Department of Soil Science, Federal University of Lavras, Lavras, MG, CEP: 37200-000, Brazil.
Science & Technology Branch, Environment and Climate Change Canada, Ottawa, Ontario K1A 0H3, Canada.
Chemosphere. 2019 Apr;221:124-131. doi: 10.1016/j.chemosphere.2018.12.195. Epub 2018 Dec 31.
Cerium (Ce) is present in high technology materials and in mineral P fertilizers and the use and discharge of such resources may change the natural status of Ce in the soil environment. Brazilian soils in farming areas are significantly exposed to increased levels of unintentionally-added Ce through intensive input of phosphate fertilizers. The aims of this study were to evaluate the ecotoxicological risk to plants growing in tropical soils contaminated with Ce, as well as to create a database to support future legislation regulating the limits of this element in Brazilian and conceivably other tropical soils. Eight crop species (corn, sorghum, rice, wheat, soybeans, sunflower, radish, and beans) were exposed to a Ce concentration gradient in two typical tropical soils (Oxisol and Inceptsol), and an artificial soil. Our findings showed that among the endpoints measured, Ce phytotoxicity was more pronounced on shoot dry matter than on percent germination and germination speed index. Sensitivity of plants is species specific and our data showed that sunflower and radish exposed to Ce were the most sensitive crop species. Soil properties such as pH, cation exchange capacity, and organic carbon may have influenced the severity of Ce phytotoxicity. Because of that, the Oxisol contaminated with this element caused higher phytotoxicity than the other soils tested. Our risk assessment results (hazardous concentration, HC = 281.6 mg Ce kg) support the idea that unintentional Ce input through P fertilizers does not pose a risk to soils of Brazilian agroecosystems.
铈（Ce）存在于高科技材料和矿物 P 肥料中，而这些资源的使用和排放可能会改变土壤环境中铈的自然状态。巴西耕作区的土壤由于大量使用磷酸盐肥料，会显著增加非故意添加的铈水平。本研究旨在评估受铈污染的热带土壤中植物的生态毒性风险，并创建一个数据库，以支持未来巴西和其他热带土壤中限制该元素含量的法规。八种作物（玉米、高粱、水稻、小麦、大豆、向日葵、萝卜和豆类）在两种典型的热带土壤（氧化土和始成土）和人工土壤中暴露于铈浓度梯度下。我们的研究结果表明，在所测量的终点中，Ce 对地上部分干物质的植物毒性比发芽率和发芽速度指数更为明显。植物的敏感性具有物种特异性，我们的数据表明，暴露于 Ce 的向日葵和萝卜是最敏感的作物物种。土壤性质，如 pH 值、阳离子交换容量和有机碳，可能影响 Ce 植物毒性的严重程度。因此，受该元素污染的氧化土比其他测试土壤引起的植物毒性更高。我们的风险评估结果（危害浓度，HC=281.6mg Ce kg）表明，通过 P 肥料无意输入 Ce 不会对巴西农业生态系统的土壤构成风险。
