摘要
为了解贵州水稻田土壤和大米Cd污染特征,对贵州部分水稻主产区开展水稻田土壤和对应水稻样品的采集,并测试土壤pH和所有样品的Cd含量。结果显示:研究区土壤pH为4.81~7.56,平均值为6.45;土壤Cd含量为0.37~3.22 mg/kg,平均值为0.88 mg/kg,点位超标(风险筛选值)率为96.43%,喀斯特地区土壤Cd含量整体高于非喀斯特地区;大米中Cd含量为0.00~0.44 mg/kg,平均值为0.04 mg/kg,超大米安全限量值的样品比率为3.65%。进一步分析发现,研究区土壤Cd除来自成土母质(母岩)贡献外,还受人为排放的影响;水稻在灌浆成熟期,由于水稻田水分条件不良,土壤出现氧化环境的频率高或者氧化环境持续的时间长,可能是导致大米Cd超标的主要原因之一。因此,在水稻种植过程中,人为保障灌浆成熟期水稻田供水充足是降低水稻Cd含量、避免大米Cd超标的有效途径。
In order to understand the Cd pollution characteristics of paddy soil and rice, the paddy soil and corresponding rice samples were collected from some main rice producing areas in Guizhou Province. Soil pH and Cd content of all samples were tested. The results showed that the soil pH in the study area ranged from 4.81 to 7.56, with an average of 6.45. The range of Cd in soil is 0.372-3.220 mg/kg, and the average is 0.883 mg/kg. The rate of point exceeding the soil standard(risk screening value) is 96.43%, and the Cd content of soil in karst area is higher than that in non-karst area. The Cd content in rice is 0.001-0.439 mg/kg, with an average of 0.039 mg/kg, and the proportion of samples exceeding the safety limit of rice is 3.65%. Further analysis shows that soil Cd in the study area is not only from the contribution of soil forming parent material(parent rock), but also affected by anthropogenic emissions. At the grain filling maturity stage, due to poor water conditions in paddy fields, the high frequency of soil oxidation environment or the long duration of oxidation environment may be one of the main reasons for the excessive Cd of rice. Therefore, in the process of rice planting, intentionally ensuring sufficient water supply in paddy field during grain filling maturity is an effective way to reduce the content of Cd in rice and avoid exceeding the standard of Cd in rice.
作者
宋江菊
卢旺彪
张珍
蒋科
张奇
曾广能
黄承玲
杨成
张林
罗维均
王世杰
SONG Jiangju;LU Wangbiao;ZHANG Zhen;JIANG Ke;ZHANG Qi;ZENG Guangneng;HUANG Chengling;YANG Cheng;ZHANG Lin;LUO Weijun;WANG Shijie(School of Eco-Environmental Engineering,Guizhou Minzu University,Guiyang 550025,China;Guizhou Provincial Engineering Geological Disaster Prevention and Control Engineering Research Center of Guizhou Minzu University,Guiyang 550025,China;Puding Karst Ecosystem Research Station,Chinese Academy of Sciences,Puding Guizhou 562100,China;State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,ChineseAcademyof Sciences,Guiyang550081,China)
出处
《地球与环境》
CAS
CSCD
北大核心
2023年第1期67-75,共9页
Earth and Environment
基金
国家自然科学基金项目(41663015)
黔科合基础[2020]1Y188
贵州民族大学校基金项目(GZMU[2019]YB11)。
