Speciation of heavy metals in marine sediments from Damietta Harbor, Egypt

Speciation of heavy metals in marine sediments from Damietta
Harbor, Egypt
Suzan M. El-Gharabawy 1
, Mohamed A. Shata 1, Mahmoud S. Ibrahim 2
,
Maie I. El-Gammal 2 and Suzanne O. Draz 1
1
National Institute of Oceanography and Fisheries, Alexandria, Egypt.
2
Environmental Science department, Faculty of Science, Mansoura University, Damietta branch, Egypt.
Received 5th October 2011, Accepted 25th December 2011
Abstract
The chemical speciation of heavy metals (Fe, Mn, Zn and Cu) in twenty one sediment samples collected from
Damietta harbor and the adjacent Mediterranean Sea area to evaluate the possible contamination of the sediments by
trace metals. Sequential extraction techniques were performed to study the different geochemical forms of these
metals. The elevated concentrations are associated with the oxides form for both Fe and Mn. While for Zn the
organic form is the major and for Cu the higher concentrations are associated with the residual form. Risk
assessment code (RAC) was calculated for the metals to assess its availability in solution. The results revealed that,
Fe gives 100% no risk, while for Mn and Zn, RAC is 62% and 67% of low risk respectively. Finally for Cu it gives
48% Medium risk and 52% low risk. The recovery of the sequential extraction for each metal was calculated and the
sum of the five fractions is in good agreement with the total content, which implies that the method used is reliable
and repeatable.
Keywords: Speciation, Heavy metals, Sequential extraction, Marine sediments, Nile delta.