Bioaccumulation and Subcellular Distribution of Metals Across Species through Quantitative Ion–Character Relationship Modelling

Metal contamination poses ecological risks to aquatic biota, especially when toxicological data are scarce and metals are not regulated. As metal toxicity is closely linked to their intracellular distribution, we developed Quantitative Ion Character-Activity Relationship (QICAR) models to predict metal bioaccumulation and subcellular compartmentalization in sensitive (mitochondria, microsomes and lysosomes, cytosolic heat-denatured proteins) and detoxified (granules, cytosolic heat-stable proteins) compartments. Our dataset included measurements for 34 metals across nine fish, one amphipod and one mammal, combined with 21 metal descriptors covering physical, electronic, binding, and redox properties. Data were modelled by linear multiple regressions, Generalized Additive tensor models and CatBoost, evaluated using leave-one-species-out (LOSO) cross-validation. Tree‑based models exhibited the best predictive performance, with mean LOSO R² values ranging from 0.77 to 0.84 across endpoints. Atomic number, Ionic index, and Covalent index captured the majority of the variance. Predicted bioaccumulation was consistent with observed values in both nmol/g and subcellular fraction contributions (%). Application of the model to 66 additional metals confirmed its reliability. SHAP explanations revealed three metal groups based on how accumulation is modelled. Thus, QICARs provide a novel and robust framework for predicting multi‑species metal accumulation and intracellular behaviour, with insights into how differential subcellular distribution relates to metal chemical properties.

Presentation Preference: Standard Oral (12 Minutes)

Primary Presenter: Cândido Rodrigues, Université du Québec à Montréal (carvalho_rodrigues.candido@courrier.uqam.ca)

Authors:

Cândido Rodrigues, Université du Québec à Montréal  (carvalho_rodrigues.candido@courrier.uqam.ca)

Luana Bauer, Université du Québec à Montréal  (luana.h.bauer@gmail.com)

Isabelle Lavoie, Institut National de la Recherche Scientifique  (isabelle.lavoie@inrs.ca)

Claude Fortin, Institut National de la Recherche Scientifique  (claude.fortin@inrs.ca)

Maikel Rosabal, Université du Québec à Montréal  (rosabal.maikel@uqam.ca)