Environmental Biology and Ecotoxicology Laboratory, Department of Environmental Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan.
Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan.
Environ Pollut. 2024 Sep 1;356:124299. doi: 10.1016/j.envpol.2024.124299. Epub 2024 Jun 5.
The coexistence of polystyrene microplastics (PSMPs) and copper (Cu) has become a pressing issue for croplands. However, limited literature is available regarding the interaction of PSMPs with essential micronutrients in Cu-contaminated soils. Therefore, the present study aimed to analyze the immobilization potential of PSMPs for micronutrient bioavailability in soil and Cu toxicity in maize (Zea mays L.). A pot experiment was conducted with maize variety "Islamabad gold" exposed to varying Cu concentrations (0, 50, 100, 200, and 400 mg/kg) and PSMPs (150-250 μm size, 0, 1, and 3% w/w) via soil spiking for 60 days. The concentrations of essential micronutrients (Zn, Cu, Mn, Fe) in soil and plant tissues were measured using an atomic absorption spectrophotometer. Moreover, malondialdehyde (MDA) and antioxidant activities (superoxide dismutase, ascorbate peroxidase, catalase, and peroxidase) were recorded. The concentration of Cu showed significant reduction in post-harvesting soil by 21, 24.8, 27.6, 29.2, and 30.2% from Cu0 to Cu400 mg/kg respectively from pre-sowing soil. On the other hand, the addition of 1%PSMPs and 3%PSMPs declined Cu by 16, 21.6, 24.4, 25.9, 27.8, and 12.6, 16.5, 19.9, 23.2, 25% from Cu0 to Cu400 mg/kg respectively. Maize showed significant improvement in growth under combined exposure of Cu and 3% PSMPs compared to individual exposure. The MDA level was decreased under the combined presence of Cu and PSMPs compared to individual Cu exposure. The percentage difference with 1%PSMPs was 98.1, 95.0, 92.0, 90.0, and 89.6%, while with 3%PSMPs was 93.2, 93.2, 87.7, 81.4, and 79.2% from Cu0 to Cu400 mg/kg respectively. Moreover, the impact of PSMPs was more prominent at a 3% dose compared to a 1% dose. The findings provided significant knowledge about the potential of PSMPs to mitigate Cu toxicity in maize. Future research should incorporate a variety of particle size distributions at natural conditions for variety-specific differences.
聚苯乙烯微塑料（PSMPs）和铜（Cu）共存已成为农田的一个紧迫问题。然而，关于 PSMPs 与 Cu 污染土壤中必需微量元素相互作用的文献有限。因此，本研究旨在分析 PSMPs 对土壤中微量元素生物有效性和玉米（Zea mays L.）中 Cu 毒性的固定潜力。通过土壤添加法进行盆栽实验，用玉米品种“Islamabad gold”在不同 Cu 浓度（0、50、100、200 和 400 mg/kg）和 PSMPs（150-250 μm 粒径，0、1 和 3%w/w）下暴露 60 天。采用原子吸收分光光度计测定土壤和植物组织中必需微量元素（Zn、Cu、Mn、Fe）的浓度。此外，记录丙二醛（MDA）和抗氧化活性（超氧化物歧化酶、抗坏血酸过氧化物酶、过氧化氢酶和过氧化物酶）。收获后土壤中 Cu 的浓度分别比播种前土壤中 Cu0 到 Cu400 mg/kg 降低了 21、24.8、27.6、29.2 和 30.2%。另一方面，添加 1%PSMPs 和 3%PSMPs 使 Cu0 到 Cu400 mg/kg 分别降低了 16、21.6、24.4、25.9、27.8 和 12.6、16.5、19.9、23.2、25%。与单独暴露相比，Cu 和 3%PSMPs 联合暴露时玉米生长显著改善。与单独 Cu 暴露相比，在 Cu 和 PSMPs 同时存在的情况下，MDA 水平降低。与 1%PSMPs 相比，百分比差异分别为 98.1%、95.0%、92.0%、90.0%和 89.6%，而与 3%PSMPs 相比，百分比差异分别为 93.2%、93.2%、87.7%、81.4%和 79.2%，从 Cu0 到 Cu400 mg/kg。此外，3%剂量的 PSMPs 比 1%剂量的 PSMPs 更能显著减轻 Cu 毒性。研究结果为 PSMPs 减轻玉米 Cu 毒性的潜力提供了重要知识。未来的研究应在自然条件下结合各种粒径分布，研究不同品种的差异。
