Laboratory of Analytical Chemistry and Applied Ecochemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium; GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya·BarcelonaTech, Jordi Girona 1-3, Building D1, 08034, Barcelona, Spain; Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China.
Laboratory of Analytical Chemistry and Applied Ecochemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
J Environ Manage. 2022 Dec 15;324:116397. doi: 10.1016/j.jenvman.2022.116397. Epub 2022 Oct 5.
Selenium (Se) and zinc (Zn) are essential micronutrients that are often lacking in the diet of humans and animals. Application of mineral Se and Zn fertilizers into soils may lead to a waste of Se and Zn due to the fast leaching and low utilization by plants. Slow-release Se and Zn biofertilizer may therefore be beneficial. This study aims to assess the potential of SeZn-enriched duckweed and sludge produced from wastewater as slow-release Se and Zn biofertilizers. Pot experiments with green beans (Phaseolus vulgaris) and sampling of Rhizon soil pore water were conducted to evaluate the bioavailability of Se and Zn in sandy and loamy soils mixed with SeZn-enriched duckweed and sludge. Both the Se and Zn concentrations in the soil pore water increased upon amending the two biomaterials. The concentration of Se released from SeZn-enriched duckweed rapidly decreased in the first 21 days and slowly declined afterwards, while it remained stable during the entire experiment upon application of SeZn-enriched sludge. The Zn content in the soil pore water gradually increased over time. The application of SeZn-enriched duckweed and sludge significantly increased the Se concentrations in plant tissues, in particular in the form of organic Se-methionine in seeds, without a negative impact on plant growth when an appropriate dose was applied (1 mg Se/kg soil). While, it did not increase Zn concentrations in plant seeds. The results indicate that the SeZn-enriched duckweed and sludge could be only used as organic Se biofertilizers for Se-deficient soils. Particularly, the SeZn-enriched sludge dominated with elemental nano-Se was an effective Se source and slow-release Se biofertilizer. These results could offer a theoretical reference to choose an alternative to chemical Se fertilizers for biofortification, avoiding the problem of Se losses by leaching from mineral Se fertilizers while recovering resources from wastewater. This could contribute to the driver for a future circular economy.
硒（Se）和锌（Zn）是人类和动物饮食中经常缺乏的必需微量元素。将矿物质硒和锌肥料应用于土壤中，由于植物的快速淋溶和低利用率，可能导致硒和锌的浪费。因此，缓释硒和锌生物肥料可能是有益的。本研究旨在评估富硒富锌浮萍和废水污泥作为缓释硒和锌生物肥料的潜力。通过在温室中用绿豆（Phaseolus vulgaris）进行盆栽实验并采集根际土壤孔隙水，评估了富硒富锌浮萍和污泥添加到沙质和壤质土壤中对硒和锌生物有效性的影响。在添加两种生物材料后，土壤孔隙水中的硒和锌浓度均增加。从富硒富锌浮萍中释放的硒浓度在最初的 21 天内迅速下降，随后缓慢下降，而在添加富硒富锌污泥后，整个实验过程中保持稳定。土壤孔隙水中的锌含量随时间逐渐增加。当应用适量剂量（1mg Se/kg 土壤）时，富硒富锌浮萍和污泥的应用显著增加了植物组织中的硒浓度，特别是在种子中的有机硒-蛋氨酸形式，而对植物生长没有负面影响。然而，它并没有增加植物种子中的锌浓度。结果表明，富硒富锌浮萍和污泥只能作为缺硒土壤中的有机硒生物肥料。特别是，以元素纳米硒为主的富硒富锌污泥是一种有效的硒源和缓释硒生物肥料。这些结果可以为选择替代化学硒肥料进行生物强化提供理论参考，避免了从矿物质硒肥料中淋溶损失硒的问题，同时从废水中回收资源。这有助于推动未来的循环经济。
