Abstract

ZARAZUA, Graciela et al. Metal content and elemental composition of particles in cohesive sediments of the Lerma River, México. Rev. Int. Contam. Ambient [online]. 2011, vol.27, n.3, pp.181-190. ISSN 0188-4999.

The concentration of Cr, Mn, Fe, Cu, Zn and Pb, enrichment factors and the elemental composition, morphology and relative abundance of particles were evaluated in cohesive sediments of the upper course of the Lerma River, México. The heavy metal concentration in the cohesive sediments decreased in the following sequence: Fe > Mn > Zn > Cr > Cu > Pb. The results of enrichment factors show that Fe and Mn are conservative, Cu, Cr and Pb are lightly enriched and Zn is moderately enriched. Generally, the particle groups decrease in the follow sequence: aluminosilicate > silica > iron > sulfur > metals > calcium carbonate > calcium/phosphorus > manganese. The Fe and Mn concentrations in cohesive sediments are produced principally by natural contributions, whereas Cr, Cu, Zn and Pb concentrations are produced mainly by anthropic contributions.

Keywords : heavy metals; X-ray fluorescence; scanning electronic microscopy; river sediments.