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HAZARD
IDENTIFICATION

EXPOSURE ASSESSMENT EFFECT ASSESSMENT
Emission Rates Laboratory Dose-ResponseTesting
Human Human
Environment Exposure Environment Extrapolation Process
Health Health
Predicted No-Effect Acceptable Daily
Predicted Exposure Predicted Exposure Concentration (PNEC) Intake (ADI)

Concentration (PEC) Dose

RISK CHARACTERIZATION
Ratio PEC/PNEC and Dose/ADI
Uncertainty Analysis

FIGURE 4.1 Framework of environmental risk assessment. (Adapted from Fairman, R. et
al., Environmental Risk Assessment — Approaches, Experiences and Information Sources,
European Environment Agency, Copenhagen, 1998.)

4.4 HAZARD IDENTIFICATION

The first step in an ERA in cases for human health and environment is to determine
whether exposure of humans and ecosystems to chemicals is likely to have any
adverse effects.

4.4.1 HUMAN HEALTH
The human health hazard identification involves an evaluation of whether a pollutant
can cause an adverse health effect in humans. The process is a qualitative risk
assessment that examines the potential for exposure and the nature of the adverse
effect expected. The information used in hazard identification includes human,
animal and mechanistic evidence; therefore, the risk assessor must evaluate the
quality of the evidence, the severity of the effects, and whether the mechanisms of
toxicity in animals are relevant to humans. The result is a scientific judgment of
whether a particular adverse health effect in humans is caused by a chemical or
process at certain concentrations. This is the work of toxicologists and epidemiol-
ogists, who study the nature of the adverse effects caused by toxic agent and the
probability of their occurrence.

4.4.2 ECOSYSTEMS
The design of an ecological risk assessment program for an environmental con-
tamination problem typically involves a process to define the common elements
of populations and ecosystems clearly; this then forms a basis for the development
of a logical framework that can be used for risk characterization. First, the devel-
opment of an ecological risk assessment includes the identification of one or

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