Metal binding by humic acids in recent sediments from the SW Iberian coastal area

The concentrations of Cu, Zn, Cr, Ni, Pb, As, Mn and Co were determined by Inductively Coupled Plasma–Mass Spectrometry both in recent sediments from different locations of the Huelva littoral (SW Iberian Peninsula) and in their humic acid (HA) fractions in order to evaluate distribution and binding...

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Bibliographic Details
Published in:Estuarine, coastal and shelf science coastal and shelf science, 2011-07, Vol.93 (4), p.478-485
Main Authors: De la Rosa, J.M., Santos, M., Araújo, M.F.
Format: Article
Language:English
Subjects:
Animal and plant ecology
Animal, plant and microbial ecology
Biological and medical sciences
Brackish
Brackish water ecosystems
Chromium
Coastal
Copper
Fundamental and applied biological sciences. Psychology
Humic acids
metal binding
Nickel
recent sediments
Sediments
Shelves
SW Iberian Peninsula
Synecology
trace elements
Zinc
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Summary:The concentrations of Cu, Zn, Cr, Ni, Pb, As, Mn and Co were determined by Inductively Coupled Plasma–Mass Spectrometry both in recent sediments from different locations of the Huelva littoral (SW Iberian Peninsula) and in their humic acid (HA) fractions in order to evaluate distribution and binding capacity of those trace elements to HAs. In addition, elemental composition (C, N, S) and δ 13C values were determined to appraise the sources of organic matter in the area. This study involved the comparison of selected samples taken from different environments including the estuary of the Guadiana River, the main fluvial system of the region, the Tinto and Odiel estuary system and the proximal shelf. Significant positive correlations were found among Cu, Zn, As and Pb in bulk sediments, suggesting a common origin of all of those elements: the mining activities and pyrite deposits located hinterland. On the other hand, results for Cr, Co and Ni pointed to the basic rocks from the low basin of the Guadiana River as their main source. Elemental (C, N) and isotopic ( δ 13C) composition of sediments indicated a significant contribution of autochthonous plankton in coastal shelf sediments, whereas estuarine and riverine sediments showed a major contribution of terrestrial biomass. Geochemical values for their corresponding HAs suggested a greater terrestrial contribution in the sedimentary OM of the coastal shelf sediments than in bulk sediments, which evidenced the influence of coastal currents and sediment fluxes. Humic acids sequester considerable amounts of Cu and Zn contributing to reduce the bioavailability of these contaminants. ► Cu, Zn, As and Pb in sediments–common origin–mining activities and pyrite deposits. ► Source of Cr, Co and Ni basic rocks – from the low basin of the Guadiana River. ► Major contribution of terrestrial biomass in Estuarine and riverine sediments. ► Binding of trace metals in Humic Acids: Cu >>> Zn >> Cr ≥ Ni ≥ Pb. ► HAs sequester considerable amounts of Cu and Zn-reducing their bioavailability.
ISSN:0272-7714
1096-0015
DOI:10.1016/j.ecss.2011.05.029