Ecotoxicity of nanomaterials to fish: challenges for ecotoxicity testing.
Ecotoxicity of nanomaterials to fish: challenges for ecotoxicity testing.
复制标题
纳米材料对鱼类的生态毒性：生态毒性测试的挑战。
DOI：
10.1002/ieam.5630030316
复制
发表时间：
2007
影响因子：
3.1
通讯作者：
Handy RD
中科院分区：
文献类型：
--
作者：
Handy RD
学习论述-综合环境评估和管理3,2007年459是，目标毒物的浓度(例如，测试有机体细胞膜上的受体)与剂量有关。纳米颗粒不会形成简单的溶液，可能在高离子强度下聚集，并可能吸附在表面(Lead和Wilkinson 2006)。这表明一些纳米材料将被困在鱼和其他生物表面上皮表面的粘液层中，而不是像我们最近用鲑鱼鳃粘液中的碳纳米管沉淀所证明的那样，以一种可预测的剂量依赖的方式被吸收(Smith等人)。2007)。这种化学表明，在使用纳米颗粒解释水毒性测试数据时需要谨慎，如果纳米材料被释放到水生系统中，吸附在沉积物界面和食品等其他表面上可能会导致通过水生食物链暴露。还可能有必要修改目前的含水测试方法，以考虑这种化学作用，在风险计算中增加额外的不确定因素，或包括额外的测试，如鱼类的饮食暴露评估。目前的测试方法需要一些证据来证明测试材料的目标浓度已经达到，并且需要就应该采取哪些测量来确认接触纳米颗粒达成一致。我们建议：1)材料的“总浓度”(例如，纳米颗粒的mg/L)；2)制造商关于产品的大小、形状、表面积和纯度的信息；3)光学测量以确认测试材料在水族馆水中的分散；以及4)在电子显微镜或类似方法上对测试溶液中的颗粒大小进行示例测量。仍需克服一些实际问题，例如缺乏经认证的标准物质和决定应使用哪种溶剂(如果有的话)。还需要简单而灵敏的方法(1 mg/L)来测定天然水中纳米颗粒的浓度。也有人担心，制造商食谱中的微量污染物可能对鱼类有毒。例如，在1毫克/L碳纳米管暴露中，1%的金属污染对鱼来说可能是显著的微克/L金属暴露，在暴露期间应该监测水和组织中的金属。使用FISH时，分散方法以及溶剂和/或声学技术的使用是一个特殊的难题。超声或长时间搅拌均可提高纳米颗粒的分散性。然而，对于许多碳基纳米颗粒，需要一些溶剂来保持分散，特别是在可能适用于FISH研究的持续时间内。在碳纳米管的情况下，从化学角度来看，一些最好的分散剂是诸如N，N‘-二甲基甲酰胺、呋喃衍生物和氯仿等物质(Ham等人。2005)。不幸的是，这些物质中的许多对鱼类都是剧毒的，在鱼类研究中作为溶剂的实际用途有限。然而，如果排除溶剂，那么碳基纳米颗粒往往聚集在一起并产生不同的生态毒理效应(Oberdörster等人)。2006)。我们部分解决了碳纳米管的这一困境，方法是使用一种在分散碳纳米管方面相当好的溶剂(带有一些超声波)，但对鱼的毒性也相对较低(十二烷基硫酸钠[十二烷基硫酸钠]；见Smith等人)。2007)。在使用分散剂时需要一些谨慎。过量的溶剂会使纳米管变形(Ham等人2005)，因此可能会改变它们的毒理特性。通过将纳米颗粒与水溶产品螯合来维持“分散性”也是有问题的--…
Learned Discourses—Integr Environ Assess and Manag 3, 2007 459 is that the concentration of the toxicant at the target (eg, receptors on cell membranes of the test organism) is related to dose. Nanoparticles do not form simple solutions, may aggregate at high ionic strength, and may adsorb onto surfaces (Lead and Wilkinson 2006). This suggests that some nanomaterials will be trapped in the mucous layer on epithelial surfaces of fish and other organisms, rather than being absorbed in a predictable dose-dependent manner, as we recently demonstrated with carbon nanotube precipitates in the gill mucus of trout (Smith et al. 2007). This chemistry suggests that caution is needed when interpreting data from aqueous toxicity tests using nanoparticles and that adsorption onto other surfaces such as sediment interfaces and food items could lead to exposure via the aquatic food chain if nanomaterials were released into aquatic systems. It also may be necessary to modify current aqueous test methods to account for this chemistry, add an extra uncertainty factor to risk calculations, or include additional tests such as dietary exposure assessments for fish. Current test methods require some demonstration that target concentrations of the test material were met, and agreement is needed on what measurements should be taken to confirm exposure to nanoparticles. We suggest the following: 1)“total concentration” of the material (eg, mg/L of nanoparticles); 2) the manufacturer’s information on size, shape, surface area, and purity of the product; 3) optical measurements to confirm dispersion of the test material in the aquarium water; and 4) example measurements of particle size in the test solution made on the electron microscope, or similar approaches. A number of practical problems still must be overcome, such as a lack of certified reference materials and deciding what solvent (if any) should be used. Simple, but sensitive (< 1 mg/L) methods for determining nanoparticle concentration in natural water also are needed. Concerns also exist that trace contaminants in the manufacturer’s recipe might be toxic to fish. For example, 1% metal contamination in a 1-mg/L carbon nanotube exposure might be a significant µg/L metal exposure for a fish, and the metals should be monitored in the water and tissues during the exposure. Methods of dispersion and the use of solvents and/or sonnication techniques is a particular dilemma when using fish. Sonication or prolonged stirring can improve dispersion of nanoparticles. However, for many carbon-based nanoparticles, some solvent is needed to maintain dispersion, particularly over the durations that might apply to a fish study. In the case of carbon nanotubes, some of the best dispersants from the viewpoint of chemistry are substances such as N, N′-dimethylformamide, furan derivatives, and chloroform (Ham et al. 2005). Unfortunately, many of these substances are extremely toxic to fish and would be of limited practical use as a solvent in a fish study. However, if the solvent is excluded, then carbon-based nanoparticles tend to aggregate and produce different ecotoxicological effects (Oberdörster et al. 2006). We partly resolved this dilemma for carbon nanotubes by using a solvent that was fairly good at dispersing carbon nanotubes (with some sonnication), but also with a relatively low toxicity to fish (sodium dodecyl sulphate [SDS]; see Smith et al. 2007). Some caution is needed with dispersing agents. Excess solvent can deform nanotubes (Ham et al. 2005) and therefore might change their toxicological properties. Maintaining “dispersion” by chelating nanoparticles with water-soluble products is also problematic …