Effects of silver nanoforms on the environment
The EU chemicals regulation REACH has been used to generate more information on the properties of nanomaterials. Silver nanomaterials are used in a variety of consumer products, such as clothing, medical garments and cosmetics, due to antimicrobial properties that keep materials clean and can thus help to make them last longer.
Missing information on environmental effects of silver nanoforms
To examine the potential effects of silver nanomaterials on the environment, the Netherlands decided to include silver in the REACH substance evaluation process in 2014. Substance evaluation is used to clarify whether a substance poses a risk to human health or the environment.
Companies registering silver under REACH claimed that the ionic form of silver could be considered as the worst case scenario when assessing risks for the environment. Authorities, on the other hand, had evidence that in some cases silver nanoforms were more harmful to the environment than the ionic forms. The situation was complicated further by the lack of sufficient information from companies on the identity of the silver nanoforms placed on the EU market.
What additional information was requested?
An extensive assessment of available information on silver led to a substance evaluation decision in July 2016. Companies registering silver nanoforms were requested to provide:
- a clarification of what specific silver nanoforms were covered by their registration; and
- more information on the physico-chemical properties of the silver nanoforms.
Companies were also required to provide information on the following environmental properties of silver nanoforms:
- toxicity to algae;
- long-term toxicity to aquatic invertebrates; and
- toxicity to soil micro-organisms.
For all the requested tests, registrants were given detailed instructions on how the study should be conducted to differentiate between the effects of silver nanoforms and ionic silver as well as to ensure the test was performed in a way that is suitable for assessing nanomaterials.
In addition to the eco-toxicological hazard information, registrants were requested to give information on the uses for each individual nanoform, so that the proper assessment of risks could be done.
What is the outcome?
Registrants had to provide information on the characterisation of their silver nanoforms, the results of their ecotoxicological studies, and the uses of the nanoforms by July 2017. The Netherlands has 12 months from the receipt of the additional information to evaluate it and agree on the way forward.