Relationships Between Total and DTPA Extractable Contents of Cu, Pb, Zn, Cd in Trace Metal-Contaminated Paddy Soils of Dabaoshan, Guangdong
LI Yong tao1, LIU Ke xue1, ZHANG Chi1, Thierry Becquer2, Cé cile Quantin3, Marc Benedtti4, Patrick Lavelle2, DAI Jun1 (1.College of Natural Resources and Environment, South China Agricutrual University, Guangzhou 510642, China; 2.UMR 137 Biodiversité et Fonctionnement des Sols, IRD,France; 3.Université Paris Sud XI FRE OrsayTerre 2566 Bat. 504 91405 Cedex France; 4. UMR- CNRS 7047, Laboratoire de Gé ochimie et Mé tallogé nie / Université Pierre et Marie Curie, France)
samples were collected from long- term trace metal- contaminated rice field in the north of Guangdong, China, resulted from irrigation with acid mine drainage. Soil properties, total contents and DTPA extractable fractions of Cu, Pb, Zn, Cd were analyzed to characterize availability of trace metals and their effect factors under acid soil condition. The results showed that contamination level exceeded national and EU soil environmental standards, based on total Cu, Zn and Cd, except for total Pb. DTPA contents of all four metals were considerably high, and percentages of DTPA Pb and Cu in total contents were higher than those of DTPA Zn and Cd. There were significant correlations between total and DTPA contents of four trace metals. It indicated that DTPA extractable metals might be considered as simple indictors of available contents in the studied paddy soils. Moreover, close associations among soil pH and trace metals showed that such acid contaminants originated from same pollution sources and long- term irrigation of acid mine drainage was one of causes leading to soil acidification. In addition, soil acidity, total nitrogen and organic carbon presented significant and positive correlations with percentage of DTPA extractable Pb, Zn, Cd in their total contents. While pH and organic carbon were not significantly correlated, and total nitrogen was negatively associated with percentage of DTPA Cu. It may be attributed to solubilization of acid and week sorption of organic matter for Pb, Zn, Cd, and specific fixation of organic acid for Cu. It may be suggested that DTPA contents and availability of metals depend on combined effects of total contents and types of metals, soil pH and organic matter, and agricultural managements in the studied paddy soil.
【Fund】： 中国法国国际合作项目(中法先进研究计划PRAE03-2);; 广东省自然科学基金(032255)
【CateGory Index】： X53
【CateGory Index】： X53