Background

The high production volume of engineered nanomaterials (ENMs) may lead to high pressure on the environment, and a scientific assessment of ENMs that bioaccumulate in organisms and biomagnify in the food web is necessary. Within the regulation of chemicals in several jurisdictions, such as the European regulation REACH, the bioconcentration factor is the standard endpoint. The bioconcentration factor is mostly determined by flow-through fish tests. However, nanomaterials tend to agglomerate, which may lead to sedimentation in aquatic environments. The bioavailability of the tested nanomaterials may be thus impaired for pelagic species, including fish, in comparison to benthic or filtrating species. Several risk assessment regulations allow the usage of data gained during tests using invertebrates and such data may allow a waiver of further tests using vertebrates. The aim of this study was to elucidate the potential of different freshwater invertebrate species to be used in laboratory bioaccumulation studies on ENMs and to give some guidance for the use of bioaccumulation endpoints derived from studies using aquatic invertebrate species in the risk assessment process for ENMs.

Results

The existing literature related to the testing of nanomaterial bioaccumulation with freshwater invertebrates was screened and reviewed to find suitable test species with regard to their ecology and physiology, as well as laboratory test systems allowing to investigate the bioavailability/bioaccumulation of nanomaterials with the respective species. Bivalvia, gastropoda, isopoda, amphipoda, and branchiopoda were reviewed and their suitability for bioaccumulation testing was assessed. Amphipods and bivalves represent worst-case scenarios and show clear advantages to be used as test organisms. However, only amphipods allow the examination of two clearly independent exposure pathways (water and diet).

Conclusion

Amphipods are suitable test organisms for bioaccumulation testing of ENMs. The results from amphipod bioconcentration and biomagnification tests can be included in a tiered assessment suggested at the end of this study allowing a clear grading of the tested nanomaterials as “bioaccumulative” or “non bioaccumulative.” Due to the worst-case scenario of the amphipod test, this approach may allow a waiver of further vertebrate tests.

中文翻译：

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利用淡水无脊椎动物物种对纳米材料的生物累积评估

背景

工程纳米材料（ENM）的高产量可能导致对环境的高压，因此有必要对ENM在生物体内生物富集并在食物网中生物放大的科学评估。在多个法规中的化学品法规（例如欧洲法规REACH）中，生物浓缩因子是标准终点。生物浓缩系数主要由流水鱼试验确定。但是，纳米材料易于团聚，这可能导致在水生环境中沉淀。与底栖或过滤物种相比，被测纳米材料对包括鱼类在内的浮游物种的生物利用度可能因此受损。几项风险评估法规允许使用在无脊椎动物测试中获得的数据，并且此类数据可以免除对脊椎动物的进一步测试。这项研究的目的是阐明在ENM的实验室生物蓄积研究中使用不同淡水无脊椎动物物种的潜力，并为在ENM的风险评估过程中使用水生无脊椎动物物种的研究得出的生物蓄积终点提供一些指导。

结果

筛选并审查了与淡水无脊椎动物纳米材料生物蓄积性测试相关的现有文献，以找到有关其生态学和生理学的合适测试物种，以及允许研究相应物种的纳米材料的生物利用度/生物蓄积性的实验室测试系统。审查了双壳纲，腹足纲，等足纲，两栖纲和支足纲，并评估了它们对生物蓄积性测试的适用性。两栖动物和双壳类动物代表最坏的情况，并显示出明显的优势，可以用作测试生物。但是，只有两足动物允许检查两个明显独立的暴露途径（水和饮食）。

结论

两栖动物是适合ENM生物蓄积性测试的测试生物。两栖动物生物富集和生物放大测试的结果可以纳入本研究结束时建议的分层评估中，从而可以将测试的纳米材料明确分级为“生物蓄积性”或“非生物蓄积性”。由于两栖动物测试的最坏情况，这种方法可能免除了进一步的脊椎动物测试。