title: Heavy metal concentrations in timberline trees of eastern Tibetan Plateau.
abstract: Concentrations of 14 heavy metals (Ag, As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Tl, V, and Zn) in needles, twigs, bark and xylem of spruce and fir collected at the timberline of eight sites along the Hengduan Mountains, eastern Tibetan Plateau, are reported. Twigs had the highest concentration for most of elements, while xylem had the lowest concentration. The connections between elements in twigs were much richer than other organ/tissues. Pb, Ni, As, Sb, Co, Cd, Hg, Cr and Tl which are partly through anthropogenic sources and brought in by monsoon, have been accumulated in twigs and needles by wet or dry deposition in south and east sites where are within or near pollutant sources. Under moderate pollution situation, vegetation are able to adjust the nutrient element (Cu and Zn) cycle rate, thus maintain a stable concentration level. Seldom V, Ag, and Mo are from external anthropogenic sources. Needles and twigs can be used as biomonitors for ecosystem environment when needles can simply distinguish the origin of elements and twigs are more sensitive to extra heavy metal input.
authors.affiliation: Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences & Ministry of Water Conservancy, #9, Block 4, Renminnan Road, Chengdu, 610041, China.
authors.forename: Ji
authors.initials: J
authors.lastname: Luo
authors.forename: Jia
authors.initials: J
authors.lastname: She
authors.forename: Peijun
authors.initials: P
authors.lastname: Yang
authors.forename: Shouqin
authors.initials: S
authors.lastname: Sun
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Yiwen
authors.initials: Y
authors.lastname: Gong
authors.forename: Ronggui
authors.initials: R
authors.lastname: Tang
mesh_terms: D028202:Abies / Q000378:metabolism*; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis* / Q000378:metabolism; D019216:Metals, Heavy / Q000032:analysis* / Q000378:metabolism; D028222:Picea / Q000378:metabolism*; D018609:Tibet
chemical_list: D004785:Environmental Pollutants; D019216:Metals, Heavy