Risk Assessment of Manufactured Nanomaterials - Environmental and Human Health Impacts of Nanotechnology - page 391

same conceptual approach outlined above. Frequently, through a weight of evi-
dence approach, they seek to understand the risks posed by sources of specifi c
chemicals released to the environment in the context of biological impacts observed
in the fi eld (at individual, community or ecosystem levels).
There are some manufactured nanomaterials (including silver, titanium dioxide
and iron oxide) that have been shown to exceed the 1 tonne/year registration
trigger under REACH (Schmid and Riediker, 2008). However, the community
most likely to be exposed to nanomaterials will be those individuals specifi cally
involved in their manufacture and handling, that is the occupational production
and use of nanomaterials. The control of occupational health risks from harmful
substances in the workplace is, arguably, the most developed system for the control
of chemical exposure. It has been developed as a result of the long history of the
industrial use of chemicals/materials and the resulting incidence of occupational
diseases and illnesses, for example silicosis from the inhalation of crystalline quartz
(Altree-Williams and Clapp, 2002; Nij et al. , 2003; Nij and Heederik, 2005) and lead
poisoning from the inhalation of the dust and fumes from lead and lead-containing
compounds (Grimsley and Adams - Mount, 1994 ; Pierre et al. , 2002 ; Sen et al. , 2002 ).
Nowadays, it is mandatory to carry out a risk assessment before allowing any
worker to be exposed to any substance in the workplace. In the European Union,
this takes place through the Chemical Agents Directive (Chemical Agents Directive,
98/24/EC), which is implemented within the United Kingdom through the Control
of Substances Hazardous to Health Regulations (COSHH, 1988 and last consoli-
dated in 2002) enforced by the Health and Safety Executive (HSE). In the United
States, the Occupational Safety and Health act (1970, last amended 2004) regulates
the occupational use of chemicals, for which there are two coordinating bodies: the
Occupational Safety and Health Administration (OSHA), which develops and
regulates workplace health and safety regulations, and the National Institute for
Occupational Safety and Health (NIOSH), which recommends health and safety
standards and provides information on hazards and prevention (Thorne, 2001).
The routes of exposure for individuals in the occupational environment are nor-
mally inhalation, dermal contact or ingestion. Dermal and inhalation exposure
monitoring, as well as biomarker monitoring, can be used to characterise the expo-
sure of specifi c workers, for example farm workers exposed to pesticides (FAO
WHO, 1986; US EPA, 1988). Although it is unlikely that exposure would be limited
to one chemical species, the toxicity of individual substances must be considered
initially (EEC, 1988; EC, 1999). There is also considerable experience of risk assess-
ment and occupational health monitoring in industries where dusts or particulate
matter are a concern. These include milling and baking industries (e.g. fi ne fl our
dust), welding and ship building (metal vapours and particulates), as well as indus-
tries that produce building materials (e.g. cement dust and sawdust). The monitor-
ing often includes annual respiratory health checks that are useful to ensure that
risk management is effective. Some of these industries may generate dusts that
contain ultrafi ne (nanoparticle) fractions, and risk assessors therefore have inciden-
tal historic experience with the nanoscale.
All occupational risk assessments require the employer to assess the risks asso-
ciated with a particular work activity or procedure. The steps include gathering