College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China; Greater Bay Area Institute for Innovation, Hunan University, Guangzhou 511300, Guangdong Province, PR China; Shenzhen Institute, Hunan University, Shenzhen, 518000, PR China.
College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China; Greater Bay Area Institute for Innovation, Hunan University, Guangzhou 511300, Guangdong Province, PR China; Shenzhen Institute, Hunan University, Shenzhen, 518000, PR China.
Sci Total Environ. 2024 Dec 15;956:177142. doi: 10.1016/j.scitotenv.2024.177142. Epub 2024 Nov 4.
Lots of studies on eutrophication, but there is a lack of comprehensive research on the repair of multiple forms of nitrogen and phosphorus under combined heavy metals (HMs) pollution. This work investigated the various forms of nitrogen and phosphorus in the water-sediment systems of eutrophic lakes with the application of biochar, Effective Microorganisms (EMs) and microplastics, aiming to deliberate the repair behavior of multiple forms of nitrogen/phosphorus and the integrated repairment of these nutrients and HMs in different remediations. For amended-groups, the application of biochar-supported EMs (BE) achieved the most desirable remediation for removing nitrogen, phosphorus and HMs in water and improved their stability in sediment due to the improved microbial activity and the developed biofilm system created by biochar. The addition of aging microplastics (MP) obviously reduced the systematic levels of nitrogen, phosphorus and HMs due to the stimulation of microbial activity and the adsorption of biofilm/EPS, but its high movability also increased the Fe(II) and S(-II) levels and the pollutants' ecological risks in sediment. The co-application of BE and MP (MBE) destroyed the ecosystem and decreased the removal of nitrogen and phosphorus, while greatly removing HMs by the superfluous biofilms/EPS. The application of biochar (BC) preferentially adsorbed and degraded dissolved nitrogen and phosphorus, releasing HMs into water. From these amended-groups, it's also knew that the removal of nitrogen and phosphorus mainly came from the degradation/assimilation of NH-N, SRP and dissolved matters, particularly those molecular weight below 3 kDa; the higher removal of phosphorus than nitrogen was attributed to the coprecipitation of Fe-S-P hydroxides and the adsorption of particulates; however, the colloidal (3-100 kDa) nitrogen and phosphorus had low accessibility and bioavailability, and it also showed the competitive adsorption with colloidal HMs, causing their relatively low removal in water. This study provides insight into the comprehensive repair of nitrogen, phosphorus and HMs in various forms by biochar-immobilized microbes and the influence of microplastics on nutrients and HMs in eutrophic lakes.
大量研究了富营养化问题，但缺乏对重金属（HM）污染下多种形态氮磷的综合修复研究。本工作应用生物炭、有效微生物（EM）和微塑料研究了富营养化湖泊水-沉积物系统中的各种形态氮磷，旨在探讨多种形态氮/磷的修复行为以及不同修复措施下这些营养物质和 HM 的综合修复。对于改良组，生物炭支持的 EM（BE）的应用实现了去除水中氮、磷和 HM 的最理想修复效果，并由于生物炭提高了微生物活性和发展的生物膜系统，改善了沉积物中营养物质和 HM 的稳定性。老化微塑料（MP）的添加由于微生物活性的刺激和生物膜/ EPS 的吸附，明显降低了系统中氮、磷和 HM 的水平，但由于其高迁移性，也增加了 Fe(II)和 S(-II)水平以及沉积物中污染物的生态风险。BE 和 MP 的共同应用（MBE）破坏了生态系统，降低了氮和磷的去除率，同时通过多余的生物膜/ EPS 大大去除了 HM。生物炭（BC）的应用优先吸附和降解溶解氮和磷，将 HM 释放到水中。从这些改良组中还可以知道，氮和磷的去除主要来自 NH-N、SRP 和溶解物质的降解/同化，特别是那些分子量低于 3 kDa 的物质；磷的去除率高于氮，这归因于 Fe-S-P 氢氧化物的共沉淀和颗粒的吸附；然而，胶体（3-100 kDa）氮和磷的生物可利用性和可及性较低，并且与胶体 HM 具有竞争吸附性，导致其在水中的去除率相对较低。本研究为生物炭固定微生物对各种形态氮、磷和 HM 的综合修复以及微塑料对富营养化湖泊中营养物质和 HM 的影响提供了深入了解。
