Heavy metal contamination is an environmental
problem in both developing and developed countries
throughout the world. Human activities increase
the release of heavy metals to natural environment
because most metals are widely used in a
variety of industrial and agricultural applications.
High concentrations of heavy metals could have
toxic effects on living organisms, accumulate in
marine food chain and affect human health through
consumption of contaminated seafood. After being
discharged into aquatic environments, heavy metals
are subsequently deposited into bottom sediments.
However, under some conditions, they can
be released back to the water column as a result of
physical, chemical or biological processes (Bakan
and Balkas, 1999). Thus, sediments serve as a potential
risk source as well as ultimate sink of heavy
metals in aquatic environments and are considered
to be a good environmental indicator of metal pollution
(Soares et al., 1999).