Griffitt Robert J, Luo Jing, Gao Jie, Bonzongo Jean-Claude, Barber David S
Center for Environmental and Human Toxicology, University of Florida, Gainesville, Florida 32911, USA.
Environ Toxicol Chem. 2008 Sep;27(9):1972-8. doi: 10.1897/08-002.1.
Metallic nanoparticles are among the most widely used types of engineered nanomaterials; however, little is known about their environmental fate and effects. To assess potential environmental effects of engineered nanometals, it is important to determine which species are sensitive to adverse effects of various nanomaterials. In the present study, zebrafish, daphnids, and an algal species were used as models of various trophic levels and feeding strategies. To understand whether observed effects are caused by dissolution, particles were characterized before testing, and particle concentration and dissolution were determined during exposures. Organisms were exposed to silver, copper, aluminum, nickel, and cobalt as both nanoparticles and soluble salts as well as to titanium dioxide nanoparticles. Our results indicate that nanosilver and nanocopper cause toxicity in all organisms tested, with 48-h median lethal concentrations as low as 40 and 60 microg/L, respectively, in Daphnia pulex adults, whereas titanium dioxide did not cause toxicity in any of the tests. Susceptibility to nanometal toxicity differed among species, with filter-feeding invertebrates being markedly more susceptible to nanometal exposure compared with larger organisms (i.e., zebrafish). The role of dissolution in observed toxicity also varied, being minor for silver and copper but, apparently, accounting for most of the toxicity with nickel. Nanoparticulate forms of metals were less toxic than soluble forms based on mass added, but other dose metrics should be developed to accurately assess concentration-response relationships for nanoparticle exposures.
金属纳米颗粒是应用最为广泛的工程纳米材料类型之一；然而，人们对其环境归宿和影响却知之甚少。为评估工程纳米金属的潜在环境影响，确定哪些物种对各种纳米材料的不利影响敏感至关重要。在本研究中，斑马鱼、水蚤和一种藻类被用作不同营养级和摄食策略的模型。为了解观察到的影响是否由溶解引起，在测试前对颗粒进行了表征，并在暴露过程中测定了颗粒浓度和溶解情况。生物体分别暴露于银、铜、铝、镍和钴的纳米颗粒及可溶性盐以及二氧化钛纳米颗粒中。我们的结果表明，纳米银和纳米铜对所有受试生物均具有毒性，在大型蚤成虫中，48小时半数致死浓度分别低至40和60微克/升，而二氧化钛在任何测试中均未造成毒性。不同物种对纳米金属毒性的敏感性存在差异，与较大型生物（如斑马鱼）相比，滤食性无脊椎动物对纳米金属暴露明显更敏感。溶解在观察到的毒性中所起的作用也有所不同，对银和铜而言较小，但显然，对镍来说，溶解是大部分毒性的原因。基于添加的质量，金属的纳米颗粒形式比可溶形式毒性更小，但应开发其他剂量指标以准确评估纳米颗粒暴露的浓度-反应关系。
