Effects of soil water content and organic matter addition on the speciation and bioavailability of heavy metals

Hernandez-Soriano, Maria C. and Jimenez-Lopez, Jose C. (2012) Effects of soil water content and organic matter addition on the speciation and bioavailability of heavy metals. Science of The Total Environment, 423 55-61. doi:10.1016/j.scitotenv.2012.02.033

Author Hernandez-Soriano, Maria C.
Jimenez-Lopez, Jose C.
Title Effects of soil water content and organic matter addition on the speciation and bioavailability of heavy metals
Journal name Science of The Total Environment   Check publisher's open access policy
ISSN 0048-9697
Publication date 2012-04-15
Year available 2012
Sub-type Article (original research)
DOI 10.1016/j.scitotenv.2012.02.033
Open Access Status Not yet assessed
Volume 423
Start page 55
End page 61
Total pages 7
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Language eng
Formatted abstract
The mobility and bioavailability of cadmium, copper, lead and zinc were evaluated in three soils amended with different organic materials for two moisture regimes. Agricultural and reclamation activities impose fresh inputs of organic matter on soil while intensive irrigation and rainstorm increase soil waterlogging incidence. Moreover, scarcity of irrigation water has prompted the use of greywater, which contain variable concentrations of organic compounds such as anionic surfactants.

Soils added with hay, maize straw or peat at 1% w/w were irrigated, at field capacity (FC) or saturated (S), with an aqueous solution of the anionic surfactant Aerosol 22 (A22), corresponding to an addition of 200 mg C/kg soil/day. Soil solution was extracted after one month and analysed for total soluble metals, dissolved soil organic matter and UV absorbance at 254 nm. Speciation analyses were performed with WHAM VI for Cd, Cu, Pb, and Zn. For selected scenarios, metal uptake by barley was determined.

Metal mobility increased for all treatments and soils (Pb > Cu > Cd ≥ Zn) compared to control assays. The increase was significantly correlated (p < 0.05) with soil organic matter solubilisation for Cd (R = 0.68), Cu (R = 0.73) and Zn (R = 0.86). Otherwise, Pb release was related to aluminium solubilisation (R = 0.75), which suggests that Pb was originally co-precipitated with Al–DOC complexes in the solid phase. The effect of A22 in metal bioavailability, determined as free ion activities (FIA), was mainly controlled by soil moisture regime. For soil 3, metal bioavailability was up to 20 times lower for soil amended with hay, peat or maize compared to soil treated only with A22. When soil was treated with A22 at FC barley yield significantly decreased (p < 0.05) for the increase of Pb (R = 0.71) and Zn (R = 0.79) concentrations in shoot, while for saturated conditions such uptake was up to 3 times lower.

Overall, metal bioavailability was controlled by solubilisation of soil organic matter and formation of metal-organo complexes.
Keyword Organic amendments
Soil solution
Free ion activity
Plant uptake
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Non HERDC
School of Agriculture and Food Sciences
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Created: Mon, 06 Jan 2014, 14:21:45 EST by Maria Hernandez-soriano on behalf of School of Agriculture and Food Sciences