贵州地质高背景区稻田土壤镉生物有效性预测方法评价  

Evaluation of Methods for Predicting Cadmium Bioavailability in Rice Paddy Soils in the Geological High Background Area of Guizhou Province

作　　者：余敏芬 戴婷 闫海鱼[1] 胡海燕[1] YU Minfen;DAI Ting;YAN Haiyu;HU Haiyan(State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;University of Chinese Academy of Sciences,Beijing 101408,China;School of Public Health,Guizhou Medical University,Guiyang 561113,China)

机构地区：[1]中国科学院地球化学研究所环境地球化学国家重点实验室,贵阳550081 [2]中国科学院大学,北京101408 [3]贵州医科大学公共卫生与健康学院,贵阳561113

出　　处：《地球与环境》2025年第1期26-33,共8页Earth and Environment

基　　金：国家自然科学基金项目(42377246);环境地球化学国家重点实验室自主部署课题(SKLEG2024102);贵州省科技计划项目(黔科合基础-ZK[2023]一般300)。

摘　　要：土壤中镉(Cd)受pH及其赋存状态等多种因素影响,其生物有效性可能存在很大差异。常用的土壤生物有效性Cd测定方法是否也适用于喀斯特地质高背景区,尚存在争议。为此,本研究选取贵州喀斯特地质高背景区的高镉浓度(DH村)、中镉浓度(XL村)和非喀斯特区域低镉浓度对照(XN村),采集水稻根际土及其对应的稻米样品,分别采用7种单一化学提取法测定土壤有效态Cd和测定土壤及稻米的总Cd,并分析其相关性。结果显示,喀斯特区域土壤pH范围和平均值分别为DH村5.59~7.02(6.29±0.45),XL村4.64~7.29(6.22±0.70),属于弱碱至弱酸性,显著高于非喀斯特区XN村3.55~5.22(4.64±0.65);喀斯特区域土壤总Cd平均值分别为DH村7.47±2.21 mg/kg,和XL村2.03±0.60 mg/kg,显著高于非喀斯特区XN村0.31±0.04 mg/kg。稻米Cd含量与土壤总Cd无正相关关系,但喀斯特区域稻米Cd含量与土壤0.1 mol/L CaCl_(2)提取态Cd呈正相关关系,非喀斯特区域稻米Cd含量与土壤0.005 mol/L DTPA提取态Cd呈正相关关系,这表明pH较高的喀斯特区域土壤高镉和中镉组0.1 mol/L CaCl_(2)提取态Cd,或非喀斯特区域土壤0.005 mol/L DTPA提取态Cd,均可代表相应区域土壤的生物有效态Cd。基于土壤生物有效态Cd和pH建立的多元回归模型,可进一步筛查和预测贵州喀斯特区域稻米Cd是否超标。The bioavailability of cadmium(Cd)in soil is influenced by various factors including pH and its chemical form.There is an ongoing debate about the suitability of traditional methods for assessing soil Cd bioavailability in areas with high background levels of cadmium in karst formations.This study collected samples of rice inter-root soil and corresponding rice from DH village(high Cd concentration),XL village(medium Cd concentration),and XN village(low Cd concentration)in the non-karstic region of Guizhou′s karst geology high background area.The study simultaneously determined the bioavailable state of Cd in the soil and total Cd in both the soil and rice using seven single chemical extractions,analyzing the correlation between them.The soil pH range and mean values in the karst region were as follows:DH(5.59~7.02,mean 6.29±0.45),XL(4.64~7.29,mean 6.22±0.70),weakly alkaline to weakly acidic,significantly higher than in the non-karstic XN villages(3.55~5.22,mean 4.64±0.65).The mean values of total soil Cd in karst areas were 7.47±2.21 mg/kg in DH village and 2.03±0.60 mg/kg in XL village,significantly higher than in XN village in non-karst areas(0.31±0.04 mg/kg).There was no positive correlation between rice Cd content and total soil Cd.A positive correlation was observed between rice Cd and soil Cd extracted using 0.1 mol/L CaCl_(2)in the karst region,and with soil Cd extracted using 0.005 mol/L DTPA in the non-karstic region.This suggests that 0.1 mol/L CaCl_(2)extracted state Cd for the high and medium Cd groups of soils in karstic regions with higher pH,or 0.005 mol/L DTPA extracted state Cd for soils in non-karstic regions,are representative of thebioavailable state of Cd in the soils of the corresponding regions.The multiple regression model based on bioavailable Cd and soil pH can further test and predict whether rice Cd exceeds the standard in Guizhou karst area.

关 键 词：喀斯特 稻田土壤 镉 生物有效性 

分 类 号：X53[环境科学与工程—环境工程] S511[农业科学—作物学]