College of Environment and Ecology, Hunan Agricultural University, Changsha, 410128, China.
School of Chemistry and Environmental Science, Shangrao Normal University, Shangrao, 334001, China.
Environ Pollut. 2024 Jun 15;351:124028. doi: 10.1016/j.envpol.2024.124028. Epub 2024 Apr 25.
Microalgae is an effective bioremediation technique employed for treating piggery effluent. However, there is insufficient study on how the presence of microplastics (MPs) in wastewater affects the ability of microalgae to remove heavy metals from piggery effluent. This study aims to investigate the influence of two prevalent heavy metals found in piggery wastewater, Cu (2 mg/L) and Zn (2 mg/L), on their removal by microalgae (Desmodesmus sp. CHX1) in the presence of four types of MPs: polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), and polyethylene terephthalate (PET). The results revealed that smaller particle size MPs promoted chlorophyll accumulation, while larger particles inhibits it. Additionally, higher concentrations of MPs promoted chlorophyll accumulation, while lower concentrations inhibited it. As for heavy metals, the presence of microplastics reduced the removal efficiency of Cu and Zn by Desmodesmus sp. CHX1. The highest inhibition of Cu was 30%, 10%, 19%, and 16% of the control (CK), and the inhibition of Zn was 7%, 4%, 4%, and 13%, respectively, under the treatments of PE, PVC, PP and PET MPs. Furthermore, Desmodesmus sp. CHX1 can secrete more extracellular polymeric substances (EPS) and form heterogeneous aggregates with MPs to counteract their pressure. These findings elucidate the impact of MPs on microalgae in bioremediation settings and offer useful insights into the complex relationships between microalgae, MPs, and heavy metals in the environment.
微藻是一种有效的生物修复技术，用于处理养猪废水。然而，对于废水中存在的微塑料（MPs）如何影响微藻去除养猪废水中重金属的能力，研究还不够充分。本研究旨在探讨养猪废水中两种常见重金属 Cu（2mg/L）和 Zn（2mg/L）对微藻（Desmodesmus sp. CHX1）去除能力的影响，同时研究了四种类型的 MPs（聚乙烯（PE）、聚氯乙烯（PVC）、聚丙烯（PP）和聚对苯二甲酸乙二醇酯（PET））对其的影响。结果表明，较小粒径的 MPs 促进了叶绿素的积累，而较大粒径的 MPs 则抑制了叶绿素的积累。此外，较高浓度的 MPs 促进了叶绿素的积累，而较低浓度的 MPs 则抑制了叶绿素的积累。对于重金属，微塑料的存在降低了 Desmodesmus sp. CHX1 对 Cu 和 Zn 的去除效率。Cu 的最大抑制率分别为对照（CK）的 30%、10%、19%和 16%，而 Zn 的最大抑制率分别为 7%、4%、4%和 13%，分别来自于 PE、PVC、PP 和 PET MPs 的处理。此外，Desmodesmus sp. CHX1 可以分泌更多的胞外聚合物物质（EPS），并与 MPs 形成异质聚集体，以抵消它们的压力。这些发现阐明了 MPs 在生物修复环境中对微藻的影响，并为微藻、 MPs 和重金属在环境中的复杂关系提供了有用的见解。
