Grouping of nanomaterials regarding their ecotoxicity

Abstract

Given the numerous manufactured nanomaterials (NM) already on the market and expected in future, the effort for the individual investigation and assessment would be enormous. Therefore, it is necessary to develop approaches that allow an adequate hazard assessment of NM while avoiding individual testing of a large number of the different forms. Approaches to meet data requirements in deviation from performing standard test requirements are already established for chemical substances. One of these is the grouping and read-across/analogue approach. In comparison to soluble organic substances, nanomaterials of the same chemical substance differ in their physicochemical parameters (e.g. surface chemistry, size, shape) and can potentially differ in their hazard profiles. But also fate related physicochemical properties which are influenced by surrounding conditions, like dispersion stability or dissolution rate, influence bioavailability and effects of NM. Annotation of NM to specific hazard groups or read-across based on their physical-chemical (PC) properties will be a great advantage to reduce the amount of testing necessary for an adequate risk assessment. To identify PC properties which are relevant predictors for ecotoxicity, a literature research was performed. It was found that sparsely or non-soluble, and ion-releasing NM need to be considered differently. We have found that ecotoxicity correlates with more than one PC characteristic. Based on this finding the tool ECOTOX BOND was developed. ECOTOX BOND was tested for robustness with experimental data on eight NM in 23 modifications. The predicted and measured ecotoxicity of the NM tested mostly fit, but the ecotoxicity of green algae for TiO2, CeO2 and Fe2O3 is higher than predicted. This effect could be caused by shading and is investigated in more detail. Quelle: Poster abstacts