Copper speciation in soil: time evolution and effect of clay amendment

MONTENEGRO, ANDREA C.; FERREYROA, GISELE V.; PAROLO, MARÍA E.; TUDINO, MABEL B.; LAVADO, RAÚL S.; MOLINA, FERNANDO V.

WATER AIR AND SOIL POLLUTION

SPRINGER

Lugar: Berlin; Año: 2015 vol. 226 p. 1 - 10

0049-6979

Copper bioavailability, specially to plants, is strongly dependent on its chemical form, as for most metals. Copper contaminated soil can be treated in situ by the addition of minerals such as Na-bentonite, which mixed with surface soil, can transform this pollutant to non-bioavailable forms. In this work, shelter experiments were conducted to study the time evolution of Cu speciation, in pristine soil as well as in amended one. A selective sequential extraction method was employed to determine the metal speciation in the samples. The results show that the major metal fraction is the organic matter-bound one, whereas the exchangeable fraction is very low, even the first day after Cu addition. The time evolution shows a slow decrease of the organic bound Cu and a corresponding increase of the most stable mineral fractions. With the addition of Na-bentonite to copper contaminated soil, the most stable mineral fractions increase whereas the organic bound one decreases,showing essentially similar time dependence of the several metal fractions. Sodium bentonite could be effectively used for remediation of soils polluted with Cu.