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Theoretical framework for the distribution of trace metals among the operationally defined speciation phases of a sediment
Author(s) -
Nome René A.,
MendiguchíaMartínez Carolina,
Nome Faruk,
Fiedler Haidi D.
Publication year - 2001
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620200401
Subject(s) - sediment , certified reference materials , environmental chemistry , genetic algorithm , metal , fraction (chemistry) , adsorption , chemistry , trace (psycholinguistics) , environmental science , mineralogy , geology , chromatography , ecology , detection limit , geomorphology , linguistics , philosophy , organic chemistry , biology
The use of a model based on Langmuir's isotherm to evaluate the metal associated with separate geochemical phases of a sediment is proposed and its validity tested with sediments of certified composition. The model takes into account a standard procedure for a certified reference material (CRM601), which defines, experimentally, a set of sequential extractions that divide the sediment into four operational fractions. The derived equations allow the treatment of data from sediment of Flumendosa Lake, Italy, and certified material CRM601 and also allow the computation of corrected concentrations, i.e., the metal affinities for each fraction. Experimental values for Ni show its low sensitivity and an equal distribution among different phases, which suggests a similar adsorption mechanism in all cases. In the case of Cd, the corrected concentration in the Fe/Mn oxide phase is nine times higher than for the residual fraction. For sediment of the Bèsos River, Spain, results show the percentage distribution of Ni over different fractions. Affinity values for Ni on a Flumendosa Lake sediment have also been calculated. The present model is simple to apply and shows satisfactory agreement with experimental data.