Department of Environmental Sciences and Engineering, Government College University Faisalabad, Allama Iqbal Road, Faisalabad, 38000, Pakistan.
Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Allama Iqbal Road, Faisalabad, 38000, Pakistan.
Sci Rep. 2021 Apr 19;11(1):8429. doi: 10.1038/s41598-021-88016-x.
Given the rapidly increasing use of metal oxide nanoparticles in agriculture as well as their inadvertent addition through sewage sludge application to soils, it is imperative to assess their possible toxic effects on soil functions that are vital for healthy crop production. In this regard, we designed a lab study to investigate the potential toxicity of one of the most produced nanoparticles, i.e. zinc oxide nanoparticles (nZnO), in a calcareous soil. Microcosms of 80 g of dry-equivalent fresh soils were incubated in mason jars for 64 days, after adding 100 or 1000 mg of biogenically produced nZnO kg soil. Moreover, we also added rice-straw derived biochar at 1 or 5% (w: w basis) hypothesizing that the biochar would alleviate nZnO-induced toxicity given that it has been shown to adsorb and detoxify heavy metals in soils. We found that the nZnO decreased microbial biomass carbon by 27.0 to 33.5% in 100 mg nZnO kg soil and by 39.0 to 43.3% in 1000 mg nZnO kg soil treatments across biochar treatments in the short term i.e. 24 days after incubation. However, this decrease disappeared after 64 days of incubation and the microbial biomass in nZnO amended soils were similar to that in control soils. This shows that the toxicity of nZnO in the studied soil was ephemeral and transient which was overcome by the soil itself in a couple of months. This is also supported by the fact that the nZnO induced higher cumulative C mineralization (i.e. soil respiration) at both rates of addition. The treatment 100 mg nZnO kg soil induced 166 to 207%, while 1000 mg nZnO kg soil induced 136 to 171% higher cumulative C mineralization across biochar treatments by the end of the experiment. However, contrary to our hypothesis increasing the nZnO addition from 100 to 1000 mg nZnO kg soil did not cause additional decrease in microbial biomass nor induced higher C mineralization. Moreover, the biochar did not alleviate even the ephemeral toxicity that was observed after 24d of incubation. Based on overall results, we conclude that the studied soil can function without impairment even at 1000 mg kg concentration of nZnO in it.
鉴于金属氧化物纳米粒子在农业中的应用日益广泛，以及它们通过污水污泥施用于土壤而被意外添加，评估它们对土壤功能的潜在毒性是至关重要的，这些土壤功能对健康作物的生产至关重要。在这方面，我们设计了一项实验室研究，以调查最常生产的纳米粒子之一，即氧化锌纳米粒子（nZnO）在石灰性土壤中的潜在毒性。在添加 100 或 1000 mg 生物合成 nZnO kg 土壤后，将 80 g 干重新鲜土壤的微宇宙在 mason 罐中孵育 64 天。此外，我们还添加了水稻秸秆衍生的生物炭，添加量为 1 或 5%（w：w 基础），假设生物炭可以减轻 nZnO 引起的毒性，因为它已被证明可以在土壤中吸附和解毒重金属。我们发现，在短期（即孵育 24 天后），100 mg nZnO kg 土壤和 1000 mg nZnO kg 土壤处理中，nZnO 将微生物生物量碳降低了 27.0 至 33.5%，而在 1000 mg nZnO kg 土壤处理中，nZnO 将微生物生物量碳降低了 39.0 至 43.3%。然而，64 天后，这种减少消失了，nZnO 处理的土壤中的微生物生物量与对照土壤相似。这表明在研究土壤中 nZnO 的毒性是短暂的，在几个月内土壤本身就克服了这种毒性。这也得到了以下事实的支持：即在两种添加率下，nZnO 诱导的累积 C 矿化（即土壤呼吸）更高。添加 100 mg nZnO kg 土壤的处理诱导了 166 至 207%，而添加 1000 mg nZnO kg 土壤的处理诱导了 136 至 171%的更高累积 C 矿化，在实验结束时。然而，与我们的假设相反，将 nZnO 添加量从 100 增加到 1000 mg nZnO kg 土壤不会导致微生物生物量进一步减少，也不会导致更高的 C 矿化。此外，生物炭甚至没有减轻在孵育 24 天后观察到的短暂毒性。基于总体结果，我们得出结论，即使在研究土壤中含有 1000 mg kg 的 nZnO，土壤也可以正常发挥功能而不受损害。
