School of Life Sciences, Sambalpur University, Sambalpur, Odisha, India.
Department of Zoology, College of Basic Science and Humanities, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha, India.
J Environ Qual. 2024 Sep-Oct;53(5):711-726. doi: 10.1002/jeq2.20610. Epub 2024 Jul 28.
Microplastics (MPs), recognized as emerging pollutants, pose a significant threat to diverse organisms and have adverse effects on agricultural soil. High-density polyethylene (HDPE) holds a prominent position among prevalent forms of MPs. In the current investigations, the impact of HDPE was assessed at four different concentrations (0.25%, 0.5%, 0.75%, and 1.0%) on agricultural soil, microbial population, exoenzymes activities including amylase, cellulase, and invertase, and alteration in carbon-to-nitrogen (C/N) ratio. Both bacterial and fungal populations exhibited a non-concentration-dependent response to different concentrations of HDPE over time. In this study, we refer to the concentrations of 0.25%, 0.5%, 0.75%, and 1.0% as HT1, HT2, HT3, and HT4, respectively. Initial MP application significantly reduced bacterial colony counts for HT1, HT2, and HT4, while HT3 showed no significant change. On the 60th day, HT1 and HT3 exhibited a higher bacterial colony count compared to the control. On the other hand, fungal populations increased to maximum on day 1 but displayed no distinct time-dependent trend from days 15 to 60. Furthermore, enzyme activities decreased with increasing concentrations of MPs over an extended period. Molecular docking studies suggest that HDPE can hinder enzyme activity by forming hydrogen bonds with enzymes. The C/N ratio was found to be significantly higher in MP-treated soils on the 60th day relative to control, suggesting relatively slower degradation of carbon compounds in the MP-treated soils.
微塑料（MPs）作为新兴污染物，对各种生物构成严重威胁，并对农业土壤产生不利影响。高密度聚乙烯（HDPE）是常见 MPs 形式中的主要类型。在目前的研究中，评估了 HDPE 在四个不同浓度（0.25%、0.5%、0.75%和 1.0%）下对农业土壤、微生物种群、外切酶活性（包括淀粉酶、纤维素酶和转化酶）和碳氮比（C/N）的影响。细菌和真菌种群对不同浓度的 HDPE 的反应随时间呈非浓度依赖性。在本研究中，我们将浓度 0.25%、0.5%、0.75%和 1.0%分别称为 HT1、HT2、HT3 和 HT4。初始 MP 应用显著降低了 HT1、HT2 和 HT4 的细菌菌落计数，而 HT3 没有显示出显著变化。在第 60 天，HT1 和 HT3 的细菌菌落计数高于对照。另一方面，真菌种群在第 1 天增加到最大值，但从第 15 天到第 60 天没有明显的时间依赖性趋势。此外，随着 MPs 浓度的增加，酶活性在较长时间内降低。分子对接研究表明，HDPE 可以通过与酶形成氢键来抑制酶的活性。在第 60 天，MP 处理的土壤中的 C/N 比明显高于对照，表明 MP 处理的土壤中碳化合物的降解速度相对较慢。
