Anhui Province Engineering Laboratory of Water and Soil Resources Comprehensive Utilization and Ecological Protection in High Groundwater Mining Area, School of Earth and Environment, Anhui University of Science and Technology, Huainan, 232001, China.
State Key Laboratory of Safety and Health for Metal Mines, Sinosteel Maanshan General Institute of Mining Research Company Limited, Maanshan, 243000, China.
Sci Rep. 2023 Feb 9;13(1):2332. doi: 10.1038/s41598-023-29125-7.
Earthworm mucus is rich in nutrients that can initiate the mineralization and humification of organic matter and is of great importance for contaminated soil remediation and sludge reutilization. In this study, six voltage and current combinations were utilized to promote earthworm mucus production (5 V and 6 V at 10, 20 and 30 mA, respectively), to explore the compositional changes of the mucus produced under different electrical stimuli, and to propose the best electrical stimulation group and mucus fraction applicable to soil heavy metal pollution remediation and sludge reutilization. The results showed that the mucus produced by the six electrical stimuli was mainly composed of proteins, amino acids, carbohydrates, fatty acids, and polysaccharides, with small amounts of alcohol, phenol, and ester organic substances. Under different electrical stimuli, each component changed significantly (P < 0.05). pH and conductivity were higher at 6 V 20 mA, total nitrogen and phosphorus contents reached their maximum at 5 V 30 mA, and total potassium at 6 V 10 mA. Protein, amino acids, and carbohydrates were most abundant in the mucus produced at 5 V 10 mA, while trace metal elements reached their lowest values at 5 V 10 mA. Finally, based on principal component analysis and combined with previous studies, it was concluded that the mucus produced at 5 V 10 mA was weakly alkaline, high in amino acids and nutrients and low in trace metal elements, and most suitable for sludge and straw composting experiments, soil remediation and amendment experiments.
蚯蚓黏液富含可启动有机质矿化和腐殖化的营养物质，对于污染土壤修复和污泥再利用具有重要意义。本研究采用 6 种电压和电流组合（分别为 5 V 和 6 V、10 mA、20 mA 和 30 mA）来促进蚯蚓黏液产生，以探讨不同电刺激下黏液成分的变化，并提出最适的电刺激组和黏液级分，以适用于土壤重金属污染修复和污泥再利用。结果表明，六种电刺激产生的黏液主要由蛋白质、氨基酸、碳水化合物、脂肪酸和多糖组成，还有少量醇、酚和酯类有机物质。在不同的电刺激下，每个成分都发生了显著变化（P < 0.05）。在 6 V 20 mA 下，pH 值和电导率较高；在 5 V 30 mA 下，总氮和总磷含量达到最大值；在 6 V 10 mA 下，总钾含量最高。在 5 V 10 mA 下产生的黏液中蛋白质、氨基酸和碳水化合物含量最丰富，而痕量金属元素含量最低。最后，基于主成分分析并结合以往的研究，得出结论：5 V 10 mA 产生的黏液呈弱碱性，富含氨基酸和营养物质，痕量金属元素含量低，最适合用于污泥和秸秆堆肥实验、土壤修复和改良实验。
