Historical change of heavy metals in urban soils of Nanjing, China during the past 20 centuries.
Two typical areas, including once commercial and residential quarters of Nanjing, China, were studied by investigating soil properties especially heavy metals of soils in various cultural layers formed in different Chinese Dynasties. The age of the soil profiles was dated by both archaeological and 14C chronological methods. The results showed that urban soils in the old commercial/workshop quarter of Nanjing were generally contaminated by heavy metals Cu, Zn, Pb, but their concentration levels varied significantly among the cultural layers formed in different dynasties. The substantial increase of heavy metals appeared in three historical periods, i.e., South Dynasty (222-589 AD), the earlier Ming (1368-1644 AD) and the late Qing (1644-1912 AD) in one area. The tremendous input and storage of heavy metals in soils was explained by the primitive smelting and the strengthened metal processing activities, which might be due to the requirement of weapon making or other industries, in the changing social conditions of the corresponding periods. Soils in the once noble political, cultural centers did not show significant increase of heavy metals. The difference in the distribution pattern of heavy metals revealed the contrasting history of the site uses. The change of contaminant level in soils is believed to be a reflection of various human activities in the city during the past 20 centuries.
Zhang
Gan-Lin
GL
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. glzhang@issas.ac.cn
Yang
Feng-Gen
FG
Zhao
Yu-Guo
YG
Zhao
Wen-Jun
WJ
Yang
Jin-Ling
JL
Gong
Zi-Tong
ZT
D002681:China; D002947:Cities; D004784:Environmental Monitoring / Q000266:history; D004787:Environmental Pollution / Q000266:history*; D049668:History, 15th Century; D049669:History, 16th Century; D049670:History, 17th Century; D049671:History, 18th Century; D049672:History, 19th Century; D049673:History, 20th Century; D049690:History, Ancient; D049691:History, Medieval; D006801:Humans; D008669:Metallurgy / Q000266:history; D019216:Metals, Heavy / Q000032:analysis / Q000266:history*; D012989:Soil Pollutants / Q000032:analysis / Q000266:history*; D014507:Urbanization / Q000266:history
D019216:Metals, Heavy; D012989:Soil Pollutants