Metal speciation in solid matrices

Heavy metal pollution in sediments of a typical mariculture zone in South China

“…3 also shows the results from chemical speciation measurements of the heavy metals in the surface sediments. Speciation analysis can provide information on the origin, the mode of occurrence, and the biological and physicochemical availability of heavy metals (Das et al, 1995). Zn (57.9-90.1%), As (78.4-96.1%) and Cr (92.2-95.0%) in all the sediment samples were mostly associated with the residual fraction, followed by the oxidizable fraction (less than 20%), the reducible fraction and the acid soluble fraction (sum of the latter two fractions was less than 15%).…”

Concentration and fractionation of trace metals in surface sediments of intertidal Bohai Bay, China

“…Trace metals interact with sediment matrix through different binding mechanisms, including adsorbed to mineral surfaces, associated with carbonates, Fe/Mn oxyhydroxides, organic matter, sulfides and the lattice of refractory crystalline minerals, such as silicates (Das et al, 1995;Tack and Verloo, 1995;Gleyzes et al, 2002;Sahuquillo et al, 2003). The mobility of trace metals in sediments is environmentally dependent on and controlled by several factors: the sediment type on the basis of the parameters that affect metal interaction, basically pH, cationic exchange capacity, nutrient status, carbonates and organic matter contents, redox potential and texture; the nature of the contamination in terms of origin and characteristics of deposition and composition; the environmental conditions that may lead to weathering, such as acidification, redox processes, temperature and water regime (Sahuquillo et al, 2003).…”

“…The mobility of trace metals in sediments is environmentally dependent on and controlled by several factors: the sediment type on the basis of the parameters that affect metal interaction, basically pH, cationic exchange capacity, nutrient status, carbonates and organic matter contents, redox potential and texture; the nature of the contamination in terms of origin and characteristics of deposition and composition; the environmental conditions that may lead to weathering, such as acidification, redox processes, temperature and water regime (Sahuquillo et al, 2003). Therefore, besides measuring their total concentrations, determining the geochemical fractionation of trace metals in sediments is equally important in assessing their potential toxicity and threat to ecosystems (Das et al, 1995;Quevauviller, 1998;Sahuquillo et al, 2003).…”

Total and extractable heavy metal, phosphorous and sulfur concentrations in slaker grits from the causticizing process of a pulp mill for use as a soil amendment

“…The high partitioning of phosphorous in the extraction fraction 3 is due to the fact that the acetic acid (CH 3 COOH) used as extractant in the stage 1 and the hydroxylamine hydrochloride (NH 2 OH -HCl) used as extractant in the stage 2 were not capable of releasing phosphorous from the slaker grits. According to Das et al (1995), extractants like electrolytes, weak acids and chelating agents, release metals mainly from coordination sites, but are not necessarily capable of releasing additional quantities of metals as a result of the decomposition of the solid matrix. These observations support the low extractability (solubility) of phosphorous in the slaker grits.…”