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sensible view, considering the fact that nothing is wholly safe per se. In fact,
whereas large amounts of toxic substances may be of major concern, simply
detecting a hazardous chemical in the environment should not necessarily be a
cause for alarm. The intrinsic knowledge of the physical–chemical properties of
pollutants, biodegradability, potential of bioaccumulation or potential effects of
the chemical substances is necessary for the evaluation of environmental risk.
Moreover, it is necessary to carry out a detailed evaluation of the emission sources,
as well as the fate, transport and distribution in the different media. Due to all
this, the analysis of environmental samples in the laboratory and the application
of mathematical models are vital (EC, 1996).

4.3 FRAMEWORK OF ENVIRONMENTAL RISK
ASSESSMENT

ERA is a formal mathematical tool used to evaluate potential hazards introduced by
pollutant emissions in human health and the environment. This risk assessment
process entails a sequence of actions outlined below:

1. Hazard identification: identification of the adverse effect that a substance
has an inherent capacity to cause
2. Exposure assessment: estimation of the concentrations/doses to which
human populations (i.e., workers, consumers and individuals exposed
indirectly via the environment) or environmental compartments (aquatic
environment, terrestrial environment and air) are or may be exposed
3. Dose–response assessment: estimation of the relationship between dose,
or level of exposure to a substance, and the incidence and severity of an
effect
4. Risk characterization: estimation of the incidence and severity of the
adverse effects likely to occur in a human population or environmental
compartment due to actual or predicted exposure to a substance, i.e., the
quantification of that likelihood

Figure 4.1 shows a framework for human and ecological ERA. The EU has
provided a technical guidance document on ERA in support of Commission
Directive 93/67/EEC on Risk Assessment for New Notified Substances and the
Commission Regulation (EC) 1488/94 on Risk Assessment for Existing Sub-
stances (EC, 1996). The U.S. Environmental Protection Agency has produced
different risk assessment guidelines: Guidelines for Ecological Risk Assessment
(EPA/630/R-95/002F. FR 63(93) 26846–26924), the Guideline for Exposure
Assessment (EPA/600Z-92/001. FR 57: 22888–22938) and the Proposed Guide-
line for Carcinogenic Risk Assessment (EPA/600/P-92/003C. FR 61(79)
17960–18011).

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