Lahive E, Matzke M, Svendsen C, Spurgeon D J, Pouran H, Zhang H, Lawlor A, Glória Pereira M, Lofts S
UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, OX10 8BB, United Kingdom.
UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, OX10 8BB, United Kingdom.
Environ Pollut. 2023 Feb 15;319:120907. doi: 10.1016/j.envpol.2022.120907. Epub 2022 Dec 28.
To develop models that support site-specific risk assessment for nanoparticles (NPs), a better understanding of how NP transformation processes, bioavailability and toxicity are influenced by soil properties is needed. In this study, the influence of differing soil properties on the bioavailability and toxicity of zinc oxide (ZnO) NPs and ionic Zn to the earthworm Eisenia fetida was investigated. Earthworms were exposed to ZnO_NPs and ionic Zn, between 100 and 4400 mg Zn/kg, in four different natural soils (organic matter content: 1.8-16.7%, soil pH: 5.4-8.3, representing sandy loam to calcareous soils). Survival and reproduction were assessed after 28 and 56 days, respectively. Zn concentrations in soil pore waters were measured while labile concentrations of Zn were measured using an in-situ dynamic speciation technique (diffusive gradient in thin films, DGT). Earthworm Zn tissue concentrations were also measured. Soil properties influenced earthworm reproduction between soil controls, with highest reproductive output in soils with pH values of 6-7. Toxicity was also influenced by soil properties, with ECs based on total Zn in soil ranging from 694 to >2200 mg Zn/kg for ZnO_NP and 277-734 mg Zn/kg for ionic Zn. Soil pore water and DGT measurements showed good agreement in the relative amount of Zn extracted across the four soils. Earthworms exposed to ZnO_NPs survived higher Zn concentrations in the soils and had higher tissue concentrations compared with ionic Zn exposures, particularly in the high organic content calcareous soil. These higher tissue concentrations in ZnO_NP exposed earthworm could have consequences for the persistence and trophic mobility of Zn in terrestrial systems and need to be further investigated to elucidate if there any longer-term risks associated with sustained input of ZnO_NP to soil.
为了开发支持纳米颗粒（NP）特定场地风险评估的模型，需要更好地了解NP转化过程、生物有效性和毒性是如何受到土壤性质影响的。在本研究中，研究了不同土壤性质对氧化锌（ZnO）纳米颗粒和离子态锌对蚯蚓赤子爱胜蚓的生物有效性和毒性的影响。将蚯蚓暴露于四种不同的天然土壤（有机质含量：1.8 - 16.7%，土壤pH值：5.4 - 8.3，代表砂壤土到钙质土壤）中，ZnO纳米颗粒和离子态锌的含量在100至4400 mg Zn/kg之间。分别在28天和56天后评估存活率和繁殖率。测量了土壤孔隙水中的锌浓度，同时使用原位动态形态分析技术（薄膜扩散梯度，DGT）测量了锌的活性浓度。还测量了蚯蚓体内锌的组织浓度。土壤性质影响了土壤对照之间蚯蚓的繁殖，在pH值为6 - 7的土壤中繁殖产量最高。毒性也受土壤性质影响，基于土壤中总锌的半数效应浓度（EC）对于ZnO纳米颗粒为694至>2200 mg Zn/kg，对于离子态锌为277 - 734 mg Zn/kg。土壤孔隙水和DGT测量结果显示，在四种土壤中提取的锌的相对量具有良好的一致性。与暴露于离子态锌相比，暴露于ZnO纳米颗粒的蚯蚓在土壤中能耐受更高的锌浓度，并且组织浓度更高，特别是在高有机含量的钙质土壤中。暴露于ZnO纳米颗粒的蚯蚓体内这些较高的组织浓度可能会对锌在陆地系统中的持久性和营养迁移产生影响，需要进一步研究以阐明持续向土壤中输入ZnO纳米颗粒是否存在任何长期风险。
