摘要
以重庆市西部粮食主产区两个区县为代表,按照系统分层布点法,采集了180对成对土壤-水稻样品,对区域土壤和稻米镉(Cd)、铅(Pb)、铬(Cr)、汞(Hg)和砷(As)这5种重金属污染状况进行了评价,结合土壤pH、有机质(OM)和阳离子交换量(CEC)等理化性质因子分析,探讨了制约稻米重金属累积的关键土壤性质因子.结果表明,土壤5种重金属元素中仅有Cd和Pb元素存在超标现象,超标率分别为9.4%和0.5%.通过空间插值法绘制的土壤重金属空间分布图显示,Cd在研究区内空间差异显著,呈现“东北-西南双核”高值.Cr在北部和中部地区含量较高,但整体含量接近背景值,其余元素的分布较为均匀.在水稻籽粒中,Cd的超标率为10%,显示出较高的生物累积性,潜在危害较大;Cr的超标率为2.23%.土壤-水稻系统的综合质量指数表明,该区域总体污染程度较轻,未出现重度污染,以清洁和轻微污染为主,分别占比49%和31%.在水稻Cd的累积相关性分析中,发现土壤OM是降低Cd生物有效性的主要因子(r=-0.27,P<0.001),总磷(TP)也展现出对Cd累积的显著抑制作用(r=-0.15,P<0.05),所以可以通过土壤OM管理和合理施用磷肥来减少Cd向水稻籽粒迁移.土壤-水稻系统的综合质量评价表明区域污染总体可控,部分区域需动态监测和采取修复措施,以保障粮食安全和生态健康.
A total of 180 paired soil-rice samples were collected from two districts in the western grain-producing area of Chongqing,using a systematic stratified sampling method.The study evaluated the contamination status of five heavy metals-cadmium(Cd),lead(Pb),chromium(Cr),mercury(Hg),and arsenic(As)-in both the regional soil and rice.The study also analyzed key soil physical and chemical properties,such as soil pH,organic matter(OM),and cation exchange capacity(CEC),to explore the critical soil factors that constrain the accumulation of heavy metals in rice.The results showed that among the five heavy metals,only Cd and Pb exceeded the standard limits,with exceedance rates of 9.4%and 0.5%,respectively.The spatial distribution map of soil heavy metals generated through the spatial interpolation method indicated that Cd exhibited significant spatial variation within the study area,showing a“dual-core”pattern of high-concentration areas in the northeast and southwest.Cr concentrations were higher in the northern and central areas,but overall,the concentrations were close to background values,while the distribution of other elements was more uniform.In rice grains,the exceedance rate of Cd was 10%,indicating a higher bioaccumulation potential and greater potential harm.The exceedance rate of Cr was 2.23%.The comprehensive quality index of the soil-rice system showed that the overall pollution level of the region was relatively low,with no severe pollution observed.The majority of areas were classified as clean or lightly polluted,accounting for 49%and 31%,respectively.In the correlation analysis of Cd accumulation in rice,it was found that soil organic matter(OM)was the main factor for reducing the bioavailability of Cd(r=-0.27,P<0.001),and total phosphorus(TP)also exhibited a significant inhibitory effect on Cd accumulation(r=-0.15,P<0.05).Therefore,managing soil organic matter and applying phosphorus fertilizer appropriately could reduce the transfer of Cd to rice grains.The comprehensive quality evaluation of the soil-rice system showed that the regional pollution level was generally controllable,but some areas require dynamic monitoring and remediation measures to ensure food safety and ecological health.
作者
黄泉鑫
蒋珍茂
木志坚
魏世强
HUANG Quan-xin;JIANG Zhen-mao;MU Zhi-jian;WEI Shi-qiang(College of Resources and Environment,Southwest University,Chongqing 400700,China;Chongqing Key Laboratory of Agricultural Resources and Environment,Chongqing 400700,China)
出处
《环境科学》
2026年第2期1206-1218,共13页
Environmental Science
基金
重庆市农业农村委员会项目(CQS23C00591)。
关键词
土壤-水稻
重金属污染
综合质量评价
相关性分析
Cd累积
soil-rice system
heavy metal pollution
comprehensive quality assessment
correlation analysis
Cd accumulation
