Potential release of selected trace elements (As, Cd, Cu, Mn, Pb and Zn) from sediments in Cam River-mouth (Vietnam) under influence of pH and oxidation

Pb, Cd and Cu distribution and mobility in marine sediments from two ports in Lebanon: Beirut army naval port and Tripoli fishing port

“…Upon resuspension, the geochemical composition of the sediment and the chemical characteristics of the studied trace metals play a major role in its mobilization to the water column (Cantwell et al, 2002). In particularly, for Cd, Cu and Pb, the leaching pattern increase at low and high pH and a readsorption process often occurs at neutral pH in suboxic sediments (Hieu Ho et al, 2012). On the other hand, diagenetic reactions that occur at different levels of the sediments, are essential to the release of these metals from the sediment to the upper water column.…”

Pb, Zn, and Cd Distribution and Migration at a Historical Zinc Smelting Site

“…The dispersion of metals is usually influenced by physicochemical factors of soil [23,24]. Metals could exhibit various behaviors during migration and leaching, which is closely related to fraction transfer [25]. Elemental ratio is an effective index applied to distinguish metal origin and migration [26,27].…”

Sediments in the Tema Harbour (Ghana): chemical pollution and sedimentation rates

“…Among the non-residual fractions, the oxidisable phase was most important for Pb, Cr, Cu and As. This indicates that complexation with organic matter and precipitation with sulphides were the main mechanisms for the immobilisation of Pb, Cr, Cu and As into the Tema Harbour sediments, which is the case for most metals under anoxic conditions Ho et al 2012a).…”

“…Investigation of the metal distribution over different geochemical phases (metal fractionation) in sediments is, therefore, relevant when screening the sediments for their potential environmental risks. A standardised procedure widely used for metal fractionation in sediments is the Community Bureau of Reference (BCR) three-step sequential extraction technique, which yields four metal fractions, namely the acid-soluble (exchangeable and bound to carbonate), reducible (bound to Fe-Mn oxides and hydroxides), oxidisable (bound to organic matter and sulphides) and residual (bound within the crystal lattice of minerals) fractions Ho et al 2012a). Since metal fractionation and potential mobility in sediments are influenced by environmental factors such as pH, buffer intensity and redox potential (Calmano et al 1993;Kelderman and Osman 2007;Palma and Mecozzi 2007;Ho et al 2012a;, these factors should be considered in characterising the potential environmental risk of metal-contaminated sediments.…”

“…Moreover, the Tema Harbour sediments have not been characterised for their buffer intensity against acidification, which determines metal leachability and associated environmental risk (Calmano et al 1993;Ho et al 2012a). The objective of this study was, therefore, to investigate the distribution and fractionation of metals (Mn, Ni, Pb, Cr, Cu, Zn, As, Cd, Hg and Sn) in surface sediments from the Tema…”