岩溶区不同母质土壤Cd地球化学特征及玉米籽实Cd含量预测  

Geochemical Characteristics of Cd in Different Parent Soils in Karst Area and Prediction of Cd Content in Maize

作　　者：戴亮亮 徐宏根[1] 巩浩 彭志刚 肖凯琦 吴欢欢 许青阳 郭军 汤媛媛 张俊[1] DAI Liang-liang;XU Hong-gen;GONG Hao;PENG Zhi-gang;XIAO Kai-qi;WU Huan-huan;XU Qing-yang;GUO Jun;TANG Yuan-yuan;ZHANG Jun(Changsha Natural Resources Comprehensive Survey Center of China Geological Survey,Changsha 410600,China;Xi'an Mineral Resources Survey Center of China Geological Survey,Xi'an 710000,China)

机构地区：[1]中国地质调查局长沙自然资源综合调查中心,长沙410600 [2]中国地质调查局西安矿产资源调查中心,西安710000

出　　处：《环境科学》2023年第4期2243-2251,共9页Environmental Science

基　　金：中国地质调查局项目(DD20211576)。

摘　　要：碳酸盐岩风化形成的Cd自然高背景值区一直以来都备受关注,但由于岩溶区不同母质土壤的理化性质、 Cd含量和生物有效性存在显著差异,导致利用土壤Cd总量对耕地进行环境质量分类存在一定的局限性.通过系统采集典型岩溶区残坡积母质和冲积母质表层土壤及玉米样品,分析玉米Cd、土壤Cd、 pH和氧化物等指标,揭示了不同母质土壤Cd地球化学特征及其生物有效性的影响因素,并基于预测模型提出科学有效的耕地利用区划建议.结果表明,岩溶区不同母质土壤理化性质分异明显,冲积母质土壤Cd含量较低,但生物有效性高,玉米籽实Cd超标率高.玉米籽实Cd生物富集系数与土壤CaO、 pH、 Mn和TC呈极显著负相关关系,相关系数分别-0.385、-0.620、-0.484和-0.384.与多元线性回归预测模型相比,采用随机森林模型预测玉米Cd富集系数的准确度更高.研究结果提出了一种基于土壤Cd和预测农作物籽实Cd含量的地块尺度耕地安全利用新方案,充分利用耕地资源,确保农作物安全.The naturally high background value region of Cd derived from the weathering of carbonate has received wide attention.Due to the significant difference in soil physicochemical properties,soil Cd content,and bioavailability of different parent materials in the karst area,there are certain limitations in using the total soil Cd content to classify the environmental quality of cultivated land.In this study,surface soil and maize samples of eluvium and alluvial parent material in typical karst areas were collected systematically;the contents of maize Cd,soil Cd,pH,and oxides were analyzed,the Cd geochemical characteristics of different parent soils and the influencing factors of their bioavailability were revealed,and scientific and effective arable land use zoning suggestions based on the prediction model were suggested.The results showed that the physicochemical properties of different parent material soils in the karst area were obviously different.The alluvial parent material soil had low Cd content but high bioavailability,and the maize Cd exceeding rate was high.The maize Cd bioaccumulation factor was significantly negatively correlated with soil CaO,pH,Mn,and TC,and the correlation coefficients were-0.385,-0.620,-0.484,and-0.384,respectively.Compared with the multiple linear regression prediction model,using the random forest model to predict the maize Cd enrichment coefficient had higher accuracy and precision.Furthermore,a new scheme for the safe utilization of cultivated land at the plot scale based on soil Cd and predicted crop Cd content was proposed in this study,making full use of arable land resources to ensure crop safety.

关 键 词：镉(CD) 碳酸盐岩 影响因素 预测 区划方法 

分 类 号：X142[环境科学与工程—环境科学]