Risk Assessment of Manufactured Nanomaterials - Environmental and Human Health Impacts of Nanotechnology - page 385

public health protection and food safety (Keerotipibul and Lekroengsin, 2008;
Rowbotham et al. , 2000), and for the management of occupational exposure in the
workplace (Duhayon et al. , 2008 ; van Leeuwen and Vermeire, 2007 ). Risk assess-
ments are routinely performed on individual chemicals or groups of chemicals (e.g.
polyaromatic hydrocarbons, pesticides and metals) and specifi c exposure scenarios
subject to multiple hazards (e.g. catchment-based risk assessments). Risk assess-
ments are inevitably technically detailed. One challenge for risk assessors and
policy makers is to ensure that the process of risk assessment remains evidence
based and transparent, so that the logic of the subsequent decisions is clearly articu-
lated, with the prospect that stakeholders may have confi dence in the risk manage-
ment decisions that follow.
There has been considerable debate as to whether manufactured nanomaterials
pose signifi cant risks to the environment and human health (RS/RAEng, 2004;
Owen and Depledge, 2005; SCENIHR, 2005; Owen and Handy, 2007). As with many
emerging risks, the evidence base is currently incomplete, though important fea-
tures are emerging. Current knowledge gaps include a lack of data on exposure
and biological effects, which are essential data inputs to most risk assessment pro-
cesses. Addressing these gaps is critical for the development of proportionate,
evidence-based regulatory controls and for facilitating the responsible develop-
ment of nanotechnologies.
In response to the identifi ed knowledge gaps, and given that many nanomaterials
are already in wide use, the international approach to policy development has been
to initiate:

• the development of an evidence base to support appropriate controls
through the commissioning of research (e.g. United States Environmental
Protection Agency (US EPA) National Centre for Environmental Research
(NCER) programme (http://es.epa.gov/ncer/nano/), European Union (EU)
Framework Programme (http://cordis.europa.eu/nanotechnology/) and UK
Environ mental Nanoscience Initiative ( http://www.nerc.ac.uk/research/

programmes/nanoscience/ );
• voluntary reporting and stewardship schemes for industry to provide information
on the types of nanomaterials being manufactured and their applications (e.g.
Nanotechnology Industries Association at http://www.nanotechia.co.uk ). These
schemes aim to complement the scientifi c research programmes, together provid-
ing the evidence basis; and
• comprehensive regulatory reviews (e.g. in the UK by Defra (Frater et al. , 2006 )
and in the EU by ECC (ECC, 2008)) analysing how, and to what extent, current
regulations cover nanomaterials and their safety.

Nanomaterials are materials of a specifi c size (considered as materials with at
least one dimension of 1-100 nm; SCENIHR, 2006), and comprise of many differ-
ent physico-chemical forms. Therefore, one approach to their regulatory control
is to bring them within existing international chemicals legislation (EP, 2006) where
a sound international consensus exists on how risks should be assessed and managed.
However, the development of a regulatory strategy for nanomaterials requires
structure. Two key questions are emerging: