title: Automatic flow-through dynamic extraction: A fast tool to evaluate char-based remediation of multi-element contaminated mine soils.
abstract: An automatic in-vitro bioaccessibility test based upon dynamic microcolumn extraction in a programmable flow setup is herein proposed as a screening tool to evaluate bio-char based remediation of mine soils contaminated with trace elements as a compelling alternative to conventional phyto-availability tests. The feasibility of the proposed system was evaluated by extracting the readily bioaccessible pools of As, Pb and Zn in two contaminated mine soils before and after the addition of two biochars (9% (w:w)) of diverse source origin (pine and olive). Bioaccessible fractions under worst-case scenarios were measured using 0.001 mol L(-1) CaCl2 as extractant for mimicking plant uptake, and analysis of the extracts by inductively coupled optical emission spectrometry. The t-test of comparison of means revealed an efficient metal (mostly Pb and Zn) immobilization by the action of olive pruning-based biochar against the bare (control) soil at the 0.05 significance level. In-vitro flow-through bioaccessibility tests are compared for the first time with in-vivo phyto-toxicity assays in a microcosm soil study. By assessing seed germination and shoot elongation of Lolium perenne in contaminated soils with and without biochar amendments the dynamic flow-based bioaccessibility data proved to be in good agreement with the phyto-availability tests. Experimental results indicate that the dynamic extraction method is a viable and economical in-vitro tool in risk assessment explorations to evaluate the feasibility of a given biochar amendment for revegetation and remediation of metal contaminated soils in a mere 10 min against 4 days in case of phyto-toxicity assays.
authors.affiliation: FI-TRACE Group, Department of Chemistry, University of the Balearic Islands, Carretera de Valldemossa, km 7.5, E-07122 Palma de Mallorca, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Rosende
authors.affiliation: The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, UK.
authors.forename: Luke
authors.initials: L
authors.lastname: Beesley
authors.affiliation: Departamento de Química Agrícola y Bromatología, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Moreno-Jimenez
authors.affiliation: FI-TRACE Group, Department of Chemistry, University of the Balearic Islands, Carretera de Valldemossa, km 7.5, E-07122 Palma de Mallorca, Spain. Electronic address: manuel.miro@uib.es.
authors.forename: Manuel
authors.initials: M
authors.lastname: Miró
keywords: Biochar; Dynamic bioaccessibility; Flow method; Phyto-toxicity; Soil remediation; Trace elements