Chronic toxicity of core–shell SiC/TiO₂ (nano)-particles to <i>Daphnia magna</i> under environmentally relevant food rations in the presence of humic acid

To date, research on the toxicity and potential environmental impacts of nanomaterials has predominantly focused on relatively simple and single-component materials, whilst more complex nanomaterials are currently entering commercial stages. The current study aimed to assess the long-term and size-dependent (60 and 500 nm) toxicity of a novel core–shell nanostructure consisting of a SiC core and TiO₂ shell (SiC/TiO₂, 5, 25, and 50 mg L⁻¹) to the common model organism <i>Daphnia magna</i>. These novel core–shell nanostructures can be categorized as advanced materials. Experiments were conducted under environmentally realistic feeding rations and in the presence of a range of concentrations of humic acid (0.5, 2, 5, and 10 mg L⁻¹ TOC). The findings show that although effect concentrations of SiC/TiO₂ were several orders of magnitude lower than the current reported environmental concentrations of more abundantly used nanomaterials, humic acid can exacerbate the toxicity of SiC/TiO₂ by reducing aggregation and sedimentation rates. The EC₅₀ values (mean ± standard error) based on nominal SiC/TiO₂ concentrations for the 60 nm particles were 28.0 ± 11.5 mg L⁻¹ (TOC 0.5 mg L⁻¹), 21.1 ± 3.7 mg L⁻¹ (TOC 2 mg L⁻¹), 18.3 ± 5.4 mg L⁻¹ (TOC 5 mg L⁻¹), and 17.8 ± 2.4 mg L⁻¹ (TOC 10 mg L⁻¹). For the 500 nm particles, the EC50 values were 34.9 ± 16.5 mg L⁻¹ (TOC 0.5 mg L⁻¹), 24.8 ± 5.6 mg L⁻¹ (TOC 2 mg L⁻¹), 28.0 ± 10.0 mg L⁻¹ (TOC 5 mg L⁻¹), and 23.2 ± 4.1 mg L⁻¹ (TOC 10 mg L⁻¹). We argue that fate-driven phenomena are often neglected in effect assessments, whilst environmental factors such as the presence of humic acid may significantly influence the toxicity of nanomaterials.迄今为止，针对纳米材料（nanomaterials）毒性与潜在环境影响的研究大多集中于结构相对单一的单组分材料，而结构更复杂的纳米材料目前已逐步进入商业化阶段。本研究旨在评估一种新型核壳纳米结构（core–shell nanostructure）——以碳化硅（SiC）为核、二氧化钛（TiO₂）为壳（SiC/TiO₂，设置剂量为5、25、50 mg L⁻¹）——对常见模式生物大型溞（Daphnia magna）的长期毒性及粒径依赖性毒性（粒径分别为60 nm与500 nm）。这类新型核壳纳米结构可归类为先进材料。实验在符合环境实际情况的投喂剂量下开展，并设置了一系列梯度浓度的腐殖酸（humic acid，总有机碳（Total Organic Carbon，TOC）浓度分别为0.5、2、5、10 mg L⁻¹）。研究结果显示，尽管SiC/TiO₂的有效浓度较当前报道的更广泛使用的纳米材料的环境浓度低数个数量级，但腐殖酸可通过降低聚集与沉降速率，加剧SiC/TiO₂的毒性。基于标称SiC/TiO₂浓度计算得到的60 nm颗粒半数效应浓度（median effective concentration，EC50，均值±标准误）分别为：TOC 0.5 mg L⁻¹时28.0±11.5 mg L⁻¹、TOC 2 mg L⁻¹时21.1±3.7 mg L⁻¹、TOC 5 mg L⁻¹时18.3±5.4 mg L⁻¹，以及TOC 10 mg L⁻¹时17.8±2.4 mg L⁻¹。对于500 nm颗粒，其半数效应浓度分别为：TOC 0.5 mg L⁻¹时34.9±16.5 mg L⁻¹、TOC 2 mg L⁻¹时24.8±5.6 mg L⁻¹、TOC 5 mg L⁻¹时28.0±10.0 mg L⁻¹，以及TOC 10 mg L⁻¹时23.2±4.1 mg L⁻¹。本研究认为，在效应评估中，由归趋驱动的现象常被忽视，而腐殖酸这类环境因素可显著影响纳米材料的毒性。

搜集汇总

背景与挑战

背景概述

该数据集研究了新型核壳结构SiC/TiO2纳米颗粒在环境相关食物配给和腐殖酸存在下对大型溞的慢性毒性，实验评估了不同粒径（60和500 nm）和浓度（5、25、50 mg L−1）的影响。研究发现，尽管SiC/TiO2的效应浓度低于常用纳米材料的环境浓度，但腐殖酸通过减少颗粒聚集和沉降加剧了毒性，EC50值随腐殖酸浓度增加而降低，突显了环境因素在纳米材料毒性评估中的重要性。