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close this bookConducting Environmental Impact Assessment in Developing Countries (United Nations University, 1999, 375 p.)
close this folder9. Emerging developments in EIA
close this folder9.4 Environmental risk assessments
close this folder9.4.2 Terminology associated with ERA
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View the document9.4.2.1 Hazards and uncertainties


Risk. The probability of an adverse effect, direct or indirect, on human health or the environment. It is, in fact, a combination of the probability of occurrence of an event and the possible extent of that event's adverse effects and consequences, in terms of human injury or adverse effects on the ecosystem. In a more mathematical sense, risk can be expressed as:

the probability of an event occurring × the seriousness of its consequences

Figure 9.3 Recommended risk assessment framework

Source: Environmental Risk Assessment for Sustainable Cities, Technical Publication Series [3], International Environmental Technology Centre, Osaka, 1996.

Hazard. The innate properties (biological, chemical, or physical) of a substance to cause harm.

Uncertainty. Doubt, lack of assurance as to the true value of a variable, considering all the possible values attributed to data or information.

Figure 9.4 Components of human health risk and ecological risk assessment

Source: Environmental Risk Assessment for Sustainable Cities, Technical Publication Series [3], UNEP International Environmental Technology Centre, Osaka/Shiga, 1996.

Assessment. Appraisal or evaluation in some prescribed endpoints in order to judge an activity.

Analysis. Detailed examination or thorough study in order to understand.

Exposure. The condition under which an organism comes into actual contact with a stressor. In site-specific considerations, the exposure value is substantially less than the quantity in the environment although sometimes it is assumed, under conservative assumptions, to be the amount of contaminant in the environment.