title: Metal(loid) allocation and nutrient retranslocation in Pinus halepensis trees growing on semiarid mine tailings.
abstract: The goal of this study was to evaluate internal metal(loid) cycling and the risk of metal(loid) accumulation in litter from Pinus halepensis trees growing at a mine tailing disposal site in semiarid Southeast Spain. Internal nutrient retranslocation was also evaluated in order to gain insight into the ability of pine trees to cope with the low-fertility soil conditions at the tailings. We measured metal(loid) concentrations in the foliage (young and old needles), woody stems and fresh leaf litter of pine trees growing on tailings. The nutrient status and stable isotope composition of pine foliage (δ(13)C, δ(15)N, δ(18)O as indicators of photosynthesis and water use efficiency) were also analyzed. Tailing soil properties in vegetation patches and in adjacent bare soil patches were characterized as well. Significant amounts of metal(loid)s such us Cd, Cu, Pb and Sb were immobilized in the woody stems of Pinus halepensis trees growing on tailings. Leaf litterfall showed high concentrations of As, Cd, Sb, Pb and Zn, which thereby return to the soil. However, water extractable metal(loid) concentrations in tailing soils were similar between vegetation patches (mineral soil under the litter layer) and bare soil patches. The pines growing on mine tailings showed very low foliar P concentrations in all leaf age classes, which suggests severe P deficiency. Young (current year) needles showed lower accumulation of metal(loid)s, higher nutrient concentrations (P and K), and higher water use efficiency (as indicated by and δ(13)C and δ(18)O data) than older needles. Substantial nutrient resorption occurred before leaf litterfall, with 46% retranslocation efficiency for P and 89% for K. In conclusion, phytostabilization of semiarid mine tailings with Pinus halepensis is feasible but would require careful monitoring of the trace elements released from litterfall, in order to assess the long term risk of metal(loid) transfer to the food chain.
authors.affiliation: Universidad Politecnica de Cartagena, Departamento de Ciencia y Tecnología Agraria Paseo Alfonso XIII, Cartagena 48. 30203, Spain. Electronic address: isabel.parraga@upct.es.
authors.forename: Isabel
authors.initials: I
authors.lastname: Parraga-Aguado
authors.affiliation: Water and Soil Conservation Department, Centro de Edafología y Biología Aplicada del Segura CEBAS-CSIC Campus Universitario de Espinardo, PO Box 164, Espinardo-Murcia ES-30100, Spain.
authors.forename: Jose-Ignacio
authors.initials: JI
authors.lastname: Querejeta
authors.affiliation: Universidad Politecnica de Cartagena, Departamento de Ciencia y Tecnología Agraria Paseo Alfonso XIII, Cartagena 48. 30203, Spain.
authors.forename: María Nazaret
authors.initials: MN
authors.lastname: González-Alcaraz
authors.affiliation: Universidad Politecnica de Cartagena, Departamento de Ciencia y Tecnología Agraria Paseo Alfonso XIII, Cartagena 48. 30203, Spain.
authors.forename: Hector M
authors.initials: HM
authors.lastname: Conesa
mesh_terms: D004784:Environmental Monitoring; D008670:Metals / Q000032:analysis / Q000378:metabolism*; D008906:Mining; D028223:Pinus / Q000502:physiology*; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*; D013030:Spain; D014131:Trace Elements / Q000032:analysis / Q000378:metabolism*
chemical_list: D008670:Metals; D012989:Soil Pollutants; D014131:Trace Elements
keywords: Aleppo pine; Metal(loid) allocation; Mining pollution; Nutrient redistribution; Phytomanagement; Semiarid climate; Stable isotopes