Heavy metalpollutionoftheaquaticenvironmentcanbe
determined byanalyzingwater,sediments,aquaticplantsand
animals (Hamed andEmara,2006). Metalconcentrationsinsedi-
ments aregenerallymuchhigherthaninwater.Sedimentsmayact
as asourceofchemicalsinthewatercolumnandalsoadversely
affect sediment-dwellingorganismsthroughdirecttoxicity
(Martı´nez-Llado´ et al.,2007; Roussiezetal.,2006). Aquaticorgan-
isms suchasmolluskslivinginpollutedsedimentsoften