Tree ring based Pb and Zn contamination history reconstruction in East China: a case study of Kalopanax septemlobus
To reconstruct heavy metal contamination history in the Yangtze River Delta region, annual growth rings of native hardwood species, Kalopanax septemlobus, were studied as the potential archive of the past Pb and Zn pollution events.Wide distribution of K.septemlobus trees in the study area and clear annual tree rings are advantages of this potential geochemical archive.In this research, tree ring increments for 48 years, from 1960 to 2007, were analyzed for Pb and Zn concentrations.Trees were sampled in two sites, Xiaoyingpan, a contaminated area around a mine (Pb, Zn, Ag) in the Yangtze River Delta region, and a reference site 19 km away.We found that: (1) distinct Pb and Zn concentrations increasing from 1960 to 1974 at the polluted site, were coincident with increasing historical open mining activities;(2) from 1974 to 1986, Pb and Zn concentrations dramatically decreased during a conversion from above-ground exploitation to below-ground extraction;and (3)after 1986, the concentration of Zn decreased gradually, but Pb concentrations initially increased with automobile traffic from 1986 to 2004, then decreased when the number of automobiles was controlled from 2004 to 2007.Surprisingly, Pb and Zn concentrations in tree rings had no effect on K.septemlobus growth.Pb and Zn concentrations in tree rings were linearly related with those in soils.Growth rings ofK.septemlobus around the Pb, Zn, Ag mine accurately recorded historical changes in Pb and Zn deposition.
Pb and Zn concentrations tree rings Kalopanax septemlobus contamination dynamics
XU Xiao-gang CHEN Zhao-kun STOHLGREN J Thomas
Faculty of Forest Resources and Environment, Nanjing Forestry University, Nanjing, 210037, China;Suz Faculty of Forest Resources and Environment, Nanjing Forestry University, Nanjing, 210037, China USGS, Fort Collins Science Center, Colorado 80526-8118, USA
国内会议
南京
英文
90-97
2012-04-15（万方平台首次上网日期，不代表论文的发表时间）