title: Assessment of trace heavy metals dynamics during the interaction of aqueous solutions with the artificial OECD soil: Evaluation of the effect of soil organic matter content and colloidal mobilization.
abstract: A micro-contamination phenomenon was reproduced and studied at lab-scale, mimicking the irrigation of a standard artificial soil with a water solution containing three Heavy Metals (HMs) at trace concentration level. To assess the dynamics of micro-pollutants accumulation and migration trough the soil, the organic matter in the soil was varied, together with sodicity of the irrigation water. Accumulation of the investigated contaminants was observed mainly in the top layer (≤1 cm) of the irrigated soil. This was attributed to the high interaction capacity of the soil compared to the low HM concentrations in the water phase. HMs transport pattern was described assuming a multi-component mechanism including: i) the interaction of HMs with the colloidal phase of the soil; ii) the slow and constant release of small molecular weight ligands detaching from the soil immobile matrix; iii) the transportation of HMs through the soil by these low molecular weight chaperon molecules. The mobility was directly related to the soil organic matter (SOM), since higher amount of SOM correspond to a higher number of chaperon molecules. In the first centimetre of the soil the metals were mostly bound to the acid labile fraction. Very low mobilization was observed with increasing sodicity in the leaching water, since such conditions were unfavourable to the colloidal mobilization of SOM. This indicated that water/soil transfer of pollutant is not only related to the contaminant concentration in the irrigation water but also to the characteristics of the aqueous solution and to the physical-chemical properties of the soil.
authors: Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, via Di Biasio 43, 03043, Cassino, FR, Italy; Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, 77454, Marne-la-Vallée, France. Electronic address: ludovico.pontoni@unina.it.
authors: Ludovico
authors: L
authors: Pontoni
authors: Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, 77454, Marne-la-Vallée, France.
authors: Eric D
authors: ED
authors: van Hullebusch
authors: Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, via Claudio 21, 80125, Naples, Italy.
authors: Massimiliano
authors: M
authors: Fabbricino
authors: Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, via Di Biasio 43, 03043, Cassino, FR, Italy.
authors: Giovanni
authors: G
authors: Esposito
authors: Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, via Claudio 21, 80125, Naples, Italy.
authors: Francesco
authors: F
authors: Pirozzi
mesh_terms: D057914:Agricultural Irrigation; D019216:Metals, Heavy / Q000032:analysis* / Q000737:chemistry; D066150:Organisation for Economic Co-Operation and Development; D059027:Recycling; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry; D012996:Solutions; D062065:Wastewater; D014867:Water / Q000737:chemistry
chemical_list: D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D012996:Solutions; D062065:Wastewater; D014867:Water
keywords: Agricultural wastewater reuse; Emerging contaminants; OECD soil; Soil colloids; Soil organic matter; Trace metals