Trees as sentinels of metallic pollution induced by mining along the Odiel River (Southern Iberian Peninsula)

Article Article scientifique Article Trees as sentinels of metallic pollution induced by mining along the Odiel River (Southern Iberian Peninsula) eng 2021 author Delapierre Annick 849292 author Ballesteros Canovas Juan Antonio 821103 author Buzzi Marcos J. author Slaveykova Vera 0000-0002-8361-2509 510054 author Stoffel Markus 131626 371-390 10.18172/cig.4740 1697-9540 https://publicaciones.unirioja.es/ojs/index.php/cig/article/view/4740 Mining activity is often responsible for the drainage of acid or metal-enriched waters to fluvial systems. The release of metals is especially disturbing due to the toxicity and persistence of these products and their accumulation in the biosphere. Hence, a systematic detection and delimitation of highly polluted floodplains and linkages between pollution and high-flow stages would likely assist the improvement of land management and ease the design of mitigation or rehabilitation measures. Here we test how trees growing in different geomorphic positions along a fluvial system uptake metal during floods and how these uptakes can be documented “a posteriori”. To this end, we apply dendrogeochemical analyses to twenty Pinus pinaster Ait. trees growing on the banks of Odiel River (south-western Spain) as well as to five reference trees growing outside the river channel. In the field, trees were sampled with a large-diameter (1 cm) increment borer. In the lab, tree-ring series were dendrochronologically cross dated and separated into 5-yr blocks, so that wood blocks contained the dates of major floods. Then, Inductively Coupled Plasma Mass Spectrometry (ICPM) was employed to evaluate toxic metal concentrations in trees. Results point to clear correlations between the accumulation of toxic metals and the geomorphic position of trees within the fluvial network. We show that morphological units along a river exert control on toxic metal concentrations in trees, with uptake being much higher in trees located on meander cut banks than in trees growing on point-bar structures. Besides, we detect chemical signatures in trees located farthest away from the main river channel after the largest floods, but not in the aftermath of smaller events. We conclude that tree position is the single-most important determinant for metallic pollution in an environment controlled by fluvial processes, but also find that more studies are still needed to determine linkages with individual floods and interactions of metal uptake in roots via the water table in the river corridor. Tree ring Flood Fluvial geomorphology Dendrochemistry Heavy metal Pollution Odiel River Dewey 333.7-333.9 Dewey 550 18 Institut des sciences de l'environnement 0DB 41 Département F.-A. Forel des sciences de l'environnement et de l'eau 153 false 943 ISE Climat Cuadernos de Investigación Geográfica 47 2 4ee77cc3-d9c4-4bc0-821f-a1cc0c5f5572 Article (Published version) Public 4740-12718-1-PB.pdf 3128389 application/pdf openAccess Centres et instituts / Institut des sciences de l'environnement Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département F.-A. Forel des sciences de l'environnement et de l'eau

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Trees as sentinels of metallic pollution induced by mining along the Odiel River (Southern Iberian Peninsula)	Cuadernos de Investigación Geográfica			2021	296	393

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Delapierre, Annick