School of Biological Sciences, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK.
School of Environmental Sciences, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK.
Ecotoxicol Environ Saf. 2020 Sep 15;201:110813. doi: 10.1016/j.ecoenv.2020.110813. Epub 2020 Jun 13.
The bioaccumulation potential and toxic effects of engineered nanomaterials (ENMs) to earthworms are poorly understood. Two studies were conducted following OECD TG 222 on Eisenia fetida to assess the effects of CdTe QDs with different coatings and soil ageing respectively. Earthworms were exposed to carboxylate (COOH), ammonium (NH), or polyethylene glycol (PEG) coated CdTe QDs, or a micron scale (bulk) CdTe material, at nominal concentrations of 50, 500 and 2000 mg CdTe QD kg dry weight (dw) for 28 days in Lufa 2.2 soil. In the fresh soil study, earthworms accumulated similar amounts of Cd and Te in the CdTe-bulk exposures, while the accumulation of Cd was higher than Te during the exposures to CdTe QDs. However, neither the total Cd, nor Te concentrations in the earthworms, were easily explained by the extractable metal fractions in the soil or particle dissolution. There were no effects on survival, but some retardation of growth was observed at the higher doses. Inhibition of NaK-ATPase activity with disturbances to tissue electrolytes, as well as tissue Cu and Mn were observed, but without depletion of total glutathione in the fresh soil experiment. Additionally, juvenile production was the most sensitive endpoint, with estimated nominal EC of values >2000, 108, 65, 96 mg CdTe kg for bulk, PEG-, COOH- and NH-coated CdTe QDs, respectively. In the aged soil study, the accumulation of Cd and Te was higher than in the fresh soil study in all CdTe QD exposures. Survival of the adult worms was reduced in the top CdTe-COOH and -NH QD exposures by 55 ± 5 and 60 ± 25%, respectively; and with decreases in growth. The nominal EC values for juvenile production in the aged soil were 165, 88, 78 and 63 mg CdTe kg for bulk, PEG-, COOH- and NH-coated CdTe QDs, respectively. In conclusion, exposure to nanoscale CdTe QDs, regardless of coating, caused more severe toxic effects that the CdTe bulk material and the toxicity increased after soil ageing. There were some coating-mediated effects, likely due to differences in the metal content and behaviour of the materials.
工程纳米材料 (ENMs) 对蚯蚓的生物累积潜力和毒性影响了解甚少。本研究按照 OECD TG 222 对赤子爱胜蚓进行了两项研究，分别评估了具有不同涂层和土壤老化的 CdTe QD 的影响。将羧酸盐 (COOH)、铵 (NH) 或聚乙二醇 (PEG) 涂层的 CdTe QD 或微米级 (块状) CdTe 材料以 50、500 和 2000mgCdTeQDkg 干重的名义浓度暴露于 Lufa 2.2 土壤中 28 天。在新鲜土壤研究中，CdTe 块状暴露中蚯蚓体内积累的 Cd 和 Te 量相似，而在 CdTe QD 暴露中，Cd 的积累量高于 Te。然而，无论是土壤中可提取金属部分还是颗粒溶解，都无法很好地解释蚯蚓体内的总 Cd 和 Te 浓度。在较高剂量下，虽然没有观察到生存影响，但发现生长受到一定程度的抑制。在新鲜土壤实验中观察到 NaK-ATPase 活性受到抑制以及组织电解质紊乱，以及组织 Cu 和 Mn 含量增加，但总谷胱甘肽未耗尽。此外，幼体产量是最敏感的终点，估计名义 EC 值 >2000、108、65、96mgCdTekg 分别为块状、PEG-、COOH-和 NH-涂层 CdTe QD。在老化土壤研究中，与新鲜土壤研究相比，所有 CdTe QD 暴露中蚯蚓体内的 Cd 和 Te 积累量都更高。在顶部 CdTe-COOH 和 -NH QD 暴露中，成年蚯蚓的存活率分别降低了 55±5%和 60±25%；且生长受到抑制。老化土壤中幼体产量的名义 EC 值分别为块状、PEG-、COOH-和 NH-涂层 CdTe QD 的 165、88、78 和 63mgCdTekg。总之，暴露于纳米级 CdTe QD，无论是否有涂层，都会引起比 CdTe 块状材料更严重的毒性影响，并且在土壤老化后毒性增加。存在一些涂层介导的影响，可能是由于材料中金属含量和行为的差异所致。
