Oughton Deborah Helen, Hertel-Aas Turid, Pellicer Eva, Mendoza Ernest, Joner Erik Jautris
Department of Plant and Environmental Sciences, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Aas, Norway.
Environ Toxicol Chem. 2008 Sep;27(9):1883-7. doi: 10.1897/07-578.1.
Studies regarding the environmental impact of engineered nanoparticles (ENPs) are hampered by the lack of tools to localize and quantify ENPs in water, sediments, soils, and organisms. Neutron activation of mineral ENPs offers the possibility of labeling ENPs in a way that avoids surface modification and permits both localization and quantification within a matrix or an organism. Time-course experiments in vivo also may be conducted with small organisms to study metabolism and exposure, two aspects currently lacking in ecotoxicological knowledge about ENPs. The present report explains some of the prerequisites and advantages of neutron activation as a tool for studying ENPs in environmental samples and ecologically relevant organisms, and it demonstrates the suitability of neutron activation for Ag, Co/Co3O4, and CeO2 nanoparticles. In a preliminary experiment with the earthworm Eisenia fetida, the dietary uptake and excretion of a Co nanopowder (average particle size, 4 nm; surface area, 59 m2/g) were studied. Cobalt ENPs were taken up to a high extent during 7 d of exposure (concentration ratios of 0.16-0.20 relative to the ENP concentration in horse manure) and were largely retained within the worms for a period of eight weeks, with less than 20% of absorbed ENPs being excreted. Following dissection of the worms, 60Co was detected in spermatogenic cells, cocoons, and blood using scintillation counting and autoradiography. The experimental opportunities that neutron activation of ENPs offer are discussed.
由于缺乏在水、沉积物、土壤和生物体中定位和定量工程纳米颗粒（ENPs）的工具，有关ENPs对环境影响的研究受到了阻碍。对矿物ENPs进行中子活化，提供了一种标记ENPs的可能性，这种方式避免了表面改性，并允许在基质或生物体中进行定位和定量。还可以用小型生物进行体内时间进程实验，以研究代谢和暴露情况，这是目前关于ENPs的生态毒理学知识中所缺乏的两个方面。本报告解释了中子活化作为研究环境样品和生态相关生物体中ENPs的工具的一些先决条件和优势，并证明了中子活化对银、钴/四氧化三钴和二氧化铈纳米颗粒的适用性。在对赤子爱胜蚓进行的初步实验中，研究了钴纳米粉末（平均粒径4 nm；表面积59 m2/g）的饮食摄取和排泄情况。在暴露7天期间，钴ENPs被大量摄取（相对于马粪中ENP浓度的浓度比为0.16 - 0.20），并且在八周的时间里大部分保留在蚯蚓体内，排出的吸收的ENPs不到20%。蚯蚓解剖后，使用闪烁计数和放射自显影在生精细胞、茧和血液中检测到了60Co。讨论了ENPs中子活化所提供的实验机会。
