Speciation of heavy metals and their distribution in surface sediments of the northwestern part of the ROPME Sea Area

ABSTRACT

Aim: To analyze samples of marine sediment at 24 stations for heavy metals as per sequential Community Bureau of Reference protocol in order to obtain metal distribution pattern in Kuwait offshore.Methodology: In the present study, a centrifugal particle-size analyzer was used for measuring sediment grain size. The Community Bureau of Reference scheme was deployed for the sequential extraction of heavy metal speciation, and the fractionation was determined by Inductively Coupled Plasma-Mass Spectrometry. Results: Grain-size analysis showed that the study area contained 71.8% silt, 22.6% sand and 5.56% clay at most locations. The average abundance of total concentration of heavy metals was found in the following order lead< cobalt< copper< zinc< chromium< nickel. The mobility order of exchangeable fraction of heavy metals decreased in the order lead> nickel> zinc> cobalt> copper; in the reducible fraction lead> copper> zinc> cobalt> nickel; in the oxidizable fraction lead> chromium> copper> nickel> cobalt> zinc and in the residual fractioncobalt> chromium> nickel> zinc> copper>lead, respectively. Interpretation: The outcome of the present study cannot establish the actual form of species of a given metal in the sediment; though, it appears to be useful in categorizing the metals within several prevailing geochemical fractions.