GAO Yuan1,2, HE Chulu1, LEI Haoran1, LIU Xu1, WANG Xun2, WANG Yongmin1, WANG Dingyong1

（1. College of Resources and Environment, Southwest University, Chongqing 400715, China;

2. Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China）

Abstract： To explore the spatio-temporal variations and its primary influencing factors of heavy metals in tree rings of Southwest China, the concentrations of twelve heavy metals in tree rings of Ailao Mountains Schima Superba, Dali Cangshan Spruce, Baima snow mountain fir and Mount Gongga fir along the propagation path of the Southwest Indian monsoon were determined, and four heavy metals (Pb, Cr, Cd and As) were mainly discussed. The results showed that the annual concentrations of Pb, Cr, Cd and As in tree rings fluctuated greatly due to the influence of human activities. Besides, the variations of Pb, Cr, Cd and As contents in tree rings of Southwest China were mainly controlled by the long distance transportation of heavy metals emitted by industry in Europe and America before 1950, while the rapid increase of anthropogenic emissions caused by rapid industrialization in southwest China is the dominant reason for the variations of tree-ring Pb, Cr, Cd and As concentrations after 1950. In addition, the average tree rings Pb and As concentrations decreased gradually along the monsoon propagation path, with the more obvious decrease trend of Pb. On the cumulative scale, this spatial variation is mainly affected by the differences of tree species, heavy metal deposition along the monsoon and soil background. The results of dendrochemistry analysis provide data for the spatio-temporal variations of heavy metals in Southwest China in nearly 200 years, as well as a new perspective for understanding the accumulation of heavy metals in remote areas.

Key words：tree ring; heavy metals; southwest China; spatio-temporal distribution

EARTH AND ENVIRONMENT Vol.51, No.3, Tot No.353, 2023, Page 308