Parameterizing the binding properties of dissolved organic matter with default values skews the prediction of copper solution speciation and ecotoxicity in soil

Djae Tanalou, Bravin Matthieu, Garnier Cédric, Doelsch Emmanuel. 2017. Parameterizing the binding properties of dissolved organic matter with default values skews the prediction of copper solution speciation and ecotoxicity in soil. Environmental Toxicology and Chemistry, 36 (4) : 898-905.

Quartile : Q2, Sujet : ENVIRONMENTAL SCIENCES / Quartile : Q2, Sujet : TOXICOLOGY

Résumé : Parameterizing speciation models by setting the percentage of dissolved organic matter (DOM) that is reactive (% r-DOM) toward metal cations at a single 65% default value is very common in predictive ecotoxicology. The authors tested this practice by comparing the free copper activity (pCu2+ = –log10[Cu2+]) measured in 55 soil sample solutions with pCu2+ predicted with the Windermere humic aqueous model (WHAM) parameterized by default. Predictions of Cu toxicity to soil organisms based on measured or predicted pCu2+ were also compared. Default WHAM parameterization substantially skewed the prediction of measured pCu2+ by up to 2.7 pCu2+ units (root mean square residual = 0.75–1.3) and subsequently the prediction of Cu toxicity for microbial functions, invertebrates, and plants by up to 36%, 45%, and 59% (root mean square residuals ≤9 %, 11%, and 17%), respectively. Reparametrizing WHAM by optimizing the 2 DOM binding properties (i.e., % r-DOM and the Cu complexation constant) within a physically realistic value range much improved the prediction of measured pCu2+ (root mean square residual = 0.14–0.25). Accordingly, this WHAM parameterization successfully predicted Cu toxicity for microbial functions, invertebrates, and plants (root mean square residual ≤3.4%, 4.4%, and 5.8%, respectively). Thus, it is essential to account for the real heterogeneity in DOM binding properties for relatively accurate prediction of Cu speciation in soil solution and Cu toxic effects on soil organisms.

Mots-clés Agrovoc : matière organique du sol, acide fulvique, modèle mathématique, complexation, cuivre, toxicité, type de sol, propriété physicochimique du sol, organisme du sol

Mots-clés géographiques Agrovoc : France, La Réunion, Nouvelle-Calédonie

Classification Agris : P33 - Chimie et physique du sol
P34 - Biologie du sol

Champ stratégique Cirad : Axe 1 (2014-2018) - Agriculture écologiquement intensive

Auteurs et affiliations

• Djae Tanalou, CIRAD-PERSYST-UPR Recyclage et risque (REU)
• Bravin Matthieu, CIRAD-PERSYST-UPR Recyclage et risque (REU) ORCID: 0000-0002-1436-7837
• Garnier Cédric, Université du Sud Toulon-Var (FRA)
• Doelsch Emmanuel, CIRAD-PERSYST-UPR Recyclage et risque (FRA) ORCID: 0000-0002-7478-4296

Source : Cirad-Agritrop (https://agritrop.cirad.fr/582583/)

Métriques

[ Page générée et mise en cache le 2024-12-18 ]