南京大学学报（自然科学版）2019，Vol.55Issue(4)：678-687,10.DOI:10.13232/j.cnki.jnju.2019.04.018
典型岩溶地质高背景土壤镉生物有效性及其控制因素研究
Factors controlling the bioavailability of soil cadmium in typical karst areas with high geogenic background
摘要
Abstract
China's karst landforms are mainly distributed in Guangxi, Guizhou, Yunnan provinces and other southwest regions. According to the national soil pollution survey bulletin, the concentrations of metal elements in soils of these karst areas usually exceed the national standard, and the relevant research on the metal bioavailability is still lacking. The total concentrations of metals (As,Cd,Cr,Cu,Ni,Pb and Zn) in the paddy soils from typical karst areas in Guangxi were analyzed, and the chemical bioavailable concentrations of these metals in the soils were analyzed by using the chemical extraction methods of CaCl2 and EDTA(Ethylene Diamine Tetraacetic Acid). The Results showed that compared with that in the upper crust,different degree of enrichment of heavy metals in soils from the study area in order for the Cd>As>Pb>Zn>Cr>Cu>Ni, which is basically consistent with the order of concentrations of these heavy metals in Guangxi limestones, it is revealed that heavy metals in the soils from geogenic background karst area has significant inheritance from the parent rock. The average concentration of CaCl2 extracted from soil Cd in the karst areas was 0.02 mg·kg-1,and the average extraction rate was 4.37%,far lower than the average concentration and the average extraction rate for soil Cd in anthropogenic contaminated areas.The average concentration of EDTA extracted Cd was 0.84 mg·kg-1, and the extraction rate was 52.86%. The study found that there was no significant linear relationship between the concentration of CaCl2 extracted Cd and the total concentration of soil Cd in karst areas. The bioavailability and ecological risk were mainly controlled by pH. When the soil pH was higher than 6.5, although the total concentration of soil Cd was high,the concentration of CaCl2 extracted Cd and the ecological risk were low. However, when the soil pH was lower than 6.5 and the total concentration of soil Cd was relatively low,the concentration of CaCl2 extracted Cd and the ecological risk were higher.关键词
地质高背景/岩溶区土壤/镉/CaCl2提取/生物有效性Key words
high geogenic background/karst soil/cadmium/CaCl2 extraction/bioavailability分类
资源环境引用本文复制引用
郭超,文宇博,杨忠芳,李伟,管冬兴,季峻峰..典型岩溶地质高背景土壤镉生物有效性及其控制因素研究[J].南京大学学报（自然科学版）,2019,55(4):678-687,10.基金项目
国家重点研发计划(2017YFD0800303),广西典型土壤重金属生态地球化学调查项目,西南典型岩溶地区多目标地球化学调查(12120114092001) （2017YFD0800303）
