Evaluation of geogenic cadmium bioavailability in soil-rice system with high geochemical background caused by black shales
Evaluation of geogenic cadmium bioavailability in soil-rice system with high geochemical background caused by black shales
复制标题
黑色页岩高地球化学背景土壤-水稻系统地源镉生物有效性评价
DOI：
10.1007/s11368-020-02802-0
复制
发表时间：
2020
影响因子：
3.6
通讯作者：
Lin Qing
中科院分区：
文献类型：
--
作者：
Zhong Cong;Feng Zixu;Jiang Wei;Xiao Lin;Zhang Xinying;Zhao Yinjun;Lin Qing
摘要近年来，黑色页岩区镉（Cd）的富集因其分布广泛、背景值极高而越来越受到人们的关注。本研究旨在探讨黑色页岩区土壤性质对水稻吸收Cd的影响，并确定Cd从土壤向水稻转移的关键因素。材料与方法在黑色页岩区和对照区稻田共采集表层土壤和水稻样品40对。分析了土壤中的相关参数，以及不同水稻组织中的Cd浓度。结果与讨论结果表明，研究区87.5%的土壤样品超过镉的风险筛选值，42%的稻米样品超过镉的允许限值。影响该地区水稻吸收镉的关键因素是土壤植物有效镉浓度。与对照区相比，黑页岩区土壤Cd含量明显高于对照区，但由于碳酸盐造成的pH值较高，植物有效性较低。即便如此，黑页岩地区稻米中的镉含量表明其生态风险要高得多。结论土壤pH值和铁（Fe）是影响土壤中镉含量的最重要变量。针对黑页岩地区中性或弱碱性土壤，提高土壤pH值不是降低水稻镉水平的可行方法。
PurposeRecently, the cadmium (Cd) accumulation in the black shale area has attracted increasing attentions, due to its extensive distribution and extremely high background values. The aim of our study is to explore the impacts of soil properties on Cd uptake by rice, and identify the key factors of Cd transfer from soil to rice in the black shale area.Materials and methodsA total of 40 pairs of topsoil and rice samples were collected from the paddy fields in the black shale area and the control area. The relevant parameters in the soils, as well as the Cd concentrations in different rice tissues, were analyzed.Results and discussionThe results show that 87.5% of the soil samples in the study area exceed the risk screening values of Cd, and 42% of the rice grain samples exceed the allowable limit of Cd. The key factor influencing Cd uptake by rice in this area is the soil phytoavailable Cd concentration. Compared to those in the control area, the soils in the black shale area have a much higher Cd level but a lower phytoavailability due to the higher pH, which is caused by carbonate. Even so, the level of Cd in the rice from the black shale area indicates a much higher ecological risk.ConclusionsSoil pH and iron (Fe) are the most important variables exhibiting direct effects on Cd fractions in soils. In light of the neutral or weakly alkaline soil in the black shale area, we concluded that increasing the soil pH was not a feasible way to reduce Cd levels in the rice in this area.