ecosystem.