Background

The increasing production of nanoplastics and the fragmentation of microplastics into smaller particles suggest a plausible yet unclear hazard in the natural environment, such as soil. We investigated the short-term effects (28 days) of polystyrene nanoparticles (PS-NPs) on the activity and biomass of soil microbiota, and the functional diversity of soil enzymes at environmental relevant low levels in an incubation experiment.

Results

Our results showed a significant decrease in microbial biomass in treatments of 100 and 1000 ng PS-NP g⁻¹ DM throughout the incubation period. Dehydrogenase activity and activities of enzymes involved in N-(leucine-aminopeptidase), P-(alkaline-phosphatase), and C-(β-glucosidase and cellobiohydrolase) cycles in the soil were significantly reduced at day 28 suggesting a broad and detrimental impact of PS-NPs on soil microbiota and enzymes. Leucine-aminopeptidase and alkaline-phosphatase activities tended to decrease consistently, while β-glucosidase and cellobiohydrolase activities increased at high concentrations (e.g., PS-NP-1000) in the beginning of the incubation period, e.g., at day 1. On the other hand, basal respiration and metabolic quotient increased with increasing PS-NP application rate throughout the incubation period possibly due to increased cell death that caused substrate-induced respiration (cryptic growth).

Conclusions

We herewith demonstrated for the first time the potential antimicrobial activity of PS-NPs in soil, and this may serve as an important resource in environmental risk assessment of PS-NPs in the soil environment.

中文翻译：

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聚苯乙烯纳米粒子对土壤微生物群和酶功能多样性的影响。

背景

纳米塑料产量的增加和微塑料破碎成更小的颗粒表明在自然环境（如土壤）中存在似是而非的危险。我们在孵化实验中研究了聚苯乙烯纳米粒子 (PS-NPs) 对土壤微生物群活性和生物量的短期影响（28 天），以及环境相关低水平土壤酶的功能多样性。

结果

我们的结果显示，在整个潜伏期，100 和 1000 ng PS-NP g ^-1 DM处理中微生物量显着减少。脱氢酶活性和参与N- (亮氨酸-氨基肽酶)、P的酶的活性-（碱性磷酸酶）和土壤中的 C-（β-葡萄糖苷酶和纤维二糖水解酶）循环在第 28 天显着减少，表明 PS-NPs 对土壤微生物群和酶具有广泛而有害的影响。亮氨酸-氨基肽酶和碱性磷酸酶活性趋于持续下降，而在高浓度（例如，PS-NP-1000）下，在潜伏期开始时，例如在第 1 天，β-葡萄糖苷酶和纤维二糖水解酶的活性增加。另一方面在整个潜伏期内，基础呼吸和代谢商随着 PS-NP 施用率的增加而增加，这可能是由于导致底物诱导的呼吸（隐蔽生长）的细胞死亡增加。

结论

我们在此首次证明了 PS-NPs 在土壤中的潜在抗菌活性，这可能作为 PS-NPs 在土壤环境中环境风险评估的重要资源。