Table 2.
Summary of EU and RIVM expert opinions on the potential needs that are specific for nanomaterials and relevant to multiple regulatory areas (note that the food and feed area include plant protection products). Information requirements (in bold) with similar needs are grouped in single rows and separated by “/”.
| Information requirements | Summary of expert opinions on nano specific needs | Relevant OECD TGs/GDsa |
|---|---|---|
| Physico-chemical properties | ||
Dispersion stability in relevant media, required for:
|
This endpoint is addressed in TG 318 and GD 318 for environmental media but further action on standardisation for biological media used in toxicology studies relevant for human health is needed, including in vitro studies. |
TG 318 |
| GD 318 | ||
Stability (physical and chemical), required for:
|
This endpoint need is relevant for all (eco)toxicity and in vitro studies during exposure. | – |
| Health effects | ||
Reactivity (catalytic activity, chemical reactivity, photocatalytic activity or radical formation potential), required for:
|
Legislation is generally not very specific on methods to be used for these endpoints, although OECD TG 442C (in addition to several ISO documents,b has been mentioned in this context. There is also a clear link with the oxidising/redox properties. | TG 442C |
| Measurements of reactive oxygen species (ROS) need to be further optimised and potentially standardised (for both acellular and cellular assays), with consideration for potential assay interference of nanomaterials. | ||
Cell toxicity (damage to cell/cell membrane, growth, metabolism), required for:
|
As in vitro assays are increasingly relevant for IATAs/ITSsc, there is a need for further guidance on cellular in vitro assays in general, addressing issues such as colorimetric interference, media depletion, dosing, sedimentation, exposure periods, target cell selection. Many of these issues are specifically relevant when testing (nano)particles. | – |
Inflammation induction (in vitro), required for:
|
Induction of inflammation is considered as a central effect of solid (nano)particles, but there is no standardised method currently available. Work towards this goal is in progress in multiple EU (nano) projects. | |
Mutagenicity: In vitro cytogenicity study in mammalian cells or in vitro micronucleus study/In case of positive results in vitro, in vivo genotoxicity study (somatic and potentially germ cell), required for:
|
Some OECD tests require adaptation for nanomaterials whereas applicability of other TGs for nanomaterials is uncertain. Focus is needed on whether particles are taken up and/or reach the cell/nucleus. There are on-going initiatives (e.g. hesiglobal.org/genetic-toxicology-gttc) to develop a protocol for genetic toxicity testing of nanomaterials. |
TG 475 |
| TG 483 | ||
| TG 486 | ||
| TG 487 | ||
| TG 488 | ||
| TG 489 | ||
Acute toxicity (oral/inhalation/dermal route), required for:
|
To date, only TGs for subacute and subchronic toxicity have been adapted for nanomaterials. As inhalation is of the highest priority, there is a need to investigate and adapt the remaining protocols with regard to dosing, administration, toxicity criteria and 3R (replacement, reduction, refinement) compliance where GD 39 is not adequate. Acute oral and dermal testing of nanomaterials are currently of less relevance but may become more important in future. |
TG 402 |
| TG 403 | ||
| TG 420 | ||
| TG 423 | ||
| TG 425 | ||
| TG 427 | ||
| TG 433 | ||
| TG 436 | ||
| GD 39 | ||
Phototoxicity, relevant for:
|
Phototoxicity and photogenotoxicity need further action and TG update to accommodate to nanomaterials | TG 432 |
| Effects on biotic systems | ||
Effects on, specifically, terrestrial organism: Short-term toxicity to invertebrates/Effects on soil micro-organisms/Short-term toxicity to plants/Long-term toxicity testing on invertebrates/Long-term toxicity testing on plants, required for:
|
So far, activities have been focused on aquatic environment. Adaptations for soil testing of nanomaterials are needed, specifically related to dosing and determining actual doses. An overarching document similar to GD 317 may be required. |
TG 207 |
| TG 208 | ||
| TG 216 | ||
| TG 220 | ||
| TG 222 | ||
| TG 226 | ||
| TG 227 | ||
| TG 228 | ||
| TG 232 | ||
| TG 317 | ||
| Environmental fate and behaviour | ||
Biotic degradation/Ready biodegradability/Simulation testing on ultimate degradation in surface water/Soil simulation testing/Biodegradation in manure/Sediment simulation testing, required for:
|
There is a need to adapt/develop TGs/GDs to provide information on the biotic degradation for nanomaterials (specifically relevant for nanomaterials with organic, organometallic components or coatings). |
TG 301 |
| TG 302B | ||
| TG 302C | ||
| TG 307 | ||
| TG 308 | ||
| TG 309 | ||
| TG 310 | ||
| TG 311 | ||
| TG 320 | ||
Biological water remediation: aerobic and anaerobic biodegradation; Sewage treatment works simulation test/Biodegradation in marine water, required for:
|
There is a need for research on the validity of the developed sewage treatment works method for nanomaterials (OECD, 2021b) (specifically relevant for nanomaterials with organic, organometallic components or coatings). Further, there is a need to introduce hetero-agglomeration into TG 318 and GD 318. | TG 303 |
| TG 209 | ||
| TG 306 | ||
| TG 318 | ||
| GD 318 | ||
These OECD documents are specifically referenced in one or more of the documents used in identifying the regulatory requirements (see Supplementary Information Table S2) or identified by experts. Listing them here should not be interpreted as a need to adapt all of these documents for nanomaterials but rather as an overview of relevant OECD documents for which the needs for adaptation requires investigation. Current versions of these OECD documents are publicly available online: https://www.oecd.org/science/nanosafety/publications-series-safety-manufactured-nanomaterials.htmhttps://www.oecd.org/env/ehs/testing/oecdguidelinesforthetestingofchemicals.htm.
Reactivity relevant ISO documents include ISO/TS 18827:2017, ISO/TS 19006:2016, ISO 20814:2019.
IATAs, Integrated Approaches to Testing and Assessment; ITSs, Integrated Testing Strategies.