As a result of increasing production and use of nanomaterials in a wider range of applications, emissions of nanomaterials into the environment are likely to occur at each stage of the nano-products’ life cycle: production, use and disposal. Nanomaterials may enter the environment through waste water treatment streams, recycling, landfill or combustion of products. They can also be released from nanoproducts and nanocomposites as a result of weathering or degradation of the products. A number of nanomaterials are also used specifically in environmental applications e.g. nano-iron for remediation, so they can be applied directly into the environment.
There is a lot of uncertainty on environmental fate and concentrations of manufactured nanomaterials in environmental compartments and the appropriate metrics for their quantification in relation to environmental risk assessment. Analytical methods for the effective monitoring of the presence of nanomaterials in environmental media are still under development and environmental studies have so far been based mainly on modelled exposure scenarios based on anticipated nanomaterial use.
The behaviour of the nanoparticles in the different environmental compartments will depend on the physical and chemical properties of the nanomaterial and the characteristics of the receiving environment. Particles released are likely to undergo transportation and transformation including processes such as (dis)aggregation or (dis)agglomeration, dissolution and speciation, biological or chemical transformation as a result of interactions with other chemicals, settling and adsorption. The release of primary particles and their subsequent modification will influence the nanomaterial bioavailability and toxicity.
As an example, current research has raised concerns over the release into the environment of silver nanoparticles, increasingly used for their antibacterial properties. Nano-silver may act as an effective delivery system of bioavailable silver to microorganisms, not previously achieved with conventional silver. This would represent a new source of environmental exposure that could potentially result in new environmental effects on natural bacterial populations. Questions have been raised about the potential for development of bacterial resistance to silver as a result of long-term exposure, however further research is needed to better understand bacterial response to silver nanoparticles.
SAFENANO can provide access to ecotoxicology expertise to support environmental risk assessment. For further information, please contact us.