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Cadmium Accumulation and Main Factors Influencing Cadmium Bio-availability in Fluvo-aquic Soils from Lower Region of the Yangtze River
Received:August 21, 2014  
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KeyWord:cadmium;fluvo-aquic soil;pollution sources;bio-availability;carbonate
Author NameAffiliation
WANG Cheng Nanjing Research Institute of Environmental Protection, Nanjing 210013, China 
LI Wen-qing Nanjing Research Institute of Environmental Protection, Nanjing 210013, China 
LI Jing Nanjing Research Institute of Environmental Protection, Nanjing 210013, China 
CHEN Sen Nanjing Research Institute of Environmental Protection, Nanjing 210013, China 
CHEN Hong-yan College of Environment and Engineering, Hohai University, Nanjing 210098, China 
ZHOU Yan-wen Nanjing Research Institute of Environmental Protection, Nanjing 210013, China 
GAO Xiao-jie Nanjing Research Institute of Environmental Protection, Nanjing 210013, China 
CHEN Yang School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, China 
LIAO Qi-lin Geological Survey of Jiangsu Province, Nanjing 210018, China 
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Abstract:
      Accelerated industrialization has brought a considerable amount of cadmium(Cd) into soils, resulting in Cd accumulation in the topsoil. Here we studied Cd accumulation and main factors influencing Cd bio-availability in fluvo-aquic soils in the lower region of the Yangtze River, a soil Cd anomaly zone. The results show that Cd accumulation occurred in the topsoil during 2003~2014, with soil Cd average concentration increased by about 40.9% relative to that in 2003. More than 50% of the soil samples had Cd concentration up to light pollution level, according to the Chinese soil environmental quality standards. Cadmium was significantly correlated with S and TOC in the soils. The most possible extraneous source of Cd in the topsoil was atmospheric deposition, which was influenced by fly ash. Soil Cd bio-availability was mainly influenced by soil carbonate, pH, Ca, Mg and Available Fe, with carbonate being the most important factor. Soil Cd concentrations did not differ significantly between carbonate- and non-carbonate soils(carbonate concentration < 5 g·kg-1), but bio-available Cd and Cd activation rate were significantly different. The average bio-available Cd and activation rate in non-carbonate soils were 2.5 and 2 times that of carbonate-contained soils, respectively. In addition, acidification occurred in the topsoil during the past. This study suggests that it is necessary to execute ecological restoration to control the acidification and prevent the risk of soil heavy metals pollution.