title: Improving the relationship between soil characteristics and metal bioavailability by using reactive fractions of soil parameters in calcareous soils.
abstract: The contribution of the nature instead of the total content of soil parameters relevant to metal bioavailability in lettuce was tested using a series of low-polluted Mediterranean agricultural calcareous soils offering natural gradients in the content and composition of carbonate, organic, and oxide fractions. Two datasets were compared by canonical ordination based on redundancy analysis: total concentrations (TC dataset) of main soil parameters (constituents, phases, or elements) involved in metal retention and bioavailability; and chemically defined reactive fractions of these parameters (RF dataset). The metal bioavailability patterns were satisfactorily explained only when the RF dataset was used, and the results showed that the proportion of crystalline Fe oxides, dissolved organic C, diethylene-triamine-pentaacetic acid (DTPA)-extractable Cu and Zn, and a labile organic pool accounted for 76% of the variance. In addition, 2 multipollution scenarios by metal spiking were tested that showed better relationships with the RF dataset than with the TC dataset (up to 17% more) and new reactive fractions involved. For Mediterranean calcareous soils, the use of reactive pools of soil parameters rather than their total contents improved the relationships between soil constituents and metal bioavailability. Such pool determinations should be systematically included in studies dealing with bioavailability or risk assessment.
authors.affiliation: Department of Soil Science, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: de Santiago-Martín
authors.forename: Folkert
authors.initials: F
authors.lastname: van Oort
authors.forename: Concepción
authors.initials: C
authors.lastname: González
authors.forename: José R
authors.initials: JR
authors.lastname: Quintana
authors.forename: Antonio L
authors.initials: AL
authors.lastname: Lafuente
authors.forename: Isabelle
authors.initials: I
authors.lastname: Lamy
mesh_terms: D000383:Agriculture; D002104:Cadmium / Q000032:analysis; D002119:Calcium Carbonate / Q000032:analysis*; D003300:Copper / Q000032:analysis; D004787:Environmental Pollution; D007854:Lead / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D015032:Zinc / Q000032:analysis
chemical_list: D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium; D007854:Lead; D003300:Copper; D002119:Calcium Carbonate; D015032:Zinc
keywords: Bioavailability; Mediterranean calcareous soils; Metals; Soil contamination; Soil reactive phases